# Replacing G0709 spindle bearings



## mcdanlj (May 7, 2022)

A few years ago, I bought a used G0709. I've occasionally been concerned about noise from the spindle, and today I was justified. Under nearly no load (slowly drilling a 7/64" hole) it suddenly sounded loaded, and when I turned off power, it stopped quickly and the chuck was hard to rotate even in neutral. Clearly a bad spindle bearing.

Looks like I have the exciting opportunity to learn spindle bearing replacement.

Would you buy the $120 set of NSK bearings from Griz, or is there a reason to consider anything else? [Edit: I have already ordered them...]
Has anyone who has been through this before willing to help out if I get stuck?
If you've done this before, is there anything that I should know ahead of time? Consumables that should be ordered with the bearings? Tools that I'll need?
Griz appear to be completely out of all gaskets; at least all gaskets associated with the headstock spindle, but I can make my own if these tear.


Edit: *TL;DR* of thread:

Grizzly is shipping regular-precision bearings in boxes marked as precision bearings, and it shows. They are almost certainly legitimate NSK bearings, but regular precision and fabricated at NSK's plant in mainland China.
Motion Industries can source precision bearings, @Cadillac reports about $400
There are lots of pictures in the thread that might help you if you are trying to do the same replacement
If you haven't already done this, 6x3mm neodymium magnets fit nicely in the oil drip channel that feeds oil to the bearings, which may help keep chips out.
The internet is full of videos of changing spindle bearings in various lathes. After I watched those recommended in this thread, The Algorithm kept throwing more at me.
You need large ratcheting snap ring pliers both for disassembly and reassembly.
Comment #23 has a summary of the official Grizzly preload-setting procedure from the manual
Comment #35 has a detailed textual description of the steps I used to put the lathe back together.
Ultimately: The Grizzly replacement bearings are not as high quality as what was included in the lathe, so if you are doing this, buy quality actual P5 bearings through a reputable distributor such as Motion Industries. This is one of the more expensive components of the lathe, so don't be surprised when you pay for them.


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## Ischgl99 (May 7, 2022)

There was a thread a couple months ago by @Cadillac where he bought the bearings I believe go in your machine.  The ones he got were not P5 precision bearings even though they say so on the packaging.  He ended up returning them and I think he found something from a local bearing distributor, but they cost considerably more.  If it doesn’t say P5 on the bearing, then you need to assume they are not unless proven otherwise.  Here is that thread:  https://www.hobby-machinist.com/threads/14x40-spindle-bearing-replacement.97976/

I would be curious to see what grade bearings are installed in your machine.  Since they are selling standard precision, I would guess standards came from the factory.  I wouldn’t recommend standard precision bearings in a machine tool, but some people do that and are very happy with it.  Higher precision bearings will give you better service, but at a significantly higher cost.

As an FYI, Grizzly prices for standard precision bearings are higher than from a local bearing distributor.  It might be cost effective to return them and buy them locally if you decide to replace with standard precision.


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## mcdanlj (May 7, 2022)

Thank you very much!

I guess I can use the NSK app to check the barcode on the bearings that are sold as 30212 P5 and 30210 P6 NSK bearings when they arrive, but it sounds from that thread like they probably aren't legit. About three months later they are still definitely listed on their web site as NSK and that's what's on the email I got for the order, so if they aren't legit I can follow up if I have the energy... [Edit: Oh, it's specifically only for NSK N-series bearings made in Japan. "The app works with all Japanese-manufactured NSK bearings featuring an ‘N’ symbol in the lower right corner of the 2D code on the packing label of the box – the print run for which commenced in 2018." And they did open a facility in China; it looks like they announced in 2011 and started production in 2013 so my lathe probably already has those bearings in it.]

Griz sold my lathe to the original purchaser missing the faceplate, and Griz had ghosted him on replacing it. When I contacted them at the time, they quoted me rather a high price for the replacement, shipped. I added the replacement to my cart while I was ordering anyway, and the total for bearings and faceplate I think is similar to what they quoted me for only the faceplate a few years ago. (This is weird, hasn't the price of everything gone way up recently?)

Draining the oil to prepare for disassembly (and/or rocking the gears moving them around) seems to have dislodged a chip or something in the bearing and the lathe started turning freely. I'm confident that catching a chip would have done surface damage to the race and/or rollers (how could it not?) so I'll still want to replace the bearings, but I can now use the lathe in the mean time. (I'm just a home gamer, no one is paying me for precision work...)


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## fitterman1 (May 8, 2022)

Timken, FAG, SKF, are the brands i look for.
Your bearings are tapered roller brgs. Good for trailers and car axles. They will do the job in your lathe if correctly adjusted.
And they are robust which is why they are used. You could get angular contact brgs, but you'll pay through the nose for that size.
How are they mounted? Is it a geared head or simple spindle arrangement?
Either way one or both bearings are contaminated and they need to be removed, washed out and inspected before purchasing replacements. No good replacing both if one is shot. Thats false economy. Rip out the spindle and inspect them. If you're creating mission critical parts buy the highest specced brgs you can afford. If not just use normal brgs, they'll be fine for sub thou work.


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## fitterman1 (May 8, 2022)

If you have a geared head lathe is there an oil circulating pump?
Or is it just splash?
Check out the sump for metal particles and run a telescopic magnet through there and see what you find.


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## Ischgl99 (May 8, 2022)

Yes, NSK has a factory in China so those bearings likely would come up as genuine.  I’ve used the counterfeiting app to check some bearings that I know are 100% genuine and it came up suspicious, so it’s not perfect.  If you look at the box in the previous thread, the sticker put on by Grizzly is the only place it says P5, so the bearings were likely genuine standard precision bearings that someone decided to call high precision and made that sticker.  It’s also possible they measured the bearings and determined they meet P5 standards, but I find that unlikely.

Since you are draining the oil, you might want to look into adding a magnet to the drain plug to capture metal particles in the oil.  I bought a small magnet from McMaster-Carr and will be adding it to mine at my next change.  I will drill the plug to accept the magnet and epoxy it in place.  Since it looks like there might have been a good size metal particle causing the problem, I would inspect all the gears and make sure there is not any damage to them, it would be a shame to put expensive bearings in there and then have them damaged because a gear is spalling and sending more metal into it.


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## mcdanlj (May 8, 2022)

fitterman1 said:


> How are they mounted? Is it a geared head or simple spindle arrangement?



Geared.



fitterman1 said:


> If you have a geared head lathe is there an oil circulating pump?
> Or is it just splash?



This is why these lathes specify ISO 32 oil; they are splash lubricated. The oil splashes on the cover, and some of it drips into a channel that feeds to the bearings to cycle oil through the bearings. There is no pump.



fitterman1 said:


> Either way one or both bearings are contaminated and they need to be removed, washed out and inspected before purchasing replacements.



I already purchased replacements. I didn't think to put my endoscope or inspection mirror down to try to see whether I could identify any surface damage until I'd already filled it back up with fresh oil.



Ischgl99 said:


> Since you are draining the oil, you might want to look into adding a magnet to the drain plug to capture metal particles in the oil.



One of the first things I did when I got the lathe was put some neodymium magnets into the headstock where I could see and reach them. They definitely collected ferrous metal. It sticks fine to the case and won't bounce into the gears; I didn't need to bond it to the drain plug. I plan to always keep a magnet in the headstock oil.

It's quite possible that some damage had already been done before I ever got the lathe. But that's a reason for me to seriously consider replacing both bearings.



Ischgl99 said:


> Since it looks like there might have been a good size metal particle causing the problem, I would inspect all the gears and make sure there is not any damage to them, it would be a shame to put expensive bearings in there and then have them damaged because a gear is spalling and sending more metal into it.



I didn't see any obvious damage on the spur gears when I spun them around. I don't think it would take a large chip to have caused bearing drag.

This lathe is such a weird mix of imperial and metric. I'd like to replace the drain plug with a drain cock to make oil changes easier, so I'm more likely to get around to doing them on a smart schedule. Of course, with the lathe broken down I couldn't cut a new drain plug, so I just measured and wrote down what I found so that I could make one later. I wrote down 5/8-16 as the thread spec for the plug, and now I am doubting myself after re-filling the headstock with fresh ISO 32, because that thread spec is a "special". Did I read an "18" as a "16"? Or was it really a metric thread and I just accidentally skipped a blade on the thread gage when I started guessing metric? Maybe I'll check at next oil change! 


Incidentally, I did discover that the spider coupling thread is the same as an ER40 collet nut. That means I could turn an ER40 adapter to fit in the back of the spindle and use an ER40 collet on the back as a very precise spider that doesn't require me to clock in four screws.


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## Ischgl99 (May 8, 2022)

mcdanlj said:


> Incidentally, I did discover that the spider coupling thread is the same as an ER40 collet nut. That means I could turn an ER40 adapter to fit in the back of the spindle and use an ER40 collet on the back as a very precise spider that doesn't require me to clock in four screws.


That sounds like a really nice feature, I had to make a spider with the four screws for my lathe.

It wouldn’t take much of a chip in the right place to get lodged in between the rolling elements and the cage.  Most metal particles are fairly small and get run over or pushed out of the way, but the bearing could be spalling and a chunk flaked off and caused the problem as well.

The drain plug could be BSPP or BSPT.  PP is parallel pipe and PT tapered like NPT.  Depending on the size, the tapered threads are close enough to NPT that they frequently fit close enough.  Here is a chart with the dimensions. https://torqbolt.com/bspt-british-standard-pipe-taper-threads-dimensions-specifications. It could be a straight metric thread as well, you never know what gets put in some of these machines.

A magnet on the bottom will work fine too, I suggested installing one on the drain plug so that when you remove the plug, the metal particles comes with it.  If you install a drain valve, then you won’t be able to do that and would need one in the bottom of the gear case.


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## mcdanlj (May 8, 2022)

Yeah, the lathe came with the typical four-screw spider. And I've used it. I'm cool with using the 4-jaw, but it's hard to reach around to turn the spindle to indicate in the workpiece, so something that was self-centering would be awesome. I've been really pleased with my ER40 collet chuck and I doubt that my 5C will see very much more use now.

A spalling bearing would make a lot of sense. I did my initial knurling work before learning that I should buy a scissors knurling tool, so the straight knurling tool definitely put some pressure on the bearings. That's what happens when a tyro buys a set of tools and doesn't know right away that one of them is an abomination! ☺

The drain is at the side rather than the bottom, so it kind of fails to drain the dregs. I put the magnet aligned with a large gear on the spindle so I know it will circulate oil past the magnet. It's in the easiest, most open part of the gear box to reach into.

I had been saving up for a PM lathe when this one came up on craigslist locally. It's not a terrible lathe, but I'm pretty sure that if I'd waited and bought the PM1440GT I really wanted I would have had a far better lathe — but then maybe also made more expensive mistakes?


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## Ischgl99 (May 8, 2022)

Sometimes it’s better to get something and start working than to wait for the better one that may never come.  Most of these lathes are probably better than our abilities anyways.  I had a 9x20 lathe and wanted to upgrade 10 years ago to something like the G4003G, but things kept getting in the way, and prices kept rising.  I decided in 2020 to stop putting it off and bought a PM1236T instead of the Grizzly, so I guess things worked out for the better anyways.  I had good timing, that lathe is $2,000 more now than I paid for it in Nov 2020.  I also didn’t need to wait 6 months, it was actually in stock!  If you waited, it might have cost you a lot more to get what you wanted. 

Sounds like the magnet in the bottom is better in your case.  I’ll have to check mine, I think the drain is right at the bottom, but now that you mention it, I’m not sure.  If you aren’t doing this already, when you clean the headstock, it would be a good idea to use a rag to remove all the remaining oil to take out and dirt or debris that has collected.  

These aren’t the same lathe as you have, but these videos might give you some ideas on removing the spindle bearings.  As was mentioned by someone earlier, it would be a good idea to change the other shaft bearings in there.  They are mostly fairly cheap ball bearings, so the cost is not much and you will have everything basically new again.  In the first video, I believe Max used standard precision bearings for the spindle.  It might be worth it to send him a message and ask if he still thinks that was a good decision.


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## Cadillac (May 8, 2022)

Replacing the spindle bearings on my lathe was more of a task than I expected. Biggest problem for me was finding genuine bearings in a p5 at a reasonable price. Local distributor could get them for both around 700.00. The bearings grizzly sells are not p5 bearings they are a standard j class that you can go buy at Napa for 30 dollars a piece.
 Every video I’ve seen including the video above they are replacing with a standard bearing and claim to get good results. the above video he mentions about the actual bearing from grizzly not having the p5 rating on the races.  
 After a lot of hassle I eventually found both bearings 30212 and 30210 in a p5 rating. They are KLF-ZVL made in the Czech Republic. I found a seller on eBay and for both they were 250. I purchased  FAG brand from a seller and they couldn’t deliver on it and eventually refunded my money because they couldn’t get them.
  I haven’t finished the spindle as of yet. Life has had me busy to get the time I need. Not something I want to rush. I will update my bearing post with my results.
 When I first purchased my lathe I put magnets on the inside of the headstock in three different places. I put quarter size ones on the bottom to catch sediment. Then little rectangle ones in the channels front and back of the holes that supply the headstock bearings. When I recently opened the headstock for the bearing replacement the magnets on the bottom had a film of real fine metal particle covering them. The little ones in the channels had a miner amount so they are definately doing their job. I’d recommend magnets. I did wonder about the effects of magnets on the casting with bearing and if it causes a problem. Idk I tried to keep away from the bearings.
 I also didn’t like how the drain plug was for draining the oil. I found a petcock drain style that’s used on small engines. I believe the thread is m16x1.5. I have it installed but haven’t needed to use yet time will tell. Here’s acouple pics of the bearings I did find and the drain valve.


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## mcdanlj (May 8, 2022)

Ischgl99 said:


> Sometimes it’s better to get something and start working than to wait for the better one that may never come.



That's exactly right!



Ischgl99 said:


> If you aren’t doing this already, when you clean the headstock, it would be a good idea to use a rag to remove all the remaining oil to take out and dirt or debris that has collected.



Yes, I definitely did that. I hadn't done it enough before and I don't know whether the original owner did either, so hopefully I did a better job this time.

Thank you so much for the videos! They do give me a sense of what I'm getting myself into. ☺



Cadillac said:


> I believe the thread is m16x1.5



I'll bet I just skipped a blade on the thread gage then. Thanks!


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## mcdanlj (May 16, 2022)

Today I started disassembling the headstock. Hopefully I'm taking enough pictures to supplement the drawing when I put it back together. I'm certainly committed at this point!

I bought the correct hook wrench for the preload nuts, as part of a set of 9, so I am hopefully set for life on hook wrenches...

The gaskets are painted to the lathe, so this has obviously not been done before. I bought gasket material at a local auto parts store along with 5 gallons of AW32 hydraulic fluid for putting this back together. I also bought a pump to pump out the oil with only about two hours of use on it since it's almost $70 worth of Mobile DTE.

The rear bearing is definitely marked JAPAN and NSK and has an X to mark the eccentric.








Sadly, my snap ring pliers are not up to the job of removing the circlips, so I'm stuck until I get something better. This means that I can't see how the front bearing is marked yet.


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## Ischgl99 (May 17, 2022)

That X is not for marking the high spot, it is likely a factory code since it looks like it was stamped in the ring before hardening.  From that picture, those are standard precision bearings that you can get for about $50 each from a bearing distributor.   Thanks for posting the picture, we now have confirmation Grizzly is installing standard precision bearings in their lathes from the factory.

If you are happy with the performance of the lathe with the standard bearings, then replacing them with the same new ones would be fine, but high precision bearings will give you better runout as well as higher rigidity since you will be able to run at a higher preload without damaging the bearings.  You’ll have to decide if the cost is worth it, but it would be for me.


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## mcdanlj (May 17, 2022)

Ah, that relieves my concern about whether I should mark the spindle itself to align the eccentric. Honestly if I get to the point where I can make use of the extra precision, I'll probably want it everywhere, and in the meantime will have learned enough to take good care of a higher-quality unit. The price of the bearings I already received from Griz is similar to that; I'd eat up the difference in shipping if I tried to swap them out for local stock.

In a few days, after the new snap ring pliers arrive and enable continued disassembly, I expect to be able to post pictures of the other original bearing set.


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## Ischgl99 (May 17, 2022)

Sorry, I misread your first post and thought each bearing cost $120, yeah, not worth sending them back to get the same thing from someone else at that price.  

If it is stamped on the bearing, it was done before hardening, so cannot be an accurate indication of the high spot.  Checking final runout for the high spot is done after final grinding and lapping and would be engraved or etched on.  The bearing will also have the precision class after the part number, if there is no precision class stated, then it is assumed to be standard precision.  In case you are replacing the ball bearings on the other shafts, the same is true for ball bearings with clearance, if there is not a clearance stated, then it is assumed to be normal clearance, all others will be marked on the bearing.  

I'm looking forward to your rebuild!


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## mcdanlj (May 17, 2022)

Since all the other shafts seem to be running smooth, my plan is to replace only the spindle bearings. I've added magnet chip catchers on either side of each spindle bearing oil tube, as well as magnets in the main sump.

I suspect that if I were putting expensive high-precision bearings in, I'd pull the whole thing apart and replace all the bearings as long as I'm in there, but for these bearings I'll throw the dice and see what they turn up. ☺


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## mcdanlj (May 18, 2022)

The $40 set of cheap 16" snap ring pliers arrived and I got back to work. Of course I ended up removing a ring that I didn't actually need to remove, but others most definitely have to come off, and these worked. (If I ever need a really nice pair of outsized snap ring pliers, I won't feel like I wasted $40 getting started.)

I heated up the rear bearing with a hot air gun, put a stack of wood on the ways just in case the nose went flying, and carefully used a rubber mallet to tap the spindle out through the bearing. There was a snap ring just inside the rear bearing that I had to keep moving every centimeter or so of progress I made, so that I could keep scootching over the gear it was retaining, using an aluminum bar to tap that gear along the spindle at each step.




This gear meshes with the feed direction lever, and it stayed meshed as I moved the spindle a bit, then moved the snap ring, then moved the gear, repeatedly.

Once I got the outer end of the spindle through the casing out, I was able to remove the snap ring entirely.




Success! Yeah, there's some grit down there. I've got some cleaning to do.




After getting the bearing ring off and moving the spindle out, I found with no surprise that the speed selector actuator brass bar fell out of its bushing hole.





Yes, there's some wear on that outer race! Also, note the two holes at the sides, towards the inside of the case:




From inside, you can see the edge of the ring through those holes:





I put a 1' long ¼" brass rod through those holes against the edge of the race, and alternated between the holes on each side, tapping it slowly out with a normal hammer on the other end of the brass rod, being sure not to wedge the race sideways:






Then around to tap out the front race towards the ways:



It was similarly worn.




Also, see that junk at the bottom? Yeah, that was a substantial accumulation of hard grit.




Looks from the back of the front race that the grit had piled up against that face and was leaking into the bearing:




I think this is paint splash on the feed direction idler set. It's not doing any harm I guess...




I have not yet removed the nose spindle bearing from the spindle. I think I have some work to do tracing and cutting a new gasket. All that is work for another day.


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## Ischgl99 (May 18, 2022)

Nice writeup.  Those races look pretty bad, once you get the grit out, hopefully the new bearing last you a long time.  Since you have the spindle out, you might want to spin each shaft by hand and see if you get any signs of that grit in those bearings as well.  In the second to last picture, there appears to be some sort of debris on the right hand shaft that you will want to get out.  I know you said you were going to leave them for now, but you might be able to flush the grit out if there is any in there before buttoning it back up again.


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## Ischgl99 (May 18, 2022)

Just noticed something else, it looks like a couple of the rollers on the spindle bearing are cracked.  It might be from the angle of the picture, but if they are cracked, then you caught this just in time.  If those failed during use, you might have a lot more parts to replace.

The outer ring you show for the 30212 bearing is a P5 tolerance class, or at least it is marked that way.  Interesting that they put a standard tolerance class bearing on the outboard side, but a P5 on the head side.  Do you have a picture of the part number on the 30210 outer ring?


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## mcdanlj (May 18, 2022)

Yes, I clearly need to check more thoroughly for grit in the other bearings. I won't rule out replacing any or all of the other bearings. And I need to make sure I can get this well cleaned.

I just checked, and I don't see any cracking on the rollers. I think it's a trick of light in the picture. Nevertheless, the wear is obvious on the rollers as well as the race. Once I get that ring off the spindle nose, I'll be able to take more pictures.


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## Cadillac (May 19, 2022)

Sounds like your experiences are about the same as mine. Although I was able to get the c clip off but knew I would not be able to get it on in a smooth manner. So I to purchased large locking c clip pliers off Amazon for 42 bucks. Nice thing is every once in awhile I come across these monster snap rings so they will get used. 
 I see your spindle side bearing is a p5 rating. Also curious what the black markings on the outboard bearing race. The two black lines going the circumference of the race. 
 My gear box gears also had overspray on some of the gears. Funny but NOT.  Like you found I also had grit on the backside of the races in that channel. Theirs no good way to flush that area when the machine is back together. Is it debris from the bearings setting or is it gearbox debris getting drowned there from the oil holes that feed the bearings. That’s why the small magnets surrounding those holes is recommended. 
 What’s gonna be your procedure for install? setting the preload? looking good keep us updated.


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## mcdanlj (May 19, 2022)

We probably got the same ratcheting c clip wrench set, even if it has a different brand name on it... Mine was HILTEX. I'll probably replace those terrible philips screws with hex heads at some point, at least if I use this much more.

I didn't notice the black interior circumferential circles on the outboard outer race when I was disassembling it. I'm guessing that google decided to "enhance" the picture and make it look more clearly focused, but in any case, that's where the ends of the rollers were running. I looked again at the cleaned bearing and there's some wear in the areas of those lines (though more distributed than you would guess from the picture) so I think that might have been the edges of the rollers grinding up grit! In case I had any doubts about whether I should be replacing them...

Tonight I removed the cage and inner race from the spindle. I removed the keys from the spindle, then I heated the race with a heat gun until the residual oil on it got hot enough to smell. Then I turned the spindle nose-up on some pieces of wood and gently tapped the race with the loose nose bearing retainer. I re-heated the race once or twice, and it took probably a couple of minutes of light tapping before the race neatly dropped onto the supporting pieces of wood (while I kept my grip on the bearing retainer to not drop it as well). To be clear, I wasn't hammering on the bearing retainer; I held it with my fingers on opposite sides, and used it as a very very gentle captive slap hammer, moving it around the bearing as I went to make sure it was getting even pressure so it wouldn't rack.

Yeah, the spindle side bearing is marked P5, and it's definitely etched not stamped. But I don't see an eccentric mark. Here it is with the oil wiped off:




Is the "1404 312" is a serial number? It matches the other half, but I don't have anything to compare it to. Sorry, was having trouble with macro focus but it's almost legible here:




Given the lack of eccentric marks (that I can see), does it seem legit that these are P5?

All the ball bearings are turning freely, and they spin freely when I let them go. No bad noises. I think that ball bearings are far more able to reject chips around the side than roller bearings, so that's not a huge surprise. For better or worse, not going to invest on replacing them all right now. I could easily imagine making another decision if I were putting in better bearings.

While I already have some magnets, I'm going to buy more, and clean out the sump with WD40 before I put anything back in.

Re-install after cleaning, something like this: (See comment #35 for what I actually did)

Cut new gaskets (I think; I bought new gasket material, but on the other hand it's not torn)
Lightly oil spindle shaft, heat new chuck-end spindle bearing, install on spindle shaft. Replace clip ring.
Re-install keys in spindle shaft
Lightly oil outer raceways, chill them in freezer
Heat-soak new outboard spindle bearing; set aside
Lightly oil outer raceways; tap with wood to install front and back flush with case
With wood on ways for support, re-install spindle, putting gears back on as it goes through the headstock case. Remember to include the speed shift block properly indexed, or I'll be very sad and have to start over later! Make sure all the clip rings are in place.
Screw spindle side bearing retainer ring in place, seating the spindle bearing race to its intended depth.
Re-heat new outboard spindle bearing, install on spindle shaft.
Screw outboard bearing retainer ring in place, seating outboard outer bearing race to depth.
Install the collar / spacer (also maybe it's a labyrinth seal?)
Use the inner spanner nut to tighten just enough to remove play, not the additional torque for setting normal preload.
Lock inner spanner nut with outer spanner nut
Run clean oil through the taper bearing holes until it flows through
Refill the sump with clean oil, close the top.
Run the full preload procedure, regularly checking temperature with an IR thermometer to make sure bearings aren't overheating, and listening carefully.
Re-install spider

The manual has a preload procedure. In the version of the manual for my lathe ("Mfg. Since 5/11") it starts on page 67.  Abbreviated:

Run the lathe at high speed for 20 minutes
Disconnect from power
Remove chuck and spider bolts
Loosen outer spanner nut two turns
Loosen inner spanner nut one turn
Hold wood block against outboard spindle end, tap lightly with a 3-4 lb hammer to introduce end play
Dial indicator on cross slide, indicate against spindle face
Move .1" closer to headstock and zero
Tighten inner spanner nut until dial indicator needle just stops moving, rocking spindle back and forth. If you move further, to back to step 5 and unload.
Tighten the inner spanner nut an additional 1/16 turn
Without allowing the inner spanner nut to tighten further, tighten the outer spanner nut against the inner spanner nut. Not over-tight because that can add excess preload and damage bearing or even crack the headstock


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## Ischgl99 (May 20, 2022)

I think those likely are P5.  The o is probably the high spot mark, the bearing on Grizzly’s website has an o in a different spot.  The number could be a serial number, or it could be a lot number, either way I think it is for identifying the bearing.  NSK’s guide on part numbering doesn’t mention how the precision classes are marked, and I haven’t been able to find a picture of an NSK TRB in P5 or higher to compare except on the Grizzly site, so not 100% sure about this.  

Your assembly and adjustment procedure looks good.  I like how they are having you heat up the spindle by running it for 20 minutes and then setting proper preload through measurement instead of trial and error.  I’ll have to see if that works for a mill spindle as well, I’ve used the run for a while and check for proper temperature, but I like having a measurement to use instead.  The only thing I would add is to set the preload light during the run in procedure to make sure you have some preload on the bearings, but not too much that it might overheat, otherwise you can cause skidding damage of the rollers on the races if it is too loose.


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## mcdanlj (May 20, 2022)

Well, the O's are where the X's were on the prior bearings that you called out as probably a factory code. ☺ I'll see the markings on the replacement bearings more clearly when I unwrap them, which I'm waiting to do until I'm otherwise ready to install them. Either they are eccentric marks and I should match them, or there are no eccentric marks and I can match them, so it probably comes out in the wash.



Ischgl99 said:


> The only thing I would add is to set the preload light during the run in procedure to make sure you have some preload on the bearings, but not too much that it might overheat, otherwise you can cause skidding damage of the rollers on the races if it is too loose.



Yeah, that's why for install I said "Use the inner spanner nut to tighten just enough to remove play" — intentionally not taking the extra 1/16 turn when initially running it in. If it starts to rattle or leak oil I can stop and take out play; if it gets hot I can stop and back off. I do have an IR thermometer to use to check early and often. I've annotated that a bit more. I've also realized that I want to put both bearing retainers on ASAP to push the chilled races in to exactly the right depth, and that the outboard spacer fits inside the outboard bearing retainer. I edited that post to improve the checklist.

I assume the 1/16 turn is actually setting torque based on the diameter and thickness of the shaft and the 1.5mm pitch on the nut, and that getting that torque right on a mill is different. I thought that mill bearing preload was normally set by spacer size though?


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## Cadillac (May 20, 2022)

Bridgeport style mills have set of angular contact at the business end separated by a precisely ground spacer. Which sets the preload in the bearings. On the topside of the mill spindle is a class3 ball bearing. 
 With the lathe setting the preload will be a touchy task. When installing the outboard bearing I warmed it up to be able to slide it on. Once that’s was installed I installed the rear bearing cover, seal and retaining nut. Then I mounted a tenth indicator reading endplay on spindle. The retaining nut took some force to move the bearing. I brought the spindle within five tenths endplay. Then I ran every speed about five minutes each. I now have around two tenths endplay and have been fiddling with it. 
 That’s where I’m at right now after a first attempt. First time I felt the spindle was to tight. Thought it sounded different which I might be imagining? Idk  
 I couldn’t get much temperature change of the headstock by bearing or spindle change. But I did not crank down on bearings. I’m relying on gauges not my IR gun. I don’t think it’s accurate enough. You will not be able to set preload with torque values. At least not that I can see.


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## mcdanlj (May 21, 2022)

Cadillac said:


> Bridgeport style mills have set of angular contact at the business end separated by a precisely ground spacer. Which sets the preload in the bearings.



Yeah, that's what I was referring to.



mcdanlj said:


> I assume the 1/16 turn is actually setting torque based on the diameter and thickness of the shaft and the 1.5mm pitch on the nut





Cadillac said:


> You will not be able to set preload with torque values.



I'm not saying "use a torque wrench to set preload" (indeed; please note a lack of any torque values). I'm saying that Grizzly's published preload instructions (see the summary I posted) say to take all the play out that can be introduced by gentle hammer taps through a wood block after 20 minutes of full-speed running, and then advance the nut 1/16 of a turn. That specified amount of tightening is applying a particular amount of torque to set a particular amount of preload. (I have no experience or knowledge that would indicate that 1/16 of a turn would be right for your lathe.)

In any case, if you still have any end play, you don't have any preload at all, as far as I can tell.

My mentioning using an IR thermometer is only to make sure that I haven't tightened it too much during the _initial_ run-up, _before_ setting the preload. It's not a way to measure correct preload; it's a way to recognize that something is going wrong before setting preload.

I hope that's clearer!


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## Ischgl99 (May 22, 2022)

mcdanlj said:


> Well, the O's are where the X's were on the prior bearings that you called out as probably a factory code. ☺


I think that is a coincidence.  I also said the x looked stamped, so it couldn’t be a high spot mark if so. .  Is the O stamped on or etched/engraved?  From the picture it looked etched, but it’s not always easy to tell from a photo.  That bearing on the Grizzly site has the O in a different position than yours, so that is further indication it is not a factory code and more likely a high spot indication.

I’m curious to see what Grizzly shipped you.  I am still baffled they would put one high precision and one standard bearing on the spindle.  That might help radial runout at the spindle, but it reduces some of the advantages of high precision with regards to rigidity.


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## Ischgl99 (May 22, 2022)

Cadillac said:


> Bridgeport style mills have set of angular contact at the business end separated by a precisely ground spacer. Which sets the preload in the bearings. On the topside of the mill spindle is a class3 ball bearing.


My mill is a Burke Millrite that uses two tapered roller bearings with one spacer on the outer rings.  You need to manually adjust the preload based on how hot it gets at the speeds you will be running, identical to this lathe, just oriented vertically.  I haven’t tried the procedure Grizzly outlines for the lathe mcdalj posted above, but might be worth trying to see if it works.


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## mcdanlj (May 22, 2022)

Ischgl99 said:


> I think that is a coincidence. I also said the x looked stamped, so it couldn’t be a high spot mark if so. . Is the O stamped on or etched/engraved? From the picture it looked etched, but it’s not always easy to tell from a photo. That bearing on the Grizzly site has the O in a different position than yours, so that is further indication it is not a factory code and more likely a high spot indication.



Ah. Yes, the P5 spindle end bearing is indeed etched not stamped. I didn't understand the point before, but got it now.



Ischgl99 said:


> I am still baffled they would put one high precision and one standard bearing on the spindle. That might help radial runout at the spindle, but it reduces some of the advantages of high precision with regards to rigidity.



Looks to me like an engineering decision to manage cost. Close to the spindle, that potential eccentricity from the P6 outboard bearing is lost in the noise from simple ratio of lever arms — the eccentricity at the chuck will be a small fraction of the eccentricity of the outboard bearing based on the the length of the spindle; further out from the spindle, I'd expect material compliance to be the biggest problem and be resolved with tailstock support or turning between centers.

I'm still considering getting two clearly legit P5 bearings. I see separately "ZVL" and "ZKL" listed by "globalpower" on ebay — https://www.ebay.com/itm/115093856956 and https://www.ebay.com/itm/133933717848 — @Cadillac is that what you found?


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## Ischgl99 (May 22, 2022)

It’s not only the radial eccentricity that is the issue, it’s also the axial.  Every bearing is a very rigid spring, and the stiffness of the spring determines how rigid the system is.  With potentially larger variation in rolling element size as well as runout with the standard bearings, you have less contact between the inner and outer races, so that means your spindle is less stiff than one where more rolling elements are in full contact.  You also have a limit to how much preload you can put on a rolling element before it overheats.  When the load is spread among more rolling elements, you can have a higher preload and thus more rigidity.  As a thought experiment, consider a situation where one rolling element is maximum size and all others are minimum, all the load goes through one or two rolling elements and you can only preload the bearing up to the limit of those elements.  Now consider all the rolling elements and races are perfectly the same, the load gets spread evenly between all of them, so your preload can be higher, and the stiffness is higher.  A real bearing is somewhere in-between those two examples, and a higher precision bearing puts you closer to the perfect situation.

Having a P5 bearing at the chuck end helps a lot, but not having one at the outboard end could be an issue, or you might get lucky and that bearing has low variation and you don’t see a difference.  I see this as a weak link in the chain. This could show up as chatter or poor finishes on your workpiece, or ability to take deeper cuts.  What some people blame on the compound might also be poor stiffness of the spindle due to bearing choices.  What it looks like Grizzly is doing is playing the odds that the standard precision bearing doesn’t cause issues significant enough to affect sales, and they can get away with just one high precision bearing to save costs.  But, based on Cadillac’s experience, it doesn’t look like they are not even using P5 any longer since the bearings they shipped him were standard precision.  If you opened the bearings, I would be curious to see if they are standard or high precision, the price indicates they are standard.

Having said all that, FAG X-Life bearings have some tolerances to P6 and would likely be better than standard precision if cost is an issue.  They cost about the same as standard precision, but you get a better tolerance quality overall.


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## Cadillac (May 22, 2022)

mcdanlj said:


> Ah. Yes, the P5 spindle end bearing is indeed etched not stamped. I didn't understand the point before, but got it now.
> 
> 
> 
> ...


Yes those are the bearings I have. Dealing with global power was a issue. Their listing had FAG bearings in a p5 rating for the same price. I ordered them and received a drivebelt for a snow mobile. Contacted them they said they send out the bearings and nothing for like 3 weeks. I tried contacting them and they said they were delivered on the date of the snow mobile belt. I stated what happen and they were like we sent you something. So I contacted eBay. They got involved and the seller refunded my money. 
 I ordered them again FAG bearings in a P5 rating from them again since I was refunded. When I received them they were KLF-ZVL 30210 & 30212 P5. I contacted the seller and they said that’s the only brand they have in a P5 rating. I asked why they have them listed as FAG brand and they said it must be a listing mistake. I said well that’s under your control and nothing ever came of it. I didn’t won’t to deal with them anymore seemed like nothing but problems. 
  So I have these bearings and they seem of good quality I have just not ever heard of them. They are made in the Czech Republic . There are not high spots etched in the bearing races but they are mark with the P5 rating on the races. 
  I have them installled in the lathe. Very similar to what you described. Once everything was clean I pressed the chuck side bearing on using a aluminum spacer on the inner race. Went smooth felt it bottom out seated with light pressure. Once installed in the headstock I had my wife hold pressure on the spindle toward the outboard side while I heated the outboard bearing with a heat gun. Once up to about 120* using my IR gun to verify. I slide the outboard bearing on. It bottomed out to the race. Then I installed outboard cover seal/spacer and retaining nut. I put a gauge on the spindle at that point and it had about .005-.007 endplay. It took some force to get the retaining nut to move the bearing. I’d say between 30-50 ft.lbs of force. Guessing here but I do use torque wrenches frequently. I’m a mechanic. I’ve got the spindle endplay down to 3-4 tenths running the bearings in. It’s been touchy and I’m trying not to rush it. Walking away and doing something else because I’m busy and I have another lathe so not pressing. 
 If and maybe when I do it all over I would probably go with know bearings. Meaning go to a bearing dis. and get them. I had contacted my motion industry dist. And he could get them I think all in for 400.00. He said he had to find the outboard but the spindle was available. Outboard would take a week. I took the chance with eBay purchase and didn’t get the FAG brand I wanted saving alittle but not getting what I wanted. Probably should have just went with the dealer and had the assurance of the quality and manufacturer. Idk


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## mcdanlj (May 29, 2022)

Here's the outer race of the spindle-side bearing. It think the writing is laser-etched (that's now relatively cheap), but it's certainly marked as a J-class bearing!




Cage and inner race:




The gaskets are cork, and except for some paint on the outside, are in very good shape, so I'm not inclined to replace them with paper gaskets; that's not obviously an improvement, and I don't know what the nominal thickness is to even cut my own. (I cut one out of paper before I realized that it was a bad idea.)

I'm going to put this all together and see whether play is acceptable. If so, great; if not, I have a motion industries supplier locally from whom to purchase quality.

I lightly coated the spindle-side seat with CorrosionX, and also the outer race, so that any condensation ice wouldn't stick. I soaked the outer race in the freezer for half an hour, and then it slipped easily into the seat. I held it in place for a few seconds as it warmed, then lightly tapped it to make sure it was fully seated, and it quickly warmed and fit securely.

Then I heated the inner race and cage with my heat gun until it was too hot to touch (the IR thermometer was inconsistent with such a small target, but I saw as high as 175°F). It didn't seat right when I first set it in place, but I tapped it loose with the bearing retainer and set it on again, and that time it fell perfectly to the bottom and seated firmly.

Then I set the circlip in place so that I don't put everything together and then discover that I forgot. ☺


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## Ischgl99 (May 29, 2022)

The J simply means the bearing contact angle meets ISO standards.  The HR is a high load rating design.  These definitely are standard tolerance bearings.  If they were higher precision, P5 or P6 would have been written on them.  The attached document from NSK goes through their numbering convention.  Something to keep in mind is each bearing manufacturer is different, so the letters on an equivalent SKF bearing might be different.

Nothing wrong with your plan to try them and see how they perform for you.  They most likely will not perform as well as a higher precision bearing, but you may not see enough of a difference to justify the cost of the higher precision, the differences may only become evident if you really push the lathe too.  One place I would expect to see an issue if they are not suitable is surface finish, you might get more chatter with these than you would with the higher precision bearings, in addition to possibly higher radial and axial runout.

For the gasket material, you can order some from McMaster-Carr, or use their website to research what you might need and check with your local auto parts store and see what they have.  My local Napa store has a lot of items that I need and saves me shipping, but I live in a semi-rural area with lots of farms.  If you bring in a sample, they might know exactly what it is.


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## mcdanlj (May 29, 2022)

The circlip that I removed near the spindle didn't need to come off; it just held together the package of low and high speed spindle drive gears. So I just re-installed it.

I bought paper gasket material at my local auto parts store, not having looked carefully at the existing gaskets, only the top gasket. I could have measured it, but really what I want to do for next time — if I'm unlucky and there is a next time — is either buy pre-cut from Grizzly or finish making my laser cutter and use that to do a better job. I think that the gasket around the top is paper, so I could have replaced that, but. it also wasn't leaking, and isn't under pressure, so hard to get excited about this. If the rear seal leaks, that's an easy fix — don't even need to take off the preload nuts — but if the front seal leaks, I'll have to take it all apart, at which point I pay a visit to my friendly local motion industries distributor.

Here's what I actually have done so far, leaving out the few do-overs I had to do:

Apply very light coat of CorrosionX to bearing seats and outer raceways
Freeze outer raceways solid in chest freezer
One at a time, slide very cold outer raceways into seats; hold and tap them in place as they warm up to make sure they are fully seated.
Lightly oil spindle shaft, heat new chuck-end spindle bearing, install on spindle shaft.
Re-install keys in spindle shaft
Oil gaskets both sides with way oil
Re-install speed shift block.
Set feed selector gear circlip into ratcheting circlip wrench.
With wood on ways for support under bearing retainer, re-install spindle, putting gears and the feed selector circlip back on as it goes through the headstock case.
Put the spindle barely into the head stock, keys up
Hold spindle drive gear roughly in position, large side towards the bed, keyway up, engaged with speed shift block
Slide spindle through spindle drive gear
Hold feed selector gear in position, keyway up. (Both gears are identical, it doesn't have a direction)
Slide spindle through selector gear but not quite through the case
Set circlip in ratcheting wrench around spindle
Slide spindle through the rest of the way

Screw outboard bearing retainer ring in place.
Install feed selector gear circlip.
Heat new outboard spindle bearing, install on spindle shaft.
Screw spindle side bearing retainer ring in place, seating the spindle bearing race to its intended depth.
Install the collar / spacer.
Use the inner spanner nut to tighten just enough to remove play, not the additional torque for setting normal preload.
Lock inner spanner nut with outer spanner nut
Install lots and lots of neodymium magnets, including many in the oil drip channel
Run clean oil through the taper bearing holes until it flows through
Refill the sump with clean oil, close the top.
Run each of the speeds momentarily to make sure that the gears mess correctly.
Run 20 minutes at 300RPM
Run 20 minutes at 2000RPM

Notes:

After 20 minutes at 300RPM, there was a negligible increase in temperature in the adjacent headstock (~1°F)
After 20 minutes at 2000RPM, there was a 5-8° increase in temperature near the bearings; slightly more outboard than by the nose.
It at least sounds better than it did, so feeling OK about not replacing the other bearings.

Next, I'll run the preload setting procedure from the manual.


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## Ischgl99 (May 29, 2022)

That’s good news the others bearings sound good.  Thanks for the writeup of your procedure, it looks like you did a great job on the reassembly.  I am looking forward to hearing how the preload procedure goes and what the final runout is.


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## mcdanlj (May 29, 2022)

Before I ran the preload procedure, there wasn't that much play. It wasn't really noticeable, but I went forward with the preload procedure in the manual like a good person. I did the preload tightening procedure a bunch of times before running it in. Maybe five or six? I thought I finally got it right and ran it for 20 minutes and 2000 RPM. It says to check the spindle nose temperature and it should be warm after 20 minutes, but not uncomfortably hot.

After 10 minutes, I checked the spindle nose temperature with my IR thermometer, and it was about 105°F inside the nose, so I let it go to 20 minutes. At 20 minutes it was similar, about 110°F. Then I touched the outboard end, and it was: Hot. Too Hot. Too... Darn... Hot! 170°F!

So I backed off a bit, ran the procedure again but was a little more cautious, and ran another 20 minutes at 2000RPM. Now it's 115°F on the outboard, and 105°F on the nose. Putting a tenths indicator on the nose and tapping it with a plastic hammer I'm not seeing meaningful deflection radially or axially. It turns freely in neutral. I'll call that good enough preload for now.

And now for the part you've been waiting for! *About a tenth of total radial runout* measured with a tenths DTI both on the nose taper and the inside of the 5MT taper in the nose, no appreciable axial runout. I haven't cut a test bar yet, but for what I need to do right now this is probably going to be good enough.


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## mcdanlj (May 30, 2022)

The surface finish isn't as good as the old bearings before they died, and I got lots of chatter trying to part 1117 cold-rolled steel; I barely put a goove in, then gave up and used a bandsaw for the cut and faced it to finish.

Not a huge surprise that bearing precision might matter. @Cadillac I think you were wise to return the Grizzly parts and buy something else, and I'll be contacting my local Motion Industries supplier for bearings. Might as well get P5 for both ends if I'm going to go through this again.

Having been through this all once, it's much less daunting to think about doing it all again. I'd expect to be able to do the job start to finish in a long evening next time, working slowly and deliberately but knowing what comes next.

I did make the ER40 "spider" adapter. It works great. I have both US and metric ER40 sets, so I can just put the best fit from the other set in the outboard end and it trues up nicely.


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## Firstram (May 30, 2022)

That's slick!


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## Cadillac (May 30, 2022)

I agree once gone through the process it is much less daunting to do. I haven’t had much success with the KLF-ZVL bearings. 
 I cannot get the spindle less than .0002 endplay. When I try tightening the retainer nut more I get a lobbing feel in the bearings. Like a high spot And the spindle still has the endplay. Then I loosen the nut tap the outboard side to loosen. Spindle will spin freely but still .0002. I haven’t tried doing any cuts I don’t like the results to start. 
 I took the cover off after trying multiple times trying to see something. I can barely see the rollers on the spindle side. While turning by hand you can see the individual rollers rolling as you turn the spindle. I can see at least one roller not spinning like the others. It’s just skating along while all the others are rolling. From what I can see which is hard because of space is it’s only one. 
 There is no room to see the outboard bearing rollers. 
 When you had the bearings adjusted did you Try pushing and pulling the spindle to try and induce endplay? Did you try taking a bar and applying force to the bottom side of spindle with a indicator on top of spindle to see if theirs any deflection? 
 Before I had taken my spindle out I took readings with a indicator so I knew what I had and what I needed to duplicate. My spindle had zero endplay had maybe a tenth of runout on any matting surface To the chuck including the mt5. The killer with mine is I had no problems I thought one of the races wasn’t seated against the headstock bore when I was doing a oil change. I ended up taking the spindle out and saw wear marks on the outer races and figure it’s out might as well replace e them. Then I found out the world of counterfeit bearings and precision bearings what a mess. 
 I was hoping to hear good things from your   rebuild. Sourcing a standard bearing is much easier and cheaper. Keep us posted on what you do. Good luck!


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## mcdanlj (May 30, 2022)

Cadillac said:


> When you had the bearings adjusted did you Try pushing and pulling the spindle to try and induce endplay? Did you try taking a bar and applying force to the bottom side of spindle with a indicator on top of spindle to see if theirs any deflection?



Yes to both, with a tenths DTI to measure.

Sorry to hear that the KLF-ZVL bearings aren't better than what Grizzly sent me. ☹


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## Ischgl99 (May 30, 2022)

I’m sorry to hear this, I was hoping I was wrong in your case about needing precision bearings and these would have worked.  

A couple other places you can try that might have better prices than Motion is BDI and Eastern Industrial https://www.easternia.com/137066/category/bearings
Bdiexpress.com


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## mcdanlj (May 30, 2022)

Firstram said:


> That's slick!



Thanks!

I made a separate thread with drawing and pictures for the ER40 collet adapter. It's not perfect (low clamping range) but where it works, being self-indicating will be a lot faster than the spider.









						Using an ER40 as a spider in a G0709
					

I noticed that the outboard end of my spindle had the same M50x1.5 thread as an ER40 nut, which made me wonder if I could use an ER40 nut instead of a spider, as a self-indicating outboard stock support.  I used some 1 7/8" CRS stock and made an adapter to hold the ER40 collet inside the end of...




					www.hobby-machinist.com


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## mcdanlj (May 30, 2022)

Ischgl99 said:


> A couple other places you can try that might have better prices than Motion is BDI and Eastern Industrial https://www.easternia.com/137066/category/bearings
> Bdiexpress.com



Eastern Industrial doesn't list any precision 30212 or 30210 bearings online, anyway. I could call them.

What is "Class C"? I know only of numeric grades, whether P, Class, or ABEC...

Edit: Ah, metric precision classes; the lowest-grade metric precision bearing.



			https://www.timken.com/resources/precision-tapered-roller-bearings-brochure/
		







			https://www.bdiexpress.com/us/en/Bearings/Roller-Bearings/Tapered-Roller-Bearing-Assemblies/30212-P-5/p/215148
		


Here are the FAG bearings with no price listed (I guess if you have to ask...)



			https://www.bdiexpress.com/us/en/Bearings/30212-A-P5/p/1143492
		




			https://www.bdiexpress.com/us/en/Bearings/30210-A-P5/p/1143487


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## Ischgl99 (May 30, 2022)

Yeah, class C is similar to P6 or ABEC 3.  Not sure if it is exactly the same as those, but relatively close if not.  Timken is the only company I know of that uses the letter classes, all the European companies use ISO ratings.  The good thing about these being metric bearings is it opens you up to all the manufacturers, if they were inch, like on my Burke Millrite, you are pretty much stuck with what Timken has on hand.

Precision tapers are not that common, so you might need to do a bit of searching.  Authorized distributors have access to the inventory at the shared warehouse in Crossville TN, so if they do not have it in their system, they will be able to see what is available from all the major manufacturers.  If they say they don’t have any, ask if that shows stock in Crossville just in case you get a lazy sales guy.  I’m a bit partial to FAG since I am most familiar with them, but I would not hesitate to use SKF, NSK, or Timken.  

As I mentioned in Cadillac’s thread, I would stay away from Ebay, you don’t really know where they came from.  They may be legit, but they could be counterfeit.  The risk of counterfeits is you are not getting a bearing that meets the specs you expect, and you will have no recourse with the manufacturer since you didn’t buy through an authorized distributor.

The lack of prices could simply be they don’t have that in stock and they don’t know what the current price is.  I would expect about $300-400 each for those in P5.  All of the bearing manufacturers usually are pretty close in price, so unless it has a special feature the others don’t have, will probably be about that same price.

Good luck with your search, and hopefully you will have a fully operational lathe soon.


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