14x40 spindle bearing replacement

Well I sent grizzly a lengthy email will see what transpires?? I will try and talk with someone Monday.
 
I call grizzly today and talked with someone in the technical dept. I will say the grizzly rep was nice helpful and as surprised as iI am. He documented everything and said they will get back to me within the week. He said this is going straight to the corporate level. He said he was going to check their inventory and see what they have. Basically said they were gonna get to the bottom of it. What does that mean for us idk. My guess is they will change their description and not change anything else. In the mean time I’m off looking for some 30212 and 30210 p5 rated bearings.
 
I have a feeling you are right and they just take the P5 off the description, but hopefully they do start stocking the right bearings since P5 is not easy to find in tapers.
 
So to update you guys I’ve been back and fourth with grizzly 4or 5 times. I explained to them on their website the bearing pictured says/etched with the number 30212-p5 on the races and shows the high spot etchings which is a small o in all the pictures.
Mine says 30212J that’s it on the box and on the races. The ONLY place it says p5 is on a grizzly sticker that’s also says it’s made in China. The nsk box says made in Japan and the bearing are etched Japan. So the only contradicting thing here is the grizzly sticker and a J series bearing.
That guy documented what I said and said they’re get back to me.
The guy today started by saying the bearing we have are nsk bearings not made by nsk in Japan but nsk bearings that are made in china. Nsk has been in China since 95 and that’s where we get our bearings from. I was shocked by his response and told him that does not make any sense? he said that what it is. I repeated the whole precision thing with a P5 bearing and that all your precision lathes list it has p5 bearings in the spindle. And that you website list them as replacements and it’s all wrong. He said they will be changing all that they are in the process of it.
I told the guy that their response on the matter was ridiculous and to just say well that’s what we have sorry. So I’m returning their wheel bearings and off on the hunt again.
Sorry to be the one to reveal all this but grizzly is misrepresenting all their precision gunsmith lathes stating they have precision headstock bearings when they are really a standard, plain Jane ‘J’series wheel bearing and charging for a p5 series. Shame,Shame
 
I am really disappointed with Grizzly. I just checked the parts listing for the G4003G lathe on their website and they list the standard tolerance bearings that you received for the spindle, with pictures to match, while claiming in the marketing text for the lathe that they are using high precision bearings. I hope they don't try and claim standard tolerance bearings are high precision, that term is reserved for higher than standard precision classes.

I sent a message to a guy that used to work for me at Schaeffler (FAG) to see if he knows of anyone that has the P5 bearings in stock and will let you know what he finds out. If you can't find anything in P5, the FAG X-Life bearings would be better than standard tolerance, but probably not as good as a P5 tolerance class.

I don't believe Precision Matthews will sell parts for lathes that are not theirs, but it might be worth a call to see if they have those in stock and would be willing to sell them to you.
 
This is a very interesting thread. Generally precision spindle bearings run in oil last much longer than 15 years. It could be issues with the oiling system as the OP stated or it could be there is some flaw in the machining that creates the problem. The purpose of higher precision ( concentricity between inner and outer , and uniformity of the rollers ) is to allow for tighter clearance to reduce runout when the bearings are cold yet still keep them from overheating at speed due to tight spots for the rollers or balls as they rotate. With very high precision bearings just changing the order of the rollers in the bearing, if possible , can change the runout. Some of my concern would be if the switch to lower precision was due only to cost or if the machining itself didn't warrant or justify the precision.

Maybe this is a Richard King question. Dave
 
Now I know more about cnc spindles than on lathes but aren’t the really high precision stuff always angular contact bearings? I thought tapered roller bearings didn’t really come in high accuracies due to the fact that high end equipment typically just used the AC bearings.

This being a grizzly I also wouldn’t expect amazing quality it is still a low cost Chinese machine.

I think if you get a decent set of tapered roller bearings made from a quality brand I think you will be ok.
 
All three types of spindle bearing design, A/C, tapered roller, or Deep Groove with a Thrust bearing can be high precision. All three designs try to provide both Radial and Axial load. There are extremely high precision roller bearings, so precision that rearranging the rollers screws up the precision. There are different levels of A/C bearings but it is also about the correct preload in combination with the bearing precision itself. In the old days, it was said to take days to scrape in spindle bearings on high end lathes. I don't know if modern manufacturing has changed that or we are less demanding. Probably both, but if designed properly, each type of bearing can yield a high precision outcome. Takes time and money of course. Dave
 
Yes the high end spindles use angular contact bearings but the design of the lathe won't work with them.
I am watching this with lots of interest because I own a lathe almost identical to this one and plan on replacing the bearings in mine. If I can't find a set of high precision bearings for a reasonable price, I will buy a set of good name brand ones and take a chance with them.
Joe
 
You can get high precision in any type of bearing, some spindles have precision cylindrical roller bearings in addition to the angular contact.

Tapered roller bearings are used in these lathes because the speeds these run at are relatively low, you can’t run most tapered roller bearings at CNC spindle speeds, you need angular contact bearings for that. TRBs have a higher stiffness than ACBs, so you can get a more rigid spindle system in the same size spindle and housing, that is likely why these machines use these instead of ACBs.

Part of the reason for using high precision in machine tools is so you can have a higher preload than you can with a standard precision bearing. Higher preloads make for a more rigid spindle and give you better performance of the machine. If you think of each rolling element in a bearing as a spring, you can visualize that the more rolling elements in contact with the races (higher precision) the more stiff the bearing will be.

A standard precision bearing might give you good performance, but there is no guarantee, you could get one that meets P5, or you could get one that just meets normal tolerances. Most of us here do not have the resources to check a number of bearings for tight tolerances and send the rest back, so you buy the higher tolerance bearings the bearing manufacturer made. Even though modern manufacturing tech allows for more precise manufacturing, that allows the manufacturer to run faster and not necessarily produce products to a higher precision. Remember, higher precision requires higher testing standards, and that costs money.

FAG makes a bearing line called X-Life that takes advantage of the higher precision of modern manufacturing and can guarantee tighter tolerances for near standard bearing prices. Most of the tolerances meet P6 tolerance class, I don’t recall which, and I’m on a project now and can’t check, but if you can’t find P5 bearings, X-Life would probably be the next best thing, definitely better than standard precision bearings. I’m sure SKF has something similar, maybe check into the Explorer series and see what tolerances those are made to, I don’t recall if they meet P6 or not, but they are supposed to be a higher quality bearing than the standard ones.
 
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