# G0602 tailstock driving me nuts



## dewbane (Sep 28, 2020)

I use the tailstock on my g0602 constantly, and it has been driving me nuts for the longest time.

One of the more common things people do is just leave a 17mm wrench on the tailstock at all times. I've read lots of posts in various places, talking about how "it only takes half a turn" to snug the thing down.

Yeah, not so much. The casting for the bed on my particular lathe is machined quite satisfactorily on the top surface, but the bottom surface is just some raw, ragged nonsense. Imagine taking a cast iron surface plate and bashing it against a hard edge at a weird angle until one end of it finally snaps off.

 If I start with the tailstock snugged down at the far right, and start moving toward the left, here's how it goes: Loosen about 1/2 a turn, I'm good to slide for some distance. Thunk. The clampy thing on the bottom has now collided with the ragged edge on the bottom. To get over the hump, I have to loosen the nut, maybe half, maybe a whole turn. I continue sliding for some distance. Thunk. By the time I get up near the headstock, I have had to back the thing off maybe three full turns.

So, the leave a wrench on it approach is never going to be satisfactory. The other main approach people take is to build a cam lock lever activated deal to actuate the clampy thing. I have mixed feelings about this approach. I have a cam-actuated tailstock on my wood lathe, and it's not difficult to cam it right over until it's completely loose. I've read some threads here and there warning about that problem on a metal lathe, and I feel like my problem is greatly compounded by the irregular clamping surface. My chances of building a cam with just the right offset seem rather slim.

So I'm just kind of scratching my head, trying to figure out what move to make on this one. I suppose I could disassemble the lathe, and try to machine the  bottom of the casting. I mean, it's not like I spent hours and hours fine tuning it, and dialing the twist out of it or anything. Heaves to Betsy no! This shining example of the output of the People's Republic of Perfection couldn't have ever had any such flaws!

I'm sort of halfway talking myself into machining some weird tapered blocks to bolt on the underside, so at least the top is a lot closer to being parallel to the bottom than it is now. That seems possibly doable, but I'd have to flip this "benchtop" machine on its back, and the last time I had to move this "benchtop" machine anywhere, I ended up renting a Bobcat.



Anyway, it was a rough day, and I zoned out and lost my train of thought. It happens. Discuss!


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## Nutfarmer (Sep 28, 2020)

Any chance of reworking the under side ways? I had to on my 6300 Clausing when the bed was re ground. Even a milled surface would be better than a raw casting. Let us know how it turns out.


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## dewbane (Sep 28, 2020)

Nutfarmer said:


> Any chance of reworking the under side ways? I had to on my 6300 Clausing when the bed was re ground. Even a milled surface would be better than a raw casting. Let us know how it turns out.


In a perfect world, I guess I would have about six strong, strapping sons who could just man handle the thing onto my little g0704's table, and hold it up while I hog off some material with a perfectly balanced carbide endmill that would never shatter. I would never have to worry about anything again, because from that point forward, a miniature leprechaun riding on a flying unicorn would rush to the rescue to solve all of my machining challenges with rainbow magic.

In the real world, what? If I had a good idea, I would have just done that, and bragged about it.

Sigh.


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## Nutfarmer (Sep 28, 2020)

I used a grinder and a file. I agree that in a perfect world we could send it off and have it ground. None of us live in a perfect world ,but I have seen some members do some fantastic work with less than optimal equipment. I am amazed at the work sometimes.


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## Mitch Alsup (Sep 28, 2020)

An Idea:: on the clamping side of the clamping thingie are two little ledges (one on either side). If you could affix (glue) some abrasive {Paper, stone, file} onto those ledges, you can then use the tailstock and push/pull/run it up and down the ways, slowly tightening the clamp, and have the abrasive on those little ledges slowly remove material that is preventing smooth operation.


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## jwmelvin (Sep 28, 2020)

My g0602 has the same issue. I’d also like to fix it. I do have an engine hoist to lift things. I’m thinking that lifting the tail stock end would allow access to find the high points of the clamping surface and ease them a bit with a grinder and/or file.


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## RJSakowski (Sep 28, 2020)

dewbane said:


> I use the tailstock on my g0602 constantly, and it has been driving me nuts for the longest time.
> 
> One of the more common things people do is just leave a 17mm wrench on the tailstock at all times. I've read lots of posts in various places, talking about how "it only takes half a turn" to snug the thing down.
> 
> ...



I  have the same issue with my 602.  I suspect that the top side and under side of the ways were milled into the casting and in grinding the top side, the parallelism was lost. 

I measured the thickness of the front side of the ways and got a minimum thickness of .6282" at the far left and a maximum thickness of .6444" in the center for a difference of .0162".  

Rather than trying to machine the underside of the bed, consider changing the clamping bolt.  The OEM bolt is a 3.5" M12-1.75mm bolt.  This amounts to ..0689"/turn.  A 1/2-13 bolt has a pitch of .0769".  In turning the nut from full lock  to loose within the confines of the tailstock casting allows around a 170º rotation and 170/360 x .0689 =.0325".  On my lathe, I required about another 1/12th turn or 30º.  200/360 x .0689" = .0383".  Substituting a 1/2-13 bolt, 170/360x.0769 = .0373" which was enough for the cross slide to freely traverse the ways.

If the 1/2-13 bolt doesn't provide enough range, a 1/2-12 Whitworth bolt  has a pitch of .0833".  170/360x.0833 = .0393" which should be more than enough.  Finding a  3-1/2" 1/2-12 Whitworth bolt may be a bit challenging but we have a lathe, right?  1/2-12 Whitworth nuts are available on eBay.

If I were making a bolt, I would make it with an oversized rectangular head.  When I looked at the bearing surface of the clamping plate, I noticed quite a bit of wear due to the small contact area of the bolt head.  Making a rectangular head of 3/4 x 1" would vastly improve the bearing surface.  For those going with the 1/2-13 UNC bolt, McMaster Carr sells square head bolts.


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## dewbane (Sep 28, 2020)

Nutfarmer said:


> I used a grinder and a file. I agree that in a perfect world we could send it off and have it ground. None of us live in a perfect world ,but I have seen some members do some fantastic work with less than optimal equipment. I am amazed at the work sometimes.


A miniature leprechaun riding in on a flying unicorn. I have to laugh at myself. I hope you took that in the silly spirit I intended, because it sounds a little snarky to me now. Anyway, as far as less than optimal equipment, I'm pretty happy with my g0602 and g0704 on the whole. There are limits, but they're pretty high, really.



Mitch Alsup said:


> An Idea:: on the clamping side of the clamping thingie are two little ledges (one on either side). If you could affix (glue) some abrasive {Paper, stone, file} onto those ledges, you can then use the tailstock and push/pull/run it up and down the ways...


That idea has merit, but that would be more for fine tuning after I work out some way to hog off about 0.100" from the high side. As far as that goes, when I think about it, this casting is already a little funky. There are some discolored areas out toward the far right that refuse to clean up with stones, because they're places where material contracted after it was machined, leaving low spots. If I create new relief in this wonky casting that clearly has weird stresses in it already, I might really screw things up. Hmmm. Better would be devising a way to add material to the low spots.



RJSakowski said:


> Rather than trying to machine the underside of the bed, consider changing the clamping bolt.


That is a line of thought I hadn't considered at all. More travel per turn could indeed make the problem go away. As screwy as the casting is on the bottom, I'm not having problems turning tapers or drilling holes off axis or anything. The clamping mechanism absorbs the error well enough. I just need a clamp that moves more for less wrench travel. If a normal thread won't give me the travel I need, I can just make one up from scratch, like a 1/2"-4 McIntyre thread or something just stupid. Intriguing. Of course, I haven't gotten around to learning how to thread yet.

Well thanks for all the ideas, guys.


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## hman (Sep 28, 2020)

I definitely agree that you have a problem on your hands.  This sounds incredibly bad for a name brand lathe!  How long have you owned it?  I'm wondering if Grizzly is letting their quality control slip?!?!

No idea how to approach the roughness problem.  Just a caution ... Most cam locks I've had experience with have had pretty limited travel.  I don't know if it's practical to build one with enough range to handle a surface as rough as you describe yours to be.  If it has too much range, it may not have the leverage needed to hold securely.  Best wishes solving your dilemma.


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## dewbane (Sep 29, 2020)

RJSakowski said:


> If the 1/2-13 bolt doesn't provide enough range, a 1/2-12 Whitworth bolt has a pitch of .0833". 170/360x.0833 = .0393" which should be more than enough.


So I scrounged a 1/2"-13 bolt in my mystery parts box, and doctored it until it met parameters. Good enough for testing purposes. It did offer a negligible improvement, and I'm going to leave it on there and get to work on something else.

After surfing McMaster-Carr for awhile, I settled on 1/2"-10. I picked up a 6" lead screw, a brass nut, and a hex nut for a total of about $30. I plan to machine the nut to fit the slot in the bottom clamp, and Loctite that end of the lead screw into the nut to make my T, then just use the standard hex nut up top. It has a 7/8" head, same as my toolpost, so that will be convenient. If I don't have enough clearance for a nut that big, well, I guess in that case I'll have something to figure out.

I think this will get it. I lose all credibility as a machinist by buying the stuff from McMaster-Carr, but another way of looking at it is that if you like McMaster-Carr as much as I do, I have a duty to do my part to keep them in business, and I am carrying out that duty here. Plus I had to order some oddball drill bits anyway.

PS - I wonder if I'm going to be able to clamp a 1/2"-10 acme screw in a 5C collet. Hmmmmmm. I ordered the shortest length they stocked, which was 2" too long. Cut it off with a bandsaw, and ideally I would like to mount it in the lathe and put a nice round top on it, like my Aloris toolpost. Not really critical, just attractive. I mean if I can't, I'll just have to freehand it into the bandsaw. Do not want to booger up the threads to make the end pretty!!!


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## dewbane (Sep 29, 2020)

hman said:


> How long have you owned it?


My wife hadn't left me yet. She's been gone going on three years. Call it three years? Going on four? The deal I've been whining about in this thread is definitely annoying, but it isn't causing me any quality of work problems. (No, my sheer incompetence is causing me quality of work problems!) Grizzly is a name brand, but realistically, it's the Asian import that has a manual written in English, and possibly higher than average quality control. It ain't South Bend. (Irony intentional.)


> No idea how to approach the roughness problem.  Just a caution ... Most cam locks I've had experience with have had pretty limited travel.  I don't know if it's practical to build one with enough range to handle a surface as rough as you describe yours to be.  If it has too much range, it may not have the leverage needed to hold securely.  Best wishes solving your dilemma.


I keep looking at the cam lock on my dusty, little-used wood lathe, and I just can't see it. As annoying as it is to use a wrench, it's not uncommon for me to start pushing the tailstock back with the tailstock quill, and having to go snug it down. A cam lock just wouldn't have enough grab, even if I improved the roughness of the casting.


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## John281 (Sep 30, 2020)

Expanding on what Mitch suggested, you could epoxy a couple of scrap files to the ledges on the clamp plate then gently slide the tailstock with light clamping pressure to remove the high spots.  Use heat to remove the files from the clamp plate later.  Switch to sandpaper for a smoother finish.  Sounds like you might want to replace the clamp plate anyway.  Not an ideal solution but it might work well enough.


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## RJSakowski (Sep 30, 2020)

I looked at the underside of my 602 and the tailstock clamp rides on a milled surface.  Cast iron pieces are usually cast in sand molds and finishes would not be suitable for a bearing surface.

After examining the clamping block, I decided that I needed a square head bolt to provide more contact area.  I found an old 5/8" square head bolt formerly from a utility pole.  The head was 15/16" and the clamp slot is nominally 3/4", actually .793" so I ground the head down to .785 across one side and reduced the other side to .895" so that I could insert it into the 1.19 bore of my 3 jaw chuck.  I cut the shank to 3.5" and turned enough of the shank to .500" to fit my chuck jaws. Then I reversed the bolt with the head inside my chuck and I turned the remainder to .500".  Then I single point threaded 1-1/2" of the shank for 1/2-13 tpi.



The bolt provides a much crisper clamping due to increased surface area.

The ironical thing is later this afternoon, I happened to pick up a bolt salvaged from a defunct HF caster. https://www.harborfreight.com/6-in-rubber-swivel-caster-61844.html.  It was a nominal 1/2" in diameter but the threads weren't 13 or 20 tpi.  At the time I salvaged it, I assumed that it was a metric thread.  Checking it with my thread pitch gage, it wasn't metric.  Actually, it was a perfect fit for 12 tpi!  A close visual examination showed the threads were 55º.  A 1/2 -12 tpi Whitworth bolt and 3-1/2" long to boot.  The bolt head measured out at .799" across the flats, about .010" too large to fit the clamp slot but that is easily remedied. Who'd have thunk?


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## dewbane (Oct 1, 2020)

I got the parts, cut one end off the lead screw, machined the square nut to fit, and put it all together.

In the plus column, the clamping action on that acme screw is really nice, and it takes about half as much wrenching to move the tailstock around. It's definitely an even better step in the right direction, and as a bonus, using the same wrench as my tool post means one less wrench to juggle.

In the minus column, it was still only an incremental improvement. If I start with the tailstock snug at the far right, back it off half a turn, and slide it, it doesn't go far before thunking to a halt. Back off more, keep sliding. Same song and dance. Fewer turns of the wrench for sure, but still enough turns to be really annoying.

While watching a random Youtube video, I got an additional idea. Somebody made a casual, passing reference to putting a spring in this setup. I have plenty of clamping oomph to overcome a spring without it being bothersome. I'm going to conduct an experiment to see if throwing a spring in here will improve anything. Easy enough to try.


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## RJSakowski (Oct 1, 2020)

I had a similar problem with the G4000 and I put a spring between the clamp and the tailstock. It did help a little but I still had binding.


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## RJSakowski (Oct 1, 2020)

I modified the 1/2" Whitworth bolt to fit and it provides slightly more range.  It has a 15/16" hex head so there is only slightly more bearing surface than the OEM bolt.  Additionally, the nut is also 15/16" which means a additional larger wrench.  For those reasons, I decided to stay with my solution in post #13 above.

I decided to make a dedicated wrench for the tailstock clamp.  It would remain on the nut removing the hunt for it when I needed to clamp the tailstock and would always be in the correct position for tightening.  For starting materials, I used a 3/4" 6 pt. socket from a cheapie 3/8" drive set that I had bought years ago as an emergency set for my truck.  For the handle, I used a broken 1/4" ratchet.  I removed about .150" from the top face of the socket and drilled socket slightly deeper to accommodate the protruding bolt threads.  Then I milled a .375"w x .375"d. slot in the top of the socket.  Next, I welded the ratchet handle in the socket and cleaned up the welds.  Here is the result.





Just over 120º of rotation is required to go from full lock to full travel on the ways.  The wrench has about 170º of motion.  The handle is short enough that it doesn't interfere with the tailstock crank and it is happy to sit in place while using the lathe. If needed to be removed for ome reason , it wrench slips on and off easily.


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## dewbane (Oct 3, 2020)

RJSakowski said:


> I decided to make a dedicated wrench for the tailstock clamp.


I totally love the idea. Sadly, even replacing the bolt with a 1/2-10 acme screw, and putting a spring on it didn't get my machine to a point where 120º would be a useful amount of rotation. I either need to go even more ridiculous on the travel or live with it until I can alter the underside of the ways. If I could think of an efficient, secure, and non-destructive way of just adding meat to the underside of the ways, this setup I have now would be the cat's meow. It's just that the difference between the "parking" position at the far right and the "useful" range toward the middle is so insanely extreme on my particular lathe. Based on what people have commented, I have to conclude that my particular example is a lot more crappy than is typical. Of course it is. I mean, that's my luck, right? I marry a woman, serve her faithfully for 24 years, and she cheats on my trusting ass, even though I thought she was a unicorn. Oops, I'm having a pity party again.


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## GunsOfNavarone (Oct 3, 2020)

Also, take a look at the step on the clamping plate. My G602 had jagged edges and the step "machined" into the plate wasn't straight. You might be able to make some improvements there. I like Grizzly, but I have gotten some unusable pieces/parts from them. Kinda scary the QC that happens somewhere along it's long travels. Seems like you could just lift one side of the lathe (tailstock side) and clean up the underside of the ways, assuming it's something that can be cleaned up.


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## RJSakowski (Oct 3, 2020)

dewbane said:


> I totally love the idea. Sadly, even replacing the bolt with a 1/2-10 acme screw, and putting a spring on it didn't get my machine to a point where 120º would be a useful amount of rotation. I either need to go even more ridiculous on the travel or live with it until I can alter the underside of the ways. If I could think of an efficient, secure, and non-destructive way of just adding meat to the underside of the ways, this setup I have now would be the cat's meow. It's just that the difference between the "parking" position at the far right and the "useful" range toward the middle is so insanely extreme on my particular lathe. Based on what people have commented, I have to conclude that my particular example is a lot more crappy than is typical. Of course it is. I mean, that's my luck, right? I marry a woman, serve her faithfully for 24 years, and she cheats on my trusting ass, even though I thought she was a unicorn. Oops, I'm having a pity party again.



Have you measured the actual thickness of the bed?  It can be measured with a micrometer.   (the drawing is for reference only and the dimensions are not to be taken as accurate) As I had stated, I measured approximately a .015" difference along the ways on my 602. 



The best way to eliminate the problem would be to tear down the lathe and recut the bottom surface with a T slot cutter.  It would require something like a 1-1/2" cutter.  Not cheap.  You would also have to mount the bed on the mill and shim it up to make the upper flat surfaces parallel to the mill table.

An in situ solution might be to scrape the bottom surface with a custom scraper.  I would envision a tool with a top plate that matched the geometry of the bottom of the tailstock and a bottom plate with two HHS or carbide cutters.  The distance between the plates would be controlled with opposing screws like a machinist's clamp.  The scraper could be coupled with the cross slide to allow for power scraping.



The third option is to just live with it. 

I can relate to your marital woes.  My ex decided to start cheating after 22 years of marriage.  It took some time to finally get her out of my life but I have since remarried and prospered now that the mill stone was removed from aroud my neck.  Going on 22 years with the second wife now.


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## ljwillis (Oct 3, 2020)

I have the Jet version of this lathe and it had the same problem.  The casting for the lock was horrendous, and it would always bind.  It wasn't flat and it didn't match the underside profile.  Still, I found that much of my problem was paint on the sides and underside, but there were some rough spots that I took care of with a file in an improvised jig.  
The original lock would bind due to the offset that you describe, and a spring didn't cut it.  I machined a much larger, heaver one that kept it guided so it would not rotate and bind, and machined the steps to match the offset.  The bottom of the tailstock also was far from flat or matching the vee, but I brought it in by filing and scraping.  Now I can adjust it to <90 degree turn of the nut to lock it, and it never slides when locked. 
Vast improvement in enjoyment operating this lathe.


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## dewbane (Oct 4, 2020)

RJSakowski said:


> Have you measured the actual thickness of the bed?  It can be measured with a micrometer.


I have. I forget the measurement, but it's something approaching 0.100". Good suggestions. Nice drawings.


> I can relate to your marital woes.  My ex decided to start cheating after 22 years of marriage.  It took some time to finally get her out of my life but I have since remarried and prospered now that the mill stone was removed from aroud my neck.  Going on 22 years with the second wife now.


My heart is lonely, and I want to find somebody, but that just isn't a problem I have the right skills to solve. I decided to turn my focus toward my shop. I also decided to get off Facebook and hang out in places like this instead.



ljwillis said:


> Vast improvement in enjoyment operating this lathe.


That replacement clamping plate is a very interesting idea. I started thinking about what I have on hand I could use to make one, and hit on this half of a truck leaf spring I picked up one day. This got me started thinking about how the clamp would perform if I left the curvature as it is. I don't know. That's worth some experimentation. You can't beat the price I paid for the steel anyway.


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## RJSakowski (Oct 4, 2020)

ljwillis said:


> I have the Jet version of this lathe and it had the same problem.  The casting for the lock was horrendous, and it would always bind.  It wasn't flat and it didn't match the underside profile.  Still, I found that much of my problem was paint on the sides and underside, but there were some rough spots that I took care of with a file in an improvised jig.
> The original lock would bind due to the offset that you describe, and a spring didn't cut it.  I machined a much larger, heaver one that kept it guided so it would not rotate and bind, and machined the steps to match the offset.  The bottom of the tailstock also was far from flat or matching the vee, but I brought it in by filing and scraping.  Now I can adjust it to <90 degree turn of the nut to lock it, and it never slides when locked.
> Vast improvement in enjoyment operating this lathe.
> View attachment 339290


Your casting looks much worse than mine..  I could see how it would be problematic.


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## ljwillis (Oct 4, 2020)

I was just using the lathe and remembered that a big contributor to the problem was that the factory clamp didn't use the entire bearing surface on the underside of the bed and most of the rough spots were to the inside.  When I made the new clamp it ended up being considerably wider than the factory clamp.  I managed to find the old one (I don't throw anything away haha) - the difference is stark!


This is the roughest spot on the bed.


This shows how the new clamp bridges the rough spot and bears on the machined surface closer to the rib of the casting.


This shows how the original clamp was too narrow and would land right in the rough spot.  Worse yet, because it is too narrow it tends to spin and ratchet.  There's almost  1/8" all around this thing, it is far too loose.
Take a close look at yours, I wouldn't be surprised if you find it's the same issue. 
It took me a long time to properly diagnose this and I tried a few kludge fixes before doing it right.  I know I had to square up that shoulder with a file, too, but I don't have any "before" photos.  It was worth it, though - now finger tight on that nut is good enough for small drills, even!


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## dewbane (Oct 4, 2020)

ljwillis said:


> Take a close look at yours, I wouldn't be surprised if you find it's the same issue.
> It took me a long time to properly diagnose this and I tried a few kludge fixes before doing it right.  I know I had to square up that shoulder with a file, too, but I don't have any "before" photos.  It was worth it, though - now finger tight on that nut is good enough for small drills, even!


You're probably right. Having recently reassembled the clamping setup several times, I'd say the part in question is pretty sloppy. When I head out to the shop later, I'm going to scrutinize all of this more carefully.


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## ljwillis (Oct 4, 2020)

dewbane said:


> You're probably right. Having recently reassembled the clamping setup several times, I'd say the part in question is pretty sloppy. When I head out to the shop later, I'm going to scrutinize all of this more carefully.



Good luck, this problem was driving me insane and it took a lot of head scratching to even figure out what the real problems with the mechanism were.  

I recommend inspecting the underside of the tailstock, too.  Mine wasn't flat and would rock, so it would take a lot of clamping force to make it stay put.  I blued it with dykem and found very little bearing against the bed.  If you try to correct it, be mindful that you might induce a permanent misalignment in the tailstock ram with respect to the spindle axis, but if it doesn't sit flat it can't possibly be aligned, anyway!  My taper adjustment was useless, too, and I took care of that at the same time.  Just remember these machines should be viewed as a kit if you want them to run like a proper precision tool haha.


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## GunsOfNavarone (Oct 4, 2020)

You know, as much as it excites me to see this manufacturer short coming and wanting to fix it...I’m finding I’m spending 80% of my shop time making tools or improving machines....both are very valuable, don’t get me wrong. I really want to start spending my time making things that don’t live in the shop. I wasn’t here.... I never saw any of these improvements...


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## dewbane (Oct 4, 2020)

GunsOfNavarone said:


> I really want to start spending my time making things that don’t live in the shop.


I can relate. I've spent most of my shop time making improvements to my machines too. That's always the thing with stuff like this. If you want something really good, you have to pay through the nose. I kind of have a foot in both camps on that one, as I just went through a round of replacing Chinese stuff with American stuff. Industrial Air compressor, Kurt DX4 vise, Aloris tool post. Getting American machinery is just beyond my reach right now though. Plus I'm pretty deeply invested in these machines at this point. They're mine. I made them so.


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