Anyone ever fix the g0602 tailstock screw-out problem?

[dewbane]

On more than one occasion, I have accidentally screwed my tailstock quill out too far. One time, I did this with such enviable grace and aplomb that I had to either make or buy a new tailstock lead screw, and a new tailstock quill. Before you become too in awe of my awesome machining skills, I'll go ahead and admit that I bought the parts from Grizzly.

While working in the shop just now, even though I'm fully aware of the problem, and this issue has already cost me a lot of Abraham Lincolns for parts, I went and screwed the damn thing out too far AGAIN.

It's obvious that I'm not going to stop doing that, so I need to do something about this quill screwing out. Surely I am not the only moron with one of these lathes who keeps doing this. I'm writing in the hope that someone already fixed this, and their fix worked really well, and they are super proud of their ingenuity and stuff.



The heart of the issue is the way they milled this slot from the end. If they had plunged the endmill in and machined it like a keyway, this would be a non-issue. I know the world class machinists at Shang Dao Machine Making Corporate Company can doing make keyway, because my machine are have many keyway make in that honorable fashion. This quill no am make like keyway, and that creating is problem.

The bits drawn in red are how it should have been made. I just stood there and looked at the part for a few minutes, and I'm not really thrilled with any of the ideas I've had for putting some material there. I could tap and drill for a set screw. I could try hitting it with the wire welder to put a good blob or two at the end of this slot. Maybe I could build up something with brazing rod, and machine it into shape. I guess I could totally go cheap cheap and just stick a blob of JB Weld right there. I might do that, actually. JB Weld solves a lot of stupid problems, doesn't it?

Well, I'll drop this off for the Peanut Gallery while I go try not to butcher my third and final attempt at making a 29-tooth gear. I ain't wasting no more perfectly good alumniums on this demonstration practice project, so either way I go, I am done.

 

[Aukai]

I have gotten carried away and popped the quill out more than once, and the keyway turns sideways, and getting it aligned again is not fun with an 14" MT3 drill bit hanging out of it. The channel has to be open to get past the key, unless it can be disassembled from the back.

 

[dewbane]

The channel has to be open to get past the key, unless it can be disassembled from the back.

It's not a key though, it's just a set screw, and there is no problem screwing it all the way out. I figure it would be a little harder to get aligned blind with this mod, but there would be less need to align it blind, since it wouldn't be screwing out every time you turned around.

The other thing I thought about was making some kind of L bracket thing, and screwing it to the tailstock. Doable, but one would have to be cautious not to drill too far. I prefer the idea of putting back the metal that never should have been machined out in the first place.

 

[Aukai]

Mine is a different brand, but it is irritating though

 

[Lo-Fi]

Looks like there's enoug meat to drill and tap axially for a small machine screw securing a little plate to cap the end?

 

[Mitch Alsup]

I might drill a small (0.0984 #40) and push in a 0.100 pin

 

[hman]

Looks like there's enoug meat to drill and tap axially for a small machine screw securing a little plate to cap the end?

Actually ... you could just drill & tap (radially) down inside the end of the slot and insert a setscrew (with blue Loctite to retain it), so its end is just below the level of the outer diameter of the barrel.
-Or-
If you could find a socket head cap screw whose head was just slightly less than the width of the slot, you could D&T, then tighten the screw down, then file down the head as needed to match the curvature of the barrel.

 

[Flyinfool]

Forgive me, I do not have this machine. But I am very curious as to what gets destroyed, and how, by screwing the quill out to far?

I do that to my Jet lathe all the time and just have to put pressure on it and screw it back in. It is just a 2 minute irritation.

 

[RJSakowski]

One of the modifications that I did was to add an iGaging DRO to the tailstock. This prevents the quill from rotating even if the quill were to be extended past the keyway engagement. If I extend the quill to far, I simply push it back while rotating the screw in reverse. The process takes only a few seconds.

As far as overextension goes, both the cross slide and the compound can be overextended in the same manner and the solution is the same.

 

[dewbane]

One of the modifications that I did was to add an iGaging DRO to the tailstock. This prevents the quill from rotating even if the quill were to be extended past the keyway engagement.

I can see that. That would be an excuse to start adding DRO.

As far as overextension goes, both the cross slide and the compound can be overextended in the same manner and the solution is the same.

Overextension in those cases has never caused harm to the lathe though, so I haven't given it any thought.

Forgive me, I do not have this machine. But I am very curious as to what gets destroyed, and how, by screwing the quill out to far?

I was plunging a 37/64" drill bit into the stock to make a series of bushings that were on the order of 3/4" long. Drill out inside, turn outside, part off. I got greedy trying to go too deep in a single operation. I screwed the tailstock out too far, and that fat drill started spinning my entire quill. The threads on the lead screw and quill did not like that very much.