Attempting to make carriage lock functional on 8.5x18 lathe....

[62Scout]

After having my lathe for a few years, and just assuming that it never had a carriage lock because there wasn't anything obviously appearing as such, I finally took a look through the manual last night and found that the one odd hex head bolt on the top of the carriage was the saddle lock. Bolt has been tight since the day I got the lathe, and attempting to tighten it any more didn't do anything (I couldn't turn it any tighter without serious force on the wrench).

I've needed to clean the lathe for a while anyways, so I figured this would be a good time to tear it all down. Got the carriage off, pulled off the rails that go under the ways to hold the carriage down (not sure what those rails are called), and found that it looks like someone took a grinder to the section that the carriage lock bolt goes through.

I'm guessing that it shouldn't be like that, but I really don't know as I've never gotten this deep into a lathe before. The lock bolt threads into the portion between the relief cuts, which is also the section that appears have been ground down, and I'm assuming pulls up that one section tight into the ways when locking?

I'm betting this a part that's going to be easily replaced, and I don't have access to precision grinders, so I'm not going to be able to easily replicate this part...perhaps my best bet will be to do some kind of an add-on carriage lock to replace it?

 

[cathead]

The carriage lock is just a clamping device. It just has to pinch down the carriage to hold it in place. If the old lock has
been ground down, you could add some metal or make a new piece to fit. No real precision is required to make it work.
I'm sure you will figure it out. Good job on ripping into the carriage and cleaning too!

 

[62Scout]

The problem that I saw, or at least I think it's a problem, is that the lock is part of the same bar that holds the carriage down, as opposed to a separate piece just for the lock itself. Maybe that's why someone ground it down too...I wonder if maybe someone cranked on it too much, deforming the bar enough that it wouldn't fully unlock?

But that's why I was hesitant to try to make a new piece, or try to do something like weld it up higher then cut it back down..if I didn't get it dead flat, I was concerned that it wouldn't allow the carriage to slide freely or that it would make something else sloppy in there. My mill is a HF mini mill with the column that can be adjusted for angle, and I have constant problems with the head going out of tram. For what I do with it, it's not a big deal, but it does mean that high precision parts never happen either.

On the other hand, I've been meaning to make a carriage stop, and it may well be a good time to do an add on carriage lock as well.

 

[Bob Korves]

Put it back together and test for play when you lift the carriage, both front and back. There is often more wear in the most used area near the chuck. If you make it fit well there it may bind everywhere else. Make whatever adjustments you need, shims, new parts, etc. so it fits snugly at the tailstock end of the lathe, and you will just need to put up with whatever you get in the more worn sections. The only way to fix it is to properly recondition the bed ways and then fit the carriage for minimal play with easy motion of the carriage.