Inconsistent tailstock clamping surface thickness

[Dirtmover]

I have seen some projects where the lathe owner used a flat file with a simple jig to flatten the underside of this type of lathe, but that was to improve the saddle fit. It contacts the bottom in different places compared to the tailstock clamp, and they are much easier to get to. It _might_ be possible to lap the regions where the tailstock clamp goes but that could be very laborious, depending on how bad the fit is.

The surface is good, just tapered. The area is not huge, maybe each side is 10mm wide at most. I'm leaning towards trying 35mm diamond abrasive disc mounted in rotary tool. Should be easy to print a custom mount to hold the tool perpendicular and in the correct position. I don't expect it to be quick but it's got to be less laborious than messing around with a hand file and I'm not too concerned about retaining the existing smooth finish as it's just a clamping surface after all. I'll be happy to see the 0.6mm improved.

 

[Dirtmover]

Just to close off on this, space is tight in there and it doesn't need to be super precise so I decided to use a thin diamond grinding disc mounted in a rotary tool.
I purchased a couple of packs of 30mm discs, chosen because they're wide enough to grind one side of the clamping surface at a time without impacting the other.
I printed a custom holder for the rotary tool that rides on the top of the bed as a reference while allowing the underside of the disc to contact the clamping surface below.
I ran the tool back and forth along the ways to gradually remove material. Using Kapton tape as a shim I gradually increased the height of the tool/disc until I'd ground out that ~0.75mm taper along its entire length on both the front and back clamping surfaces.
Now, it was quite slow going and took 4 diamond discs and probably about 40 minutes of grinding in total over a few sessions.
It's probably not the best, most accurate or fastest way to do it but I'm happy with the results. The tailstock can now be locked along the entire length of the bed with the locking nut at the same angle.
Now to move on and make that cam lock for the tailstock and carriage lock I was originally planning.

 

[francist]

Nice fix!

 

[SouthernChap]

Just to close off on this, space is tight in there and it doesn't need to be super precise so I decided to use a thin diamond grinding disc mounted in a rotary tool.
I purchased a couple of packs of 30mm discs, chosen because they're wide enough to grind one side of the clamping surface at a time without impacting the other.
I printed a custom holder for the rotary tool that rides on the top of the bed as a reference while allowing the underside of disc to contact the clamping surface below.
I ran the tool back and forth along the ways to gradually remove material. Using Kapton tape as a shim I gradually increased the height of the tool/disc until I'd ground out that ~0.75mm taper along its entire length on both the front and back clamping surfaces.
It was quite slow going and took 4 diamond discs and probably about 40 minutes of grinding in total over a few sessions.
It's probably not the best, most accurate or fastest way to do it but I'm happy with the results. The tailstock can now be locked along the entire length of the bed with the locking nut at the same angle.
Now to move on and make that cam lock for the tailstock and carriage lock I was originally planning.

Now that's a great idea and one which, when I get round to doing Steve Jordan's carriage rigidity mod, I will use before hand.

 

[Dirtmover]

Now that's a great idea and one which, when I get round to doing Steve Jordan's carriage rigidity mod, I will use before hand.

I looked at Steve's mod a while ago and couldn't see an easy way to implement it with my 'H' shaped saddle. Plus the grinding I've done so far is perfect for what I intended but there's a lot more work to be done to get it ready for that mod.

 

[SouthernChap]

I looked at Steve's mod a while ago and couldn't see an easy way to implement it with my 'H' shaped saddle. Plus the grinding I've done so far is perfect for what I intended but there's a lot more work to be done to get it ready for that mod.

Ah, I don't have that cutout in my carriage.

The consistency of those inner, underneath surfaces on these mini lathes as regards surface flatness and thickness is dubious enough, that applying this grinding technique carefully can only improve things (it's certainly not going to make those surfaces worse ) for Steve's mod.

Artisan Makes is another useful youtuber who's done a bunch of mini lathe upgrade videos and he had an 'H' shaped carriage and I think for most of his upgrade videos, if not all, he only had access to a hacksaw and files. Might we worth seeing how he did it.