What is wrong with my lathe?

[John Hill]

Probably nothing really and actually a problem with the operator!  But anyway, I get set up for a nice cut and everything is humming along nicely then the cross slide handle does a sort of 'flop' and I get a mark on the work.

I think it is because the handle is not balanced?  Lets say the handle is at the 11 o'clock position then partway through the cut the handle flops down going to the other end of the backlash and thats what makes the mark.

John Bogs has the same lathe and I just bet his never does that   

[bogstandard]

It surely used to, but not any more, I tweaked up the gibs and adjusted the split lead nut to tighten it up, it must have been a couple of hundred years ago, it was one of the first things I did on the lathe.

The handle does wobble a bit, but I take no notice of it because I only use my DRO for settings, not the dials.
I was only discussing it this afternoon with Darren when he called.

One of the jobs to be done in the future is to fit a couple of thrust bearings to get rid of the backlash.


John

[Davo J]

John H
As John said tighten the gibs up and that should fix it.
John B
If your lathe is like mine it would already have thrust bearing in there, (the type that has the 2 hardened grooved washers and the separate round cage of ball bearing). I used shims to take up the backlash in mine, doesn’t take long to do.
Dave

[bogstandard]

Thanks Dave, never having stripped it down, I didn't know what was in there.

I suppose I should read the destructions one day.


Bogs

[Davo J]

If I remember right, I used some of the left over shims from fitting my power feeds on the mill.
Also if you need to get the cross slide screw out for any reason the drive gear (under the sheet metal plate) is held on by a grub screw and comes out by sliding it to the rear. I found this out after never seemingly being able to get the nut adjusted right, I investigated and found that the cross slide nut needed to come down, as it was 1.1mm too high. After fitting a made up shim, it now runs smooth and have not had any more problems with it since. Might be something for you  and others to check on?
 I found this problem with my mill as well 1.0mm shim on the X and a 1.2mm shim on the Y.
Dave

[bogstandard]

Many thanks for that Dave.

Before I do any more projects, I will most probably have a look at it.

Can't do it right now, I am just turning up some special t-nuts to finish off the chuck fixture for the RT.

John

[John Hill]

Well I guess I do not have to worry too much! Thanks Dave and Bogs.

 According to my diagram in the 'manual' there is a bearing in there but tightening up the collar enough to take the slop out means the index ring is impossible to use so I will be taking a look in there 'one day', meanwhile I will continue what I have grown accustomed to and that is holding the handle when doing a fine cut.

[bogstandard]

Don't worry John,

Piccies in books can be notoriously misleading.

As I said, I have no need to 'fix' mine, but I will. So when I strip mine down, I will show you what is in there, and see what can be done to cure the problem.

The only problem I can envisage, I might need a lathe to fix the lathe. We will see.


John