Myford 254 Apron

I am putting a 254 together and have run into a problem with the apron. When I tighten the bolts (M8 I think) that hold the gearbox under the apron to the cross slide, the apron becomes impossible to move. When they are loose the apron moves freely.

I can't think what needs to be done to correct this. Any help will be appreciated.

Chris Harris

Hi Chris,

Welcome to the forum. Is it locking because the half nuts are gripping the leadscrew or could it be distorting or jacking up the saddle?

Neil

Chris

Do you have the 254 manual?

Silly comment, but if either the cross feed lever (10) is raised, or the leadscrew feed lever (9) lowered, either will lock the apron/saddle from longitudinal movement.

Is the saddle clamp screw (15) slackened off?

Also, do you need to slacken off the gib strip at the rear of the saddle (1)?

Don't know the 254, but obviously something is out of line.

Have you put everything back in the right order, and in the right place?

Insult.

The half nuts are not engaged in the Leadscrew,?

Is it possible to engage the feed when this is the case?

Is the Saddle Lock engaged?

Or the power Cross Feed?

if it has a separate feed shaft as well as a leadscrew, Is the worm housing misaligned and causing the lock up? If it is, you will have the fun of slackening off the screws that hold the worm housing to the apron, to allow to align with the feed shaft before retightening them.

"Fun" is a relative term, based on my experience with another lathe!

HTH

Howard

Where are you located Chris?

Thanks for the help.

The half nuts are not engaged

The saddle lock is not tightened

The cross feed is not engaged

The saddle gets increasingly more difficult to move as one tightens the two M8 bolts. It is almost if it needs some clearance.

I am going to fiddle with it a little more so as to provide you with better description.

I do have a parts beakdown for the 254

This particular 254 is a one of a kind. It was the only prototype ever made and Chris Moore gave it to me when the factory closed. So I really want to get it working.

I live in Fargo, North Dakota USA

This sounds a bit like a S7 problem as well. Try moving the saddle to the extreme right; close the half nuts REALLY TIGHT, and then tighten the M8 bolts. It solved a problem on my lathe - Malcolm Townsend suggested it - might work on the 254 as well?

I think the likelihood is is that clearance between the hand feed gear and the rack on the lathe bed is insufficient. It's possible that as a prototype this was not perfectly aligned. I don't know if you can adjust clearance easily, or perhaps raise the rack slightly, if not you will need to fit a shim between the apron and saddle.

Otherwise, the 254 is unusual in having very small clearances around the apron. I'd suggest using a feeler gauge or similar to check there are clearances in all the necessary places.

It also has a saddle that is particularly massive in construction, so I think the apron causing it to distort is unlikely. Loosen the apron just enough that you can move it. If it is possible to move it around when almost locked in place it is unlikely that it is rubbing somewhere, which does then leave the final possibility it is causing the saddle to warp.

Neil

This is good advice. I will try it out. I think you are on to something with regard to the apron impinging on the rack.

Was the machine in one piece and working ok? If is was dismantled when you got it it may have lost some shims or a packing piece.

Mike

No, it had missing parts. I had to assemble parts for the compound and so I. I am pretty certain that this is the problem. I never had any shims. I will make some up and get it properly fitted. Any idea how many shims are typically used?

The 254 has laminated shims between the left and right hand keep plates and saddle, they look like washers the fixing bolts go through them.

The above refers to the saddle adjustments fitting.

Mike.

Edited By MichaelR on 30/08/2019 15:11:57

Edited By MichaelR on 30/08/2019 15:13:23

The problem was the missing shims. It needed just another 0.010" each side. Thank you so much for the help. I am looking forward to getting this lathe working.

It is nice to know I have this resource for Myford machine tools. Chris Moore used to help me with all my questions but since he has gone I have been stuck from time to time. I do miss the man.

Thanks again,

Chris

Glad that you got it sorted!

You will always find help on here. Either the solution found by someone who has already had the problem, or suggestions as to how to solve it. There is an almost infinite pool of knowledge, skill and experience on here.

That's what makes the Forum so great, and addictive!

Howard

Edited By Howard Lewis on 31/08/2019 11:51:47