Faceplate was the cause

Hiya all,

you may remember my issue with work pieces not being centred in a three jaw chuck.

low and behold, the chuck had a a wobble not only that the face plate had it too.

took it off and there it was, the hole on the faceplate was off.

So I ditch it.

Now I need a new one but I want to fit a 100mm chuck.

Where can I get a proper faceplate from?

What lathe was it Becky ?

whether the faceplate is out of true or not, surely you use a DTI or something similar to center work pieces so that they run true ?

can you not simply turn the faceplate so that it does run true ?

from what ive learnt over the small amount of time ive put in ive learnt that you dont rely on chucks or faceplates to ever be true to your spindle unless you have worked them to be so

Z

Edited By Ziggar on 03/02/2014 00:20:04

With a self centring chuck, it helps if the faceplate is centred.

But if you can see with the naked eye that it's off then you're on a loser straight away.

i think it's an ML 7 or 10.

problem is that it's been modified, very nicely modified, but just not sure which it is.

I've posted pictures of the gears on this forum before.

It's about 1000mm long if that helps.

Yes i remember it now I think it was an ML4 but as you say modified.

problem is what spindle nose it has.

if its a ML7 then quite a few people do backplates but if it's the ML4 it has a smaller thread and no register, or is that the same thread and no register.

Can you get some pictures please?

Also Becky i think you have your descriptions mixed up.

A faceplate is a disk with slots in the bolt things to but you don't bolts chucks to this. chucks normally fit on a backplate which is a plain disk with holes for the chuck.

When these are new you need to skim them on the lathe concerned to true them up to the spindle, then fit the chuck.

No off the shelf backplate will run dead true without doing this.

Yep, I mixed them up. It's a back plate.

i'll take picture soon as.

well the threaded hole which screws on to the main shaft was off. So skimming the face wouldn't have done anything.

What's a register?

The plain bit behind the thread if it has one.

This is an ML4 spindle with a thread and the register [ plain bit ] at the same diameter.

**LINK**

This is the ML7 with the register bigger.

**LINK**

So which do you have ?

BTW Becky, sent you an email yesterday about something unrelated to this.

Ah,

if my memory serves me well, the shaft is the same size all the way.

the smooth part from the thread is no bigger

OK so you want a backplate for a ML4 series and I don't think any of the normal suppliers does that one but it is the same thread as the ML7 so you could always fit a spaced to take the register from 1 1/4" back to 1 1/8"

Let me check tomorrow and see if i do have any early plates. is your live.co email still valid ?

John,

7/8 rings a bell.

so it's possible that one isn't available? That's not good, being naive but can't any with 7/8 thread be used?

becky

It's a matter of who uses 7/8" whit.

This is all real hazy and 7/8" does also ring a bell with me but there was a model that used the same modern thread 1 1/8" Whit form but did not have a register. In fact in that top link you can see it clearly and that is not a course whit form.

Lathes.co.uk has this to say about it.

"Lathes with the smaller 1-inch diameter spindle carried a 7/8" diameter 9 or 12 t.p.i. thread while the larger were equipped with the same 11/8"12 t.p.i thread used on the post-war ML7 - though some examples of the latter have been found without the step-up register behind the thread as found on all 7-Series machines."

But to be honest I have never seen a ML4 with a register.

Becky,

Look at Lathes.com and compare the piccies of lathes to ascertain exactly what you have. From memory, I think ML10 has a solid bar of mteal for a bed but ML7 + ML Super 7 have 2 strips of metal forming the bed - crude description - railway line like! I think ML4 also like this. ML7 also has a large clear lubricator each end of the mandrel - main spindle.

John

Why not skim the backplate to true it up and refit the chuck?
You could then centralise the chuck on the backplate with a DTI... or have I missed something?

Martin.

hi becky, there is always another way thread a lump of steel same as the mandrel nose or get someone to help you do this, then locktight it on to the mandrel.then turn up a new nose to suit say ml7 ml10 chucks plates ect

I'm with Martin on this Becky - why not just skim the backplate?

Regards,

IanT

Hi Becky!

For what my advice is worth, try the following.

Before fitting any Chuck or faceplate, or anything else, to the Mandrel, always ensure that the thread and register are clean. Don't forget the thread in the Chuck or backplate, also!

An old toothbrush is handy for cleaning threads, (or Taps) in this way.

1) Screw the Faceplate onto the Mandel, (it may be worth marking, after skimming, the Faceplate and the Mandrel - if possible, so that in the future you screw the Faceplate onto the same point each time), and then lightly skim the face of the plate until it cleans up all over.

2) Having done that, then lightly skim the Outer Diameter of the Faceplate, until that just cleans up all round.

Those operations should cure your Faceplate problems.

If the three jaw, or four jaw chucks wobble, I suggest that you remove the Backplate. If the backplate has been removed previously, there ought to be pop marks on Chuck Body and Backplate that are in alignment.

Are there? Or if they are away from each other, remove the Backplate, clean the plate and the register in the chuck body, and refit it with the marks aligned, and check if it still runs out or wobbles when fitted on to the Mandrel.

If the Chuck Body and Backplate have not been marked, BEFORE separating, pop mark each one with the marks close together, so that when refitting, they go back in the same relative position.

Screw the Backplate on to the Mandrel and again very lightly skim the face until it cleans up all over.

Do not skim the Outer Diameter, or you will lose the concentricity of the chuck.

Remove it from the Mandrel, wash or wipe it clean, and refit to the cleaned register in the Chuck Body.

Incidentally, do not expect a workpiece held in a three jaw chuck to run absolutely concentric. A good chuck will be within 0.005 inch, a bad/worn one may be anything up to 0.030 inch or more.

If there are diameters or bores that have to be concentric, machine them at the same time, without moving the workpiece.

If this is not possible, then for the second operation(s) the piece needs to be held in the four jaw chuck and the original diameter clocked to run true before starting to machine the later ones.

Sorry if this latter bit is what you already know, and do, not trying to teach you, or anyone else, to suck eggs!

Good Luck!

Howard

This is is it.

regarding skimming the back plate, the hole isn't centre not at an angle. I am pretty sure it's flat.

Edited By rebekah anderson on 03/02/2014 12:38:46

Edited By rebekah anderson on 03/02/2014 12:39:09

Okay, so remove the chuck from the backplate (leave the backplate in position on the spindle) and slightly reduce the diameter of the register that holds the chuck 'central'. When you refit the chuck you will find it is not concentric, but can be made so by using a DTI either on the circumference of the chuck body or on a good piece of bar held in the chuck jaws. Just leave the backplate bolts loose(ish) whilst you nudge the body to its best location. It's a similar process to that used when using a four jaw chuck.

Martin.

hi my comment was ment as a last resort I had assumed you had done all the checks on threads ect lovely little lathe and well worth the time to get it right good luck

That's a very clean looking machine Becky! Very nice.

IanT