Thread: Face plate runout

Hi

A general query for the " experts "

When using a face plate. What would be an acceptable runout at the outer edge of the faceplate , of say 9" diameter ?

If there is any runout at all in the centre of the faceplate, or spindle, where the faceplate is fixed to the spindle , this error would be amplified at the outer edge .


Mike

Schlesinger says for a facing lathe, face plate run out should be maximum 0.06mm per 1000mm of diameter. Nothing for more normal beasts.

Michael

As a flate plate and my "trued up" on the lathe...... I'd say as close to nothing as makes no difference.
The next question is "how much runout is acceptable to you?"
Or am I not understanding the question again?

Stuart

Funny this question has come up. I was measuring my lathe runout last night and found on the outside edge of the spindle plate (ie. no chuck or faceplate installed). I measured a difference around 0.05mm between minimum and maximum readings.

I have been trying to find a good definition it ion of runout and I think I need to divide that reading by 2 to attain a runout spec making my runout being 0.025mm. Can an "expert" confirm?

Measuring the runout on the inside of the spindle taper, my DTI did not show any deviations. It is only accurate to 0.01mm so I was considering purchasing a more accurate one that could measure 0.002mm.

Originally Posted by rodweb

I have been trying to find a good definition it ion of runout and I think I need to divide that reading by 2 to attain a runout spec making my runout being 0.025mm. Can an "expert" confirm?

No expert here but I'd just go with TIR(total indicated runout). I think that will get your point across.
*if I understand the question

Stuart

Depends on how far out it is, if it's more than 0.1mm ( 4 thou ) I'd think about taking a skimming cut just to true it up. Less than that, it would depend on what you were making as to whether it mattered.

Oh, and don't forget there are two axes involved, radial and axial...

Regards
Ray

Originally Posted by Stustoys

No expert here but I'd just go with TIR(total indicated runout). I think that will get your point across.
*if I understand the question

Stuart

Is that what I measured? I saw stuff that said to halve observed runout to determine TIR.

Have you used the face plate before,if so was there any run out then.

If not then you must have some problem with the spindle register.

If this is the first time you have mounted the face plate then take a truing cut from the face and OD,if the rear of the plate is also running out and this distracts you also take a skim of the rear edge of the plate.

If you wish to just know what might be acceptable runout,then I would say what ever you would accept for a 4 jaw chuck,in most cases this would be none.

Originally Posted by RayG

Depends on how far out it is, if it's more than 0.1mm ( 4 thou ) I'd think about taking a skimming cut just to true it up. Less than that, it would depend on what you were making as to whether it mattered.

Oh, and don't forget there are two axes involved, radial and axial...

Regards
Ray

Yes, I meant to write: the runout in the direction from headstock to the tailstock e.g., that's the axial runout I think.

Yes I did think of a skimming cut as a solution to this problem . But, if the faceplate register ( the face that closes onto the spindle register ) is not true, then the face plate will always be wobbly - in that case maybe it would be worthwhile face grinding the register of the face plate .

BTW I am talking about threaded spindles here .... not those modern camlock things

Mike

Originally Posted by pipeclay

Have you used the face plate before,if so was there any run out then.

If not then you must have some problem with the spindle register.

It is a theoretical question... not a actual practical question , but it could be a real problem

If this is the first time you have mounted the face plate then take a truing cut from the face and OD,if the rear of the plate is also running out and this distracts you also take a skim of the rear edge of the plate.

Yes That would work Ok if the faceplate register was in good cond.

If you wish to just know what might be acceptable runout,then I would say what ever you would accept for a 4 jaw chuck,in most cases this would be none.

I think a zero axial runout at the outer edge of a 9" faceplate would be nigh on impossible to achieve

Is it custom to face the faceplate on a lathe when you first purchase it to ensure it runs true and then stamp somewhere on both the faceplate and spindle so that you can marry up the two surfaces again for repeatability?

OK now I'm thinking this may only be relevant to camlock spindles where you have 3 different positions to mount said faceplate? What's the go with these old fashioned screw on spindles? You just screw them on and hope for the best?

Edit: Also is it fair to say that radial runout is irrelevant on a faceplate?

Simon

If you were to grind the register what would you set up to.

If the face plate has been made for the type of lathe it is to be fitted on then the register would of been machined when the thread was cut,and should be running true/square to the spindle. to the spindle

OK now I'm thinking this may only be relevant to camlock spindles where you have 3 different positions to mount said faceplate? What's the go with these old fashioned screw on spindles? You just screw them on and hope for the best?

Edit: Also is it fair to say that radial runout is irrelevant on a faceplate?


Screw on spindles whether on older machines or current models have a register face that locates tooling square to the spindle.

As long as the register on the spindle or register on the tool is not damaged/burred tooling that is placed on the spindle should locate to the same position all the time.

Axial runout in my opinion should try to be removed just for appearance if for no other reason,it can be very off putting when you see a wobble.

All good advice if you have a threaded spindle but I don't. My chuck is held on by 3 bolts.

i have tried my 3 jaw chuck in all three possible positions and have not seen any significant difference in runout and I know my 4 jaw (or collet spindle adapter) can fix the misalignment however, I was really interested in the definition of runout which is pretty elusive when a noob does a bit of googling.

Originally Posted by morrisman

I think a zero axial runout at the outer edge of a 9" faceplate would be nigh on impossible to achieve

What makes you think that?

Thats why you face the faceplate on the machine it will be used on. Now you'll want a good cross slide etc etc. But even if the cross silde is shocking and the flate plate doesnt end up "flat". it should still have zero axial runout.

Hi Rob,
TIR to me means exactly what is says. Half TIR to me may mean "runout"

When you move the 3 jaw. does the run out move with the chuck or stay with the spindle?

Stuart