VMC Mill spindle runout

[John DParticipant @johnd]

What kind of runout is typical/ acceptable on a Myford/ Warco VMC mill spindle as measured on the bottom of the spindle taper? I'm getting 0.035mm and not sure if that's terrible and if so what I can do about it?

Edited By John D on 13/11/2022 14:19:34

[John DParticipant @johnd]

[JasonBModerator @jasonb]

About 10 times worse that I get on the X3, thought Myfords were built to a better standard than the far eastern machines or maybe that is only if you can find a good second hand one..

It's not that good. For example I often run with a chip load of 0.02mm per tooth so if I was using a 2-flute cutter it could well be acting as a single flute with one flute taking almost all the cut and the other just rubbing on the surface.

Not familiar with how they go together but I'm sure someone will be along who has one.

[Brian WoodParticipant @brianwood45127]

Hello John,

That doesn't sound good to me. Have you tried a taper shank drill in the socket to see what happens at the tip of the drill? Is the effect progressive or confined to a particular area?

As to recovery, before you do anything take a very good look to see if there is local bruising at the mouth of the socket in which case a taper reamer may well be all you need to whip it out and clean it up. Not easy working upside down to check progress so it may help to grip the tang in a drill vice and hand hold the combo where you can better feel and judge any 'orbital' effects and bias the action accordingly.

Best of luck Brian

[John DParticipant @johnd]

Posted by Brian Wood on 13/11/2022 15:19:16:

Hello John,

That doesn't sound good to me. Have you tried a taper shank drill in the socket to see what happens at the tip of the drill? Is the effect progressive or confined to a particular area?

As to recovery, before you do anything take a very good look to see if there is local bruising at the mouth of the socket in which case a taper reamer may well be all you need to whip it out and clean it up. Not easy working upside down to check progress so it may help to grip the tang in a drill vice and hand hold the combo where you can better feel and judge any 'orbital' effects and bias the action accordingly.

Best of luck Brian

Thank you for the reply, Brian. It's an R8 taper and I don't have any R8 drills, only ER32 and Clarkson Autolock collets. I don't seam to be getting much worse a reading when the quill is lowered. I have measured on the inner edge of the taper and the outer edge of the spindle nose and get the same reading. I bought it from a guy who i thought reputable and well thought of on here. I've spent ages fitting a 3 axis DRO and now gutted to find this.

I can't find much info on line about the Myford Taiwan imports and which other branded models might share the same spindle. (e.g. it doesn't have fine feed quill) Is there any way of re-machining the taper to take out the runout? Is replacing the spindle the answer – if indeed i could find one? The parts diagram is pretty unclear – i'm not sure how to remove the spindle.

[BazParticipant @baz89810]

No reason why you can’t remachine the R8 taper on the mill itself, just swing the head over to the correct angle and clamp a carbide tool in the machine vice. If you can borrow a toolpost grinder or a Quorn grinding head you could set that up on the table and grind it.

[Dave WoottonParticipant @davewootton]

Hi John

It is quite possible to remachine the R8 taper on the machine itself by tilting the head at half the included angle of the R8 taper and using a boring tool fitted to the table and feeding the table up to advance the cut. I've done it on a couple of old Bridgeport clones at work that had very damaged tapers from misuse. But it's a fiddle to set up and not for the faint hearted.

But and this is a very big but, only as a very last resort, If the spindle has been bent somehow, and it does happen then the bearings will be under strain due to misalignment, the best way is to dismantle the spindle checking for straightness, which will also give an opportunity to check and regrease the bearings. I have dismantled a VMC spindle to replace the thrust bearing but it was a long time ago, but don't think its too difficult a job.

I'm sure someone will come along who's dismantled one of these and can remember the specifics, but I would stress don't attempt any remachining or drastic action until everything has been checked, If you are anywhere near Folkestone in Kent I'd be happy to help with the checking. I had a Hayes diemaster milling machine with a bent spindle a few years ago and a company in Coventry, Spindle Services completely rebuilt it with new bearings,and reground the 2mt taper for a very reasonable amount, so all is not lost there is proffessional help available.

Good Luck

Dave

As an afterthought if you have a collet and a length of bar that is known to be straight, or preferably a ground test bar you could see if the runout changes at a distance from the spindle nose, not an exhaustive test but would give some indication. I don't think Myford would have let it leave the works with that level of runout.

Edited By Dave Wootton on 13/11/2022 16:48:08

[JasonBModerator @jasonb]

Before getting to drastic I would suggest checking the bearings are correctly adjusted and then test the runout without the belt connected.

[John MCParticipant @johnmc39344]

Posted by Baz on 13/11/2022 16:32:34:

No reason why you can’t remachine the R8 taper on the mill itself, just swing the head over to the correct angle and clamp a carbide tool in the machine vice. If you can borrow a toolpost grinder or a Quorn grinding head you could set that up on the table and grind it.

Not sure that will work, what about the plain diameter further up the spindle?

Has the OP measured the run out of the plain diameter? Not easy to do what with it being "down a hole" and the key in the way.

[Brian WoodParticipant @brianwood45127]

Hello again John,

Ouch! Obviously my plan is not viable and with respect to Baz, I don't think his plan is as easy as he makes it sound.

Have you spoken to the man who sold it to you? It would be fair to get his reaction rather than try to correct matters yourself.

Brian

[John PParticipant @johnp77052]

Posted by John D 13/11/2022 15:58:27

Thank you for the reply, Brian. It's an R8 taper and I don't have any R8 drills, only ER32 and
Clarkson Autolock collets. I don't seam to be getting much worse a reading when the quill
is lowered. I have measured on the inner edge of the taper and the outer edge of the spindle
nose and get the same reading. I bought it from a guy who i thought reputable and well
thought of on here. I've spent ages fitting a 3 axis DRO and now gutted to find this.

I can't find much info on line about the Myford Taiwan imports and which other branded
models might share the same spindle. (e.g. it doesn't have fine feed quill) Is there any
way of re-machining the taper to take out the runout? Is replacing the spindle the
answer – if indeed i could find one? The parts diagram is pretty unclear – i'm not sure
how to remove the spindle.

——————————————————————————-

The spindle on my Warco A2F has about .0002" run out at the lower edge,the
top end the parallel part has some runout also ,i just make arbors to suit
what i need and finish them in situ as there is a locating pin they allways fit
back is the same place with zero runout.
Lowering the spindle won't make any difference to the run out reading.

It would be possible to regrind the tapered part of the spindle in its
own bearings on the machine as you can set over the head to
the required angle and use a toolpost grinder mounted on the table
providing the bearings are good , but is not possible to regrind the
upper parallel part for obvious reasons .

There is in my album for the A2F mill the complete handbook
which has a parts list ,i don't know if these machines are identical,Chester
still sell this machine as as the 830 VS so may have or be able to get parts.

John

[Michael GilliganParticipant @michaelgilligan61133]

Posted by John P on 13/11/2022 16:46:46:

——————————————————————————-

The spindle on my Warco A2F has about .0002" run out at the lower edge, […]

.

That’s rather impressive !

MichaelG.

[John DParticipant @johnd]

Posted by John P on 13/11/2022 16:46:46:

Posted by John D 13/11/2022 15:58:27

Thank you for the reply, Brian. It's an R8 taper and I don't have any R8 drills, only ER32 and
Clarkson Autolock collets. I don't seam to be getting much worse a reading when the quill
is lowered. I have measured on the inner edge of the taper and the outer edge of the spindle
nose and get the same reading. I bought it from a guy who i thought reputable and well
thought of on here. I've spent ages fitting a 3 axis DRO and now gutted to find this.

I can't find much info on line about the Myford Taiwan imports and which other branded
models might share the same spindle. (e.g. it doesn't have fine feed quill) Is there any
way of re-machining the taper to take out the runout? Is replacing the spindle the
answer – if indeed i could find one? The parts diagram is pretty unclear – i'm not sure
how to remove the spindle.

——————————————————————————-

The spindle on my Warco A2F has about .0002" run out at the lower edge,the
top end the parallel part has some runout also ,i just make arbors to suit
what i need and finish them in situ as there is a locating pin they allways fit
back is the same place with zero runout.
Lowering the spindle won't make any difference to the run out reading.

It would be possible to regrind the tapered part of the spindle in its
own bearings on the machine as you can set over the head to
the required angle and use a toolpost grinder mounted on the table
providing the bearings are good , but is not possible to regrind the
upper parallel part for obvious reasons .

There is in my album for the A2F mill the complete handbook
which has a parts list ,i don't know if these machines are identical,Chester
still sell this machine as as the 830 VS so may have or be able to get parts.

John

Thank you everyone. I think the Myford VMC is almost identical to the Warco VMC and Chester 626 rather than the 830 VS/ A2F. All the newer machines have fine feed quill which I assume would also mean a different spindle design. Anyone out there done the strip down?

The bearings are quiet and it runs so smoothly i trusted that all ok. I can't believe i didn't pop a dial on it. I've now not only spent all my money i've also spent hours fitting the DRO.

Finding a replacement spindle is likely impossible so living with it or getting it reground sounds like my only practical option. Does anyone have any idea on cost?

…and I just want to check – is 0.034mm far outside what most people would consider ok?

[Brian WoodParticipant @brianwood45127]

From what you say John with the outside run out it is beginning to sound as though the machine has had some kind of crash in the past. If these two run out values, internal and external are in much the same position that would confirm my thinking and left it with a bent spindle.

Re-machining the T8 taper won't put that right and new bearings will also be sensible to fit as well. Dave Wooton had knowledge of the Bridgeport clones he recut the tapers on along with run out values for the outside of the spindle so he would have known the taper was all he had to correct.

I still think you should now talk with the vendor, it is beginning to sound as though he has unloaded it

My sympathies Brian

[John PurdyParticipant @johnpurdy78347]

John

I have just measured the run out of the inside of the R8 taper on my VMC type mill and it is .0003" (.00762 mm ) The mill was bought in 1983 and is not a Myford or Warco but one imported from Taiwan by an Canadian company, and has been in regular use since then.

John

[John DParticipant @johnd]

I’ve spent the money and done all the work to fit a DRO and with the DRO fitted I can’t expect him to take it back. I need to find a way forward that leaves me in a workable place but don’t know what that is.

[Michael GilliganParticipant @michaelgilligan61133]

It’s very clear, John D, that the numbers you are getting are unacceptable … The question is: Do they reflect a major problem [like a bent spindle] or are they caused by some localised damage in the R8 socket ?

Without very careful inspection, you [and definitely we] will not be able to answer that.

MichaelG.

[John DParticipant @johnd]

Thanks Michael. I’m given to thinking it’s a spindle problem given that the runout is mirrored when indicating on either the interior R8 face or the external face of the spindle.

[Robert ButlerParticipant @robertbutler92161]

Surely if the quill is bent it would not be possible to lower it? As advised before strip out the quill and check measurements or seek specialist help to check and repair?

Robert Butler

Edited By Robert Butler on 13/11/2022 20:43:15

[John DParticipant @johnd]

Robert, am I right that you mean spindle rather than quill?  My plan is to remove the spindle and get some proper measurements. I just need to work how the spindle is removed.  If anyone has done this on a VMC then your guidance would be much appreciated.

Thank you all for all your help.

Edited By John D on 13/11/2022 21:19:32

[Mike PooleParticipant @mikepoole82104]

I would strip the spindle and check that the bearing seatings are not damaged, it may be that the bearings have been replaced and not been seated correctly, maybe picked up or some other damage. Some careful checks should reveal where the problem exists. I doubt that the error existed when manufactured so is likely to have occurred with a crash or careless rebuild. I suppose the error could have existed since manufacture but I would find it incredible if it was allowed to be shipped without such a basic check not being made.

Mike

[Dave WoottonParticipant @davewootton]

John

As an idea of the cost of the repair I had done to my Hayes Diemaster spindle that was very bent, if I recall correctly runout was about .015" four inches from the spindle, how it got bent I can't imagine as it was a chunky spindle. Spindle Services charged around £300 about six or seven years ago, which may sound a lot, but the work carried out was, Straighten the bent spindle, regrind the bearing seatings on the spindle to enable a more easily available metric bearing to be fitted, for the same reason bore out the quill housing,supply and fit new bearings,adapt to take a modern garter oil seal, regrind the 2mt internal taper running in its own bearings, quite a lot of work all done to a very high standard..

The original imperial bearings were only available from a specialist in obsolete bearings at a cost not far short of the charge for the whole job, so for me it made economic sense. In your case I'm sure the job would be much more straightforward. Fortunately mine wasn't an expensive machine but it was a shock to find the bent spindle, and the state of the bearings where they had been running out of line for years was horrendous.

I'm sure yours won't need such drastic measures.well worth checking the bearings as advised by Jason above before pulling it to bits.

Dave

[LathejackParticipant @lathejack]

It might be worth just first checking the preload on the spindle bearings, although you confirm they are smooth and quiet. If the spindle is floating about a bit then this would show up on the outside diameter as well as the taper, a slight adjustment of the preload may eliminate the excessive run out you have.

I have once machined an INT 30 milling spindle taper in situe on the mill, with the head tilted over to the correct angle, using a boring tool secured in the milling vice. Only as a last resort, and it worked well.

I can vaguely remember removing the quill and spindle assembly from my Warco VMC many years ago. I'm sure once the quill handwheel and pinion shaft and spring are removed, together with the depth stop, the quill will slide out the bottom of the head. The spindle has two castelated lock nuts for adjusting the preload, as far I can remember. If the gear rack teeth cut on the rear of the quill continue to the top edge of the quill then the pinion shaft may not have to be removed.

The very early Warco VMC mill that they offered in the 1980's was identical to the Taiwanese made Myford VMC, but in the 1990's the Warco VMC was no longer the same machine, using different castings and other detail differences, although overall it looks the same, and has similar dimensions and capacity. The Warco VMC I have was made in Taiwan in 1997 and is the version that has now been produced in China for some years.

Anyway, prompted by this thread, I have just been in my workshop to measure the run out on my Warco VMC R8 spindle. I get a reading of 0.0002" run out on the lower portion of the spindle taper, and no change further up the taper.

Although the Taiwanes made Myford VMC is generally made to a higher standard than my later differing Taiwanese made Warco VMC, I can recall a conversation I had while on a visit to the original Myford plant at Beeston in Nottingham, around the mid 1990's I think. While being shown some machines hidden away in some back rooms I spotted a new Warco VMC that they said they were examining, I think because the Myford VMC was being discontinued. They didn't really like the way the Warco VMC was made, but they did admit that they did have to put a stop to the Myford VMC manufacturer's method of "finishing" the spindle taper by inserting a piece of wood wrapped in sand paper.

Edited By Lathejack on 13/11/2022 23:31:07

Edited By Lathejack on 13/11/2022 23:37:27

[John PurdyParticipant @johnpurdy78347]

John

I don't know if it will be any use to you but you haven't said whether you have a diagram of the headstock/spindle but here is the one for mine. As I said earlier mine was made in Taiwan same as the Myford so may be of some use.

John

[HopperParticipant @hopper]

Yes I would definitely inspect the spindle and all bearings and seatings very carefully before any regrinding etc. You will need to put the spindle between two V blocks and rotate it with a dial indicator at various locations to check for straightness.

Bearings should be checked for runout too. And check what brand of bearings it has in it. If no name or cheap Chinese fare, replace with SKF or similar quality. (FAG, Timken, Koyo, Nachi)

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