Stiff Quill Travel on Myford VMC Milling-machine

Advice please...

The quill travel on my Myford mill is very sticky, to the point that is useable but lacks drilling sensitivity and its return-spring won't return it.

Thinking - simple solution first, ensure the clamp is not jammed. It was not, but I cleaned and oiled it before replacing it.

Broken or unhooked spring? I do not have the appropriate tools and knowledge, beyond knowing that handling powerful clock-springs without is hazardous and very difficult. Luckily, VERY careful inspection suggested the spring is intact.

So could the problem be dried grease on the rack and pinion? If so can this be sorted with the machine intact or would I need to remove the head - as I suspect? I know I'd need to tram the re-fitted head, but I have an indicator for this purpose, bought from this Forum's sponsor!

I have a copy of the manual, which gives a sectional drawing, but does not advise on taking the thing to bits and re-assembling it.

All help gratefully received!

They're simple to dismantle.

Lock the quill in its retracted position. Slowly loosen the hexagon screw that locks the return spring drum whilst carefully releasing the spring tension. Slide the drum out of its bore complete with spring.

If I remember correctly, it's necessary to knock out a roll-pin to remove the downfeed handle, which allows for the removal of the 3 or 4 cap-head screws that hold the pinion in position. Once these are out, the pinion can be slid out of mesh from the rack.

Unlocking the quill lets it drop down & out of the head - beware that it's quite heavy and possibly longer than you might have thought.

Lube the quill with oil (not grease) to reduce lethargic return movement.

Martin.

Might not apply to the VMC, but I have found with my Beaver milling machine that even oil on the quill can make it very sticky. Spotlessly clean and dry works very well.

I took a different approach to blowlamp when removing the quill from my Warco VMC, which I believe is basically the same as the Myford version.

Following removal of the depth stop threaded rod and nuts I removed the guide block - this is held onto the quill with a single M5 capscrew. To release the quill itself, wind it downwards using the downfeed lever until the quill disengages from the drive pinion, taking care to provide support as it is released. One word of warning here - control the return of the lever rather than just release it as the return spring is quite strong and it will hurt if the lever hits you. Reassembly is the same procedure in reverse - wind the handle down and re-engage the pinion.

It is worth supporting the quill on the machine table (onto a piece of wood to protect the table surface). In that way you will have control of the quill by moving the knee up or down.

FWIW a few years ago I had a sticky quill on a Meddings drill press - in the end it turned out to be nothing to do with the quill itself. Instead it was a plastic bushing binding on the shaft that goes between the operating lever and the pinion that drives the quill rack. Worth checking this rotates freely...

Edited By Bikepete on 25/03/2019 08:48:58

You could try squirting a bit of WD40 up there to loosen up the dried grease. Easier than pulling the whole thing apart so worth a try first.

The quill might just need oiling. Extend the quill and lubricate with a 32 weight oil, or slideway oil if you have it.

I have experienced in the past on these mills a poorly aligned quill relative to the pinion shaft. This will throw burrs up on the rack teeth on the quill. These burrs will cause the quill to become tight. Try winding the quill down as far as it will go and see if there are burrs on the teeth edges of the rack, on the portion of rack which is exposed. If there are then an India stone used carefully will remove the burrs. The only problem is it will only remove those burrs exposed, to get at the rest you will need to strip the quill out.

Regards

Gray,

Thank you all for these various suggestions.

I'll work from the easiest and safest first of course, but studying the machine and the manual suggests I may need go as far as removing the head..

What for? I'd have thought the most you'd need to do is tilt it or swing it to one side.

Exactly what Myford mill are you talking about? I currently have a Myford VME & have worked on many different types of turret mill over my career, taking the head off to fix a 'sticky quill' doesn't make any sense to me.

Tony

It is the Myford VM-C. I have just verified it.

By "head" I mean only the section containing the spindle: the whole unit appears to be called the "turret" although not strictly accurately since the machine is not a true turret mill.

The parts drawing shows the (spindle) head to have a large hole through the bracket by which it's bolted to the rest of the turret, and this would give access to the interior. There is no matching hole through the bracket.

Sounds like you're speaking from experience there

Useful comments here, I need to strip my Myford VM-C to change the bearings, although I'm having a bit of difficulty finding the plain thrust bearing at the bottom (NTN 2907) - I prefer not to order online as there seem to be a lot of fake bearings around.

I was also considering doing away with the thrust altogether and fittings a pair of angular contacts top and bottom, but I'm not sure what I'd gain, if anything. If it isn't broken.... etc......

I fitted angular contact bearings to my Myford VMC many years ago. After having the lower radial ball races pack-up due to debris getting past the bearing shield. Fitting angular contacts does require some form of end cap to stop debris getting into the lower bearing. The end cap does require some form of seal. I used a labyrinth seal nearest the cutter and an INA running seal inboard nearest the bearing to retain the grease.

Regards

Gray,