Myford Spindle

The discussion on scraping a bed prompts me to ask about my Super-7
spindle.
Very early in the life of this machine, now over 30 years old, the
spindle, um, got slightly damaged - on the conical bearing surface and
register shoulder (don't ask). There is now a run-out of the register
diameter and the Morse taper of about 1/2 thou. I feel it should be
better than that.
How much run-out would you accept?
Not having asked them yet, can I take them just the headstock for new
spindle & bearing(s) or would that be a bad idea? Would it cost the
earth?
Reply to
Charles Lamont
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Spindle (Part Number A1992) is £120.23 + VAT Front Bearing (Part Number A3609) is £23.28 + VAT
Go on. Treat yourself.
Mark Rand RTFM
Reply to
Mark Rand
That's very reasonable indeed considering the arm and a leg you have to leave behind when you want an ML7 spindle and bearings. Nothing exotic in it either, just case hardended EN32 and plain old Phosphor Bronze.
Peter
Reply to
Peter Neill
Charles
-out of curiousity I put a DTI on the spindle register of my 49 year old ex-factory Super 7. TIR was around 2/10 to 3/10 thou, with the variation depending on lateral position. I tried to measure the run-out on the inside of the morse socket, but light scoring made the readings rather erratic. I think the run out is probably about the same as on the register, around 3/10 thou.
Mike
Reply to
mike.crossfield
Have you tried machining a long bar between centres and measuring th
runout then? Might be worth a go just to see how bad it really is. Cheers Coli
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Reply to
colinheath
Colin, I don't quite follow.
Reply to
Charles Lamont
It wont tell you anything other than how far out of concentricity your tailstock is with your spindle.
Wayne....
Reply to
Wayne Weedon
True to an extent. The tailstock needs to be dialled in as well as you can first. If the concentricity is a problem you would expect to see the machined work piece tapering towards the headstock because the headstock end is moving eccentrically whereas the tailstock is not.
Knackered bearings will be more apparent when you look at the surface finish of the machined cut. If the surface finish gets worse towards the headstock when turning between centres it obviously means there is play in the headstock.
Mark
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Reply to
Mark_Howard
Apologies for coming into this at a late date. Insanity, incontinence and too long a shelf life!
I have just aquired a ML7 and had the bed "Blancharded" locally and at minimum cost. Then, someone offered me a Super 7B- a bit rough but OK for its age and price. Whilst doing up the 7, found some wear in the spindle and of course, whitemetal bearings are now unobtainable. Can I change beds? Both beds are the solid old fashioned variety.
Oh, and no cracks about beds as I have already fed the hospital cat.
Norman Atkinson
Reply to
ravensworth2674
Just as a point of interest I fitted a new spindle and bearings to my ML7 yesterday. I got new laminated shim packs to go with this, which measured up at between 0.0179" - 0.0185" across the four sets.
After refitting the bearing caps without excessively tightening them down, the spindle was so tight as to be completely immovable. Couldn't turn it even a thou' or so. I blued up the spindle and tightened the caps back on (with shims) to check this.
On the front bearings I got pretty much total contact top and bottom with quite a heavy transfer of blue, and a lighter but again almost total contact on the rear bearing. I ended up peeling a 0.0025" shim off the old pack to put under each side of the front cap and I can now turn the spindle with a reasonably heavi-ish 'damped' degree of resistance.
Levering up on the spindle nose with a bit of 2x4 i can get a total deflection of about half a thou', but can measure bugger all run out with the spindle turning. Running it for half an hour the bearings get warm but nowhere near hot, so I think it must be pretty much spot on now. Still far more accurate then I need at the moment anyway for fitting the end of broom handles.
Peter
Reply to
Peter Neill
Should be no problem at all.
Mark Rand RTFM
Reply to
Mark Rand
Thanks, Mark, for the info. The next daft question is the jig to bore the holes for the gearbox. Does anyone have a drawing, please?
I have the manuals for both machines and the box itself. Again, I have quite a lot of ML7 stuff from Martin Cleeve's work. In the spirit of the Forum, I would be delighted to pass on such information as I have. My E-mail is snipped-for-privacy@n-atkinson.wanadoo.co.uk.
Thanks
Norman
Reply to
ravensworth2674

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