ML7 spindle change

[Mick BaileyParticipant @mickbailey28509]

I like the look of the 5C chuck, especially the key operation. It seems to be more inclined towards work holding rather than as a toolholder, though the tolerance on work diameter isn’t as flexible as an ER holder. No worse than the Myford collets though.

However, something unexpected is the offer of a brand-new spindle which would restore my lathe to the original functionality. I’m back to the original question – other than fitting up the spindle to the existing shells, is there any other consideration?

[JasonBModerator @jasonb]

With 5C there is the option to fit a 5C to ER32 converter. I don’t use mine very often but it can come in handy for odd sizes. I only have imperial 5C collets in 1/32 increments not 1/64, also got metric ones which get the most use now. You can also machine the “emergency” collets if you have a particular size you want to hold but not really worth it for a one off.

5C was always designed with workholding in mind, the Hardinge spindle tapers accepts 5C not MT.

[Mick Bailey]

On Mick Bailey Said:

 

However, something unexpected is the offer of a brand-new spindle which would restore my lathe to the original functionality. I’m back to the original question – other than fitting up the spindle to the existing shells, is there any other consideration?

If you have the skills, or the ability to develop them quickly, and a nice little curved three-sided or half-round scraper, you should be able to scrape the old white metal to suit then insert the shims for a bit of clearance for oil. Other than that, changeover is very straightforward.

Remove the extraneous guff like belt guard etc and take off the two top bearing caps and lift the spindle out. Gear on the end is held by a small grub screw. With that and the thrust bearing removed, spindle should tap out of the bull gear and job’s done. Assembly, as the Haines Book of Lies always says, is the reverse of disassembly.

Well worth putting a new belt on while you have the spindle out.

[Mick Bailey]

On Mick Bailey Said:

Maybe though in the end the best concentricity would be had by using a plain Loctited insert with the taper machined in-situ, as already suggested. Given the existing state of the bore there’s nothing to lose.

Mick apart from going down the 5C route this is defiantly the best and easiest option and will give the best accuracy. The 5C collets are possibly one of the most used collets in medium size lathes in industry and do come in 1/64″ increments as do the Myford collets but 5C are readily obtainable whereas the Myford ones are not.

John

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