Myford Super 7 Spindle Lock

I suspect this has been done to death but I can't get anything useful from a search.

The Suggested way to remove a screwed chuck is to grip the belt and unscrew. No chance - not on my Super 7!! Are there any good, simple designs out there for a spindle lock without resorting to the backgear?

Phil H

Repeating what has been said many times, Do NOT engage back gear unless you are prepared break teeth off the gears!

You may ignore this advice, and get away with it. But I have made several gears for people who have engaged Back Gear to lock the spindle, on early MLs. And stripping out the mandrel to repair, and then readjusting is a right fag! Best avoided.

Various suggestions that have been made.

Tighten belt, grip a piece of hexagon bar in the chuck, apply a long ring spanner, or socket and long bar. Hit hard on the outer end.

Tighten belt, grip a long bar across the chuck jaws, again, hit hard on outer end.

Hopefully, the inertia of the motor will resist the suddenly applied rotational torque and the chuck will come free

It may need more than one attempt to jolt it loose.

An alternative might be to grip the hexagon bar in the chuck, and use a socket and a pneumatic impact wrench, to hammer it free.

The suddenly applied load will be double that of a gradually applied load.

once the chuck is off, check for bruises to the thread and register which may cause the trouble.

To prevent recurrences, do not spin the chuck on under power, just push it round by hand. It will tighten under the cutting loads.

Howard.

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I thought all Myford S7s had a built in lock, mine does and it's shown as 'item 32' a 'pulley lock assembly' in the Myford handbook, pages 40 & 41, just push it in while turning the chuck and it locks letting you unscrew the chuck.

As Sandgrouder says, there is a spindle lock to the left of the top cover (look just to the left of the handle for raising the cover and to the right of the primary belt housing (motor to layshaft)). Once the spindle is locked a strap wrench (oil filter remover) works well to loosen the chuck without damage.

Re gripping belts, my way of doing it, and you don't have to tighten the belt, is as follows.

Wear a stout glove, and grip together hard BOTH parts of the belt, front and rear. It then locks the spindle against itself.

You can then use your chosen method of turning the chuck.

Rarely fails.

This was discussed here less than a month ago:

**LINK**

This site's "native" "search this site" facility is C***P but Neil has added a very useful Google box on the site's home page - took only a few seconds to find the link I just posted.

Slightly tongue in cheek, but going by the comments of previous generations of Myford owners I had always imagined that Myford were a classic example of good design and skilled manufacture. Surely such a professional organistion would have designed in an appropriately adequate mechanism for safe, quick and easy chuck removal. After all, changing chucks can be a fairly regularly performed operation. Certainly on my Chinese mini lathe today, I changed from a (bolt on) collet chuck to a 3JC to a 4JC, all without mishap and total elapsed time of between three and four minutes lost metal mangling time, with little risk of damage to anything.

Or have I just misunderstood how marvelous Myfords are??

cheers

Bill

As has already been said Super 7's have a built in spindle lock to the rear of the headstock behind the change wheel casing. It locks the pully cluster to the headstock casting. Amazing how many people don't know its there.

regards Martin

Howard/ David, The lathe is from about 1975 but has hardly ever been used. The genuine Bernard chucks supplied with the machine seem to be very stiff on the spindle nose. Perhaps a few more hundred chuck changes and it will be fine just gripping the belt.

Bill Ellis/ Soundgrounder, Thanks. Ill have a look at the manual. I honestly didn't realise it already had one.

John, thanks I wasn't aware of the google search thing. Ill use that in future.

Bill Pudney, Yep you have misunderstood - Myford really do seem to be far superior. They've thought of everything. Spindle lock located!!!!

Thanks Martin. I'm pretty good but I don't know everything.

Phil H

Someone might help me, I have a thread in the manual machinery section How to remove a chuck from a Boxford model A. It's back on the 1/5/18. I had quite a battle over a number of weeks(only able to work on it 2 mornings a week).

Ian S C