Clarke CL500M – locking chuck

[Danni BurnsParticipant @danniburns84841]

Hi there

Stopping the lathe chuck from rotating (for using hand tools e.g. Tapping) on this lathe is a pain.

I’ve been using a bar in the chuck-key hole to stop it from rotating reverse (which falls out as soon as opposite movement, e.g. backing-off) and a piece of wood on the chuck jaw to stop forward movement, with the same annoying results.

I see lots of gear chocks for Myfords, etc. (see similar below) but nothing for a Clarkem lathe.

The Clarke CM500M gears pic below.

Does anyone have a simple solution (save me over-engineering something)?

Cheers

[bernard towersParticipant @bernardtowers37738]

Just put it in the lowest gear.

[Howard LewisParticipant @howardlewis46836]

For using taps or Dies, I have advocated holdingbthe Tp or Die in a Sliding tailstock holder (The Holder slides on an arbor; not bthe tailstock) and rotatingb the chuck mwith a mandrel handle.

The advantage of the sliding holder is thet the newly cut thread vhas only mto pulln the mholder malongb the arbor, not the Tailstock, avoiding the risk of stripping the new thread.

As usual, of course, setting out to do one job creates others.

To tap a hole, now means making a suitable arbor to fit the tailstock taper, suitable holders and a mandrel handle. That should delay cutting the thread for a day or two!

Howard

[Danni BurnsParticipant @danniburns84841]

Thanks Howard

As you know Ive solved by immediate dilemma

I may look into a mandrel handle though. Any ideas on how to do that?

[Howard LewisParticipant @howardlewis46836]

Danni,

I’ve sent you a couple of pictures, by E mail, of one that i made for a Myford ML4, (Taken from my article on Recommissioning a ML4)

I’ve made a similar one for my mini lathe.

If anyone else is interested, instead of a split, internally taperd body, into which a tapered plug is pulled, clamping could be arranged in the same way that handlebars are now clamped to a bicycle.

The end piece is ciut at 45 degrees, and pulled against the end of the body, which is also cut at 45 degrees.

The tension forces the two parts sideways, to grip the bore of the Headstock, so that the handle rotates the Headstock.

Howard

[old martParticipant @oldmart]

That plastic part is not for locking chucks, it is for holding threaded spindles whilt the chuck is being removed. You could probably use one in the reverse direction when replacing the chuck as long as you did not spin it up to the register. That would overtighten the chuck and make it very difficult to remove at a later date. The lock greatly reduces the danger of breaking off teeth by hamfisted force.

On your lathe, I would remove the large pulley on the spindle and drill a couple of pin holes and make a large pin spanner to fit it, but I have access to mills and facilities to carry out such work. There might be a much simpler method, but I cannot see the right hand end of the spindle. Please add a photo.

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