There are many occasions where it is sensible to power the lathe by hand, - the most frequent of these is when screwcutting an internal blind hole. Do this under power at your peril !!

There have been many designs published for lathe mandrel handles, some of them with complicated mechanisms enabling the handle to be made loose on the shaft in case the power to the lathe is inadvertently switched on, causing the handle to thrash about dangerously.

The handle shown here is perfectly balanced and therefore will spin without vibration should the lathe be started under power. It will of course still constitute a hazard.

The handle started it's life as the top slide handle on a large and very old lathe. I found the lathe being smashed in a scrap yard and rescued the very rusty handle, thinking that it "would come in useful".

Unlike other "useful" items, this has proved to live up to it's name. I made a central boss to fit the handle and keyed it into the original keyway in the handle. The boss is split at the other end as shown in the lower photograph and is bored axially to fit a tapered plug (nut) that is drawn into the body of the boss by a bolt.

Thus the boss tightens on the inside of the lathe mandrel giving a friction drive to the lathe.

You may be able to see from the photograph that the conical nut carries a pin which runs in one of the slots cut into the boss. This stops the nut from spinning when the bolt is either tightened or loosened.

I am sure that many such handles must be scrapped nowadays and it is pleasing to give this one a new life. The size was just right for the Myford and the thick part of the boss was made of sufficient length to enable the handle to clear the "bodywork".

On occasions I have spun the mandrel at full speed with the handle in place when wanting to simply chamfer a shaft and not wishing to remove the handle. Not a trace of vibration, but make sure the workshop door is locked and no-one is with you. Better still, do it right and remove the handle.