Myford chuck not gripping

[RoParticipant @ro]

Posted by Hopper on 12/07/2020 02:42

Possibly because when you held the top hat ring in the rear of the jaws and tightened the jaws inwards, the front tips of the jaws were pushed inwards, the opposite of the way they are pushed when in use holding a piece of round bar etc.

That is why the clover leaf plate I posted above works better. It pushes the front tips of the jaws outwards while they are being machined, replicating the position they are in during normal operation.

If there is a bit of slack between the jaws and the slots in the chuck body they run in, it can make quite a difference.

I got the chuck on my 1937 lathe to run within one thou using this method.

Yep, I understand what you’re saying, and can see how the clover leaf could be a better solution.

However, in my scrap box I had the material to make up a top hat, and didn’t have the material for a clover leaf.

When I find myself with a scrap piece of plate large enough and some spare time I’ll give it a go.

[HopperParticipant @hopper]

You can actually substitute 3 pieces of flat bar maybe 1 inch by 1/8 . Cut the hacksaw slot in each after drilling the 1/4" hole to give a bit of spring to allow for slight dimensional variation between jaws. Bit more fiddly to get all 3 in place but ok if chuck is laid flat on the bench. Much easier to make than the full plate though.

[Author]

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