This man would have measured his lathe first and bought a chuck to fit. Most minilathes seem to be 72mm now but some can vary.

Either send it back and get a 72mm recess one or make a backplate for it or as a last resort bore out the back of the chuck but check bolt PCD

Edited By JasonB on 30/01/2021 19:06:20

I have a CJ18A mini lathe from Amadeal. I bought a 4 jaw chuck from Amadeal at the same time as the lathe.

I have measured the recess and it is 72 mm with a PCD of 84 mm. The 4 fixings are M8 tapped holes in the chuck.

There was a previous post about the a chuck for a Warco mini lathe.**LINK**

This page from Warco shows the dimensions of their chucks. It looks like the item 8044 is the same size as the Amadeal Cj18a. **LINK** but they list an item number 4902 for their mini lathe.

Probably easiest to return yours if possible and buy one to this spec with 72 mm register and 84 pcd.

Stuart

Edited By Stuart Smith 5 on 30/01/2021 19:26:13

Edited By Stuart Smith 5 on 30/01/2021 19:29:18

I have one of the 7 X 12 Warco lathes at home and treated it to a new 80mm three jaw and a 100mm independent. The 80 just fitted on and is much better than the original one. The four jaw had rear mounting holes and was easily modified by boring the register and adding front mounting holes at the same pcd as the original. I had the advantage of a bigger lathe for the boring, but it could be done well enough just using the three jaw chuck with a piece of 30mm bar, skimmed true and then mounting the four jaw on the bar and doing the boring. The holes are reasonably easy. This would not work with a four jaw scroll chuck.

Edited By old mart on 30/01/2021 20:52:08

My chuck uses threaded studs and nuts, not bolts. (The threaded holes in the chuck don’t go through.).

Is the one you have bought like that?

Stuart

Basically as I see it the absolute location is not paramount (it’s a 4 jaw) but it needs to sit well on the spindle.

Do you want to risk an unbalanced chuck revolving at 2000rpm? I wouldn’t.

Edited By not done it yet on 31/01/2021 18:47:48

My CJ18 came with a 100mm 3 jaw which had M8 threaded holes and a 72mm recess, when I ordered a 100mm 4 jaw from ARC that to came with the 72mm recess and that also had the M8 holes. I fitted both of them with M8 grub screws of suitable length, I used Loctite to keep them in position and maintain the correct amount of protrusion for the flange and nut, it worked well.

The fit of the register should be a light push or no more than 0.003" , 0.075mm clearance. 4 jaw independents are often loaded with very offset work, and the speed will have to be reduced as the out of balance forces increase.

The bolts hold the chuck on the spindle and the register makes sure the body of the chuck runs reasonably true.

Edited By old mart on 31/01/2021 20:01:45

So does a strip of masking tape on the back edge of a spanner.

If you do that a lot, one of THESE clipped onto the spanner is good.

There is not much room for fingers behind the chuck on a mini lathe. Plenty enough for a nut to fall though!

I sealed the studs into my chucks and made up the DannyM2Z "Widget" which does just what is required to hold the nut while you start each nut on, or remove from, the thread.

It is only a bit of steel strapping with two sheared cuts, and the centre "tongue" bent to locate in the nut.

Time making it was well spent.

Howard.