Thread: Centering rectangular stock in 4 jaw

Originally Posted by racingtadpole

For a job like that, seeing as you mentioned using a mill, I’d use a face mill or fly cutter, then bore the centre hole. Only have to clean and oil one machine then...

Thanks, and yes I tossed up which way to go. I don’t have a fly cutter yet and the fact that I want to turn a register for a small 3 jaw chuck onto the rectangular piece drove me to the lathe. My mill has a rotary table so all could have been done on it but I guess I though lathe may have been better.

I am calling it a mill but really it is a jig borer (BCA Mark 3). So really it is a very nice mini-mill if you like.

The plate is going to be a backplate for small 3 jaw chuck that will mount on the rotary table to hold round stock vertically for milling. I will use the mill to drill the centre hole and the hole circle for the chuck. I guess if I bore the centre hole (mill has a 1/2 inch hole in rotary table so I want to have a quick register using a pin through the backplate), drill the mounting holes, I may as well mill the register using the mill and know everything is concentric.

at the moment the backplate has been faced in lathe (average but passable finish) so now starts the tricky bit of getting register etc sorted.

Originally Posted by Danger Mouse

Thanks, and yes I tossed up which way to go. I don’t have a fly cutter yet
.

Hi Danger Mouse,

Fly cutters are not difficult to make. Mine took about an hour on the lathe and drill press. I think the hardest part was tapping the M6 thread in the right place.

New_Flycutter-1.JPG New_Flycutter-2.JPG Fly Cutter 01.png

Pictures of mine and the drawing for it. That disc is a 20 mm thick off cut from a stainless steel bar out of the scrap bin. I just cleaned it up and drilled it on the lathe. The shaft is a hot press fit, it isn't going to slip.

HTH.