New Cutter Idea?

[madman]

Yeah i need a idea. One and a quarter inch thick wood. Have to cut the outside diameter to 9 3/4 inches and the inside diameter to 5 1/2 inches. How the heck do i build a cutter that will do this? It will be mounted on a excello milling machine. Thanx Im stumped (as usual) Mike

[pntrbl]

Madman, I got no idea what an Excello milling machine is, but am I understanding this piece of wood will resemble a giant washer when cut out? And they want to do it in one operation?

If that's the case how about a 5 1/2 hole saw with something resembling a flycutter welded across the top to do the 9 3/4? Sounds like it'd be dangerous at rpm tho.

I think I'd set it to operate remotely somehow and get behind something for the 1st test!

SP

[Malc-Y]

I would rough saw the outside diameter slightly oversize with a jigsaw then chuck it in the lathe and using suitable tools and fairly high speed, cut the hole to size and then using inside jaws grip the wood by the inside diameter and turn the OD to size. This sounds fairly simple to me, am I reading your problem correctly or am I missing something?
Malc.

[Rustybolt]

You might want to fixture this to take two cuts. Bore the center out first and mount it on a rotary table to finish the OD. If you're going to use a trepanning tool for the inner circle make sure it's balanced. For wood, use carbide and run it as fast as you can go.

[cmiller231]

Madman: Does this Excello mil have a power fed rotary table per chance?I was thinking of hole saw for id and stick it on a 5 1/2" plug mounted on rotary table Then let the rotary table do the cranking for the 9 3/4" . Chris

[madman]

No it doesnt and it should be cut all at once. Theres thousands of them to be done.

[ralphe]

Why not a "double hole saw": one for the inside and one for the outside to cut pieces out of a sheet of plywood.

[madman]

That sounds good but whats the best way to make one., It should be able to cut through 1.5 inch thick wood.

[Evan]

That's a serious amount. What sort of wood?

I don't think the mill has the horsepower to do it in one operation.

I can think of a cutter that won't be too difficult to make but to cut that sort of part in one go is going to take some serious torque and at a reasonable rpm to make it economical.

I would cut a doughnut of 1/2" aluminum and screw on portions of 2" or 2 1/2" bandsaw blade around the OD and ID, probably about 8 TPI x 2" in sections spaced equally about 10 teeth each piece. Then use another disc smaller than the OD with an arbor and fasten it to the cutter disk to chuck it in the machine. The disk with arbor should have a center drill to locate the work while sawing. The center drill can be held in the end of the arbor by setscrew so it can be easily changed. The pieces of bandsaw blade should be screwed to the cutter disk so they can be changed. The pieces of blade can be drilled for screws with a carbide drill bit, especially if bimetal blade is used.

But I don't think the Excello will turn it.

BTW, an aluminum disc will assist greatly in keeping the blades cool.

[DR]

Double hole saw with a spring loaded part ejector between the saws.

Standard hole saws likely won't be available in the sizes needed (they aren't good for poduction in wood anyway). Make a holding assembly and substitute band saw blade wrapped in a circle. Use an extremly coarse toothed blade. Peck drilling may be needed unless you can get saw blade material with gullets deeper than part depth.

If pecking isn't an option you may have to go with single cutters ground to throw the chips up and out of groove. A setup similar to those cheapo adjustable circle tools meant for use in drill presses.

Whatever way it's done you need a method of ejecting the cut piece.