Gallery, Projects and General > How do I??

How do I cut some rings?

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John Hill:
I want to make myself a gimballed gyroscope.  The plan is to cut the gyro wheel and the gimbal rings from a sheet of 1/4" plate.

The first experiment was a bit of a failure,  I put a square of plate in the 4 jaw chuck and made a trepanning tool.  The first cut was to cut the gyro wheel itself and it came out clean enough.  Cutting the first ring started OK then the tool began to chatter and no amount of phutzing with the tool tip seemed to make a difference, the only thing that would stop the chatter was to increase the feed pressure.

You can imagine what happened, when the tool broke through the ring tumbled out, got tangled and ended up twisted like a pretzel though it didnt stall the lathe or seem to do any damage except to the tool tip.  Oh well...

So, what is the orthodox way of cutting a ring from a sheet?

sbwhart:
Hi John

What diameter disc are you after making ?.

Bernd started a thread on some trepanning he did that may help

http://madmodder.net/index.php?topic=624.0

If the problem is the disc flicking out when the tool breaks through you could try sticking it to the back plate with some two way tape or supper glue (tape would be best) before you start.

Hope this helps

Stew

John Hill:
Stew, the first cut, the solid disc, is 50mm diameter, the ring about 70mm.

Yes, the ring being cut off has to be restrained somehow, I will need to get some more steel so that I can have a sacrificial backing on the plate as using the 4 jaw chuck is obviously not going to work unless I can think of a way or restraining the cut off bits.

I dont think I need a tool like Bernd made unless I go up in size a little!

sbwhart:
John

John or was it Ralph ?.  :scratch:

Had a link friction turning some hubs for a fly wheel that will do what you want.

Basically what you do it rough your disc out with a saw, put a centre in the middle on a pillar drill, put some masking tape on the back of the disc then trap the disc up against the chuck jaws with a running centre and trim up the OD.

If you do a search of the forum you may find the link or perhaps John/Ralph will point you to it when they read this.

Just read your post again 50mm and 70mm (2" and 3") Have you thought of a tank cutter ?. When you've got the bore done you can mount it on a mandrel to trim up the OD

Good Luck
 :wave:
Stew

Darren:
Hi John, the latter part of this video shows one way to go about it.

http://techtv.mit.edu/videos/172-machine-shop-10

PS, the whole series is worth a good look.. :thumbup:

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