[rmwood777]

I am trying to program a radius chamfer around a 145mm wooden circular pattern to make ends for a model steam boiler, I am obviously doing it all wrong, any help??

[handlewanker]

Hi....BTDT.......I made the pattern using some hardwood turned to the diam needed on a lathe.

The radius on the corner of the wood pattern was finished, after turning the diam, with a radius form tool.....at fairly high speed and some file work.

I assume you are going to beat a copper disc to the end cap form around the wood former......you will need to machine the finished end cap in a lathe to get it round and a close fit in the boiler barrel.

This will get you there, but making a mild steel die and punch to press the copper disc to shape will give you a finished item that will be round and a very close fit in the boiler shell for silver soldering.
Ian.

[rmwood777]

Hi Ian
Thank you for your reply.
We don't have a lathe big enough unfortunately so my idea was to mill a circle using the CNC machine, I have been told it could be finished with a radius cutter.
I'm pretty new to G Code, cutting the circle was easy, but I cannot figure out how to put a radius on it.
The boiler is 6" or 150mm round, so it would need some weight to make a die and punch.
Richard

[handlewanker]

Hi,.......OK, all you need is a radius cutter.....one that produces the radius on the edge of a work piece, not one that is ball ended etc.........for wood you can make a cutter from silver steel and make the end a flat cutter with the cutting edges on each side.....done that many times.

I also make wood working cutters by brazing pieces of HSS from hacksaw blades or broken slitting saws into plain round steel shanks and hand grind them to whatever profile I need.

You can buy the cutters on EBAY or your local tool supplier.....and they also come for router use with carbide tips and already profiled..

If you already know how to make the cutter go around in a circle just adjust your offsets for the diam of the cutter to give you the rad on the edge of a round square edged blank.

BTW.....many people use a bench vice to do service as a rudimentary press......but in your case the diam at 145mm is a bit much.......a 16 ton shop press perhaps......for a one off, the method you are proposing is tried and trusted.
Ian.

[handlewanker]

Hi....just had a thought....why not mount the wood disc on a spindle and hold it in the chuck on the mill.....than you can "machine" it as if it was a wood lathe and finish it with a coarse file etc.
Ian.

[rmwood777]

Ah we have a large drill press, could put a bolt in the centre and do as you suggest, excellent idea.
Thanks.

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