Re: Hole saws

stans4@xxxxxxxxxxx wrote:
On Jul 29, 6:41 pm, "Michael Koblic" <mkob...@xxxxxxxxxxxx> wrote:
Another recent thread got me thinking:

In the near future I shall have to cut a doughnut like structure from
0.5-1.0 mm brass. The outside diameter 114 mm, the hole diameter 57 mm. The
cut has to be a) clean and b) reasonably accurate (within1 mm).

There are number of options:
1) Snips
2) Fret saw
3) Jig saw

The concern is about the final edge appearance with these three. I fear that
even supported the edge is going to get ripped up by the saw (especially the
jig) and there will be some bending with the snips.

I have never used a hole saw and I believe that sizes reasonably close to
those above are available. How good are these things at producing clean
edges?

Another option I was wondering about is using a router with a straight 1/4"
cutting bit. I have a very nice small circle jig which allows for increasing
radii by 1/16" and does a really nice job in wood. Has anyone tried this
with brass or aluminium? I am thinking supporting the brass plate on a piece
of wood and having at it.

Finally, thre are these Roto tools for cutting dry wall which come with bits
ostensibly capable of cutting non-ferrous metals. I tried one of these bits
in a Dremel tool cutting kydex freehand but not with great succes due to
lack of control. Some sort of jig would definitely be needed. The advantage
is that the bits are about 1/8" diameter.

My supply of brass is limited and I am trying to make sure that I know what
I am doing rather than using a "try it and see" approach.

--
Michael Koblic,
Campbell River, BC

Barring the use of a metal lathe which makes the process trivial,
here's another choice:
http://www.drillspot.com/products/100412/General_Tools_5B_Std_Circle_Cutter
First up on Google

The local hardware store has these in two sizes on the peg, I've used
them on plastic, wood and thin *** metal. Best used in a drill
press. For thin *** metal, you're going to want to sandwich the
stuff between two sheets of wood, preferably with some sort of easily
removed glue or contact cement(shellac?). When I use one of these, I
put a hole in the center of the workpiece with the drill bit, then
swap it out for a rod so the pivot hole doesn't get wallowed out. You
want to run this thing sloooow, some cheapy drill presses won't go
that slow. The workpiece gets clamped, you adjust the flycutter radius
for the outside and cut that first. Then do the inside. 1mm
tolerance shouldn't be too hard to do, just be careful measuring and
setting the cutter. I've done wooden toy wheels with one.

Stan
If you look at Abrasha's website you will see he has done just about what you are needing to do. His videos are amazing!
http://www.abrasha.com/
.

Quantcast