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

Drill the inner hole1/2" or so. Rough cut the OD. Mount on an arbor
and turn the OD to spec on the lathe. Remove the arbor, clamp the
piece in a 3 jaw chuck and turn the ID. None of the options you list
will provide the edge finish or accuracy you need.
JR
Dweller in the cellar

On Tue, 29 Jul 2008 17:41:44 -0700, "Michael Koblic"
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.
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth
If you're not the lead dog, the view never changes
Doubt yourself, and the real world will eat you alive
The world doesn't revolve around you, it revolves around me
No skeletons in the closet; just decomposing corpses
--------------------------------------------------------------
Dependence is Vulnerability:
--------------------------------------------------------------
"Open the Pod Bay Doors please, Hal"
"I'm sorry, Dave, I'm afraid I can't do that.."

Woodworkers routinely cut thin soft meals by sandwiching them between
two sheets of thin plywood. Use double sided tape or glue to adhere the
assembly together. You can then saw with whatever power saw you have
on hand. A router with a straight sided carbide bit will clean the edges up
quite nicely. Use a solvent or heat to soften the adhesive and open the
sandwich.
Art

"Michael Koblic" wrote in message 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).

Michael Koblic wrote:

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.

Use a wood like a dense particle board, bore a hole the proper diameter
in the board, clamp your brass over the hole and drill a pilot hole for
your router bit, rout out the inner hole. Then make a second jig the
diameter of your outer cut, use a turned dowel to locate the center hole
in the center of the outer ring, clamp and rout.

Aluminum routs very well, I assume brass will too, the soft metal will
stick in the bit, so take light cuts and coat the bit with a good lube
before, during and after.

Stuart

"Michael Koblic" wrote in message
rvecommunications...
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


Get tubes with the right dimensions and turn or grind a knife edge. With the
sheet on a block of hardwood tap the tube through it with a hammer.

On Jul 29, 6:41*pm, "Michael Koblic" 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/10..._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 sheet metal. Best used in a drill
press. For thin sheet 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

wrote:
On Jul 29, 6:41 pm, "Michael Koblic" 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/10..._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 sheet metal. Best used in a drill
press. For thin sheet 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/

wrote in message
...

Barring the use of a metal lathe which makes the process trivial,
here's another choice:
http://www.drillspot.com/products/10..._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 sheet metal. Best used in a drill
press. For thin sheet 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.

******

I forgot about these! I looked at them some time ago but dismissed them on
account of the said cheapo drill press. However, since last month I have
been a proud owner of a new drill press that goes down to 220 rpm. That
should be OK for a 4-1/2" circle?

The hint about the swapping the drill bit for a rod seems crucial, thanks.

Sadly, lathe has been so far present only in my dreams...

--
Michael Koblic,
Campbell River, BC

Thank you. I had a look. Now I am depresssed.
Please see the following link, not to boast but mainly to demonstrate the
ever so slight difference in the level of skill.

http://www.flickr.com/photos/2768312...7605638700703/

"Michael" wrote in message
...
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/

On Wed, 30 Jul 2008 12:18:39 -0700 (PDT), wrote:


Barring the use of a metal lathe which makes the process trivial,
here's another choice:
http://www.drillspot.com/products/10..._Circle_Cutter
First up on Google

These can be very interesting to use cutting a hole in car body metal
powered by a 2000 RPM, non variable drill motor. DAMHIKT
Gerry :-)}
London, Canada

On Wed, 30 Jul 2008 18:35:05 -0700, "Michael Koblic"
wrote:

Thank you. I had a look. Now I am depresssed.
Please see the following link, not to boast but mainly to demonstrate the
ever so slight difference in the level of skill.

http://www.flickr.com/photos/2768312...7605638700703/

"Michael" wrote in message
m...
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/

He is a marvelous craftsman. He is also an Idiot Savant. Good for one
thing (other than composting) and one thing only.

You are multi talented compared to him, if you can at least tie your
own shoes

Gunner