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Posted by Michael Koblic on July 29, 2008, 8:41 pm
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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
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Posted by JR North on July 29, 2008, 11:09 pm
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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"
>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
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Posted by Artemus on July 30, 2008, 12:15 am
Please log in for more thread options 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).
>
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Posted by Stuart Wheaton on July 30, 2008, 12:19 am
Please log in for more thread options 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
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Posted by Tom Gardner on July 30, 2008, 12:46 am
Please log in for more thread options
> 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.
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>
>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.