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Anyone know of something I could use to punch some 3/4" blanks (discs) out of thin sheet brass? Or where I could buy some, or someone who can make some and doesn't want an arm and a leg :)

I tried using a 3/4" diamond hole saw but the results were not very good.
 

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McMaster-Carr sells such things. In general, be aware that industrial punches are designed more to create an accurately sized hole rather than an accurately sized disc. Depending on how chewed up the disc comes out, you may need to consider the larger 13/16" size and file it to shape.

http://www.mcmaster.com/

Type 3427A19 into the Find Product search box.

Brian
 

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Discussion Starter #4
RE: Looking for metal punch that will make a 3/4" blank

Thanks Brian, I'll check that out. Have you used these on thin sheet brass?

The brass is pretty thin, .016" sheet. It would be better if no hole in the middle, but a very small hole would be okay.
 

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RE: Looking for metal punch that will make a 3/4" blank

You might try sandwiching a rough cut circle between a couple of hardwood dowels of the desired diameter in a lathe... dowel in chuck|brass rough cut circle|dowel|tailstock. Crank the tailstock tight against the sandwich. Turn slowly so that if it "catches" it won't throw schrapnel at you.

EDIT: use a Live Cup Center in the tailstock.
 

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RE: Looking for metal punch that will make a 3/4" blank

I'm trying to make a railroad signal like this:



I've got the lens, thank you for the link a while back :) I can cut the hole for the lens to go into. Now I need to make the visor over the lens. As a test, I cut a round disc out of a piece of paper 3/4" diameter. If I then cut that in half and curve it around a 1/4" dowel, it makes the perfect lens visor. Now I just need to make it out of brass :)
 

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How about a 1" circle and some filing?

The reason I ask is that McMaster-Carr has brass Metal Engraving and Stamping Tags - but the smallest is 1" diameter. They're also a bit thicker than you might want. I used them for the targets on my switch stands.

You might try cutting it with a nibbler. You can get them from Micro-Mark.


You could scribe a circle and then use the nibbler to make the disc. You'd have to finish it with a file, but the nibbler is a nice tool for cutting brass accurately.
 

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RE: Looking for metal punch that will make a 3/4" blank

Took a look at the tags; yes 18 gauge will be too thick for me to bend in the shape I need, but thanks for the tip. I've never used a nibbler, but I'll take a look at them.
 

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RE: Looking for metal punch that will make a 3/4" blank

Steve, that is another good idea. I was hoping to make a bunch of these, so I'm not sure how good I could get at shaping the visor, but I'll keep that on the list of options.
 

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In regards to the repeating the visor shaping. What I was thinking is, since the tubing of a given wall thickness is telescoping in nature. Meaning that as you step up in size, the O.D. of the smaller matches the I.D. of the next largest size tube.

So if you found that the 1/4" tubing fit the existing lens. Then you could use the 9/32" tubing to make your master for the visor's shape and once you got that done, for each of the 1/4" visors all you'd need to do is slip it into the master and use it as the template while shaping the visor profile on the 1/4" blank. That way all that you make should come out pretty darn close to being the same.
 

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Jim, here may be another answer to your problem.

6 Piece - Jeweler's Disc Cutter Punch Tool Set
Sizes 1/2", 5/8", 3/4", 7/8", & 1"
 

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Discussion Starter #15
RE: Looking for metal punch that will make a 3/4" blank

Steve, your idea about making the master out of the next size smaller is ingenious. I'll have to try it just to see it :) Also, the cutter punch link is great. I'm going to go for it!

Dick, It looks like that tool is for paper, will it cut thin brass sheet, .016"?
 

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RE: Looking for metal punch that will make a 3/4" blank

Perhaps another tool to try is a gasket punch, available at tool suplliers or maybe auto parts stores.
I have used 1/2 inch to cut brass shimstock to make street lamp shades
John
Manitoba Canada
 

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Try this

Take two pieces of steel say 3/8 or 1/2 thick. Drill a hole through both of the two pieces the required distance apart and the diamater of the required hole with a drill press.

Sandwich the brass between the two pices of steel. Possition the sandwich under the drill press. Turn the drill press on and run the bit down throught the two holes you drilled. This should give you the exact hole in the brass you want and it should be neat and clean.

Then trim the brass to make the signal face plate.
 

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Discussion Starter #19
RE: Looking for metal punch that will make a 3/4" blank

John, thanks for the tip on the gasket punch! I'll poke around at the auto stores around, there seem to be plenty.

John, that seems like a cool trick, kind of like making your own punch and die? I'll have to give it a try, thanks!
 

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RE: Looking for metal punch that will make a 3/4" blank

How about a piece of copper tubing?
A coupling that you sharpened?
 
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