Cut discs out of sheet plastic?

[Kit Basher]

I need to cut several discs out of .030 styrene. They need to be fairly accurate circles, and I have to cut multiples of the same size. Most are going to be in the 3/4" to 1" diameter range. Any suggestions?

[turn1wonder]

You could make a punch out of a sharpened end of a pipe/tube. If a hole in the middle is ok you can use a hole saw. If a very small hole in the middle is ok you can use a vernier caliper .

Bob

[Chief Joseph]

Easiest way would be with a set of gasket punches, but good ones that make clean, sharp holes are not cheap. Another option is not cheap either: a mini lathe. You can use an Olfa circle cutter, which is quite a bit cheaper, but the one I have doesn't do smaller circles like 3/4" very well.

[Mike Kucaba]

Ask this seller,maybe he can help.

http://www.ebay.com/itm/PLASTIC-DISCS-TRANSLUSANT-1-16-THICK-/380444753301?pt=LH_DefaultDomain_0&hash=item5894463d95

[Greg Wann]

http://www.ebay.com/...=item53ed59e86a

Try this style of punch set. You will be amazed how clean a circle it will make. This one has a cheap starting bid.

Edited June 8, 2012 by Greg Wann

[jamesG]

You can stack a few square pieces together and cut them out on a scrollbars saw if you gave one.

[MicroNitro]

This is the one I use, It works good but I do not have anything for comparison. http://www.amazon.com/True-Power-Pc-Punch-Die/dp/B0010ZM6EW/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=LTBCK5O977ID&coliid=I34GXHOAWJE7TR

[crazyjim]

Cut the discs close to shape, drill a hole in the center and chuck them in a Dremel tool. Run a sanding stick to get to finished diameter.

[Kit Basher]

I knew you guys would come through. That's a bunch of good ideas. I do have a scroll saw and a Dremel, and I think I'll try making punches out of pipe. I wondered if I'd get any suggestions about a compass, I may try mounting a knife on one. Thanks to all.

[Greg Wann]

I knew you guys would come through. That's a bunch of good ideas. I do have a scroll saw and a Dremel, and I think I'll try making punches out of pipe. I wondered if I'd get any suggestions about a compass, I may try mounting a knife on one. Thanks to all.

putting a blade in a compass will work too but it takes some engineering to get it to work OK.

[bill w]

You can use compass cutter blades, available at art supply stores.

Hosted on Fotki

[Greg Wann]

You can use compass cutter blades, available at art supply stores.

Hosted on Fotki

AWESOME! What will they think of next? I think when I tried it I just put two of them pointy things in and let one of them do the cutting.

Edited June 9, 2012 by Greg Wann

[bill w]

I die the same with the pointy things, on thinner sheet styrene and with my dividers.

[Kit Basher]

I have some of those blades in a hobby knife set. I need a better compass, the one I have does not have the threaded adjustment. How does that rig work on smaller circles?

[Crazy Ed]

Another idea given you seem to only need a batch the same size but not a specific size try and get ahold of a surplus .50 BMG shell case. If you were to cut it down to say 3/4 inch long the opening would be just under .8". Drill out the spent primer and chamfer from the outside in, which will result in a straight walled disk. Pop out the disk with a flat tipped nail

[sjordan2]

What are you going to use the discs for?

Without knowing the purpose, I would toss in the idea of using self-adhesive, die-cut paper dots that are available in a multitude of sizes, on sheets and in rolls like Scotch tape.

[Kit Basher]

Skip, I'm making hose reels, like you would see on a fire truck or fuel tanker, so the discs are structural. Thanks for the suggestion, tho.

[Ace-Garageguy]

The compass cutting tip is by far and away the preferable option, in my opinion. You don't have to cut all the way through the plastic, just score it enough so you can snap the discs out and clean up the edges with 400 grit sandpaper.

Nice thing about a good cutting compass rig is that you can then use it for any diameter circle you want. There are also hole punches, like for notebook paper, for several size small holes. I use them for small things like coil spring seats.

Another cutting compass trick is to make whitewall tire masks out of frisket paper. Then you can spray your whitewalls with vinyl interior dye, and they look like factory printed jobs and don't end up with the lettering filled like acrylic paint will do.