Advice needed - Getting 5" OD and 7" OD punch for gasket material

Suggest you look into clamping the pieces onto a lathe faceplate and feeding an X-Acto knife mounted in a toolpost at the appropriate diameter to cut your circles. If you don't have a lathe but have a drillpress, you can do a similar job using a circle cutter.
GWE

Steel rule die, cutting against a piece of polypropylene. A smallish bench hydraulic press will do the cutting nicely. There are various companies who will make the die very precisely for you using laser cutting on the plywood, or you can try to make it yourself. You need to back up the die with a piece of metal if there's no press platen.
Best regards, Spehro Pefhany

Or a clicker die if something sturdier than a steel rule die is required. Still reasonably priced for simple shapes.
I *do* have a connection with these folks - they're a long standing customer of mine...
Ned Simmons

Make the dies on a lathe Use it with a big arbor press against a propylene cutting board.

Locate a carton or puzzle maker. They use continuous razor blade stock that can be simply mounted on an arbor of the correct size. If you're physically close, they'd probably liberate a few feet for you.
LLoyd

Thanks for everyones help.
I found an arbor press from Jet that comes in 1/2 ton, 1ton and 2 ton.
What would be the right size for cutting 7" OD neoprene rubber with rule die or clicker die?

Are the gaskets simple circles, something like pipe flange gaskets, or something more complicated?
A steel rule die might be one option for you, especially if you have or can rig up some sort of press. We've had a few made for work over the past few years and prices seem to range from $100 to $500 for simple to complex dies. Simple circles might run even less. If you are in the Chicago area I can point you to a good source.
I've also seen employees at the above outfit cutting out circles with some sort of compass-like cutting tool.

I don't know the numbers for neoprene (it will also depend on the thickness, at least it does in other less rubbery materials), but my WAG is that 2 tons sounds a bit light. If it's a simple 7" circle you have 22" of cutting length with a steel rule die. Maybe someone here has some design numbers for you. Clicker dies should require less.
BTW, if you get the die made commercially you can get it to cut inner circle, outer circle and bolt holes simultaneously if you like (but the pressure required increases proportional to the total length of cut). OTOH, you don't need to worry about lining things up.
Best regards, Spehro Pefhany

try apple die for fast and accurate service. A die like that shouldn't cost more than 40 bux.

What Rex said.
Through the years I've cut hundreds of rubber discs with such instruments. They work great spun in the spindle of a drop spindle mill at low speed, and can be fashioned from soft material (mild steel) if you don't expect a large number of pieces to be cut. The cutter itself should have a straight face on the side that sizes the object----with relief for a sharp edge generated on the opposite face.
Harold

My favorite for dies is (great quality, fast turnaround, great price). I agree that 2 tons sounds light, especially if you are punching inside and outside circles together. However, the common way around this commercially is with a traveling head cutting press. Works just like it sounds: head comes down on die, moves over some, comes down again, etc. That's how you punch something like an oil pan gasket without needing hundreds of tons of press :-). Moving the punch keeps the cutting board, stock, and die all stationary and aligned. In this case with your low volume and circular shape it would be real easy to go around the die with an arbor press and hit it as often as necessary. You just have to maybe think about clamping the stack to keep it from slipping as you go around, but a little experimentation will answer that.
-- Regards, Carl Ijames carl.ijames at verizon.net

I have always used one of these gasket cutters. Enco model number 422-2605.