I am wanting to make custom gaskets from 1/8" neoprene rubber.
I need low volume and would like to use a punch stamp to make them as
needed instead of ordering 100-1000 at a time.
Where can I get a n inexpensive punch to cut 5" OD and 7" OD circles.
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.
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.
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...
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.
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.
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.
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.
Carl Ijames carl.ijames at verizon.net