Tapered holes

[Jlg]

can you get hole punches to put tapered holes in 10mm neoprene

 

[LewisT]

Cant see how a punch could produce a tapered hole

 

[angellonewolf]

heat up a taper drill and drill out the heat should melt the neoprene ?

just an idea do not actualy know if it will work

 

[pcwizme]

How tapered? I know leather punches make "tapered" holes but they are only slightly tapered

 

[Paul.]

The way to do it is stretch the neoprene over a dome, then punch it on the dome, then when its flat the hole will be tapered, some experimentation required to get it right.

 

[cumbriasteve]

How tapered? I know leather punches make "tapered" holes but they are only slightly tapered

I am struggling to understand how they can, I have a box full of leather punches and the dia of the punch cutting face is the diameter it cuts through the leather.

On leather because the cut face of the punch often has a taper going back to the shaft they can give the impression the hole is tapered but all they have done is force the top layer wider, it soon returns to the punch diameter.

 

[daedalusminos]

I would have thought controlling a taper in neoprene would be difficult (a straight punch might naturally form a tapered hole as the material collapses under pressure)...might be best to explain why you want it in case a better solution is available.

 

[Jlg]

I'll take a picture of what it's for later the hole needs to be about 50mm

 

[Jlg]

This is what it is for you can see why I need the hole taperd

 

[MattF]

What's its purpose? If it's just to make a seal, I'd be inclined to use an O-ring.

 

[Paul.]

Is that foam?, if it is you can rout it, one of my work neighbours is a plastic fabricator and they cut this stuff all the time on a cnc router.

 

[Jlg]

It's to seal round the petrol tank on my jetski the chain that holds the petrol cap stops it sealing so I thought that the neoprene would work to seal it



It's neoprene

 

[pcwizme]

I am struggling to understand how they can, I have a box full of leather punches and the dia of the punch cutting face is the diameter it cuts through the leather.

On leather because the cut face of the punch often has a taper going back to the shaft they can give the impression the hole is tapered but all they have done is force the top layer wider, it soon returns to the punch diameter.

I think I mis-typed what I meant to say, I really meant exactly what you say, they have a tapered cutter, and could if used on foam make a tapered cut (potentially)

I cant imagine a new seal would cost that much from the original manufacturer

 

[Screwdriver]

Hot wire cutter will do that (bit of wire and a battery). Arrange it so that the wire can sweep a cone, dimension it so that it cuts the conical section you're after.

<edit> if it's not obvious what I suggest: fix one end to the floor, the other end sweeps a circle, the bit in between sweeps out a cone and cuts your desired taper(s).

 

[daedalusminos]

the chain that holds the petrol cap stops it sealing

Why does it stop i sealing - has it always been like that or have you modified something?

 

[Cobbler]

Would a "doughnut" off a close coupled WC suite do the job for you? Save a lot of messing about.

 

[Jlg]

Why does it stop i sealing - has it always been like that or have you modified something?

It's always been like that I've just bought new petrol cans to refuel it but the nozzle needs to seal around the opening

 

[Jlg]

Hot wire cutter will do that (bit of wire and a battery). Arrange it so that the wire can sweep a cone, dimension it so that it cuts the conical section you're after.

<edit> if it's not obvious what I suggest: fix one end to the floor, the other end sweeps a circle, the bit in between sweeps out a cone and cuts your desired taper(s).

That sounds like a good idea what size battery and what tips of wire do I need

 

[Screwdriver]

There are a million ways to do it and the way to pick which is best relies on knowing what you might have "on hand", what your budget/timescale might be and if you have much electronics skill.

Easiest/cheapest/quickest and safest (!) is probably to buy a cheap soldering gun and string a bit of thin SS lockwire around a suitable frame. Big lead acid (car) batteries work well but will melt a spanner let alone a bit of wire so require some knowledge of electronics - you can rig up a "resistance" in series with a bulb for example.

 

[Hopefuldave]

There are a million ways to do it and the way to pick which is best relies on knowing what you might have "on hand", what your budget/timescale might be and if you have much electronics skill.

Easiest/cheapest/quickest and safest (!) is probably to buy a cheap soldering gun and string a bit of thin SS lockwire around a suitable frame. Big lead acid (car) batteries work well but will melt a spanner let alone a bit of wire so require some knowledge of electronics - you can rig up a "resistance" in series with a bulb for example.

The posh setup is a fairly chunky low-voltage transformer and a variac - that's what I use, but mine's too scruffy with wires everywhere to be posh...
Guitar string works ok for the wire until you get it too hot, then it stretches like a rubber band!

Dave H. (the other one)