Today's project... "machining" soft rubber.

[RiverDave]

Now you might be asking yourself.. How in the fock does someone machine soft thin walled rubber? My answer.. Well I'm not entirely sure yet.. But give me a half an hour, and I'll come back with the answer.

Gotta get creative.

RD

 

[Terminal Velocity]

if he machined a condom that would make it bigger wouldn't it? And that would certainly defeat the purpose. j/k Dave, always curious and impressed with your machining abilities.

 

[RiverDave]

So here's what we came up with..

We have these rubber diaphrams. We need to get rid of this ridge on top outside edge, as it's getting hung up on a rough surface finish on the mating part. The problem is just on the inside of that ledge is a sealing surface, which means if we do cut it away it has to be precision.

 

[RiverDave]

I mounted the rubber on a mandrel (sp?) By just machining a peace of plastic that is just slightly larger then the inner diameter of the diaphram. (By slightly I mean slightly)

Then mounted a hand held dremel tool in a collet. I dressed the dremel tool wheel with the diamond for a surface grinder to make sure it's flat in both directions..

Fired the dremel tool up wide open, and ran the lathe slow in the opposite direction.

RD

 

[RiverDave]

At the end of the day we did some precision work on a soft part. The area is now "flush" with the original sealing surface. It's exceptionally smooth, and will work as a sealing surface. The only reason you can tell the part is re-worked in this area is because a slight difference of appearance. The machined area is slightly less "glossy" then the original part.

Before and after shot.

 

[Kindsvater Flat]

Why not use liquid nitrogen?

 

[Racey]

Why not use liquid nitrogen?

Now you're talking, when i bore urethane bushings its either put em in the deep freeze (if you can work fast) or dry ice.

 

[Yellowboat]

I've always just used sand paper... ( done many a flaper valve for surge systems and lots of but pads that way.)

 

[RiverDave]

Why not use liquid nitrogen?

Now you're talking, when i bore urethane bushings its either put em in the deep freeze (if you can work fast) or dry ice.

Didn't have any liquid nitrogen on hand.. as well I'm not even sure it would work? If the parts were "hard" then how would i hold them? On top of which if they hardened a little mishaped, then it'd be tough to get a true "flush" cut.

When they are flimsy they conform to the mandrel.

Interesting tip though, I'll keep it in mind for the future.

RD

 

[Infomaniac]

We cut soft rubber all the time on the lathe with high speed steel cut to a special top secret tip.

and .... we grind it on the crank grinder or Blanchard also.

Good Job Man.

 

[lebel409]

My dad gave me a tip when cutting rubber. Get it wet. Rubber seems to stick to a smooth surface, but water seems to be enough to let the blade do it's job.

Ever cut a garden hose? Tough as hell, then the blade hits the water and it goes through real quick. Same deal.

Works good on sheet, tubing, etc.

 

[RiverDave]

My dad gave me a tip when cutting rubber. Get it wet. Rubber seems to stick to a smooth surface, but water seems to be enough to let the blade do it's job.

Ever cut a garden hose? Tough as hell, then the blade hits the water and it goes through real quick. Same deal.

Works good on sheet, tubing, etc.

Thanks for that. Going to have to try that the next time I have to cut gaskets etc..

RD