pinch roller questions

[benjmn33]

I recently came into a good deal on an otari mx 7308 1" 8 track, with a bad pinch roller. So far the best I can do is $150, but since I’m in tech school for CAD and have access to a machine shop I was considering how hard it would be to make one.

I know it will have to be well made but the shop teacher says that as long as I can get the right material we should, in theory be able to machine it.

The pinch roller is on a metal hub that I think I can press out then press back in to the new "tire."

Does anyone know what material I need?
Could I use urethane?

This does not have to be a permanent solution I just need to pull some tape and not damage the machine.

Any help would be -- helpful

Benjmn33

[The Ghost of FM]

You say the roller is "bad".

What exactly does that mean? Is the rubber cracked or completely mis-shappen?

The are some very, very good rubber rejuvenator products on the market like Caig Labs, Caikleen RBR which is a true miracle worker at bringing worn out, sticky rollers back to life.

http://shopping.netledger.com/s.nl/c...jGr5XDqQLvpAe_

Cheers!

[benjmn33]

sticky,sticky---
and there are a few nicks at the top (i don't think they're in the tape path) which led me to belive that the roller was deteriorating. I had read a post somewhere that had said that the otari rollers of this era were bad about desintigrating and were not worth fixing.

refurbing it sounds like a winner if it can be done.

thanks alot once again.

[tusksut]

The rubber of the pinch roller is moulded to the hub and is not a press fit. In order to renovate the roller you will have to make a split tool and inject liquid rubber into the mould and follow by curring. Then you have to ensure that the composition when cured is the correct hardness so that you can grind the outer surface to the required accuracy of concentricity. This is not an easy proposition.

[The Ghost of FM]

If the nicks are minor enough, I would recommend trying to use the Caig labs stuff first as it only has to be in tact enough to pull tape at an even speed against the capstan so, if it's just sticky beyond that, try cleaning it with Caikleen RBR first.

I think you'll be pleasantly surprised at the results.

Cheers!

[ausrock]

Another alternative may be this guy..............http://www.terrysrubberrollers.com/

[Vintage TX]

Yes, Terry does a great job re-rubber rollers.
Some pinch-rollers get "fungus" not kidding, and kind of melt.
Otari has the sticky type... after awhile it even leaves black rubber on the tape.
Pioneer 909 has the worst bad quality I have seen, those disapperar.
Old Akai's get's hard as a rock with small cracks instead.
Tascam 42 and 44 melts the same was as Pioneer.
Tascam 22, 24, 32, 38 has a more softer rubber and never seen one melt, but get sticky instead.
That's enough about rubber for today.

Good Luck !