RE: [T3] Pressure Sensor diaphrams

["Keith Park" <topnotch@nycap.rr.com>]

And ME with an 037 and bad diaphragm!  Fantastic Jim!

Keith


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-----Original Message-----
From: Jim Adney [mailto:jadney@vwtype3.org] 
Sent: Saturday, January 23, 2010 4:25 PM
To: type3@vwtype3.org
Subject: [T3] Pressure Sensor diaphrams

It looks like I may be on the way to reproducing the diaphrams that 
crack in our 70-1 D-Jetronic diaphrams. I've been meaning to do this 
for years, and have saved a few bad pressure sensors just to have 
some copies to try to emulate.

Finally, this past week, I had some time to cut the center slug free 
from its (badly cracked) diaphram, do some measurements, and make a 
CAD drawing for a die that I thought might do the trick. Later that 
week, our shop used my CAD program to give some of their people 
something to practice using a new CNC program. Friday afternoon we 
tried it out. I tried .004 copper and .002 & .003 brass.

The first efforts were poor: The brass cracked along the 
convolutions. But we added some lubrication, so the metal could slide 
along the die and no more cracking. 

We're not there yet, and I haven't decided on the best choice of 
material, although copper looks good and that's what the originals 
look like. I'll do more next week, and eventually I'll need to put 
one in a pressure sensor and drive with it.

So if you have a damaged one, don't throw it out. It may soon be 
fixable for a fraction of the cost of a whole new pressure sensor.

-- 
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************

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