Bristo wrenches

[P3D Bob Wier <wier@xxxxxxxxxxxxxxx>]

Someone asked about a source of supply on Bristo(l) wrenches. Reaching
into my pile of trivia (which is only slightly higher than Mt. Everest),
I pulled out the following....

Actually this is a topic of conversation among those who restore old
radios as one particular military unit (the R-390(a)) which is highly
regarded used these screws to attach the knobs. Getting the knobs off
without breaking them is required to do any serious maintanence work.

Hence the following discussion...

================================

> 
>   Tom NU8D wrote he is looking for a source of bristo(l) wrenches.
> I haven't found any supply of single wrenches.  Last Saturday I invested
> $35.95 for the Xcelite 11 piece wrench set.  The only one needed for
> the R390A is the number 8 size.  Seems to work fine.

Top of the line set.  Much better than my cheap  4.95 Global set.


>   Which is it?  Bristo or Bristol???  I've seen both, as well as
> fluted socket.  Can anyone shed some light on this trivia?
> Richard  N6NAE
> 

Bristo is what I have heard and seen over the years, but when I was in
the service too many years ago to worry much about it, the wrenches were
called:

allen wrench:  socket head set screw wrench

bristo wrench:  fluted socket head set screw wrench.

Needless to say, we always called them ``allen'' or ``bristo'' wrenches.


Here's some info on Bristol multi-spline wrenches for R-390 knobs:  The
proper wrench hase six splines with a diameter of 0.096". Xcelite has a
"screwdriver" bit for their "99" series known as a 99-66.  You'll need to by
a handle (99-1) if you don't already have one.  Snap-on has L-shaped
"multi-spline keys" under part number MS8.

I bought my original Xcelite 99-66 from Techni-tool in suburban Philadelphia
(215-825-4990) some years ago.  Although they had a $25.00 minimum for mail
orders, they let me pick it up as a "will-call" order and pay cash for what
was then a $2.05 item.  You might try Jensen for mail order.

Hope this helps get the knobs off.  The other approach is to file an Allen
wrench to sorta fit, and then replace the set screws with the Allen
equivqlents.

================================

   ====== wier@xxxxxxxxxxxxxxx ======
  7:31 PM Sunday, August 18, 1996
   keeper of the Photo-3d, Motorola
 MC68HC11, Overland-Trails, LDS State
Research Outline Guides and other stuff
     (currently in Ouray, Colorado)



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