[Hallicrafters] Bristol Spline drive set screws

[Mike Everette]

I have found a few instances where the small Torx
screwdrivers, say in the range from T-3 to T-10 size,
are compatible with Bristol set screws but I don't
know how universal this may be.

If I encountered Bristol screws, I'd replace them with
either Torx or Allen if they are bad.  I am inclined
to think that the Bristols are a holdover from
military specs, both for Halli and Collins.

73

Mike
WA4DLF

--- Charlie <pincon at erols.com> wrote:

> I have been asked several questions about the
> Bristol drive set screws so 
> here's a compilation of them.
> 
> 1)The Bristol drive set screws have generally become
> obsolete with the 
> introduction of the Torx drive.  They are still used
> in some commercial 
> applications, as they are superior in their torque
> ratings.
> 2)The Bristol drive resembles a splined drive shaft
> with square sided 
> flutes, whereas the Torx drive has rounded flutes
> which will remind you of 
> an end view of an umbrella.
> 3)There are incidences where an Allen hex drive key
> will fit into a Bristol 
> socket, but it is not a true mating fit.   If the
> torque required is VERY 
> low, the Allen wrench MAY be made to work, but the
> risk of damage to the 
> splines is not worth it.
> 4)The actual set screw threads used are identical to
> all other set screws, 
> so either a slotted or Allen drive set screw can be
> substituted for the 
> Bristol drive with no worry.
> 5)I'm not sure what determined whether the various
> Bristol sizes used six or 
> four splines.  You would think that the smaller
> sizes would all drop to 
> four, but this is not the case.
> 6)Possible sources for the Bristol wrenches are:
> Jensen Tools, Techni-Tool, 
> McMaster-Carr, MSC Hardware, Grainger and probably
> any commercial 
> hardware/tool supplier.
> 7)The Xcelite part numbers for the four I use are: 
> 99-67, 99-66, 99-64 & 
> 99-63.  These will fit any of Xcelite's various size
> handles.  The complete 
> set of inserts and a drive handle is packaged under
> their part number 
> 99-PS-60 which typically sells for around $40.00
> 8)Sets of "L" wrenches are also available at the
> Bristol website
> 9)I have a source for Bristol set screws that I
> bought in order to supply 
> the correct ones with the new production Dakaware
> knobs I purchased a few 
> years ago.  As I am contemplating another large
> quantity knob buy, I find 
> that unfortunately, the Bristol set screws have gone
> up considerably in 
> price.
> 
> 73' Charlie k3ICH
> 
> 
> 
>
______________________________________________________________
> Hallicrafters mailing list
> Home:
>
http://mailman.qth.net/mailman/listinfo/hallicrafters
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Hallicrafters at mailman.qth.net
> ----
> List Administrator: Duane Fischer, W8DBF **for
> assistance**
> dfischer at usol.com
> ----
> Hallicrafters Collectors International:
> http://www.w9wze.org
> 


__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com