[Fot] Rod question

[J.C. Hassall]

At 03:57 PM 10/25/2008, Tony Drews wrote:
>I'm trying to help one of the list members buy a connecting rod, and 
>the rod manufacturer wants the small end and big end weights of the 
>existing rods to match to.  Then it occurred to me - I have no idea 
>how to go about doing that.  Anyone know the technique for weighing 
>each end of the rod?  This is just for future reference for me, but 
>may help out my cohort.
>
>Thanks, Tony Drews

Tony, my first attempt at balancing my own rods involved weighing 
each end, then grinding to match.  Perhaps a workable plan, but I 
came up with an even better method.
Anyway, the fixture I made supported one end while I weighed the 
other.  Having the rod exactly horizontal didn't seem to be 
important.  I found some small ABEC 5 (fairly high quality, from 
McMaster Carr if memory serves) ball bearings.  I made a vertically 
adjustable T fixture from scrap Aluminum.  Into the upper piece I 
threaded a 1/4" bolt, on which the bearings sat.  One end of the rod 
was suspended on the bearings while the other end sat on a beam 
balance.  It's important to use 2 bearings, or a very wide one, so 
the rod doesn't wobble.

BTW, I tried simply balancing the rods on a nail, but the coefficient 
of friction was too variable to give reliable results.  That's why a 
set of quality bearings are needed.

jim

--
J.C. Hassall
Blacksburg VA
'63 TR4 in autox preparation
96% finished, 90% to go