[R-390] RF geartrain screws

[Chris Farley]

Hi all, 


Well I finally nailed down what is seemingly the one and only *realistically priced*  source some of the .096 spline/bristo/bristol screws used on the r-390a shaft collar/clamp screws.  *(Still not what I'd call cheap, but then again I had one supplier quote me $35 EACH!)  

These are the 4-40 x 9/16" long ones,  4-40 x 1/2" are also used on some of the smaller clamps.  9/16" being 1/16" longer than necessary for the smaller clamps, they can be left as-is or cut down 1/16" if preferred.  It was discovered that these screws are basically unobtanium, as the "standard" spline drive size for a #4 cap screw is .111-6, not .096-6.  These screws were a specially made item for these (and probably other) radio equipment.  The square nuts and washers are much easier to source.  


This screw purchase will likely be a one time buy due to the price and minimum order requirements.  Thus this is an email blast to see how many of you might also like some, so I can order the appropriate quantity.  


These are the same national stocking number that crosses to the original Collins part:  4-40 x 9/16" cap screw with 0.96" 6 flute spline drive, Spec'd to be zinc or cad plated steel, MIL-F-14072, yada yada yada. (Surprised these weren't originally stainless steel, but indeed they are not upon a closer look).  


For fellow list members interested, my final cost will be about $2.00/ea.  With a quick count 13 screws appear to be used per unit, including the two main tuning knob clamps.  Cost for a set of 13 with CONUS shipping in a padded envelope would be $28.  I may also put "kits" together with the washers and square nuts required, but haven't gone there yet.  If some of you wanted much larger quantities, say 100+, I can offer a slightly better price per unit.  

If you would like to be a part of this purchase, please let me know ASAP and I will place the order.  Note this is for the R-390A geartrain, I have not done research for the R-390 to see if they use the same hardware.  


Regards, 

Chris kc9ieq