[R-390] RF geartrain screws

[Chris Farley]

Greetings-

Thank you to those who have responded to this "screwy" deal, you have all been marked down.  

Due to a larger than expected response, further reservations are CLOSED as of now-  I only have 300 available to me at this time, and they are all spoken for.  I WILL continue the search for more, and will advise the group as to their availability.  

I will update you all next week, as (due to popular request) I will also be getting some square nuts and possibly lock washers to go along with the screws.  (Can anybody tell me WHY they used split lock washers under the nuts on later units??  They aren't even shown on the earlier Collins mechanical drawing.  It would be impossible for that nut to loosen, as it is kept from spinning by the nut).  

I should have everything here and ready to mail out in about two weeks, hopefully sooner.  

Thanks again for helping out.  Our radios (and future service technicians!) will thank you.  

Regards, 
Chris kc9ieq




________________________________
 From: Chris Farley <kc9ieq at yahoo.com>
To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net> 
Sent: Thursday, February 27, 2014 1:51 PM
Subject: [R-390] RF geartrain screws
 

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
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