Mike A Posted June 25, 2021 Report Share Posted June 25, 2021 Anyone know the specs on the screws that are installed at the front of the 231 top cowling? Quote Link to comment Share on other sites More sharing options...
steingar Posted June 25, 2021 Report Share Posted June 25, 2021 On mine it's mostly whatever fits. Those holes are so stretched out from 50 years of screws going in and out. They were probably something altogether different in 1962. Quote Link to comment Share on other sites More sharing options...
PeteMc Posted June 25, 2021 Report Share Posted June 25, 2021 (edited) Pretty sure this is it: AN526-1032R10. Aeronautical Standard Machine Screw. Description: length: 5/8", thread: 10-32, cadmium plated steel - Phillips recess. But I'd take one with you if you're going out to pick one up locally. Edited June 25, 2021 by PeteMc 1 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted June 25, 2021 Report Share Posted June 25, 2021 (edited) 39 minutes ago, PeteMc said: Pretty sure this is it: AN526-1032R10. Aeronautical Standard Machine Screw. Description: length: 5/8", thread: 10-32, cadmium plated steel - Phillips recess. But I'd take one with you if you're going out to pick one up locally. I may be wrong but something makes me think that the countersink angle for aviation hardware is different than normal, so a hardware store fine thread 10/32 screw won’t fit correctly. I prefer SS for panel screws myself Edited June 25, 2021 by A64Pilot Quote Link to comment Share on other sites More sharing options...
PeteMc Posted June 25, 2021 Report Share Posted June 25, 2021 Never gave it much thought. But I guess that's why the description from my part guide has "Aeronautical" in the description. I've had a couple come out over the years. Usually shortly after an annual or oil change, so I just went back to the shop and got one from them. Now if I'm on an extended trip or I notice a new guy at the shop that probably gets the duty of putting on cowlings, I pull out the screwdriver and give them a quick twist. And not a panel screw. There are four screws up by the prop on the K in addition to the camlocs on the side. (Guessing that's the same on all M20s, but actually never noticed....) Quote Link to comment Share on other sites More sharing options...
PT20J Posted June 25, 2021 Report Share Posted June 25, 2021 39 minutes ago, A64Pilot said: I may be wrong but something makes me think that the countersink angle for aviation hardware is different than normal, so a hardware store fine thread 10/32 screw won’t fit correctly. I prefer SS for panel screws myself Yep, aviation screws are 100 deg. and hardware store screws are 82 deg. (lower profile and more surface area to distribute the load). But, I believe the cowling screws are AN526 truss head as @PeteMc noted. 1 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted June 25, 2021 Report Share Posted June 25, 2021 (edited) Ones on my J are not, they are countersunk, and maybe #8, not sure https://www.aircraftspruce.com/catalog/pnpages/MS24694-S109.php?gclid=Cj0KCQjw_dWGBhDAARIsAMcYuJzAiv4Zc71qnOs3AdR7PcGKBHcw82GA_xlkNNo1lkM-ZuF3veQCTukaAkgzEALw_wcB Edited June 25, 2021 by A64Pilot Quote Link to comment Share on other sites More sharing options...
Guest Posted June 25, 2021 Report Share Posted June 25, 2021 It is a combination of truss head and countersunk screw. Clarence Quote Link to comment Share on other sites More sharing options...
PT20J Posted June 26, 2021 Report Share Posted June 26, 2021 6 hours ago, A64Pilot said: Ones on my J are not, they are countersunk, and maybe #8, not sure According to the IPC, they should be 10-32 truss head. That’s what’s on mine. Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 26, 2021 Report Share Posted June 26, 2021 Might depend on what part we are calling the front of the cowl… Either way, I think we covered it really well… Go MS! Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
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