B

b432291

Active Member
I have looked everywhere for 8/32x1/2" Truss head Torx/Sixpoint machine screws.

Found some at: http://www.mutualscrew.com/Torx-Alt...d-steel-zinc-plated-machine-screws-34367.html

These are not Stainless, but zinc plated steel.

The guy there was nice and let me buy a half-order of 4500 screws. If folks show interest I am willing to sell most of the 4500 at cost + some sort of shipping and handling fee. When the screws arrive I will take hi-res photos and maybe even take a few to ASU and let students do actual destructive testing to see real limits.

Ted
 
I would be interested in purchasing some.

Will the Zinc plating be less desirable than the standard Cadmium plating that is on the current screws?
 
8-32x1/2" truss head steel Torx screws

The different platings are to prevent corrosion when used with certain materials. Stainless steel will cause corrosion in aluminum but cadmium plated screws don't. I don't know where zinc plated ends up. I believe there was a mention of this effect in a thread not too long ago. Ask Vans before substituting screws with a different material/plating.
 
I swapped a bunch of my floor pan screws for stainless hex-head (or allan-head) screws but swapped them all back at the next annual... When I dropped one of the screws and it fell under the floor and back to the rear of the cavity, and I found that I couldn't retrieve it with a magnet on a stick.

Ferrous screws make a lot more sense to me. I'll have to check my corrosion tables and see where zinc falls relative to cadmium.
 
Well the box of 4,500 Zinc Plated 8-32 by 1/2 inch Truss Head screws arrived this week. I will try to post a pic here. They look nice.
 
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It was ~$275 for the 1/2 order of 4,500 screws. I'm asking $20 for 200 screws which will include USPS. Contact me at six zero two 318-five five six five. Ted in Phoenix.
 
I don't know where zinc is relative to aluminum galvanically, but the firewall on my 170 is zinc coated steel, and it's been holding up fine riveted to an aluminum fuselage for over 58 years. I think those screws would work OK.

I used part # 93701A408 from McMaster-Carr. They are "black coated" steel. I assume this to be a phosphate conversion coating. I don't know where that is either on the galvanic scale relative to aluminum, but since I was only using them on the tank covers and they are embedded in sealant, I didn't figure it mattered much.
 
longranger said:
I don't know where zinc is relative to aluminum galvanically, but the firewall on my 170 is zinc coated steel, and it's been holding up fine riveted to an aluminum fuselage for over 58 years. I think those screws would work OK.

I used part # 93701A408 from McMaster-Carr. They are "black coated" steel. I assume this to be a phosphate conversion coating. I don't know where that is either on the galvanic scale relative to aluminum, but since I was only using them on the tank covers and they are embedded in sealant, I didn't figure it mattered much.
Click to expand...

I think the "black coated" is an oxide and is not really the best finish...

http://www.designnotes.com/companion/manual-1.html
 
Mutual is the only place besides a odd guy in LA (that never seems to have stock) that has TRUSS head six-point/torx screws. I want a large diameter head to spread load with a low profile - hence truss. Just what I wanted to use.
 
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