LD1
Epic Contributor
Personally, I would just tap them out to 5/16 then. You are only talking about .050" of material. Thats only .025 per side...Thats not much loss of material.
1/4-18 thread machine screw?
- Thread starter cockeyedMFer
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cockeyedMFer
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Good suggestion. The mystery of it is what bugs me...who in the world was making 1/4-18 fasteners in the 1950's? Hasn't everything been UNF since the 30's? I have seen unique threads on early American cars, but this is a relatively "new" window compared to the cars.
oldnslo
Super Member
Dumb question but are self tapping screws? Possible that someone like CamCar made them special per customers request just to have the "repair" / replacement business. I know CamCar made a lot of specialty screw products and I am sure other companies did also.
Mace Canute
Elite Member
I went looking through some Thread Specifications but couldn't find a 1/4-18 thread listed. My guess would be that it was a proprietary thread spec'd by the manufacturer. :confused3:
Midniteoyl
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Are you sure its not a #14 Type B point sheet metal screw? It prolly is. I bet the thread gauge leaves some daylight, correct?
#14 .25 1/4
Type B point: A thread forming screw for use in heavier metal .050 to .200 thick. Larger root diameter with finer thread pitch for light and heavy sheet metal non-ferrous castings, plastics, impregnated plywoods, asbestos combinations, and other materials.
PeterK
Gold Member
Maybe bspp threads 1/4-19 ?
bandaidmd
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i think you nailed it! or would that be screwed it for this thread.
Soundguy
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a m4 would be 17.8 tpi right?
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cockeyedMFer
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Actually, its a perfect fit with the thread gauge. Also matches with a 5/16-18 threads when stacked on top of each other.
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cockeyedMFer
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M7 is the closest in diameter, but none of the thread gauges match