Schwinn Fender thread size??

[scale]

What size thread is the bolt that threads into the fork crown from the bottom to hold the fork in the center of the fork on an old schwinn dx......probably late 40s - 50s? I have tried everything i have on hand and have nothing that works.

I attempted to hand thread my taps into there and it seems like a m5x0.9 will thread in and feels ok but im not sure this is the correct size.

Does anyone know what size this is?

 

[PCHiggin]

10-24 or 1/4-20,probably 1/4-20

 

[Danny the schwinn freak]

Definitely 1/4-20!

 

[scale]

Definitely 1/4-20!

i tried 1/4-20 and it was way too big. I also tried standard and fine m5 and they were way to small.....slide right in. For the heck of it i tried an m6 and it went in and tightened up nicely. I guess i will run that. It probably doesnt matter much. I am almost certain they were not metric back in the 1940s - 1950s?? Strange....but this will work.

 

[Danny the schwinn freak]

i tried 1/4-20 and it was way too big. I also tried standard and fine m5 and they were way to small.....slide right in. For the heck of it i tried an m6 and it went in and tightened up nicely. I guess i will run that. It probably doesnt matter much. I am almost certain they were not metric back in the 1940s - 1950s?? Strange....but this will work.

Whatever works, but definitely not metric. I’ve never seen anything used for that application other than 1/4-20. Crazy.

 

[schwinnduke]

I'm desperate for one of these screws too! What length should I use? EG I can find these, but the length seems too long?

1/4-20 UNC x 1/2 inch Imperial Slotted Pan Head Screws (ANSI B18.6.3) - A2 Stainless Steel: Accu.co.uk: Precision Screws

Buy 1/4-20 UNC x 1/2 inch Imperial Slotted Pan Head Screws (ANSI B18.6.3) - A2 Stainless Steel from Accu's Precision Screws range, specialists in precision component engineering.

www.accu.co.uk

Many thanks

 

[Tom Hand]

I retapped my 1952 D12 with 1/4" -20. and it was perfect.

 

[1motime]

i tried 1/4-20 and it was way too big. I also tried standard and fine m5 and they were way to small.....slide right in. For the heck of it i tried an m6 and it went in and tightened up nicely. I guess i will run that. It probably doesnt matter much. I am almost certain they were not metric back in the 1940s - 1950s?? Strange....but this will work.

Someone was probably in there before you and stripped it. If it snugs tight than you are good. Use washers in case!