Clam shell sprocket adapter button head cap screw size?

Just thought I'd ask if anyone knows off the top of their head what thread the button head cap screws are that mount the sprocket to the hub on the Pirate or manic type sprocket adapters.

I have one on a bike but didn't bother to look at what size the sprocket mounting bolts were before I installed it on the bike, I have a couple more of the adapters but no bolts for mounting the sprocket, I'm gonna need to get a few of the button head cap screws so I can use the adapters on other bikes.

Seems that they look to be either 3/8" or 10mm but I have no idea which they are.

Anyone know for sure (NOT a guess please) let me know if you don't mind.

Thanks, Shan

MotorBicycleRacing said:

3/8" ......

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Thank you Neil

GoreWound said:

this is not completely on topic but I just wanted to ask this question:
I bought one of these adapters and it came with flush head screws instead of button head ones. the sprocket was machined to accept them properly.
this sin't gonna screw me over is it?

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no it will be fine, I'm gonna use button head screws because the sprocket Im gonna use is to thin to have the mounting holes counter sunk for the flush head type cap screws.

I think the flush head type with a sprocket made for them is by far the best and most secure hold, the sprocket and adapter I have on one of my project bikes has is the piarate adapter and I have a few more from Jake's that are also made b6 the same as Pirates, these all use the flush mounting hardware and its good.