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M1 Crankpin hole size.

Posted: Mon Mar 21, 2016 4:14 pm
by sam.makins
Hi all,

Could anyone tell me what size hole to drill for m1 crankpins in AG plastic centre wheels?

Thanks,

Sam

Re: M1 Crankpin hole size.

Posted: Mon Mar 21, 2016 4:37 pm
by Tim V
Same as 14BA? 0.8mm.

Re: M1 Crankpin hole size.

Posted: Mon Mar 21, 2016 4:48 pm
by Alan Turner
Strictly it's 0.75 mm but I'm sure 0.8 mm is OK

Regards

Alan

Re: M1 Crankpin hole size.

Posted: Mon Mar 21, 2016 5:07 pm
by sam.makins
Thanks gents! Time to start drilling holes in wheels then.

Re: M1 Crankpin hole size.

Posted: Mon Mar 21, 2016 5:34 pm
by Andy W
I'm sure you know this Sam, but it's best to tap the hole and put a slight rebate on it to allow the screw head to sit flush with the back of the wheel.

Re: M1 Crankpin hole size.

Posted: Mon Mar 21, 2016 5:54 pm
by Flymo748
Andy W wrote:I'm sure you know this Sam, but it's best to tap the hole and put a slight rebate USING A DRILL TIP IN THE CRANKPIN HOLE ON THE REAR FACE OF THE WHEELon it to allow the screw head to sit flush with the back of the wheel.


I hope that Andy won't mind the added emphasis on which side of the wheel to countersink...

And do be careful with a 14BA tap, if you use one. They are fragile little things!

Cheers
Flymo

Re: M1 Crankpin hole size.

Posted: Mon Mar 21, 2016 6:57 pm
by Tim V
The screw should cut its own thread.

Re: M1 Crankpin hole size.

Posted: Tue Mar 22, 2016 9:38 am
by Alan Turner
I meant to say that the tapping drill size is easy to calculate for metric screws. It is the nominal diameter - thread pitch.

1 mm screw - 0.25 mm pitch = 0.75 drill

regards

Alan

Re: M1 Crankpin hole size.

Posted: Tue Mar 22, 2016 7:04 pm
by sam.makins
Thanks for the help everyone. I didn't tap the first wheel and struggled so tapped the other 5 which made life a lot easier. All holes have been countersunk aswell. Fingers crossed they've gone in nice and square!