M1 Crankpin hole size.

sam.makins
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M1 Crankpin hole size.

Postby sam.makins » Mon Mar 21, 2016 4:14 pm

Hi all,

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

Thanks,

Sam

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Tim V
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Re: M1 Crankpin hole size.

Postby Tim V » Mon Mar 21, 2016 4:37 pm

Same as 14BA? 0.8mm.
Tim V
(Not all railways in Somerset went to Dorset)

Alan Turner
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Re: M1 Crankpin hole size.

Postby Alan Turner » Mon Mar 21, 2016 4:48 pm

Strictly it's 0.75 mm but I'm sure 0.8 mm is OK

Regards

Alan

sam.makins
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Re: M1 Crankpin hole size.

Postby sam.makins » Mon Mar 21, 2016 5:07 pm

Thanks gents! Time to start drilling holes in wheels then.

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Andy W
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Re: M1 Crankpin hole size.

Postby Andy W » Mon Mar 21, 2016 5:34 pm

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.
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Paul Willis
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Re: M1 Crankpin hole size.

Postby Paul Willis » Mon Mar 21, 2016 5:54 pm

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
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Tim V
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Re: M1 Crankpin hole size.

Postby Tim V » Mon Mar 21, 2016 6:57 pm

The screw should cut its own thread.
Tim V
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Alan Turner
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Re: M1 Crankpin hole size.

Postby Alan Turner » Tue Mar 22, 2016 9:38 am

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

sam.makins
Posts: 23
Joined: Sat Feb 06, 2016 2:03 am

Re: M1 Crankpin hole size.

Postby sam.makins » Tue Mar 22, 2016 7:04 pm

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!


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