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Drill sizes

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Joined
Sep 14, 2020
Messages
6
Hey everyone,

I am based in eastern Canada, and I am surprisingly having a hard time finding #20, #30 and #40 drill bits over the counter. It would seem I need to special order from my local tool store. It is for my CH 750 project.

My question is if I dare use the fractional drill sizes instead. I did a small comparison.

Comparison #20

#20 = 4.089 mm
5/32 in = 3.96875 mm
Difference is 0.12025 mm (approx 2.9%)

Comparison #30

#30 = 3.264 mm
1/8 in = 3.175 mm
Difference is 0.089 mm (approx 2.7%)

Comparison #40

#40 = 2.489 mm
3/32 in = 2.38125 mm
Difference is 0.10775 mm (approx 4.3%)

So in all cases, the difference is that the holes with fractional drill bits are 0.1 mm smaller, or about size of a human hair.

I don't want to mess up when drilling. Should I just order a batch of the gauage drill bits?
 
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