hole size

[tonym]

What size hole would i need to drill to be able to put a M10 thread through it, I thought 8mm but would appreciate the correct answer :tu

[Purple AK]

Hi Tony
I assume you mean the hole size to tap an M10 thread?.If so here goes,
M10 x 1.5 (normal) 60% thread 8.80mm, 75% thread 8.50mm
M10 x 1.25 60% thraed 9.00mm, 75% thread 8.75mm
M10 x1 60% thread 9.20mm, 75% thread 9.00mm

Use the 75% figure for holes of 15mm or less depth in soft metals and mild steel. And the 60% for deeper holes.
HTH Cheers :tu

[CobraMat]

Tony

A rough and ready way of checking what tapping drill is required is to get the relevent nut and then find which drill in your collection is the tightest fit through it.

Ok, ok people, I know the correct way is to get out your little Zeus Engineering Pocket book (or similar) and look up the correct size, but how many people have an 8.8mm drill bit in their collection? For most non-critical tapping jobs, if you've got a 9mm then that will have to do!

As for yours, Metric coarse is 8.6mm dia, Fine is 8.8mm dia, so you may have an 8.5mm or 9mm drill bit which would suffice for whichever thread you have. If you've got imperial drills, then an 11/32" would be the closest you'll find.

HTH

Mat
Current progress: Dax rediscovered, 383 Chev arrived from in the USA, Tremec TKO in a box, and various bits on the shelf!

[Purple AK]

Ok Mat :tu Point taken
Tony did ask for the correct size.
Nothing worst than breaking a tap or pulling a thread cos you guestimated wrong :} :}
Cheers

[Jake]

Tony

As a general rule if you deduct the pitch dimension from the diameter then this will give you the drill size and this applies to any metric thread ( 5, 6, 8, 10 etc.)

i.e. for a 10mm x 1.5mm pitch (standard for 10mm) the drill would be 8.5mm (10 - 1.5) and this will normally give a reasonable strength thread form.

Good luck with the MOT and SVA !! :tu :tu :tu :tu

Keith

"WHO'S IDEA WAS IT TO BUY THIS ANYWAY" ?

[CobraMat]

Chris

My comments weren't aimed directly at your reply, so I wasn't making a point at your expense, honest! :tu I just know from my own experiences that it's usually a compromise with finding the closest drill to that stated.

You are so right when you say there's nothing worse than breaking a tap...a 5 minute job turns into a 3 hour nightmare just because of impatience, haste or the wrong tools.

Cheers :7

Mat

Current progress: Dax rediscovered, 383 Chev arrived from the USA, Tremec TKO in a box, and various bits on the shelf!

[Purple AK]

Mat
http://www.pistonheads.com/gassing/icons/beer.gif
Cheers :tu