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Tapping M10 hole
chrisg - 22/4/09 at 02:39 PM

I need to fix my engine in place, it has M10 x 1.25 fine threads into an aluminium crankcase, but I don't have the correct bolts.

Would it be ok to tap these out to standard pitch M10?

Cheers

Chris


Humbug - 22/4/09 at 02:46 PM

I would have thought it would strip or cross the threads, making it less effective.


tegwin - 22/4/09 at 02:56 PM

NO... dont do that! Course threads in aluminium dont work at the best of times hence why most are fine....

Trying to switch between fine and course would just FUBAR the hole!


chrisg - 22/4/09 at 03:00 PM

Message received and understood!

Thanks chaps

Chris


mad-butcher - 22/4/09 at 03:06 PM

try these chris http://stores.shop.ebay.co.uk/WVS-FASTENERS_METRIC-FINE_W0QQ_fsubZ13QQ_sidZ124709800QQ_trksidZp4634Q2ec0Q2em322


chrisg - 22/4/09 at 03:18 PM

Cheers Tony


02GF74 - 22/4/09 at 03:26 PM

quote:
Originally posted by tegwin
NO... dont do that! Course threads in aluminium dont work at the best of times hence why most are fine....




you sure about that? I thought aluminium and cast iron both use course threads?

e.g. on ford crossflow, head and alloy inlet manifold use UNC.

.... but then I don't know for sure, it is google time I guess....


AdamR - 22/4/09 at 04:10 PM

Agreed. Everything on a Rover V8 (aluminium block) is UNC.


mad-butcher - 22/4/09 at 04:25 PM

japanese


minitici - 22/4/09 at 04:38 PM

You could always fit helicoil or re-coil wire inserts and convert to 'standard' metric pitch.


Jimbob - 22/4/09 at 05:03 PM

Just buy the correct bolts!
They wont be expensive and its the right way to do it


chrisg - 22/4/09 at 05:29 PM

quote:
Originally posted by Jimbob
Just buy the correct bolts!
They wont be expensive and its the right way to do it


BUY!!!!

I nearly choked on me whippet!

Are you a REAL Yorkshireman or a foreigner?

(Actually that's what I've done, via Tony's link It was just an idea to save some time)

Cheers

Chris


David Jenkins - 22/4/09 at 05:45 PM

Soft metal should have coarse threads - stuff like aluminium is too weak to support fine threads in the way steel can.

It depends on your definition of 'fine' of course!


chrisg - 22/4/09 at 06:58 PM

quote:
Originally posted by David Jenkins
Soft metal should have coarse threads - stuff like aluminium is too weak to support fine threads in the way steel can.

It depends on your definition of 'fine' of course!


That being the case, I wonder why Honda went for fine threads?

Cheers

Chris


richmars - 22/4/09 at 07:05 PM

It's no the finest M10, you can also get M10x1.0
So maybe x1.25 is a good comprimise.


David Jenkins - 22/4/09 at 07:17 PM

I have taps and dies in my toolbox for 1/2" x 40tpi - that's fine!

(It's a model engineering thread, easy to set up for thread-cutting in an imperial lathe)