10mm x 1.25mm tap

In article , Dave Baker writes

Dave,

Seven quid from these people (and a wonderful source to bookmark for future use):

David

You may have a friendly local bicycle shop, in which case they might do it for you while you're there - it's the standard for bolt-on rear derailleur gear hangers which often get their threads a bit knackered y mountain bikers knocking the gears off on rocks etc.

I assume this was a Japanese cylinder head, one of their 10mm standard threads is/was 1.25 pitch rather than the ISO 1.0 or 1.5mm...

Dave H.

Indeed, it's a Mazda head and I only just touched it for about a quarter turn with the 10 x 1.5mm tap before realising it felt wrong so it'll take little sorting out if I can find the right tap to borrow. Failing that I'll buy a bolt and grind some flutes in it.

Aksherly I've just had a thunk. An 8mm x 1.25mm helicoil tap is near as dammit 10mm. About 9.63mm anyway so I'll run that through tomorrow and see what it does. With a bit of side pressure as I wind it about it might just clean everything up close enough to do the job.

If it's just for cleaning a thread in an ally head, it might be just as simple to turn the thread on a bit of silver steel, cut some flutes in it and use it as-is. Even more so if the Helicoil tap does some, but not all, of the required cleaning.

regards Mark Rand RTFM

I just checked and I have 1.5, 1.0 and 0.75 but no 1.25 :(

Pete.

If only thread cutting was one of my skills. Buying a bolt and grinding some flutes in it is a quicker way for me.

In that case:- Five quid from

We need to get you educated. Think of all the non-profitable time you're not having :-)

Mark Rand RTFM