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M12x1.5 sender into M12x1.75 threads
RichieC - 17/5/06 at 09:23 AM

Hi all,

Guess who had my R1 oil cooler bolt tapped with M12 coarse rather than M12 fine! Whats the chances of being able to fit my M12x1.5 fine thread sender into the M12x1.75 coarse threads?

Clearly the last thing I want is for it to let go flat out on the track. Ideally Id want an M12x1.75 union or adaptor but ive yet to find one.

Any thoughts short of having it redrilled and going up to M14 or M16?

Thanks in advance

Rich

[Edited on 17/5/06 by RichieC]

Marcus - 17/5/06 at 09:26 AM

Don't do it!

Get some brass bar, drill and tap one end for the M12 fine and the other for M12 coarse. Local machine shop should be able to do this for a pint!

Marcus

02GF74 - 17/5/06 at 10:10 AM

no. you'll probably bugger up both the sender and cooler.

can you not get the sender in the right thread?

you'll need an adapter of some sort.

can you not fill the threads/hole, drill and tap again? Of fill it up and drill another hole/tap?

RichieC - 17/5/06 at 11:04 AM

quote:
Originally posted by Marcus
Don't do it!

Get some brass bar, drill and tap one end for the M12 fine and the other for M12 coarse. Local machine shop should be able to do this for a pint!

Marcus

Yeh that was another idea, just getting one made up. That way I get exactly what I need not numerous adpators.
quote:
Originally posted by 02GF74
no. you'll probably bugger up both the sender and cooler.

can you not get the sender in the right thread?

you'll need an adapter of some sort.

can you not fill the threads/hole, drill and tap again? Of fill it up and drill another hole/tap?

You cant get a coarse thread sender. I suppose drilling and tappng to say M14 would work.

Thanks

Rich

rpsmith - 17/5/06 at 11:36 AM

The other option is to have one side drilled out larger and fit an M12 Helicoil / Threaded Insert, local machine shop should be able to do it easily.

Richard

russbost - 17/5/06 at 12:45 PM

I'd go the helicoil route, you should be able to buy a helicoil kit for the thread size you require from a local tool merchant if you can't find a local machine shop with the required size already from stock (which would be cheaper). If you go the brass bar DIY route don't forget you need to be able to have a flat flange to clamp against the cooler to give a seal, it won't seal on the thread alone, hence you'd need to start with a larger size than required & turn each end down then thread it.
I take it you have checked out the Goodridge range of fittings to see if anything proprietory is available?

RichieC - 17/5/06 at 01:49 PM

Hadnt thought about helicoil option, sounds like a plan.

The cooler is held on with the large bolt down the middle, its this bolt which Ive drilled, there shouldnt be any probs with sealing the cooler as that part of it is un disturbed.

Thanks

Rich

ChrisGamlin - 17/5/06 at 05:23 PM

Just bear in mind that an adapter will be no good for a temperature sender as it will put the sender out of the flow of oil, so it won't read correctly. Fine for a pressure sender though, although you should be mounting that remotely anyway so may well be able to get a hose with course one end and fine the other.

RichieC - 17/5/06 at 08:36 PM

Yeh the plan is to mount it remotely via a hose but I havent found anyone who can supply one with a coarse thread.

Rather than mess about too much I think the obvious choice is to have the bolt re drilled and tapped to M14 and then just go M14 to adaptor via a hose.

Cheers

Rich