Morris Minor Owners Club

The threads on my B post captive 5/16 BSF nuts are a little mucky,rusty, painted, is there such a tool available anywhere that can be used to screw out the threads so they're as good as new, and whats it called? where can I get one?[frame][/frame]

Hi

Theyre called taps, you should probably also buy a tap wrench also.

Google ' Tracy tools'

Give them a call and describe what you want to do - they will sort you the correct one for the job.

You probably want a 'tee' tap wrench as they are easier to get into restricted spaces.

Agreed- get a set of BSF taps and a tap wrench. Can also get these from Ebay, Namrick and Frost, among other suppliers. Or the cheapest- for 2nd hand taps and dies, is autojumble stalls at classic car shows, now that the show season is about to start.

By the way, a trick that might get you out of trouble for now is to carefully cut a slot into the thread of a bolt of the right size. (Cut a slot into the thread along the side of the bolt, with a dremel or 1mm cutting disk). Then carefully work this bolt in and out a fraction of a turn at a time. This is not a substitute for a proper tap that will re-cut the thread but might clear out any rubbish that is preventing you bolting back to the B pillar captive nuts.

Whilst a tap of the correct size will do the job what should be used is more commonly called a 'thread chaser' looks very similar but actually does the process differently. Tend to be less readily available (except for spark plug threads) and are really only affordable second hand from fleabay and probably the chance of finding a 5/16 BSF would be remote

billlobban wrote:Whilst a tap of the correct size will do the job what should be used is more commonly called a 'thread chaser'

well you learn something new every day...

a thread chaser is...These taps work by forcing the metal back to its original shape, unlike cutting taps which leave metal chips

Guess none of us are too old to learn Charlie.
Thread chasers are not designed to cut threads in new metal but effectively reform the damaged thread. Actually I think chickenjohn's method of cutting a groove or 2 into a correctly sized bolt is a good alternative. It wont cut a new thread but should clean out all the crap thats built up in the existing thread (and it dosnt cost much - remember I'm Scots). The problem with using a 'tap' is that if you are at all hamfisted you end up knackering the bit your trying to improve.
Had a look in the bottom of my tool chest and I've got a couple lying around unfortunately not 5/16 BSF

Thanks gents, great advice as always.
Regards Dave

Chickenjohn you sir are a clever fellow, I tried your idea of cutting a slot in a bolt the right size 5/16 bsf and it worked better than I could have hoped. It went in well and came out with rust and dirt particles in the groove. Brilliant, and it cost nowt. The bolts just glide in nice and smooth now, in fact they go in by hand right up to the last fraction where they require the spanner to tighten them up. Thanks to you all for such great advice, saved me a lot of grief.
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Great to hear the suggestion solved your problem!

Alas, though I can't claim it as my idea, i have a few friends who are/were engineers, one of those fine fellows told me this tip, which I used for clearing some 2BA captive threads.