Odd thread size??

[scottnewcombe]

Here's hoping someone has a better reference book than I.

I am fitting a new wiper motor to my brother in laws boat. Not a problem except that the spindle requires a new nut.

No problem says I, I'll pop down the road and get one. No joy. Car spares shop, bike shop, stores at work shop. Still no joy.

I have tried to look up the thread so at least I know what I'm looking for, but my zeus seems to fail me.


It has 34tpi and is about 11/32" OD very fine. Crest has a flat top

I would contact the manufacturer but can't remember who it was and there are no markings.

Any ideas

Thanks

Scott

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[Graham_Wright]

I can find nothing with 34 tpi. There are threads at pitch 0.75mm but not at the diameter you want.

Wynn Marine in Cheltenham are marine wiper manufacturers. Maybe?

Good luck

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[philmayfield]

Could be BA
Try an industrial fastener stockist.

e.g South Essex Fasteners - Southend on Sea in your county. Visit the trade counter. They may have a minimum order quantity but I have found on many occasions that dealers will let you have just one for free.

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[cliff]

Sounds like a 9 mm X 0.75mm metric fine or a 11/32 x 32tpi nc/unc thread (american)

Depends on how accurate your measuring / counting is/was.

Yes they do exist but best of luck finding one.


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[cliff]

Largest BA bolt listed in my book is 0BA and is only 5.999mm dia (6mm for the 4lb hammer and chisel engineers amongst us).

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[Talbot]

You are not talking a large tension on this, so I would consider removing the existing thread, and cutting a new one of a smaller diameter with a tap and die set. You will then not have the same problem in the future. A large washer will make sure the arm is held securely.

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[philmayfield]

Try http://homepages.tesco.net/~A10bsa/intro.htm

You might be able to make some sense out of this! I agree it's not BA.

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[cliff]

Someone has made a nice set of tabl;es for common threads used in the uk over the past 40 years or so.

There is a company in London that specialises in standard, but not so common, sized taps and dies and fasteners - I am just trying to find their details - got to find their last invoice. - hope they are still in business.. - watch this space......

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[scottnewcombe]

Thanks all

Graham/Cliff, I agree that it is probably 0.75mm pitch. Remeasured (actually I put some felt tip pen on the threads and rolled it onto a piece of paper, put the steel rule next to it and counted under a magnifying glass) and it is just under 34 tpi so more likely 0.75mm. Thanks.

Phil, link was good. Lots of info in one place is always good. Thanks

Talbot. Not sure there is enough meat in the spindle. It is more like a sleeve actually with the spindle running through the middle. You're right though that there is not much weight on this thread. Might consider casting one from epoxy round the existing threads (Or two pack chemical steel?). All the nut will do is hold back a rubber seal onto the eyelet in the bimini.

Thanks all again.


Scott


<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by scottnewcombe on 04/11/2004 08:49 (server time).</FONT></P>

 

[Ships_Cat]

If falling back to the likes of having to cast one from epoxy, and given the light load, perhaps making up a plastic nut might also do it. Using a piece of polyethylene (like the kitchen cutting board) or something that won't fall apart in the sun, drill a hole through it at the approx tapping size and screw it on. Given the fine thread it may happily self tap itself on the spindle's thread.

Obviously the real thing is the best solution though.

John

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[scottnewcombe]

Hmmmm.

Might be worth a punt.


Scott

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[brianhumber]

Clerkenwell screws just down from Grays Inn Road have a large selection of Metric, Amercian and Imperial.

Are you sure its not Japanese. We used to get this problem in the 70s with the new VLCCs built in Japan. The threads were almost but not quite metric. I have to admit some butchery jobs here as when in the middle of the ogin with no matching taps, dies or spares, not much choice but to muller the threads if you were in a hurry.

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[pampas]

probably an american auto thread, try a Lucas agent, or an old rheostat lock nut. also it could be a "one off" manufactures thread. thats all that I can glean on this matter.

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[TrueBlue]

If desparate you could try Namrick aka The Nut and Bolt Shop, in Portland Road, Hove, East Sussex. They do mail order and will supply singles (just as well as their prices are a bit steep. If you're polite they will be very helpful (get lots of peeps whingeing about prices)

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Stop what you're doing and wait my signal