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[stinkwheel]

Forks are off a late 90's 350 bullet. I'm going to need to have a go at tidying up the threads on the fork tops. Hopefully with a file but might have to buy a tap to chase them through. Just wondering if anyone knows what size thread it is?



The two new fork plugs I bought (ebay forks, didn't come with the plugs) are absolutely rough as a badgers bottom with one having badly cut, flattened thread sections and the other having a distinct "wave" on the threads causing it to wobble as it's screwed in. In fact, I'd go so far as to say they are the worst finished enfield part I've purchased to-date. Which must be some sort of record!

[stinkwheel]

I should elaborate as the above is slightly ambiguious. It's the thread size of the female threaded hole in the top of the fork stanchion I'm looking for, the one you screw the plug screws into.

[Jamesy]

Your plug thread size is the same as the female.If you measure the plug thread outside diameter and the pitch between the threads consult thread sizes online to establish your thread size.

[stinkwheel]

Yes, but the plugs are made of poo (possibly elephant dung dried in the sun then chromed?). The pitch of the thread varies wildly depending on where you try to measure it and none of my thread guages fit neatly enough to be confident they are corrct. The ones in the top of the forks are damaged.



So. The brand new plug measures 17.8mm in diameter. Roughly 45/64". Which is almost entirely unhelpful. I can't get the 2mm thread guage to go in it but that's not to say it isn't M18, although why anyone would deliberately select that size? Could be a really badly made 11/16" cycle thread but doesn't really look fine enough. Actually wondering if they've thrown a UNF in there just to mix it up a bit.

[Jamesy]

Or a bsf.Its a long time since I turned that size of thread.Get a M18 bolt and see how it fits.B&Qhas loads of metric size bolts.

[Jamesy]

Woops I was forgetting your female thread was knackered in the first place.Sorry.You do need to know that size 100% before running a tap in it.

[Alan R]

Hi Guys---------trouble with B & Q is they only supply Metric-course threads for general House and Garden use............Have a look at this chart for some inspiration}------- https://www.newmantools.com/taps/tapsmetric.htm ---------- Quite often I use one of the chasers from a Coventry die holder to make a hand-held chaser to re-form a damaged thread........

[PeteF]

I would get the proper plugs from our hosts. Buy a spare one and use this to chase the threads in the tubes. If you file grooves across the threads in the spare plug it will be quite effective as a cheap and cheerful thread chaser.

[stinkwheel]

The plugs are from our hosts. I'm afraid they wouldn't chase anything you'd want to catch. The metal seems quite soft too, I suspect they usually get pulled into shape when they are screwed into the steel collar at the top of the fork stanchion.



They do sell stainless ones too but they are pricier and I don't fancy using them as chasers, I suppose there is a fair chance they have a decent thread cut on them I could measure though.

[Alan R]

Hi Guys-------why not just phone our hosts workshops / stores, and ask them to measure a stainless plug for you and let you know ??.......Simples, ( from "Compare the Plugs dot com" ....squeek !!)