Author Topic: Fork thread Die size (Read 4585 times)

mivvi · « **on:** October 13, 2005, 11:57 AM »

Hi All, my recently purchased GT performer has the same old fork thread problem. Threads damaged from the headset being too loose. So I am getting the damaged threads welded up on the weekend but need to know what size the thread (Well more importantly the diameter size) is? I can then get a Die to re-thread it. I could work it out by measuring the diameter and I have a thread guage but don't want to get it wrong as the Die will be quite expensive to buy, I would have thought? Any one got the size? Cheers!

stidds · « **Reply #1 on:** October 13, 2005, 04:24 PM »

I can't help on the thread size, but if the die is going to be really expensive why not take it to a bike frame repair workshop? My local repair shop charges £15 per inch re-thread.

mivvi · « **Reply #2 on:** October 13, 2005, 05:08 PM »

Hey Stidds, I didn't know that bike shops done that kind of thing? I might just ask in mine but im sure they would just look at it and say "God, that's an old pair of forks, they use thread less head sets these days, you want to buy a new bike! We have a special on this week!" Might give it a go though, cheers!

ash · « **Reply #3 on:** October 13, 2005, 05:58 PM »

OK HERE GOES

THREAD ON MK2 RALEIGH BURNER FORKS

THREAD O/D IS 25.3 MM (0.996") SO SAY 1"
THE PITCH IS APPROX 1 MM (.039")......25.6 TPI
I'M NOT AT WORK 2MORO OTHERWISE I'D GO IN AND CHECK IT ON THE SHADOWGRAPH FOR YOU
THE THREAD IS NOT IN THE ZEUS BOOK SO ITS PROBABLY A SPECIAL
HOPE THIS HELPS
ASH

stidds · « **Reply #4 on:** October 13, 2005, 06:05 PM »

Mivvi, not many bike shops will do this service, but Argos Cycles in Bristol will, but they do make their own frames so that is probably why. They are also predominantly a road bike manufacturer so they will not be frightened of 1" threaded as that is what road bikes still use.

The-flying-banana · « **Reply #5 on:** October 13, 2005, 06:51 PM »

Ash are you a turner

as that is "in the know" matey

and i bet you cant get a die that size for love nor money.

graeme · « **Reply #6 on:** October 13, 2005, 07:00 PM »

Cut off the threaded section, and weld a new threaded section on, from another pair of forks.
As long as you use a jig to keep it all straight, and 45 degree chamfer the cut ends for good weld penetration it will easily be strong enough.
I recon it will take an hour tops.

mivvi · « **Reply #7 on:** October 13, 2005, 08:35 PM »

Hey Ash, your a star mate! Can you just let me know what you would have checked on the 'Shadowgraph'? Do I need this info?

Stidds, your further info explains a lot. My bike shop would have been scratching their heads all day.

Graeme, I think your plan will be my last resort as I don't have an old pair to cut down and my welding ain't up to that amount of skill. Im a software and electronics kid, all this welding is new to me!

Well thanks all, you never let me down. Really appreciate your input!

Ash, if you could let me know if I can just go and buy one of these (off the shelf) so to speak, with the info you gave me? Ta,,,,,,

ash · « **Reply #8 on:** October 13, 2005, 09:17 PM »

YEP I'M A TIME SERVED SKILLED MACHINIST

turning milling grinding welding cnc etc etc

now work in quality control $:-\$
the shadowgraph just blows up an enlarged image of the form so you can
measure it more accuratley
i was going to check the thread angle to give us a bit more of a clue
and no i dont think you'll get a die that size $:-\$
unless they use them in the states (they use some strange threads over there)

not BS (british standard)
this link may explain a bit better http://www.colinusher.info/Livesteam/mewdata.html

Donker · « **Reply #9 on:** October 13, 2005, 09:27 PM »

time served here aswell mivvi and i agree that you will not get a die, and even if you did its very unlikely you will re-thread over weld without it being machined first, in which case you could fit an axle to the forks and get a turner to grip it in a 4-jaw chuck and screw-cut the threads. (using a fixed steady of course) this is unquestionably the most accurate method ensuring perfect threads but graemes option is the way i would go, easiest and cheapest, but to make it as strong as possible (especially if riding) i would weld a supporting piece of tube inside.

ORB · « **Reply #10 on:** October 13, 2005, 11:53 PM »

Well, I had to do a 'repair' at home in a hurry on a Curtis about 2 years ago, I got the grinder and cut 1/4 out of a headset lock nut and threaded it on and off over and over.

It started to go easy, but i figured that this was the nut stretching not the threads being 'cleaned' so i ran the opened nut the the base of the threads and then clamped a set of mole grips on as tight as they would turn. then slowly ran it back with the gas lamps keeping it warm.

took about an hour,

Done.

QUADROPHENIA · « **Reply #11 on:** October 14, 2005, 08:11 AM »

mivvi you mental
I have had the same problem twice now mate, and its a fecker to sort out, they broke 2 dies doing it and said next time it was gonna cost me a fortune and some chocolate, are they the forks you are going to sell me ?

mivvi · « **Reply #12 on:** October 14, 2005, 11:48 AM »

Right, have done a bit of research this morning. Looks like a Die would be very expensive, found a cycle fork thread tool kit for £250! Also like you say, re-cutting threads over weld probably won't work. So (Thanks to stidds) I spoke to Argos in Bristol and they said it was no problem to silver weld the fork and cut new threads. £15 for the job! So I don't think its worth messing around. I will let you all know how it goes cause I did warn Argos that the forks were in a rough state.

fatboymal · « **Reply #13 on:** October 14, 2005, 01:48 PM »

Marcus,

Argos are superb, they restore old racing frames (as well as make custom frames), stove-enameling them and then hand pinstriping them. The finish is just amazing. They did my Sunn and my DP, and just could not be faulted.

Highly recommended.

ps missed your post about the DP mini - I have a chrome one being built up for my 4 yr old daughter - must show you when it is finished!

mivvi · « **Reply #14 on:** October 14, 2005, 02:01 PM »

Hi Mal, you staying off here and saving money mate? You got me into this craze in the first place, thought you were a mate, lol. Yea, was up for a mini DP but now on the bottom of the list as other things have come up. Would like to see the pic of yours when its done though. Glad you recommend Argos, will send the forks off to them next week. Nice to hear from you mate.

graeme · « **Reply #15 on:** October 14, 2005, 05:04 PM »

Graeme, I think your plan will be my last resort as I don't have an old pair to cut down and my welding ain't up to that amount of skill. Im a software and electronics kid, all this welding is new to me!
Well you'd better learn if thats your porshe!

mivvi · « **Reply #16 on:** October 14, 2005, 05:23 PM »

Hey, the porsche is all sorted in that respect, restored from the chassis up (Not by me). Spent £3000 on a reconditioned engine but now sick of the thing. It ain't moved out the garage for 3 years, bloody money pit!

graeme · « **Reply #17 on:** October 14, 2005, 05:29 PM »

Only joking, no offence!
Im planning on buying a late 60's 911 (when weve sold my nans house), but it will be a weekend toy only!
I can imagine they cost loads to look after!

currio · « **Reply #18 on:** October 14, 2005, 06:14 PM »

I had some forks that had a couple of damaged threads.
My local bike shop (still going from BITD) had the thread die.
You are looking for a 1" 24 or 26 (cant remember, you should check using thread gauges) T.P.I BSC thread.
(British Standard Cycle)
Try here, http://www.tapdie.com/html/bscycle__dies.html
They dont list the 1", but they have an ask us a question link.

Try finding a die before you chop 'em !!

Shaun

ash · « **Reply #19 on:** October 14, 2005, 10:41 PM »

BSC eh?

never come across that one before!!!

well you live and learn!!! :o
as the forks have been welded you'd need to turn them down to the thread O/D anyway
once up you may as well screwcut them
but i do like the sound of ARGOS' solution

they do sound experts in all of this
i just make bits for fighter aircraft!!

mivvi · « **Reply #20 on:** October 16, 2005, 10:25 AM »

Greame, if you buy an old 911 and need parts let me know. I have some good contacts!

Thanks for the info Shaun, I will contact them if Argos can't do them,

Ash, you might make bits for aircraft fighters but we are talking bmx here. A much higher spec, lol.

weston · « **Reply #21 on:** October 16, 2005, 10:45 AM »

most frame building bike shops re-thread so you should have no problem sorting it, look for shops that sell racing bikes (them with the skinny wheels & sily bars

)

Author Topic: Fork thread Die size (Read 4585 times)

ash

The-flying-banana

ash

Donker

fatboymal

currio

ash

weston