Imperial measurement seatpost bolt

hi. i'm building up a vintage mercian frame. i need the seatpost bolt... but it's an old imperial measurement (a bit bigger than an m6). anyone else have this problem? anyone got a spare going? an incredibly nice/helpful guy at condor told me that i'd have a really hard time finding the bolt, but it will be out there. he gave me an m6 seatpost bolt (for free...) and suggested that i strip the threading by forcing it through, but that doesn't sound like the best option to me. suggestions?

Well, a bit bigger than M6 would be 1/4 inch right?

clerkenwell screws?

If i were you id try 2 places to get it... bicycle magic (open tomorrow at 9) whitechapel and kiwi cycles (which sat afternoon job). 1/4" is slightly bigger than m6.

drill it through and use a QR.

cheers, shin. i'll give those guys a go tomorrow. am i really just looking for a 1/4" screw? that makes things easier.

(i've tried clerkenwell screws already; they don't have what i'm looking for)

You could also consider tapping it out to the next M size up (M7?).

I have a tap set if you want to use it.

ooh, fancy. cheers. pm on the way...

it could be a 1/4" whitworth????
if so, i might have a hex bolt.

dunno. who knew there were so many screw diametre/pitch variants? can i borrow it and give it a try?

yeah, i'll see if i can dig it out, will be at west end beers thurs, could pass it on to someone for you, if it fits, you owe me a beer :)

Got your PM, you can use my tap set whenever you want, but careful you don't damage your hole (oh er !!!) take your time - I would try 31t®um's bolt first before you under take any permanent frame alterations.

Like all the folk here say 1/4": is slightly bigger than M6

M6 = 6mm
1/4" = 6.35mm

Also the bolt used for cameras that attach the camera to tripods is a 1/4" - you could have a quick trawl through a couple of local camera shops.

PM me again if all fails and you want to tap out the hole to M7 or even M8.

cool, cheers guys. that's great.

Teddy, did you have an luck? I also have a Mercian frame and have ahd the seatpost in the same place for ages as a result of it being fine and also becasue I don't have an allen key for it. However yesterday, my bike took a slight knock and the seat post moved so I would like to tighten it. If I can get a key, I'll also take the post out to clean etc.

Could you let me know if you found one in a shop or if you managed to borrow one from somewhere.

Thanks

Joe

p.s my email is jtsilvester[at]hotmail.com

You can get imperial allen keys all over! I've seen them on multitools, in homebase, etc..

if not i have a set...
Shin

Ace. I apologise if they are widely available as I have looked in exactly 0 shops so far. Just remembered this thread and thought I'd ask. Will have a look this weekend.

You can get imperial allen keys all over! I've seen them on multitools, in homebase, etc..

Waht eh siad.

I dont get what your on about, is your frame threaded for a seatbolt?

All the ones ive seen are a separate nut & bolt.

If your after the nut and bolt type my local bike shop has plent, they fit vintage frames perfect and hav the little bit thatsticks out into the notch of your seatclmp to stop it spinning around.