Fork top caps - thread size?

Motocod · Post by **Motocod** » Thu Jun 20, 2013 7:35 am

I'm looking to make something to adapt a phone mount I have, and secure it on to the brass threaded fitting in the fork top. Seems like it might be a fine-pitch M7 thread. Can anyone confirm?

thanks,

Nik

Motocod · Post by **Motocod** » Thu Jun 20, 2013 12:05 pm

Seems like it's an M8 fine-pitch thread (no such thing as a fine-fitch M7!).

Going to order some nuts off ebay and give it a try...

Nik

feralworks · Post by **feralworks** » Tue Jul 02, 2013 9:05 am

Same thread as valve caps

Corvus · Post by **Corvus** » Tue Jul 02, 2013 6:08 pm

Is the schrader valve thread American? Something like unf or unef?

How about sourcing some nuts from a bicycle inner tube?

feralworks · Post by **feralworks** » Tue Jul 02, 2013 6:33 pm

Corvus wrote:Is the schrader valve thread American? Something like unf or unef?

How about sourcing some nuts from a bicycle inner tube?

It's an odd fine thread & I just happened to find that tyre valve caps fitted perfectly. Valves are about 7.7mm OD & have a pitch of 0.8mm but not actually sure why that thread would appear on a BMW

As I remember, Those brass fittings also screw out of the top of the fork leg & the internal thread is different ( but I can't remember what it is

)
so you may be able to thread in a bolt /stud & nut.

My plastic caps were missing so I stuck on some 'bling' valve caps only for some light fingered Spanish 'Youff' to run off with them....

Corvus · Post by **Corvus** » Tue Jul 02, 2013 9:52 pm

[quote="feralworks"]

"It's an odd fine thread & I just happened to find that tyre valve caps fitted perfectly. Valves are about 7.7mm OD & have a pitch of 0.8mm but not actually sure why that thread would appear on a BMW

"

There are similarities to 5/16" unef.

Mad, I know.

If it is the same thread as used on a schrader valve, that would explain how it finds itself aboard a bmw.

Dunno?

Blackal · Post by **Blackal** » Tue Jul 02, 2013 9:54 pm

RAM Mounts do a Ramball fitting for that stud.

Al

feralworks · Post by **feralworks** » Wed Jul 03, 2013 5:55 am

Blackal wrote:RAM Mounts do a Ramball fitting for that stud.

Al

Yes they do, Al, but that's cheating....

Where's your spirit of adventure ????

conkerman · Post by **conkerman** » Wed Jul 03, 2013 7:54 am

feralworks wrote: Yes they do, Al, but that's cheating.... Where's your spirit of adventure ????

On Wednesdays she works at Sketchleys.

Motocod · Post by **Motocod** » Wed Jul 03, 2013 11:57 am

feralworks wrote:
Corvus wrote:Is the schrader valve thread American? Something like unf or unef?

How about sourcing some nuts from a bicycle inner tube?
It's an odd fine thread & I just happened to find that tyre valve caps fitted perfectly. Valves are about 7.7mm OD & have a pitch of 0.8mm but not actually sure why that thread would appear on a BMW
As I remember, Those brass fittings also screw out of the top of the fork leg & the internal thread is different ( but I can't remember what it is )
so you may be able to thread in a bolt /stud & nut.

My plastic caps were missing so I stuck on some 'bling' valve caps only for some light fingered Spanish 'Youff' to run off with them....

I'm guessing then that the thread that the round black plastic cover screws in to is the 7.7mm diameter thread? I only ask because the other end (that screws in to the top of the fork leg) is a different thread. Does anyone know what thread that happens to be? If I can find out what that is then chances are I can buy a screw to go in to in, and make a satnav mount that attaches to it.

Thanks,

Nik

Boxadog 2000 · Post by **Boxadog 2000** » Wed Jul 03, 2013 5:55 pm

Motocod wrote:Seems like it's an M8 fine-pitch thread (no such thing as a fine-fitch M7!).

Going to order some nuts off ebay and give it a try...

Nik

Er yes there are fine pitch M7 threads 3 different ones from memory.

It will be the same thread as a schrader valve 24 tpi whitworth form from memory.

I will check when I get to work tomorrow.

The reason I know this is because I sell cutting tools for a living

Ah its actually 0.302" diameter 32 tpi just cant remember the thread form

Motocod · Post by **Motocod** » Wed Jul 03, 2013 6:07 pm

That'd be great, thanks!

Perhaps I should back-track, and say that from the point of view of readily available off-the-shelf stuff, M7 fine-pitch is not commonly available!

Anyway, if you can identify the thread inside the fork top (on the underside of the brass fitting) that'd be great!

Thanks,

Nik

Corvus · Post by **Corvus** » Wed Jul 03, 2013 6:30 pm

I'm going back a bit (well, a lot actually) but I seem to recall whitworth form is 55 degrees, whereas unified form is 60 degrees?
Metric thread form is 60 degree I believe.

I just made the assumption that the schrader thread would be unified, but it was just an assumption. Some might say a guess.

Boxadog 2000 · Post by **Boxadog 2000** » Thu Jul 04, 2013 6:13 pm

Bugger forgot to check will do it Friday