Seat Bolt Size Question.
 

I posted this in the Mezzo thread a few days ago and got no response. My guess is that now the weather is fine everyone is off their computers and out riding! - - Hopefully that is.
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Do any of you know the size of the bolt that binds the seat to the seat post? I need the diameter and thread pitch.

I purchased a Brooks B72 and it has two rails on each side and required a spacer between the two rails. The spacer makes the bolt that comes on the bike too short for the job.

I think it is an M5 with a 1.0 pitch. The length I need is either a 50 or 55 mm, but dang if I can find one anywhere local.

Edit: I may have asked this already, but cannot find my post.

Take the short one with, into the hardware store, or like Fastenal,
or similar that specializes in machine hardware.
and have someone show you how to match thread , and diameter..
Here we also have a marine supply store,
to keep the fishing boats afloat.
a good source of stainless steel stuff..

ACE Harware stores, here in the NW at least, also have a great selection of Stainless Steel bolts. My local one in Vancouver, WA has only been stumped once - for front hub nuts for my Electra Cruiser. The ACE out here in Ocean Shores is the go-to place for just about everything in this community of 5,000 full-timers.

Lou

M5 is waterbottle boss, size, I suspect its bigger ..
FWIW, standard pitch for 5mm bolt is 0.8/MM
for a 6mm bolt, it's 1 per MM..

Thanks all - I finally got to (go back to) the ACE to try the bolt I have in their "chart" and found that it is an M7 x 1.0 x 35mm. They didn't have an M7 in any length. Fastenal this morning did not have it in any length (nor does their website). Everyone I checked carries a M6 and M8, but no M7.

So, I decided to try a M6 longer than needed (65mm) and place a Nylock nut and washer on the top instead of threading an M7 through the top (threaded) part of the seat post binder pieces. Two other options are to drill out the top threaded piece to accept an M8, but then I'd have to also drill/widen the hole in the seat post as well. Since this is a unique seat post (for the folder) I thought that would be my last option.

Another option offered to me by a relative of mine is to have him make an M7 for me (or I can order something from England). However, I need it in about 55mm length. Hate to have him go through all that trouble and will try the M6 with Nylock first.

Try a store that sells British biycles. They may have the correct bolt. That's how I got the one I needed.

Lou

McMaster lists 7mm up to 50mm .. possibly a lifetime supply for less than having someone make one..

Tampa and Pensacola should have something, they have boats to repair..

IDK OP's location, but no place in Fla is that far from the Ocean..

Close, I looked at that online last night, but the one listed is a hex head and doesn't fit in the place the socket head sits (it is recessed). I considered using a hex head and fill the recessed hole with washers, but the way the seat post come into play with the mounting area it does not allow any room to turn the hex head. They (McMasters) don't list a socket head in a M7 (nor in a "button head socket")! They do have one of the easiest websites to navigate though.

Thank you Bruce.

Also, checked West Marine and they are littlered with M6s and M8s, but no M7s!!

Good one! you need a socket head in 7mm :eek: .. that will be tougher.. I'd use an M8x1.0 socket head, my little lathe (or alternatively, a belt sander or bench grinder) and a 7x1.0 die and cut my own.. M7x1.0 dies aren't too hard obtain..

What about supplying us with some pictures so we can go trough our partsbin(s) and know exactely what we are looking for?