Seat post binder bolt w/10mm head?
#1
Senior Member
Thread Starter
Seat post binder bolt w/10mm head?
I'm working on a frame and the seat lug has a recess for the binder bolt.

I have a number of binder bolts. Campy, Simplex, Tange, Sugino and unbranded. All of them measure 12 to 12.5 mm heads.
I need one with a 10 mm head in order for it to fit the recess. When looking on-line, no place gives that measurement. Can anyone give me a brand with that size? Or, if anyone has one that size, are you willing to swap for one of mine?

I have a number of binder bolts. Campy, Simplex, Tange, Sugino and unbranded. All of them measure 12 to 12.5 mm heads.
I need one with a 10 mm head in order for it to fit the recess. When looking on-line, no place gives that measurement. Can anyone give me a brand with that size? Or, if anyone has one that size, are you willing to swap for one of mine?

#2
Shifting is fun!
Join Date: Aug 2009
Location: South Holland, NL
Posts: 9,363
Bikes: Yes, please.
Mentioned: 236 Post(s)
Tagged: 0 Thread(s)
Quoted: 1590 Post(s)
Liked 1,254 Times
in
668 Posts
If it's a vintage frame, you might be looking for the wrong type of bolt. How about something like this?
EDIT: first pic now showing, my suggestion is off-target.

Disclaimer: I can't see your first pic, so I may be missing vital information.
EDIT: first pic now showing, my suggestion is off-target.

Disclaimer: I can't see your first pic, so I may be missing vital information.
#3
Señor Member
Join Date: Dec 2018
Location: Pac NW
Posts: 4,007
Bikes: Old school lightweights
Mentioned: 55 Post(s)
Tagged: 0 Thread(s)
Quoted: 1636 Post(s)
Liked 1,669 Times
in
948 Posts

Is the lug also keyed so the keyed nut will stop when tightening the bolt? Or is that an additional problem to consider?
I recently used jb weld on a nut that wasn't keyed, so I could avoid the need for two tools to tighten the bolt.
#4
Senior Member
Thread Starter
I forgot to say, it's not keyed. I don't mind using two Allens to tighten it up.
#5
SE Wis
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 7,470
Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 1535 Post(s)
Liked 1,048 Times
in
719 Posts
Seems like 8mm is common.
https://problemsolversbike.com/produ..._bolts_-_29451
You could contact these guys and check OD.
https://framebuildersupply.com/colle...t-binder-bolts
Appears they are out there.
https://www.ebay.com/itm/Campagnolo-...oAAOSwAvpbrjE7
https://problemsolversbike.com/produ..._bolts_-_29451
You could contact these guys and check OD.
https://framebuildersupply.com/colle...t-binder-bolts
Appears they are out there.
https://www.ebay.com/itm/Campagnolo-...oAAOSwAvpbrjE7
Likes For dedhed:
#7
Crash Test Dummy
The screw is just a standard M6 socket head. The nut you might be able to improvise. Check the link below.
Univega Super Strada
Univega Super Strada
#8
Senior Member
Thread Starter
^^^^ That's an idea, but it's not gonna be pretty enough for me. I'm in no rush and will hunt around some more.
#9
Senior Member
Thread Starter
I just had an epiphany. A recessed brake nut's head fits perfectly. Two of those, slightly trimmed down with a stud epoxied into one of them...done....homemade seatpost binder bolt. Any negative thoughts?
Likes For gearbasher:
#10
Senior Member
Join Date: Jan 2016
Location: Ventura County ,California
Posts: 1,576
Bikes: 1973 Windsor Profesional,1976 Kabuki diamond formula with full Campy, 1977 Raleigh Competition GS , 1971 Stella original Campy equip. 1978 Raleigh Super Grand Prix, 1972 Italvega Gran Rally ,1972 Super Mondia Special,Medici Pro Strada,Colnago
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 351 Post(s)
Liked 530 Times
in
356 Posts
If that doesn't work out I can grind one of your 12 or 12.5mm bolts to 10mm for you.I am a tool grinder with my own shop, it's what I do! I wouldn't charge anything , just helping a fellow KOF .Let me know, Joe
#11
Senior Member
Thread Starter
Thanks for the offer. That was going to be my last-ditch-effort plan. The main drawback being the removal of the chrome and rusting.
#12
Banned
Most are 8, ( that's shaft diameter not head ) , but for the all aluminum AlAn , they used a 10*, even Campagnolo offered one, .. stock one not as shiny..
*chain ring bolts are also 10 mm shaft
*chain ring bolts are also 10 mm shaft
#13
Member
Join Date: May 2015
Posts: 34
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
gearbasher Curious what you ended up doing.... I just acquited a SOMEC frame and i've run into the same problem! Not sure what to do. It looks so much better when I put in a brake bolt and it sits inside...
My campy one just sits on top. looks terrible. did you figure out a solution with something that fits into the brake bolt with the same size diameter? or were you able to put 2 together as you said? What would have to be done in my situation if i was to try that would be trimming the barrel length down. brake bolts do come in shorter sizes sometimes but the only one i have that's extra definitely takes up more than half the clamp length. I dont know what to do!
My campy one just sits on top. looks terrible. did you figure out a solution with something that fits into the brake bolt with the same size diameter? or were you able to put 2 together as you said? What would have to be done in my situation if i was to try that would be trimming the barrel length down. brake bolts do come in shorter sizes sometimes but the only one i have that's extra definitely takes up more than half the clamp length. I dont know what to do!
#14
Senior Member
Thread Starter
I took two recessed style brake nuts. I cut a threaded section off a bolt and threaded it into one of the brake nuts with epoxy (to keep it from spinning). Let the epoxy cure. I put that on one side and threaded the other brake bolt on. I use two allen keys to tighten it down. You just have to get the right size brake nuts (or file them shorter) so they don't bottom out.
Basically, description in post #9
Hope my description is clear, I've been using it for over a year with no problems.
Basically, description in post #9
Hope my description is clear, I've been using it for over a year with no problems.
Last edited by gearbasher; 12-25-20 at 02:37 PM.
#15
Member
Join Date: May 2015
Posts: 34
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I took two recessed style brake nuts. I cut a threaded section off a bolt and threaded it into one of the brake nuts with epoxy (to keep it from spinning). Let the epoxy cure. I put that on one side and threaded the other brake bolt on. I use two allen keys to tighten it down. You just have to get the right size brake nuts (or file them shorter) so they don't bottom out.
Basically, description in post #9
Hope my description is clear, I've been using it for over a year with no problems.
Basically, description in post #9
Hope my description is clear, I've been using it for over a year with no problems.
Yeah that's an option! There's gotta be something that's out there that will fit! damn. so crazy
#16
GDFTR
Join Date: Dec 2020
Location: Torrance CA
Posts: 71
Bikes: '74 Falcon San Remo, '80 SR Semi Pro, '88 Trek 360
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 35 Times
in
19 Posts
Also interested because I am in the same boat with my SR frame it’s got to be 10mm max diameter to fit the recess and look clean.

#17
Senior Member
Likes For seypat:
#18
Senior Member
Join Date: Apr 2007
Location: Thunder Bay, Ontario, Canada - burrrrr!
Posts: 10,580
Bikes: 1958 Rabeneick 120D, 1968 Legnano Gran Premio, 196? Torpado Professional, 2000 Marinoni Piuma
Mentioned: 182 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Likes: 0
Liked 749 Times
in
462 Posts
I am pretty sure that you need a splined, rather than a keyed, seat post binder bolt. Pretty sure that I have a couple at the lake cottage. Will look next time I go there, if you wish.
__________________
"98% of the bikes I buy are projects".
"98% of the bikes I buy are projects".
#19
Senior Member
Join Date: Feb 2020
Posts: 1,006
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 349 Post(s)
Likes: 0
Liked 336 Times
in
216 Posts
What's the other side look like/need.
It'd be dead simple to turn a stainless socket-head or button-head capscrew to 9.9mm, can I assume the hole dia is 8mm.
It'd be dead simple to turn a stainless socket-head or button-head capscrew to 9.9mm, can I assume the hole dia is 8mm.