Chombi

1) Why the heck did Campagnolo decide to change the "pitch" of the serrations on the 8mm seatpost bbinder bolts from coarse to fine for?? I need a coarse one for my 70's bike and most out there are the newer fine pitched versions, while the older ones are more expensive. I was hoping the finer pitched ones would just fit in with the serrations on the frame, but it doesn't and the bolt head sits proud of the seatpost clamp tang.....And why did they even bother with serrations if there's an allen head fitting on that end of the bolt that one can use to keep it from spinning when turning the male end?? Most people tended to strip the serrations anyway when they don't bother to back it up with an allen head wrench.....

2) Why were there two sizes 8mm and 10mm diameter. The 10mm seems to be much less common...did it go "Betamax" and get totally replaced by the 8mm bolts??... I'd think the bigger 10mm ones might have been less prone to cracking/snapping....

Chombi

cyclotoine

I have a 10mm on and have never found a bike to use it on. It's NOS! The serrations worked on the right seat lug, usually the fully forged ears kind... not the notched hollow kind... I sympathize with yout frustrations!

Chombi

FYI,
Alan Carbonios use a 10mm bolt.....
Only one I encountered myself so far......but I thought I read somewhere that Cinelli framesets might also use the bigger sized bolts too....

Chombi

repechage

Actually, the old ones circa 1973 did not have an allen key fitting on the back side. Also, no washer.
I will have to check the circumference knurling, I always thought it was quite fine, and later went coarse.

One thing we often did back in the day was file or grind .5 mm to 1mm off the female thread side to prevent the bolt bottoming out and then failing when continued torque was applied.

gaucho777 

You say 70s project bike. Is this for your Lineseeker with Dura Ace and other non-Italian parts? If so, you might consider a Sugino binder bolt; they are less expensive, and less prone to snapping.

Chombi

Yes,......I heard of that suggestion before to avoid the dreaded campy smapping bolt thing.... I might just go that direction....I guess I was just trying to replace the original with the same style/era Campy bolt....

Cache

My graftek has a Miche binder bolt, so that may be an option for you too. I'll be shopping for a Campy one before long, too many non-bicycle priorities these days.

rootboy 

This has been my observation too, based on my limited experience.

RobbieTunes

I just put an NOS Campy binder bolt in a Cinelli-made Columbus frame, works great.
I've also noticed a Cinelli 1A clamp bolt works like a charm, too, and seems to be stronger.

Even with the serrated end, I use Loctite red in the L binder ear, then "seat" the serrated end by holding it with an allen key while tightening it.

If you use a non-notched or filed down Sugino, that will work, but I recommend a washer on each end.

With an allen key head on each end, the serrations and notches aren't necessary to install and hold a seatpost,
but if you are just carrying a multitool on the road, having one end "fixed" is the key, pardon the pun.

repechage

Shimano made a seatpost binder bolt in the 70's also. Often not identified correctly, they had 12 point allen key fittings and knurling on the outer circumference. No identification otherwise.

onespeedbiker

I've also wondered about why the allen socket would be on the side that is not supposed to turn; I guess it's in case the splines fails, but as you say many pay no attention and strip them out anyway. I have bikes that use both versions; the course version in on the older bike (along with a notched hole on both sides of the clamp in the event one wants to go that way) and has no allen socket on the spline side. Anyway if this is really important to you I have a used clamp in perfect functional condition but some of the chrome is peeling off the head on the splined end. I rarely sell parts but I'm sure we can work something out; it's not like it's a high value item..There is also one on Ebay; BIN with shipping for $23 https://www.ebay.com/itm/Vintage-Pate...item460ada4184

gaucho777 

^Hey, I recognize that seller's name!