Simplex _ No. 3649 _ seat pin binder bolt

The 8mm. Campagnolo bolt set [No. 1072] was first seen in the Supplement to their Catalog No. 16 published in November 1971. This similar Simplex version was formally introduced in the 1974 Simplex catalog. __ This bolt accepts a 5mm hex-key while the flats of the "nut" portion of this unit is held with a 10mm. open end wrench. Each side of the Campagnolo model was held with a 5mm hex-key. The ends of the Campagnolo parts are clearly more finely finished and beautifully stamped beneath the flawless chrome plating. Not that it matters in terms of function, but in comparison, these seem crudely stamped with the heads rather coarsely milled. On the other hand, I have had Campagnolo bolts break off inside the nuts while (admittedly with far less experience with the Simplex bolts) I have never seen that failure with these. The difference may be due to users over-tightening the Campagnolo parts when trying to close the bolts beyond its intended closure range of just under 21mm. without adding a washer. The bolts of these binders will pass completely through the nuts to close them at just under 19mm beneath the heads. Without an extensive collection of Allen wrenches, perhaps the need for only a single 5mm, wrench might be seen as an advantage for the Simplex part. However, the obvious damage seen on the head of this particular nut may have resulted from a poorly chosen available tool which might have slipped during use. I would never depend on the serrations beneath the head of either Campagnolo or Simplex nuts to adequately hold the part in place while tightening – seatlug openings were never perfectly sized and the teeth could easily damage frame enamel.

Posted by Stronglight on 2014-07-11 18:57:12

Tagged: , Seat Bolt , Simplex , Binder Bolt