Cycling UK Forum

Hi all,
I've wanted to query this for a while but my Jack Taylor Tandem http://smutpedaller.blogspot.co.uk/search/label/jackyll came with what appears to be mostly Bronze Silicon fasteners, on the bottle cages, mudguard fixings and the rack bolts. I'm guessing this was because they are more resistant to corrosion?

I'm a little concerned by the rack bolts as I know Bronze bolts will be weaker than steel bolts, is it worth replacing these with new stainless bolts? Anyone have any experience with bronze fasteners on bikes as this is the only bike I've ever seen these on. Thanks!

I'd be surprised if they are bronze. Some sort of coating on steel? Have you tried taking one out and testing to see if a magnet picks it up?

they could well just be brass. This won't be that strong, but it isn't that difficult to carry spares if you want to.

NB from the head shape I would say it is quite likely that the screws might be imperial not metric threaded, so check carefully before replacing them with something else.

cheers

3/16" BSF?
I would be tempted to run an M5 tap through the frame, insert some buttonhead screws http://www.westfieldfasteners.co.uk/A2_ScrewBolt_SHBtn_M5.htmlfrom the inside (the heads aren't very deep, I can measure some if you like) and fix the carrier with nuts/washers. The bolts can be cut off flush with the nuts for a neat job.

4BA were used for this sort of thing and are very close to M5
4BA are still available for those that like originality.

cadmium plated steel?

greyingbeard wrote:4BA were used for this sort of thing and are very close to M5
4BA are still available for those that like originality.

You mean 2BA.

Neilo wrote:cadmium plated steel?

That's what I thought, but they look too dark and I would expect the cad plate to have worn by now.

tatanab wrote:

Neilo wrote:cadmium plated steel?

That's what I thought, but they look too dark and I would expect the cad plate to have worn by now.

or Japanned steel?

tatanab wrote:

greyingbeard wrote:4BA were used for this sort of thing and are very close to M5
4BA are still available for those that like originality.

You mean 2BA.

3/16" BSF is 32tpi and
2BA is same diameter (4.76mm nominal, actual ~4.7mm screw OD) but 31.35tpi and with a 47.5 degree thread form

M5 x 0.8 is 31.75 tpi and is of course nominally 5.0mm actual ~4.9mm screw OD.

Both BSF and Metric threads have a 60 degree thread form.

3/16" BSF is almost identical to #10 UNF 32 which is 4.826mm major dia 60 degree thread form and 32 tpi

It can be very difficult to tell many of these screws apart, but smut pedaller's screws look like BA head forms to me.

cheers