hi folks
iv'e grinded the fittings for leaver brakes off an old set of fork with a mind to turn it into a s.speed.. now there's a 3.5 inch space between the fork fitting and the wheel rim (if you know what i mean?), can i get calipers that have a 3.5 reach?? mark

Yes, there are some very long reach calipers that would fit. They're made for 20" wheel and BMX bikes, and for some low end mtn bikes that don't have Cantilever brake bosses (what you removed). The problem is that long reach brakes don't work all that well because the long arms are much more prone to flex than their shorter counterparts.

However, in your situation they're your only option.

Here's an example of that one that might work available in the USA

You didn't mention your wheel size. It may be possible to build one with a larger diameter and reduce the brake reach. Moving from a 700c to a 27" will only gain you 3/8" or so, though. Maybe that plus a drop bolt may put you in the right range. Drum or disk brake may work too. Your other option is to reverse your mod by brazing the canti bosses back on.

Sounds like you have a challenge. Don't be tempted to go rear brake only though.

Good luck

-G

Or just go on eBay and get a cheap fork.

My fixed gear conversion started life as a 26" wheel mountain bike. I cut the canty mounts off of the fork and stays and installed 700c wheels. A standard reach 105 front caliper fits perfectly to the reforctor mounting hole in the fork. Since it's a fixed gear I don't have a rear brake but I assume a standard reach brake would fit on the rear also.

If you do decide to go with a long reach brakes, hopefully you can go with the brake prior to the one FBinNY showed in his link. I have used this brake (still have it if your still interested) and disagree with SB; it would not lock up my rear wheel when the bike was being pushed; as FBinNY said The Tektro 984 long reach https://sheldonbrown.com/harris/brake...ers.html#70-88 works significantly better. you need about 3.5" (88.9mm) and the Tektro have an 88mm reach.