Can I use a fork from a smaller frame?
 

I have been looking to replace the fork on my Bianchi Sport SX with an original for a while. Since it is a tough find, I've been looking for a parts bike on Craigslist for a while. I finally found one, but the frame looks like it is a little bit smaller than mine. Would I be able to use the fork from this, or should I keep looking?

Parts Bike:

[IMG]http://i.imgur.com/Cy3SwXd.png?1[/IMG]

My Bike:

[IMG]http://i.imgur.com/BEIeL6P.jpg[/IMG]

Can't see pics but will say nope. There won't be enough steer tube to thread your headset lock nut on safely. Go fish.

I'll keep looking. Thanks!

You could ask the seller to measure the head tube length

The frame being sold is definitely smaller. There is a pin for a frame pump on the head tube, and there is not as much space between the pin and the bottom of the head tube on the seller's.

You can splice and weld tubes from two forks using an inner sleeve machined to fit the ID of the steering tube. The splice should be as low as possible so it will not interfere with the stem. The inner sleeve should be as long as possible so it keeps the steer tube straight during the welding process. Leaving a 1/4" between the two steer tubes to be filled by weld, and a couple 3/8" holes on both sides of the splice through the steer tubes to also be filled with welding (plug weld). Keep the heat down by letting it cool between welds to prevent distortion. I did this with a mig welder but I don't see why it couldn't be done with brazing as well.