Testing 1, 2, 3…

See just below the sleeve's fillet...?

I killed my first segmented fork….on purpose.  I wanted to test the strength of the fillet brazed sleeves since when I cut up a couple of test brazed sleeves thebrass was only getting down 1/2″ at most from the edge of the sleeve.  I’m pretty sure it’s not my brazing technique, since there is a relatively large gap between the sleeves and heating up the sleeve doesn’t get the inside tube as hot as it should.  I could have used silver to better fill the gap in the sleeve but man, that would be incredibly expensive right now.  Silver is now around $38/oz.

So, before even riding this fork i did this test.  I put the fork in the vise, got out the big Park frame & fork alignment tool and started lightly pulling forward on the left leg (disc mount side).  Kind of like a Rutchblock test in backcountry skiing, I upped the pressure after each set of 10 pulls.  It lasted a good amount of pulls, until I really used my weight to crank on the lever and the 1″ diameter (0.035″ wall) tube failed about 1cm below the sleeve.  Good to know that brass brazing the sleeve makes a pretty strong fork leg, and that even though this is not scientific failure testing by any stretch, or even a direct comparison to riding stresses on the fork, there’s no way in hell I’d ever put that much torque on the fork unless i ran into something solid going pretty fast.

Now it’s time to build up another fork to replace this one on the RivBomb! The trails are drying out fast 🙂

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