Sunday, March 17, 2013

Tube Cutting and Jig Fitting

Here are the tubes for Neil's frame going through the process of being cut to fit together in the jig.

First is the seat tube being mitered with the abrasive belt system.  I cut the seat tube using vee blocks in the vice to make sure it's exactly 90 degrees.
Here it the fit to the BB shell.  You can see the scribe line that I "sand" up to.
Next is the BB joint.  You can see that the blocks I use to hold the tubes in the mill are still attached to the down tube. That way I can easily put the tube back in the mill if required.
Here is the head tube joint at the same point in the process.
This frame will have a titanium tube inserted into the top tube to act as a brake cable guide.  Here is the somewhat Rube Goldberg method I use to cut the guide holes for now.
It leads to a nice smooth transition for the entrance and exit.  Once bonded in place the tube will but ground flush with the carbon.
Finally, just for Neil, who likes this sort of thing, the weight of the titanium guide tube (prior to being trimmed on each end).  Not including the cap of course.
Next step is bonding in the tubes and bottle bosses.

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