PVD Head Tube
Push the limits.
While I get tooled up for a nice light steel integrated head tube, I have started doing a high quality 4130 machined head tube.
I'm making this tube for my wife's new bike.
A 4.500" head tube for 1 1/8". Only 49 grams! Crazy light!
The weigh in:
Stock. 1.500"x.083" 4130
Clean up the end for the live center.
Marking start and stop points.
Roughing out to 1.400"
Finished to 1.375" OD.
Cut the rings to 1.438"
Clean up the ends after cutting off.
The initial tube had a few issues that I could not live with. While I need to keep this design on the cutting edge, a slightly more conservative design should be done first.
93 grams before post welding machining of the ID step for the cups press fit.
Rev A v. Rev B.
In the jig. Keeping the bearings spread apart helps increase the strength of the system.