I had the opportunity to fab up a ti bar/stem combo for Andy, so took some pics along the way to share with y'all...
I started out by taking a piece of 1.25" x .065" tubing and boring it out to fit our titanium forks steerer tube outer diameter of 1.125". After boring, the piece is parted off and faced on both edges.
A double bolt clamp is mitered and then welded to the steerer clamp. I use a double stacked slitting saw to make the cut in the clamp section, which gives me enough width to insure that when the ti section shrinks during welding, then stretches during clamping, that a moderate spacing still exists for adjustment.
I then mitered a section of tubing for the mating surface of the clamp section. I normally miter this using an auto-feed on the quill of the milling machine so that the miter is well paced and deliberate. Folks often ask what type of hole saws I use and how long they last...well here is a 1.25" Starret bi-metal hole saw that has probably a thousand miters on it, over 4 years old, and just now broke a tooth. Not bad for a $12.00 consumable item.
As each bar stem combo is unique, it makes it tough to devise a fixture that is fully adjustable for each one, so I often fabricate each in a progressive build. As the entire piece is built off of the steerer tube, I will use a steel piece clamped in place and indicated off of to insure each step of the following processes is accurate. Here, because the Luv Handle uses a 1.00" center section and the body of the stem is 1.25", I need to swage down the handlebar end to fit. I measure with a dial height guage as well as a level to insure the stem is squre in the swaging dies before applying pressure. This insures I have an oval section that is at a perfect right angle to the steerer.
With the piece successfully swaged, I then move it to the miter set up. As the oval section is now taller than the round portion of the stem, I slip a piece of paper under the miter and watch carefully, my hand on the quill feed release. When the cutter touches and moves the paper, I disengage the feed. This insures that I do not move the cutter into the vise table. It is literally a hairs distance, so it pays to have small tips like this to preserve your tools.
The miter made, checking the alignment and fit...
Everything is cleaned up and then purged for welding with argon...
The finished product...
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