The 1-Day Leadpipe.
About one year ago, I was contacted by a friend of the shop to complete an emergency project. He needed a new leadpipe for a triple horn but wasn't able to send the horn, only a replacement unbent blank from the manufacturer and a photo of the horn. He wanted me to craft a plug and play leadpipe solution that looked original and (of course) played great.
New tapered mandrels can be extremely expensive to job out, making experimentation risky. Making mandrels in house is a much better way to develop new tapers, if it goes bad, all that was wasted was a few hours. Mandrel making is a rite of passage for horn makers much like Jedi and their first lightsaber.
In this case, turning a new mandrel was the only option since I don't dabble much in triple horn making. The taper was backward engineered from the original stub provided by my friend.
After drawing. My stub (left) is much smoother and more accurate than the OEM part (right). It's hard to say if the mandrel or the drawing was bad on the old part. That's one thing that makes just copying numbers off of a leadpipe problematic. Having some sort of adjustment algorithm is important.
One big challenge was that I didn't have access to the horn in order to fit the pipe. I designed a bending jig in CAD software and cut out a bending form on the CNC machine in order to bend the pipe to the correct geometry without needing to test fit it to the horn. I sent it out to Oregon and it fit perfectly.
If you're curious, here's a video to the full build. It was a great 1 day build that turned out with both a happy customer, and more lessons learned in rapidly prototyping designs to completion.
-Jacob
May 23, 2018