This one doesn't exactly fit anywhere, so I'll put it in gun building. Some of you who are interested in rifling barrels might like to copy this machine.
I was down at the American Precision Museum in Windsor, Vermont last Sunday. It is in the old Robbins & Lawrence building where they first mass produced the 1841 musket with interchangeable parts. Some brilliant individual preserved a number of the old hand powered and water/overhead belt powered tools they used in the 19th century.
The one that caught my eye was a hand powered rifling machine.
This is a blank barrel in the holders. You can see by the pairs of bolts on the right side of the base that the holders are adjustable for various barrel lengths.
Here's the barrel from the other direction. The indexing disc and arm allow the operator to rotate the barrel to a specific number of positions. The rod for the cutter is poised in front of the barrel.
And here's the business end. The cutter rod is supported on two pillow blocks mounted to a sliding frame. The bar angling up and to the right is adjustable. There's a rack running through two guides on the frame that engages a pinion and rotates the cutter rod. The far end of the rack has a couple of pads that go either side of the angled bar. As the support frame gets shoved back and forth the rack moves side to side. Depending on the angle of the guide bar the rifling can be adjusted to an infinite number of twist ratios.
It's a brilliant design, beautifully executed. The Precision Museum also has a powered model that uses ratchets and pawls to index the barrel to a new groove. The cutter runs up against some kind of actuator when it comes out the end of the barrel, which adjusts the cutter deeper with each stroke.
I can imagine someone copying this with some angle iron and bearings. It wouldn't be as durable or elegant, but for low level production it would offer great flexibility and accuracy. Is anybody using anything like this?
