HI, Old man learning new stuff. I'm thinking about building a custom CNC machine to use in creating clarinet bells. The concept is that the machine would cut both the inner and outer profiles simultaneously. The attachment is a conceptual drawing. As the bell is being turned by the lathe, the lathe table will move the bell in the X axis. One cutter (spindle or turning tool - not sure) would follow the inner profile through the opening in the tailstock while the other cutter follows the outer profile. I suppose one cutter would be the Y axis and the other the Z axis, although in the same physical plane. I have no experience in CAD/CAM, though I've drawn many woodworking/construction projects using Sketchup and am beginning to learn Fusion 360. Is it possible to do this? Thanks, Ken
Not sure how you would finish the end of the bells. If I was doing it, I would probably start with a uniform diameter block, gripped entirely at the drive end leaving the bell end open. And then slowly whittle it down on both axes toward that drive end. The only other potential issue I see is the length of the interior bit. The longer bits get the less interested they seem in cutting as they tend to flex. You may need a router at the end capable of holding a larger diameter bit.
I have found some longer 8mm ball nose and regular end mills I use for roughing out deeper 3D carves. They are fairly stiff. You can get 8mm ER11 collets for the OB RoutER11 and Elaire makes them for the Makita and DeWalt (maybe others, too). Router Collets - Elaire Corp
I would not run router bits but instead consider it a lathe, then ordinary boring bars can reach into the bell. the bell is then rotated as in a lathe (just buy a cheap woodworking lathe and modify it, no sense trying to make a spindle) I would use one of those dovetail chucks to hold the blank. The rest is just mucking with software. if you arrange the axes in a standard way then there is a good chance that Fusion360 can generate Gcode for it. This means ZX for the outside cutter (standard lathe) and UW for the inside cutter, but now the Blackbox cannot assign those letter so you will ahve to look at some other controller, maybe Masso? However, a 'very' custom postprocessor could be done that translates 'UW' into 'YA', IFF you can figure out how to configure Fusion as a dual axis lathe in the first place. IE, if there is an exisitng similar machine wih a matching post then it can be modified to suite the blackbox.
Thanks. Here's a photo of a bell and 3 barrels. I've been making them with my 8x16 machinist lathe. However, getting the interior profile cut in a gentle curve is problematic at best. I've done lots of woodturning on my old manual lathe, as well as years of general woodworking, so I'm very familiar with using a router. As mentioned in my first posting, I'm considering using turning tools mounted to tool posts instead of the spindles. Most of my recent work on this project has been single point turning with a little use of standard lathe tools. I put a 1/2 inch round bar into a boring bar tool holder and use it as a tool rest for manual turning. My primary concern is the possibility of programming the controller to run it. That's where y'all's expertise is much appreciated.
Oh, yeah. The two cutters would only move in the physical Y axis (one in Y and the other in Z horizontally). The router would move along the X axis. Tricky!
Does it *need* to be simultaneous? If not, you would 'just' need a CNC lathe (with either one or two tool posts) which would be relatively straightforward to program.
A problem with using a lathe is work holding. My design holds both ends of the workpiece while allowing access to the interior. Holding one end securely without any deflection has caused me many headaches. Cutting simultaneously is likely to be difficult to program, and if that is the case then running two separate operations would be ok.
Both ends will be glued to sacrificial wooden rings. Most of the end turning can be done by cutting beyond the bell into the extra ring. The remainder will be hand shaped.
