I am in progress of developing an overhead lathe using only standard parts and 3D printed parts, as I do not have easy access to a machine shop. Nor do I have a 3D printer, but as of now I am using the materialise 3D printing service. I started looking around on ebay, and bough myself a THK 140mm linear slide, and a sigma koki Z axis slide. Then ordered adaptor plates in a material called Alumide, looks nice and shiny
, and fitted them to a bridge made out of Maytec aluminium extrusion profiles. As I found out stupidly yesterday, I had the slide mounted on the wrong side of the lathe, but thats an easy fix.A couple of days ago I received the parts for the suspension assembly, and a 3D printed suction tube (I tried and failed a couple of times making a nice looking suction tube the manual way)
But It seems I had made a couple of mistakes in my STL files, as a couple of smaller parts were not printed, and the lever for the cutterhead drop movement was fused with the main body. Luckily the crucial parts were printed OK, and a dremel severed the lever from the rest. One small note is that the dye of these parts was not as nicely finished as the adapter plates, because of the box containing the components. The better was was probably to connect all the pieces using rods, and cutting them when received.
I used some metal plates as a quick makeshift counterweight, used some small RC bearings which were press fitted into the 3D print, and attached a Airpot Dashpot.
Since I was quite excited to get up and running, I did a fast assembly of everything, not really measuring and aligning thing etc. and got some quick and dirty test cuts. The head is an 500 Ohm Fairchild 541A overhead. The stylus holder was originally bent, but opened it up and bent it back to straight. I was pretty scared to open the thing up, but the process of disassembly and assembly was actually pretty straightforward. Only the gap alignment was a bit fiddly. I wired a nice 70V toroidal transformer and a fuse between the amp and the head, and fused it with a 100mA F glass fuse on the secondary side. I now came to the conclusion that the assembly was mounted on the wrong side of the record player. I just installed a steel needle and tried some embossing (since the needle is backwards when mounted "correctly"), with mediocre results. Audio level was very good, frequency response not bad but a lot of distortion, and my lesser turntables have difficulty tracking the grooves. On the plus side, when cutting silent grooves I found no evidence of noise from the stepper motor, and under a 100X microscope I could not detect any 'stepping'. I used a Trinamic TMC2100 based stepper driver controlled by an arduino. This driver has 256x microstepping, and more importantly a mode mode called StealthChop. This makes the steppers motors very silent, but at the cost of most of the torque. But the torque is still more than enough to move the carriage. There is also a inline rubber coupler to the slide axis, and a viscous damper, which should be good for the faster lead out moves. I will do some more proper testing when I have some time, and decide later to maybe upgrade to a belt driven setup with DC / Brushless / Whatever motor.
I hope to free up some time this weekend to start building a floor plate, control panel, ...
In the meantime I'm still waiting for a stereo cutterhead print. I ordered the body in Polyamide as well as Alumide, and the torque tube will be 3D printed in aluminium.
jokes
