rolling mill stand

Sam Hatchett came over on Monday and I made a stand for her new Durston rolling mill. I used a bunch of scrap that I had lying around. She's going to throw a coat of hammer-tone silver paint on it and it should be good to go.

 

rhino gear gen script

The damaged rolling mill gear sent me down a rabbit hole of learning more about spur gears that I previously knew. I went searching for a replacement gear that I might be able to modify for the rolling mill. The measurements that we took with the machinist microscope helped me narrow down the specs on the gear. I wanted to make sure this would fit before purchasing so I took the additional specifications from the gears found on Motion Industries and went looking for a gear generator. In the past I had used geargenerator, but when I went and tried the program, it didn't let me create the gear with these specifications. I went looking for a different program that would allow me to type in the specifications and then I could generate a gear that I could 3D print and test to make sure the gear would work before ordering one. I also thought about casting such a gear from the print since I have been doing quite a bit of casting from prints lately. I knew this would be too soft though. Regardless, having a 3D printed gear would allow me to test things to make sure the part was correct. I found a much older Rhino Script called GearGen (it was written for Rhino v3 and v4), and downloaded the script to see if it would work with Rhino 5. Sure enough the script worked. It requires that you have a base circle to apply the script to, but it allows you to set pressure angle, number of teeth, pitch, etc. I generated a gear, extruded it in Rhino, and made a print. The printed gear fits nicely. I think I can place an order now. Good to know that I can generate gears easily within Rhino...

durston rolling mill gear

The rolling mill at school lost a few teeth last semester. It turns out the handle gear has been wearing for quite some time. Check out the twist in that spur gear! I couple teeth just finally wore down and then cracked. I've been trying to get a reply from Durston for quite a while and they finally came back with an answer of "no replacement parts for this model". I decided I would press the gear out of the handle. There was originally a set screw that held the threaded gear into the handle. This set screw had sheared sometime during the life of the rolling mill and there was no way to unscrew the gear. I turned a mandrel on the lathe to press the gear and started heating up the handle so I could throw the whole thing on the hydraulic press. It pressed out easy regardless if the threads and then I was able to clean things up. I'm going to try and order a new gear which I will have to modify. The Durston is just too nice to not repair, so I hope I can nurse this tool back to life.