Finally got around to updating the .stl file release of my locomotive project: https://github.com/butcherg/DRG_168/releases/tag/v0.2 The engine as a static model is print-ready; I've modeled most of the tender, but haven't printed any of it yet. Here's render of the complete model: and a photo of the printed engine: Currently working on fabricating metal versions of the operating parts, bought a Sherline lathe/mill setup and having fun learning all things machining...
Looks real nice! How well does the plastic drive animate? Is your Sherline equipped with CNC or are you going "old school" on your metal fabrications? I have a Taig CNC desktop mill I bought 20 years ago but I've barely touched it since I started 3D printing. I'd really love to get back to using it for some metal work but I'd definitely need to update the electronics to something more appropriate for 2023/2024. Right now it will only run on an XP machine (using Mach 3) and the controllers are inside an oversized sheet-metal box with I think an old parallel connector. Cheers -Mike
- The version pictured is a static model, no animation. All the parts are as close to proper dimensions as I could make them, and they're correspondingly too flimsy to animate. - Me, old-school. I may get a DRO at some point, but I'm presently I'm enjoying getting results from manual attention. Currently working on side and connecting rods, yesterday was "tool day", made these: The rotary table is a Sherline product, the fence and clamp are my creation. Thin brass is challenging to mill, currently working on perfecting a technique I found on the internets where you glue the 0.02" brass sheet to a thicker piece of sacrificial aluminum, cut the part, then separate it from the aluminum with a heat gun and acetone. The fence is keyed to right-angle align with the t-slot to which it's mounted. It's designed to let me slide the part up and down the Y axis for centering the crankpins to cut radii. The clamp is specifically cut for the brass-aluminum sandwich. I'm liking the discipline it takes to do this stuff manually; you have to be careful with each cut, making sure you're turning the right handwheel AND in the right direction. But, it's a good thing my first project is a Stephenson valve-gear locomotive...
That's awesome. Knowing myself I'd always mess up and accidentally roll the wheel forward when I shouldda rolled back then have to start all over I'm sure like everything else though practice and repetition is the key then you start building up muscle memories. Nice improv on the fence and clamp! Mike
Looks like you are off to a good start in machining. I've really enjoyed it over the years and still some small projects like milling for decoder installs. It is an endless field to explore. I never got a DRO and was fine without it. I can see where they can speed things up but I was never in a production line situation and sometimes going a little slower also avoided making mistakes. Saying that if I went back to using my mill a lot again I'd go that way considering how cheap they have become. For most of the projects I've done, which were one off having a CNC setup wouldn't of done much for me. Again great for repetitive projects but for one off you need to have or write the program for what you are going to make. Kind of like a 3D printer. The majority of people find an object online they want to print and download the print file and print it. If you come up with something other than what you find you are going to have to design the object in a cad program and the take that file and print it. For metal work I'd stay old school also unless I was the type that had access to a good CAD program and the time to learn how to use it machining metal. Keep the reports coming, great work on the project, Sumner
Thanks for the re-enforcement, @Sumner. I've got zero-settable handwheels, and dealing with the backlash isn't all that tedious, so even DRO will be a questionable upgrade for me. I am finding CAD to be useful even with manual operations. For instance, you probably know about the intricacies of laying out radial work, things like spokes in a driver, where accounting for the tool diameter can be mathematically complex. I've got a similar situation with the ends of the siderods, where the crankpin bearing makes a nice radius. I've read about a lot of trigonometry to calculate the angle at which to stop sweeping the tool around the bearing to meet the rod, but I decided to use my CAD program to just mimic the operation: define a cylinder the same diameter as the endmill, center it in the crankpin hole, translate it out to the bearing radius, then rotate it around each direction until it barely touches the rod. Make note of the degrees, ta-da. The center-translate-rotate-rotate is the same thing I'll do on the mill when I actually cut the part. Here's a drawing: The two balls on the 138.2 and 221.8 radials are the 1/16" endmill (shoulda colored them different...), at the end of the respective center-translate-rotate operation. This is OpenSCAD; I wrote a few drawing-support modules to do the linear and radial dimensions, in parentheses are the Sherline handwheel turns/ticks to span the associated measurement, automatically calculated in the dimension() module. Keeps me out of the bars...
