i recently started diving into the world of scratchbuilding rollling stock. I model the DRGW and to get a prototypical caboose I either have to go with brass or find the ever elusive Protowest resin kits. I decided I wanted to scratch-build a few cabeese to add to my fleet. I have been doing structures for quite a while but there are quite a few more intricate parts for rolling stock.
My other hobby outside trains is 3D printing and CAD (2D and 3D) design. The CAD becomes really useful but for me 3D-printing on a hobby grade printer is not quite there yet (at least on mine). The one thing I discovered though is alot can be made once the cad drawing is made.
I already knew how to make the drawings I just needed something to cut out the designs. Cutting the raw material is the hardest thing for me. I always have trouble cutting out styrene and getting nice straight edges and clean cuts in things like windows even though I have the plans I created right in front of me.
So last December I decided I would buy a CNC Router kit ($650) or the price of two brass cabooses. The exact model is called a Shapeoko 2. found here. This really made cutting the parts quite a bit easier for me, especially for things like windows.
I don’t have a picture of the CNC router at the moment but I thought I would share the results of my scratchbuilt caboose project.
The majority of the parts were cut from 0.040 inch sheet styrene using a 0.03125 inch end mill bit. I just received the diamond plate tread and apex hole brass sheets from Plano Model works today so hopefully I can get the end plates and roof walks made today.
A Shapeoko2 just might be my retirement gift to myself!!!
If i may, I would like to add one more question to Tom’s list… Are you using the resin rivet paper from Micromark or do you have another source? I am interested in obtaining some “rivet decals” for a future project (a stripped down locomotive boiler like you would see in a back shop) and I’d like your opinion on the resin rivet decals.
The only thing cooler than a cool machine is when someone knows how to put it to use. Nice work on those cabeese. You will no doubt get a LOT of good use out of that router.
I used autosketch (2D)/Solidworks (3D) to make my drawings. I save the file as a .DXF. I use a CAM program called CAMBAM (not free, about $150, got it as a birthday gift). It is not free but it seems like the best bang for your buck. I tried about 20 programs and settled on it as it seemed to fit my needs and didn’t have a huge learning curve.
The hardest part was getting the proper dimensions. This involves alot of research and scaling things correctly. I used autosketch pretty frequently so I have become pretty profiecient. I am not the best judge when it comes to difficulty because I do my best to learn almost anything I can.
CAMBAM has a really nice set of tutorials to follow. It has a pretty good base of user experience.
The CNC router takes Gcode files. CAMBAM generates the Gcode files for the router.
Tolerances are about ± 0.005". This is about the best i could get. It took a little while to get everything tuned on the shapeoko but I am satified with the results so far.
I built a hold down board with tabs to hold parts in place (sorry still no picture yet).
I have the speed set to about 10,000 rpm (about a 1/3 max speed). This is only an estimate since I haven’t got an RPM sensor for it yet. The big key thing is don’t rush things. The default setting I believe is 30 in/min. I use 5 in/min.
I have yet to use the rivets I bought. They are Archer brand. I got them from Caboose Hobbies. I will post pictures once I get them applied.
Nice work there. This sorta stuff will really get the Rio Grande fans going. The caboose is cool, but otherwise available, like you say, if you want to pony up the big bucks. But if you get that Ski Train car going, there’s nothing else out there. Looking forward to seeing more of your fine work.[Y]
Thanks for answering my questions. I was wonder if that’s what you used. SolidWorks is a great program. Wish it were more affordable though. [:(]
One more question, if I may. Is there any type of delay with the router in the Z-travel when it enters the work? Or, is it two-positions only - i.e. raised and lowered? Thanks.
There is no delay. The Z-axis actually the most accurate of the three axis. It is mostly dependent on how you program it. I use an 1/8" height clearance to move the tool out of the way when it is positioning between cuts.
So, basically the endmill plunges into the work vs. easing into it slowly? The CNC board router at a previous job was like the former. We also had a CNC milling machine that I could control the Z-axis speed. Since the CNC router you purchased was under $1K, I figured it probably had only two positions (raised and lowered) and nothing in between.
For this kinda of work and the endmill OD you’re using, it’s not really an issue. I was just curious.
It is all how you program the g-code and what lead-in/out you use. It is a truly a 3 axis machine. I generally don’t need a lead-in/out in my code but it is pretty easy to add one in CAMBAM. The machine is capable of it but I just don’t use it for the speeds I have been cutting at. You are correct that there are times lead-in (easing into the material is much preferred but I am only cutting 0.003" at a time on brass and up to 0.010" in plastic at a time. While this takes longer it does create so very precise parts.
It is a very capable router. Its not for machining things like steel but is capable of doing brass an aluminum which all I need it for.
Here is an overall view of the router. It uses a dremel for the spindle, which is currently the biggest tolerance error at the moment. I didn’t use the one that came with it simply because it reduced the throw of the Z-axis by almost an inch.
Here is the build area. It is roughly 12"x12". I drilled 100 holes and inserted t-nuts on the bottom side. These are used for the clamps to hold the stock in place while it is being cut. I haven’t tried any type of adhesive type fixing because that gets messy for me. I am still working on implementing a vacuum system to pick up the chips at it goes instea of doing it at the end.
Here is the electronics drawer underneath. I put it under the machine to protect it from the cuttings.
My apologies on the blurriness of the images. I was using my phone to take the images. The brain of the whole thing is the black and blue box in the upper left side. The interface with the computer is an arduino dev board with a grbl sheild on top. It is powered by a 24v
Thanks for the posting the extra pics, Renegade. That’s a neat set up. Yea, the vacuum will help with the chips and dust.
FWIW, I’ve found that double-stick tape (the thin stuff; NOT the foam) works amazingly well in holding down material. It would come in handy for holding the inside of the material being cut so that it doesn’t shift when you make that final pass. It worked great when machining thin material w/o coolant so it should work in your application, too.
I have made some progress on the caboose. Although most of it is not with the CNC router. That was to get alot of the major parts cut.
Here you can see I found some trucks for the caboose and added the right amount of wieght. I also started working on the brass components. I still need to get some couplers for it but those are still a little ways off.
Here are the brass ladders and endplates. They were cut out on the CNC router. They are cut from 0.015" brass sheet
Here are the roofwalks. I cut them by hand because I only had one chance to cut these. The roofwalk material is 0.008" inch brass walkway material I got from Plano model works.
I started adding the rivets. The rivets are Archer resin rivets on decal paper.
As you can see I had some filling in to do. I found out after the fact that on the cupola end there are no windows
Wow! so much of this just flew right over my head, with programs and all, so, to dumb done a little, how did you get such nice straight cuts on the Plano stock? I usually cut my own walks for well cars, etc, and looking for a way to make clean cuts, other than a scissors.
I used a metal straight edge (my scale ruler) and a brand new exacto blade to cut the Plano stock. I use a dremel with a ruby blade (they are called ruby slitters) to clean up the burrs that are left over after cutting out the pieces. I gently press the walkway against the wheel and the brass cleans up nicely.
Cool, thanks. I just have to learn to slow down! Your caboose project looks great! I like the rivets, and, NO, I didn’t count them! I could never get a $650. router through the finance committee. I could put insulation and a ceiling in my garage up north for that much. I’ll just buy more #11 blades !
This off topic, but I saw a photo of your refinery, part of it was cornerstone, but the other piece was known to me and would like to find one or informed how to make it if that is the case. Again I have looked everywhere and cannot locate one, I would really appreciate the help . Thanks
I believe you are talking about the Cylindrical Heater. That was scratchbuilt. It was made from a cardboard tube covered with sheet styrene. The convection box (between the stack and cylindrical part) was formed from sheet stryene cut out with an exacto and metal straight edge. The metal “framing” on the outside were strips of styrene glued to the side. The stack is a brass tube I had sitting in my brass stock box. All of the piping is solid copper wire that I bent to shape with a pair of pliers. The whole thing was then airbrushed gray and then weathered with weathering chalks.
Well I finally made it to the painting stage and here are results so far. I masked off all the windows since i painted the interior green and didn’t want to get any orange paint on the inside.
I added all the grabirons prior to painting. There were 4 coats of paint before decaling. There was a primer coat and a based orange coat. I then added all the detail work including grab irons and the walkways on the roof. I didn’t want to try and air brush under the walkways and have paint run. This is why I airbrushed a coat on before adding them. Next cam another orange coat to paint the walkways and details. After that a gloss clear coat was added. This helps make the decals blend seamlessly into the model (thank you to a fellow modeller for this tip!)
Here is the completed underframe. All part other than the brake cylinder, resivoir and valve are all sratched from stryene and brass wire. It is a little hard to tell what is what since it is all painted black.
Here are the end Decals done.
Here is the other end. This is the end where I messed up and had to fill in the window holes with milluput two party putty. I think it came out well. You can barely make it out when looking at it under the worklight.
Here is the end result after all the decals have been applied and before the final clear coat.
