Locomotive Wheel Lathe

 

My roundhouse has a machine shop attached to one side and I'm slowly populating it with an overhead belt drive system and machinery.  When I built the drop pit for the roundhouse I knew I wanted to have a locomotive driver wheel lathe in the shop to complete the narrative but there aren't any models available on the market.  My Anycubic Photon resin printer is the answer but the lathe design is going to be pretty complex.

I spent several days in TinkerCAD working on the face plates.  The two work stands and the gear and belt drives will take some time too.

Because my layout is On30, 1:48 scale, the drivers on my two larger locomotives, 2-8-0 Consolidations, are only 48" in diameter.  The drawing that I'm working with is of a 66" lathe and that seemed just about right figuring the shop would have felt that would accommodate any new locomotives for quite a while.  So the photo at the top of the page here is pretty much what I'm trying to build.

 
 The drawing I'm working from is from the East Broad Top RR book about their shops.The only known dimensions I had to work with are the 48" drivers and the 66" face plates so I drew those with the CAD program and worked out everything from there purely by looks.  The first thing I printed out was a face plate, mostly as an experiment, just to see how it came out.  When I stood the 5'10" shop foreman next to it I realized I needed the face plates to be larger for visual impact.  I Googled the Lathe manufacturer and found a book they had printed in 1917 to show their product line.  They had several different sizes of lathes and I chose 88".  As I worked out the design in TinkerCAD and started printing parts I again changed the face plate size and ended up with 82".  That's my final answer.  This was all driven by how it would look overall.  I changed the face plate size but not the dimensions of anything else and it worked out pretty well.

These lathes had several interesting features and I tried to include several of those details.  Instead of using a crane to lift the wheel set onto the lathe centers they built an I beam that fit into slots on the face plates.  A chain with hooks at each end was hung from an eye on the beam.  The hooks were attached to the wheels and the face plates were rotated to lift and center them.  Pretty slick.  They also had a plate on the backside of one of the face plates that had hills and valleys along it's rim.  A small wheel and lever rode along the rim creating a rocking motion as the lathe turned.  The lever was connected to rockers on an overhead shaft which were, in turn, connected to a lever on each work station.  As the lathe turned the rocking motion caused the cutting bit to advance across the surface to be cut.  An automatic feed.  That too was pretty slick.

With the design completed I printed out my parts in groups.  The housings and end frames were printed with the centers and hand wheels but the face plates were printed separately.  The two work stations were printed with their rack plates attached.  Each gear was printed out individually.  About 15 parts altogether.  The picture below shows the work stations as they came out of the printer.  Very little cleanup was necessary once the base and supports were removed.

I used 3 different sizes of brass rod for the various shafts on the lathe and again this was decided strictly by looks.  The gears were printed with the correct size holes for their shaft and the final print was so clean they only needed a slight cleaning out with a drill bit.

Before final assembly I'll complete the painting and most of the weathering.  At this point I've airbrushed everything with a coat of water based Acrylic grey.  Gear teeth will be painted "steel".  Tracks for the workstations will be grimy bronze.  Bolts will be black.  I used a "metal silver" Sharpie for the face plates, hand wheels and levers.  Here's a shot of what I have so far.  The streaks on the face plates will hopefully be hidden by oil stain type weathering.  More to come.

Update 7/28/2022 -

It took me a while to figure out how to add aging to this model.  I had seen the prototype for it at the East Broad Top RR shops in Pennsylvania.  The belt driven lathe was built in the 1880’s and used continuously into the 1950’s.  It then sat unused for 70 years.  The faceplates and exposed metal surfaces have a beautiful patina most likely caused by surface rust and carbonized oil.

My model represents a lathe that’s been in constant use for about 30 or 40 years, in 1927.  I wanted a look somewhere between shiny new and decrepit old.  I added “grimy black” to the gear teeth and bearings to represent grease and smeared some on the floor to represent splatter from the gear teeth.  For the dirt and grime on the floor of the lathe I used black and brown chalk dust mixed with water and applied in puddles, smeared around and left to dry.  I used “metal” magic marker, chrome on the faceplates and a combination of brass and gold on the guides and drive cogs.  To get a patina on the faceplates I used orange, dark red, tan, brown and black chalk dust, each applied with water.  I lightly rubbed the surface with a dry paper towel to blend the colors, added more color where needed and then sealed with satin clear spray paint.

Rail Trucks

I have two Bachmann On30 Rail Trucks that I got through eBay.  They were advertised as having operational problems but didn't mention them missing windshields and visors.  Fortunately Bachmann still has these available as part of their cab body kit ($20.39) so I ordered two of those.  I also ordered two "Cab and Driver" packages ($11.33) for the snow plow and driver.  I didn't realize at the time that this package also included a windshield and visor so I guess I'll have spare parts for a future project.

My plan for the Rail Trucks is to make the necessary repairs to get them running and then convert them to RF control with battery power and sound.  One truck has broken gears and the other has an electrical short.  On both trucks I'm replacing the gears with NorthWest Short Line (click here) metal gears and replacing all the wiring on both.  For the electronics I'll be using components from Stanton S-cab (click here) and Soundtraxx (click here).

When I first sat down to work on this project I knew right away that I'd need a way to conceal the electronics.  The Rail Trucks come from Bachmann with a short stake bed and a small plastic box in the bed to hide a DCC decoder.  My plans include a 1" speaker, a TSU 2200 decoder bundled with an RF receiver, a battery controller board and two 1000 mAh Ni-Cad batteries.  I needed a bigger box.

I Googled "Galloping Goose" for pictures of the rail trucks that had been used by the Rio Grande Southern (RGS) railroad during the first half of the 20th century.  They had at least one that Bachmann copied for their flat bed rail truck but most of the RGS Geese had long enclosed boxes in place of the open bed and were used for LCL (less-than-carload) freight.  Some of these were later converted for passengers.  I found one Goose model that had a freight box but it was still too long.  I did like the style of it though and used that as an inspiration for my own design.

I sat down at my computer using TinkerCAD to work up what I needed and printed it out on my Anycubic Photon SLA 3D printer.  I've worked with a filament printer for the past two years so I was familiar with the design software but this was my first project on a resin style 3D printer.  With a filament printer this cargo box would have to be done in 5 separate pieces, 4 sides and the top, to improve the details.  I wanted to see what I could get away with on the resin printer so I attempted to print the whole box in one shot.  My first try showed some distortion, warping, in the walls so I flipped it over in TinkerCAD and printed it upside down.  The second try came out great, just as I had planned it.  I went back to TinkerCAD and drew up a "ghost" box using the interior dimensions so I could work out how to arrange the electronics.  I made boxes with exact dimensions of the boards, batteries and speaker and placed them in the "ghost" box.  The picture below is a screenshot from TinkerCAD.  I slid one of the 800 mAh batteries back to show the placement of the other components.

By planning my use of space in the CAD program I realized if I widened the box just a bit it would have room for a pair of 1000 mAh batteries instead of the 800 mAh ones I first planned to use.  This is probably overkill for a rail truck but both sizes of batteries cost the same.  I'll probably be able to run these trucks for a week without a re-charge.  Cool!  Because I had designed the walls of the cargo box extra thick for printing I was able to find the additional interior width without actually making the box any wider on the outside.  In the picture above you can see the speaker and it's baffle box are placed in the forward half of the truck so it'll fire down through holes drilled in the bed.  I placed the BPSv4 near the top because it has two reed switches (on, off) that can be controlled with a magnetic wand.  The decoder / RF receiver has an antenna at one end that should work fine with the plastic cargo box.

While using TinkerCAD I added 0.032" holes for ladders and door handles.  I'm thinking about adding a "roof rack" so I included holes for that too.  Using the CAD program for this works well because you can get perfect alignment whereas drilling them by hand they'd be all over the place.

Using the filament printer I would send my CAD generated designs as .stl files to be processed for printing by Cura, a "slicer" program that I found to be intimidating because of it's 100's of controls.  I found that Cura wouldn't work with my Photon resin printer so I downloaded Chitubox, another slicer program, which I was pleased to find only had 16 controls.  I'm really impressed with the easy and intuitive controls of the resin printer and the prints are finished much quicker than with the filament printer, at least half the time.  Best of all, the quality of the print is light years ahead with smooth surfaces, super detail and very little "post-processing" cleanup such as sanding and filing.  Filament prints required a lot of cleanup.  The downsides to the resin printer are that it requires using gloves when coming in contact with the uncured resin (which is slightly caustic) and parts need to be cleaned with isopropyl alcohol (I use an ultrasonic cleaner) and then cured in direct sunlight or under a UV lamp.  I use paper towels to soak up excess resin right after a print and place the part in the cleaner for 10 minutes.  Once that's done I put the part under a UV lamp in my curing box for 45 minutes.  Under the sun it can take about 2 hours.  I'll usually start printing another part while I'm going through the cleanup/curing process.  This box took 3 hours 48 minutes to print which included 903 layers, each one .050 mm thick.

I'll update here as I make further progress.

8/14/21 - I've been in contact with Neil Stanton about what parts would work best for this application.  The batteries I originally wanted are not available right now.  After discussing it with him I decided the rail truck didn't really need all that battery power so I'm going with a single 800 mAh instead.  Since one of the rail trucks already had a decoder he quoted me a price for just the RF reciever and a BPS with an 800 battery.  Good deal.  Placed my order today.  I'll order the electronics for the other truck when my oil well comes in.