train tutorial 2
Making a Train...Start to Finish
Part 1 - Building Articulated Trucks
Part 2 - Building the Locomotive
Part 4 - Attaching Axles, Wheels, and Connectors
Part 2 - Building the Locomotive
Part 1 (building articulated trucks) was the difficult and tedious stage. It was an exercise in engineering and manufacturing. Now we get to the fun part--actually building the locomotive! I've laid out all my detailed steps below in excruciating detail but there's really no need to follow them closely. You can pretty much do your own thing.
For the base of this locomotive and many other types of cars, I often start with a plank that is 1/8" thick and 1 1/8" wide. Several pieces like this come in a package that sells for a about $2 at Hobby Lobby. It's a relatively soft wood, unfortunately, but this won't be last time soft wood makes it onto this locomotive. Of course, a 1" thick hardwood dowel or other stock could be ripped down to size on the table saw and used instead. Ultimately we're looking for pieces that are 1/8" thick and 1" wide. I layout my trucks and wheels to eyeball the right length. This is totally a "feel" thing.
After cutting the piece to my desired length I measure a 1" width down the length and rip it on my micro table saw from Harbor Freight. This cheap little saw costs about $25 and struggles cutting wood more than about 1/2" thick. But for small, detail cuts like this I think it's great.
Here I've set the "base" on the trucks just to show how our nicely cambered trucks look with the base.
This locomotive needs a roof on the cab so I cut another piece off my 1/8" plank. It's so small that I simply sand it to size. Before I had a disc/belt sander, band saw, or micro table saw I would have cut this on a full size table saw. It's a miracle I still have all my fingers.
The rest of cab comes from a 1" hardwood dowel. The boiler comes is made with a 7/8" dowel.
I pull the rest of the locomotive components from my bag of tricks. A few years ago I picked up a bag full of randomly sized pieces of bass wood from a hobby store for a couple dollars. Bass wood is, unfortunately, very soft. But the precut sizes are ideal for these little trains. I'm willing to sacrifice some durability for not having to manufacture mine own micro-components. For this locomotive I've selected a piece that's about 1/8" thick and 3/16" wide to sit atop the boiler. I'll also be using a piece that's that's about 1/16" thick and 5/16" wide (not pictured yet).
After cutting all these pieces to size I loose fit them to make sure my proportions are correct. As a side note, the locomotive itself (not including trucks) is 1" tall. As a general rule I try to make all my trains 1" tall (excluding trucks and wheels) and 1" wide.
This particular locomotive design requires a rounded boiler front. I'm sure an experienced wood worker could use sophisticated methods for rounding the end of a dowel. But I'm not very sophisticated. I start by marking a line all the way around the dowel by laying my pencil flat and rotating either the dowel or the pencil. This reference line will serve as a guide. My goal is to constrain all the rounding in the tip of the dowel below the mark.
At this point I simply use my disc sander and sand paper to shape and sculpt the dome. This is more art than science. If this is your first time you may find yourself needing to scrap your first attempt and trying a second time. It takes a little practice.
I've already glued on the cab components and it's time to glue on the boiler. You're probably saying to yourself, "Whoa! This guy used way to much glue!" Maybe I did. But I want this to be really solid. As you will see in a minute we will drill several holes up through the bottom of the locomotive into the dowel and I don't want to risk these parts every coming detached.
Here's that 1/16" by 5/16" piece of bass wood I mentioned earlier. It's perfect for the lower side walls of the boiler. I set it in place, mark the length, and cut two pieces.
I lay the left and right side walls on top of each other and and mark the downward angle that looks about right. I keep both pieces together and sand off the excess material. By holding the pieces together and cutting them (well, sanding them, actually) simultaneously I ensure the angles and lengths are identical. I find that if I try to make small pieces such as this individually, they always turn out slightly different.
I glue the side panels in place. After they dry, I do some light sanding with a belt sander to ensure the sides of the all the components (the base, cab, and roof) are flush with each other. None of the pieces were perfectly sized and very slight differences would be quite noticeable unless I sanded off the imperfections.
I lay the trucks in place and mark the position of the apexes. I also draw a line through the base lengthwise. The intersection of the lengthwise line and apex marks are were the pilot holes for the truck-connecting screws will be drilled. I also make additional marks about 1/2" in towards the center of the locomotive along the lengthwise line from the apex lines. These correspond to the positions of the limiting pegs that protrude from the trucks. Larger holes will be drilled that will accept the truck limiting peg and dictate the amount the truck will be permitted to twist back and forth. Scroll down to a few pictures to see the end result. It will make more sense--I think.
There's one quick thing to do before I drill holes in the bottom of the locomotive. I temporarily put in place the piece that sits atop the boiler. This will ensure that the train sits flat on the drill press in the next step.
I drill 1/8" wide pilot holes for the truck-connecting screws. I drill 3/8" holes for the truck limiting pegs. The limiting holes can be any size you like. The larger the diameter, the more the truck will be able to twist. Keep in mind that I'm using relatively skinny limiting pegs. The thicker your pegs the wider your limiting hole will need to be to achieve the same range of motion. The depth of these holes is not very important. I think it's best to be conservative and drill them deep. It would be an inconvenience to have to come back later if you find you they are too shallow. Quick side note: I really like using brad point drill bits. Their extremely pointy tip is very helpful in making precisely positioned holes. Although you can see I still managed to mess up on the right-most hole.
This particular engine requires the top of the cab to be rounded. I start by drawing a center line on top of the cab. Again, this is just a guide to aid in rounding the roof with the disc sander. I want to make sure I leave the line intact. If I sand off the line then I've removed too much material.
Again, this step is all about "feel". Note that I still haven't permanently attached the long piece of wood to the top of the boiler. This is to avoid accidentally sanding it down while working on the roof.
Once I'm satisfied with the shape of the cab roof I attach the piece to the top of the boiler. Now I move onto another challenge. The front of the engine has gapping holes on either side of the side plates. This is unacceptable. You might try to cut tiny pieces of wood to the fill the space but I find wood filler is much easier.
I pack the spaces with wood filler. Before it dries, I do my best to mold the filler to it's final shape. Molding the filler before it dries is easier than sanding it to shape after it hardens. But sanding is required regardless. I also put a little wood filler in other cracks and crevices that aren't to my liking and sand everything smooth.
There's one final detail that needs to be added to this locomotive, a headlight. I cut a small piece of dowel using a band saw. I find a pair of pliers is very useful is keeping the tiny piece from shooting across the workshop and getting lost.
After the glue dries I sand down the headlight so it doesn't stick out so far.
Now I hand sand all the edges and corners of all surfaces. I prefer the look of softened edges to sharp corners. Plus I think this it makes the edges slightly more durable when the train is being bashed and battered. Corners and edges take the most abuse. Finally, I glue into place the "limiting" peg on the trucks. Now it's on to painting!
Part 1 - Building Articulated Trucks
Part 2 - Building the Locomotive