Wheels

Wheels and Axels (Updated 4/28/13)

When I first started building wooden trains I was obsessed with rolling performance. Even as a wanna-be woodworker without skills or tools I felt I could duplicate (approximately) the look and feel of commercially available toy trains in my garage but I couldn't duplicate the performance of wheels and axels. This bothered me.

I used Todd Hoogerland's screw axel system as a starting point and set out to find a better alternative. I tried contacting Whittle Shortline Railroad, which is the only American wood toy train manufacturer I know of (they're in Missouri), to see if they would sell their wheels and axels to me. They won't--unfortunately. So I experimented with different materials and techniques until I found a wheel and axel system which, in the right conditions, can out perform commercially available wheels.

Axel Systems

First I'll discuss three different axel systems.

#6 Wood Screws

#6 wood screws are simple, effective axels. However, the threads of the axel create a lot friction. Also, I don't think the head of the screw (either regular or philips) is very attractive. But children most likely won't care either way. Under the right circumstances wood screw axels might be the right thing. It's been a long time since I've looked but once I stumbled across #6 wood screws with a smooth upper shank. This screw helped reduce friction quite a bit. If you can find them I'd strongly recommend these smooth shank screws over standard wood screws. See the wheel and axel test section for performance results.

Brass Tubing and Furniture Tacks Directly Through Wood

3/32" brass tubing makes an excellent axel which extends all the way through the truck structure. Small furniture tacks inserted and glued into the tubing securely hold the wheels in place. This system results in much better rolling qualities than screw axels. Initially my concern about this system was durability. I was worried that the abuse inflicted on a train by a child would result in the furniture tack caps coming dislodged from the axel. But I've yet to see one of these axels actual fail in the real world and this includes some trains which have been played with for four years by four different children. In fact, once or twice I've made a mistake and tried to pull the furniture tack out with pliers. No matter how hard I tried I couldn't do it. I believe the key to the strength comes form the fact that the polyurethane glue I use expands as it dries. The expansion wedges the tack very firmly in the already tight fighting axel tube. In its simplest form this axel can be used by drilling a hole through the truck.

This gives the axel a little play and alows the entire axel to rotate in addition to the wheels rotating around the axel. One of these days I'll add some detail about the easy way to cut brass tubing a consistent length. It can be done with a simple hack saw but it's very difficult and the results are usually inconsistent. I've made myself a little jig and use a Dremel rotary tool to get easy, consistent cuts.

Brass Tubing and Furniture Tacks Suspended With Washers

A picture is worth a thousand words but, sadly, I don't have any decent pictures of this system. Here's the best I've got at the moment.

Note that the washer is not used in the traditional way but, rather, is slightly inset into the truck and glued in place to hold the axel, suspend it away from the wood, and minimize the surface area which is contact with the axel. To put it another way, the washers do not move. They are momented onto the truck and the axel rotates within the washers. For details on these materials and where to find them look at the Materials page. This system is somewhat difficult to build and, to be honest, probably isn't worth the effort unless you are really obsessed with wheel performance like me.

This is the best performing system I've come up with but it is quite a bit more complicated. Is it worth the extra effort? Not really--at least for me. I usually use the simpler hole through truck method. It works nearly as well and is much easier.

Split Rivet Axels

Someone recently shared with me a link to a website where the train builder used split rivets for axels. I have not tried this technique but it seems like it has potential. It's simple and I think it might be able to provide a sturdy and unobtrusive alternative to my furniture nail "caps". Although, I am a little concerned about their holding power because, in this application, they won't be used the way they're intended. If anyone tries these I'd love to hear how they turned out.

Performance Comparison of Axels

I've done some testing to see how different axel and wheel systems match up against each other. This wasn't exactly laboratory science but I think it gives a good sense of relative performance. To do the tests I ran nearly identical train cars down an inclined track raised 4" and measured the distance each car coasted. I ran the test many times to get an average of each system. After testing each system I added a little dry graphite powder into the mix. Graphite dramatically improves the distance a wheel will roll. However, graphite is a bit messy and has a tendency to find its way onto the paint job you spent so much time on. Use it with caution.

Wheels

Standard Wood Wheels

Standard turned wood wheels are widely available online, are easy to use, and work fine. They often suffer from manufacturing imperfections. Sometimes they are not quite round and sometimes the hole is not centered (or both). Also, their appearence (to me) is more like a rubber tire than a train wheel. Some of the cosmetic problems can be solved by just turning the wheel over because the opposite side (not pictured) is basically flat and smooth. Once nice thing about these wheels is that their hole diameter works great without modifications if you use the brass tube axel system. The hole will need to be enlarged slightly for use with wood screw axels. See the Materials page for some links to online retailers who sell these wheels.

Wooden Nickels

I've recently discovered an interesting alternative to the standard wood wheels mentioned above. These are sold at my local woodworking supply shop as "wooden nickels". Online retailers appear to just call them wood disks. These disks can are slightly narrower than standard wood wheels (which I think is a good thing), roll better than standard wood wheels, don't have the tire-like appearance of standard wood wheels, seem to be more consistently round than wood wheels, and give the illusion of being slightly larger than standard wood wheels (also a good thing) because the edge is less rounded. The big downside is that they do not come with a pr-drilled hole. To have any hope of making your own perfectly centered hole you need a drill press. Even with a drill press I sometimes end up with uncentered holes and toss the wheel out. If you're game for a some extra work and happen to have a drill press a wooden nickel makes a nice train wheel.

Plastic Airplane Wheels

My search for a perfectly round wheel comparable to commercial wheels resulted in this option--Guillow's plastic wheels. They are intended for light-weight toy airplanes. They are very thin but perfectly round. The axel hole is very small but can be enlarged, of course. In my opinion they are not "substantial" enough for trains. They're a little too thin. The other big problem is that they are significantly more expensive than wood wheels. I've seen them for as cheap as $0.25 per wheel (excluding shipping). I don't actually recommend these but I'm just sharing an alternative that I've tried.

Dowel Wheels

I recently came across a website by Benjamen Johnson who demonstrates how to make your own wheels out of a 3/4" dowel. I haven't tried it myself but it seems like it would be an effective way to basically create your own wooden nickels: http://oldshop.electronsmith.com/content/completed-flat-cars

Performance Comparison of Wheels

I performed tests similar to those mentioned above but this time kept the axel constant and ran different wheels to compare them against commercially made trains.