My Bender

JJ & C RailRoad

My Homemade Rail Bender

My bender is made up from cheap parts and some items that were laying around the house. First off, cost. I have less than $11.00 invested into the whole deal. Its made up from the cheapest drill press vise I could find at one of the local El' Cheap O tool stores and ran me $9.95. The fact that it was a cheap vise also meant that it was soft metal and easy to work with. I had to buy 4 fine thread 5/16" hex head bolts, 4 fine thread 5/16" hex nuts and a wing bolt that all cost less than $.50 with tax. The wheels are made up from an old pair of roller skates that I bought way back when the movie Roller Boogie came out with Linda Blair (remember that one?).

The pictures above are the finished bender. It works like a charm.

Here's what I did to make it.

1. I started off with the cheap drill press vise by removing the metal jaw plates from the inner sides of the vice for extra room. The jaws were also useless at this point because the vise will never be used as a regular vise again. Using a drill press I drilled three holes in the vise. The first two holes are drilled in the top of the stationary jaw near the ends making sure enough material was left at the sides for good strength. The key to hole placement was making sure enough space was left so the mounted wheels wouldn't touch. The wheels were rather large for this type of project but hey, they were free and worked out very well. I believe the bolt holes were about 3/8" from the ends of the jaw. I also made sure the holes were centered front to back on the jaw. The third hole is on the adjustable jaw of the vice. This hole was drilled in the center of the jaw from side to side and front to back. The finished holes were tapped at 5/16" 28 threads per inch.

2. The second step was the hardest part of this project. At the time this bender was made I didn't have a metal lathe in my bag of goodies so I ended up using a drill press as a makeshift lathe. If you closely at the picture on the upper right you will notice the bearings in the wheels. The bearings were "old" school unsealed bearings which needed to be taken apart and the empty races reinstalled for the work. A old nut and bolt was used to hold the races and wheels snug for the maching. By using the outer races from the wheels I was able to take advantage of the bearing tapers to ensure the wheel assemblies were centered. The temporary assemblies were then chucked up in the drill press. Turning the press on gave me a quick check to see if each wheel was centered and allowed me to make some fine adjustments before doing any cutting. To cut the grooves in each wheel I needed a bit with the correct rail profile. The quick solution was to use a small section rail. In this case I only had Brass code 332 rail so I used a small piece about 4 inches long and faced the end on a bench grinder so it was perfectly straight and sharp (a clean 90% angle). The new makeshift bit was mounted in another drill press vise on the deck of the drill press. The press deck height was adjusted so the bit lined up with the location I wanted the grooves to be on the wheels. I then proceeded to grove each wheel with small easy cuts until the rail cut a perfect profile on each of the wheels. A bit of a slow process but it was only repeated three times so it was manageable. One thing I should mention is the fact that the wheels used were extremely old and the rubber material was harder than some metals I've worked with. Because of that it was necessary to regrind the end of the rail/bit to keep it flat during the cutting process. The brass used by Aristocraft is fairly hard but in the end it's still brass so each wheel required the makeshift bit to be reground about 6 times. I would imagine trying this with the harder stainless steel rail made now would be a bit better.

3. When the wheel grooving was complete the bearings were reassembled using the new 5/16" nuts and bolts. The length of new bolts/axles gave me about an extra 1/2" of length to screw into the vise for mounting. I also added small washers under the nuts and bolts to add extra reinforcement to the races but it was probably not necessary. Each of the 3 wheels was then screwed into the new holes on the vise and tightened. A quick test of the new bender resulted in a pleasant surprise. It actually worked on the first try so I hurried to finish it up (a mistake I'll tell you about in a minute).

4. The last step was to add a simple crank and handle to make the bending easy and safe to operate. During the test bends I used my fingers to turn the wheels which got me a couple of pinches when my fingers got between the wheels. I found some flat metal stock in junk bin that was 1/8" thick by 3/4" wide and cut a piece about 5 1/2" long. I wanted it to be clean and smooth so I ground one end to match the radius of the wheels and put another 5/16" nut and bolt at the other end to serve as a handle. To complete the handle a couple of #10 machine screws were used to attach it on the center wheel. If you look at the upper left picture you will notice that the handle also has a bend to it. The bend was added so the crank doesn't hit the other wheels when turned.

Done!?!

The Mistake:

When I finally started to bend my rail I quickly noticed a problem. The very first rail came out of the bender with a nice smooth radius that went up to just about the very end of the rail (which is a good thing). But, when I laid the rail on the cement floor in my garage I noticed the rail had a odd angle to it. What I mean is, when set on the floor looking down, it was perfect. When you looked at the profile of the rail from ground level, the rail was not perfectly vertical (strait up and down), it leaned inward toward the center of the radius. "What the heck?" was almost the exact words that came out of my mouth. Time to think. More time to think. Looking at the bender.... Uh oh. The wheels were not perfectly aligned to each other. When I looked at the bender from the side I could see that the three wheels were not at the exact same height. So the groves that the rail moved through were miss aligned a tiny bit. I ended up shimming the adjustable center wheel about .010" and one of the stationary wheels .020". Then I re-bent the misaligned rail and it came out perfect. Another rail?. Perfect. Success!

Later I noticed my bends were not all coming out the same. After inspecting the bender I thought the adjustable jaw had too much endplay. After all it was a cheap vise right? To fix the problem I installed a couple of thin washers between the adjustable jaw and the bolt that adjusted it. It seemed to help a bit but it wasn't solution. My next attempt to a fix was to add the wing bolt as a way to hold the adjustable jaw during the bending process to keep the jaw from moving. That helped a bit too but it wasn't the fix. In the end I realized that it's important to make several small easy bends on each rail. This insures nice smooth uniform bends along the entire length of the rail. You may have also noticed that the groove's on the wheels are very close to the bottom. I did that with the thought that I would be putting less pressure on the bolts thus giving less flex to the wheel assemblies. After using the bender on hundreds of feet of track I've come to the conclusion that stress on the bender is minimal. So, it should be possible to cut another set of grooves for another rail code... Just make sure the grooves are lined up perfectly.

The picture below shows 4 sections of 5 foot long rails bent with this bender. They are 8' radius and the tie strips are the standard Aristocraft US ties. To make them match the new curve of the rails you can snip every other section of webbing between the rails on one side of the ties. With one side more of less free nothing else is needed to make them match the new radius.