One of the best things to have around the shop when you are building a robot is a good set of calipers. They don't have to be expensive digital calipers to work well. I bought these calipers for $20 two years ago and they are still like new. The trick is to always keep them in the box when you are not using them.

Here is a plate of 1/8" 7075 Aluminum that I picked up at a local surplus store for $1.50 a pound. What a deal! I have it set up on my compound sliding miter saw with a Diablo blade.

When cutting metal you cannot use a normal wood cutting blade. The tooth spacing is much too great and it is designed for the softness of wood. This is the same type of blade that we use on the set of Robot Rivals. It is a Diablo 80 tooth blade with carbide tips on each tooth.

Do not try to use a blade like this on anything other than aluminum or other soft metals.

After creating a jug out of wood I cut several lengths to be used for the motor mounts. Each is as wide as the Pittman motor that is used for the drive motors.

The hole pattern on these small Pittmans was a little difficult to recreate without a milling machine. So, I created a rubbing of the hole pattern on a piece of paper and then transferred the holes to a piece of the aluminum to be used as a template for the six motor mounts.

These motors were purchased at a local electronics surplus store for $14.50 each. Not bad for a solid gear head motor with built in noise cancelling capacitors.

Once the template was made I drilled a 1/2" hole for the output shaft and used a scrap piece of keyed shaft from Moebius to align the holes and then just drill down through the holes.

And here are two of the motors on one of the front motor mounts. This will pivot in the middle to allow the front and the middle wheel to track over obstacles.

Here I am tapping the holes to bolt the motor mounts to the top of the robot. One of the most useful things to know how to do is drill and tap holes. I am tapping these to #10-32 so that I can use some of the left over bolts cap head bolts from Moebius.

Here is two of the four motor mounts. Notice the thread cutting oil in the background. When tapping holes make sure that you use some type of lubricant to cut the threads easier and cleaner.

The rear third of the chassis is allowed to twist using this joint that was made from some surplus aluminum sqare tube. $0.75 for the tube and I didn't even use half of it.

Here I have the chassis turned upside down with the motor and motor mounts attached. The top of the robot (the bottom here in the picture) was actually an aliuminum clipboard ($1.50 at SkyCraft)

This is how the rear third of the robot is allowed to pitch independant of the rest of the robot.

Part of the robot is having an arm that can reach down and pick up objects. Here is the tap again tapping holes to attach to the lifter motor

A little test fit on the 3mm output shaft of the motor and we are ready to start modifying it. The lifter bar was more scrap aluminum costing $0.75.

Now that the lifter bar works it is time to lighten it up a little bit to make it easier on the lifter motor. After all, I still have to add the servos and the grabber frames.

One of the things that I really enjoy is making metal shine. I have polished many parts of my motorcycle to a mirror finish and I like to apply it to my bots too. Here you can see the difference in the polished lifter bar on the left and the rest of the stock on the right. Aluminum polishes very well so I shined up all of the motor mounts and a few other parts as well.

Okay, remember that I said there was one exception to everything being made with regular hand tools? Well, here are the exceptions, the hubs. The motor shafts are 3mm and the hubs of the RC truck wheel have a 17mm bore and it has to be precise for it to work. So, I had to make these on a lathe. If you were to pay a machine shop to make these you may pay $5 per hub or may be able to talk them into just donating the time since they are a simple job. All that I did was create a 3mm hole through the stock and then turn them down to 17mm and back .15". I didn't need to alter the outer diameter of the stock to fit.

Next I needed to drill each hub to tap them for set screws. I tapped all the way through the hub so to I could put a set screw in on both sides.

Now that all the hubs are drilled and tapped it is time to start polishing. Here are the two things that I use to polish aluminum, a bench grinder with a cloth buffing wheel and a palm sander.

The first thing is to smooth out any rough areas with the sander. I start with a 220 grit then go to a 600 grit. After that I fire up the bench grinder and put some cutting rouge on the wheel and go to town on the work piece. One thing to be very careful of is the fact that the peice that you are polishing will become extremely hot so wear gloves. Eye protection is also a must as the buffing wheel is churning along at 6000 rpm and throwing bits of cloth around. Here you can see the various stages of the polishing; regular stock, one sanded hub, and one polished hub (not the final polish yet)

After a little work I had a nice little stack of shiny hubs. Why spend the time on polishing the hubs? Attention to detail. I am as passionate about the wiring as I am about these little hubs.

Next comes the attachment of the hubs to the wheels. The hubs require a little press fitting which is good. All I do is add a little epoxy and voila, a hobby RC truck wheel and tire ready to mount to a small DC motor. One thing to note is that the wheels are actually mounted backwards to the way they would be mounted on an RC truck.

Okay, now things are starting to look like a robot. What is supposed to be the inside of the wheel is now the outside and I personally like it better as it gives the wheel more depth.

Now lets see what it looks like on its wheels... Not too bad. A quick check with the tape measure shows that the bot is exactly 15" long from knobby tire to knobby tire and almost as wide. This thing should have incredible stability. If you look closely you can see the machined hubs in the center of the wheels.

How about a check to see if all of the work on the articulated chassis and motor mounts was worth it.

Hmmmm... seems pretty nimble to me

And a shot down low so that you can see that every other wheel is at a different position.