Every year the kids from Hazard Factory run a Power Tool Drag Race & Derby at Artopia (as well as other more nefarious events)  The basic structure of the event is, modify a power tool to run as a dragster, Bling it out with anything from lights and a blow up doll, or chrome it out with heavy duty hydraulics and a flame thrower. Pretty much anything goes, as long as its not going to obviously blow up and hurt someone, then simply have fun,..

The "Derby" part of the name is far more accurate than the "Race" portion. with tug of wars, flaming ramp jumps and even dragster ski ball, and only one award is given out for raw speed, with a majority of the trophies going to racers with the most outrageous design, or simply the coolest technological effect, and even one award for the best one that did not make it past the starting line.

In 2008 I decided to participate one day before the event. I generally do my best work under pressure,. so I figured why not take on a time challenge. To further add to the complication, since I only had a few hours to build, I decided that I would only use parts that I already had in my workshop,.. so basically no hardware store runs, if I didn't have it, id have to design around it, this certainly resulted in a few interesting decisions.

Due to those two limitations I chose to go simple. a cheap dust covered angle grinder left over from my boat project, that was likely not to be used again for quite some time was my candidate for donor tool. From that I decided to build a basic sled that could be built out further for next time when I had more time.

Nothing was planed ahead, I just grabbed scrap materials from previous projects and let them fall into the most appropriate places. I wanted it to do something more than just run down the speed way, and I wanted to bling it out,.. but still keep it simple,.. again this was built in one evening after work and just prior to the next mornings race, about 4-5 hours in total. I didn't quite reach my usual level of creativity, but I definitely have something to work with and upgrade from.

Construction Begins:

The first thing I grabbed when I walked into my workshop was a length of scrap angle aluminum, it was just long enough to cut two 18 inch length from, I found it oddly appropriate that the very power tool I was going to use for the racer helped cut materiel to then build said dragster. I cut the length roughly in half.

After cutting the lengths in half, I cut a 45 degree notches in one end of both lengths. (again using the angle grinder)

Then I bent the two points together by hand to form a point on each length. this gave me to V style "sled" that would hopefully keep me from catching on any loose wood chips on the race way. I was likely to only have vertical wheels, with little time to work horizontal buffer wheels, so I wanted the two sides to just barely fit in the 1 foot gap and to slide fairly well with as few friction points as possible, knowing I could always upgrade this later and still keep the basic "sled" design for purely aesthetic reasons.

Next I cut a length of 1/8 thick scrap polycarbonate (I raid Tap plastics scrap bin regularly so that I have scrap plastics on hand) to just a hair under 12 inches this way with the sleds attached with 4 bolts, the racer would be right about 11-1/4 inches wide leaving approximately 3/8 inch on both sides for "play". After that I "dry" fit the basic parts together and as you can see it was almost done. After the dry fit I decided that I didn't want the back half of the sled to just drag, I wanted to use real wheels on the back, but I didn't have anything that was the correct diameter, so I grabbed my drill press circle cutter and some more scrap plastic and cut my own back wheels. I really was not sure at that point how I was going to mount them,.. but that's the beauty of a rush build,.. you don't have the time to stress those details till you get to them. 

Mounting the wheels was tricky, I had a hundred and one ways to do it in my head, but I kept hitting "parts on hand" issues,.. (remember I had to build this only with parts in my workshop) I finally decided to fabricate the whole darn wheel assembly, including a fiber carbon leaf spring. most of the scrap for this portion came from the Red Rover combat robot build. A little carbon fiber to give the assembly bounce, UHMW poly brick to put a shaft on, (UHMW poly is very low friction, particularly when used with polished metals like aluminum.) and a washer and zip tie to hold it all together. later on I shortened the carbon fiber length a little to lessen the sag/springiness, and added a second zip tie closer to the wheel to add even more strength. The shaft itself is an aluminum stand off with both ends lock-tited to wide pan bolts that loosely hold the wheels on. I had thought that if any one part was going to fail in this build, this was it,.. but surprisingly it held strong, and really helped balance the racer.

I had marked the location of the grinder on the poly carbonate cover sheet so that the wheel would be fairly close to center,.. I then marked where the nub for the brush access on the grinder would sit on the plastic and cut a hole for that bit to go through and basically hold the grinder in place. I then used a hand full of long zip ties to fasten the grinder to the polycarbonate. I was also careful to position the zip ties in a way that would limit rotation of the tool and also lock the power switch to ON. however I forgot to remove the protective sheet before assembly, so that cover sheet is still there under the tool... it was one of those,.. yah I meant to do that moments,..

That was that, the basic sled was built, I cut a 12 x 12" square of garolite in half, corner to corner to form the two wings. I had a bit of a balance issue, the weight of the tool was all on one side, this was causing the whole racer to badly lean to the right, I fixed this by zip tying a brick of old dead batteries opposite the tool to help level it so it would run fairly straight.

I could have very easily stopped there and had a functioning racer,.. but I still had an hour or two to work, and I wanted it to do "something" more than just go. I had flirted with the idea of adding a fire effect to the racer, but it turned out the regulator from the coffee camp fire pit I had on hand would not do the trick and to really be safe I would need an appropriate solenoid valve which I also did not have. I did one experiment to try to work around that, but quickly stopped after emptying an entire camp canister of propane in my garage by accident,.. (thank jeebus I don't smoke).

After the garage aired out, and I regained consciousness. I decided to mount a few squirt gun innards on the racer I had ordered a while back for some half dreamed up project that eludes me now. I had seen something similar to this a year ago on another racer,.. that was just a super soaker duck taped to the racer with a zip tie or something holding the trigger down, I wasn't being overly original, but I was taking it to a higher level, with the two pump motors, tied into a power supply that was also tied into the tools power supply, this way the squirt guns would only fire while the racer was going. a slightly more elegant approach to a deviously fun tactic.

Unfortunately the 5v 3 amp power transformer, (the largest I had in my spare parts drawer) did not have the kick to run both water pumps, at 2.7 amps each I could only just barely power one pump motor, Of course I only realized this after everything was assembled and wired up. at that point it was to late to really do much more, I cut the power to one of the pumps and called it done. I would have liked to have twice as much time,.. but I did get a particular rush from the "rush" job,. At the race I switched back and forth from the left to the right pump so that the crowd would never know which side would get sprayed. for the most part the crowd reaction was comical,.. I think only one guy with a camera gave me a dirty look for the few droplets of water that probably landed on him,..

The racer itself was not very fast, but if it was much faster it would have not been as effective as a mobile squirt gun, so in the end I was quite happy.

This one will most definitely get developed further,... next event I am going for the "hold my beer, and check this out" award, with both an air rocket assisted launch and a fire effect that should rock if it works, plus I am definitely going to add more art,.. I just did not have enough time to do things to my usual odd standards.

Link to the Flicker Pool of images taken at the 2008 derby ----->

Hazard Factory website ----->

Artopia Website ----->