Powertool drag racing

[Whiskeymike]

Austin Maker Faire is coming up next week and just saw that they are hosting a hand power tool drag race, where you build up to a 12" wide drag racer from a 120v hand power tool.

I'm thinking about trying to put one together this weekend, but need some expertise from the tool gods.

What kind of tool should I start with? Circular saw? Grinder? Weed eater? Chainsaw? What's going to have the right torque and rpm?

How would you do a drivetrain? Chain drive? Pulley/belt?

Any thoughts on how to fab something quickly that won't be finicky? I'd rather finish the race in the middle of the pack than DNR.

I have access to a variety of tools like CNC plasma, welder iron worker, shear, saws, etc...

 

[JJThrasher]

Grinder with some sort of wheel instead of a disc with a bracket and a couple wheels bolted on?

 

[bczygan]

I would look for something with the most amps and torque and set up gearing to match the traction of the tires.

Using something that allows me to take the rotational force and couple it directly to the drive wheels would simplify things.

Is there a limit on battery size?

How long is the course? Straight track I assume.

Heats or individual timed runs?

Just off the top of my head (Which is mostly empty space).

Bill

 

[djjsr]

I tried a belt sander. Now it's sitting on the shelf in non-running condition after a crash.

 

[rsanter]

I helped a friend modify a belt sander for racing.
We picked one that was belt driven and I machined a new set of pullies for it that doubled the SFM. Then he went out and bought the coursest belt he could find for it.
That thing damn near flew

Bob

 

[notlob]

Get yourself one of the vintage locomotive-style belt sanders and a 30 grit belt. Won't be the fastest, but likely will be the most stylish.

 

[bczygan]

Reading up a little, in 2009-2011, circular saw powered machines ruled, but in 2012 a grinder powered machine took first at one event.

Don't know what the latest and greatest are, but blades that dig into the wooden 75' track seem to rule. And cord layout is critical (Not battery powered as I originally thought, but that seems like a new class of racer could be formed for that).

https://scontent-lga3-1.**.fbcdn.net/hphotos-xaf1/v/t1.0-9/576305_10151165160873631_2117142613_n.jpg?oh=f3fba8c3fed6630d3e34979fd8d6652f&oe=57B089CC

Bill

 

[Whiskeymike]

Grinder with some sort of wheel instead of a disc with a bracket and a couple wheels bolted on?

I was thinking something similar. Could cut a gear blade on plasma table, make a smaller gear on axle and use a short bike chain. Nervous about calculating the gear sizes. I've never done anything like that, so it would be a shot in the dark. But it sounds like fun and I would definitely learn something. Or maybe connect it to a wheel directly in rear and build it as a reverse trike?

Regarding other questions, track is 75 ft long. I believe it's multiple heats. No batteries - vehicles are connected to a 100' extension cord and carry it a long the track.

 

[Whiskeymike]

Reading up a little, in 2009-2011, circular saw powered machines ruled, but in 2012 a grinder powered machine took first at one event.

Don't know what the latest and greatest are, but blades that dig into the wooden 75' track seem to rule. And cord layout is critical (Not battery powered as I originally thought, but that seems like a new class of racer could be formed for that).


Bill

That looks like a cool design! And dangerous, so it should impress the judges!

Looking at new cheap grinders...

These look interesting. First is 11k rpm, second 10k rpm, both pretty similar in weight 3-4 lbs.

http://t.harborfreight.com/power-tools/grinders-buffers/4-12-in-43-amp-angle-grinder-60625.html

http://t.harborfreight.com/power-to...h-angle-grinder-with-paddle-switch-65519.html

This one is 7800 RPM at 11 amp, but 2.5 times the weight of above.

http://t.harborfreight.com/power-to...in-11-amp-heavy-duty-angle-grinder-69454.html

Any idea what a steel saw blade is rated at in RPM? Noticed circ saws were running about 4500 rpm. Doubt the grinder would get to 10-11k.... But...

 

[Leaflessshadetree]

My first thought was to use a router motor. High RPM and HP but it would probably require a more complex drive/speed control system.

 

[AA/FC]

Maybe a worm drive circular saw, then chain and sprockets between the motor shaft, and the 4 saw blade wheels. (4-wheel drive maybe?) Using chain a sprockets will allow you to get the correct "gearing". Should haul *** if you get it right.

 

[Evilunclegrimace]

I just looked up some of the older PTDR videos and all I can say is WTF! and do you have good health care. Open saw blades running down a plywood track and ZERO safety protection for the spectators. We need a crashes video of out of control power tools and the carnage that happens when things go awry.

 

[Professur]

And I thought ******** racing was silly.

 

[four.cycle]

While re-working an old oak table out in a gravel driveway, I inadvertently yanked the extension cord out of the outlet.
I laid the sander down, walked over to where the outlet was - about 30 feet away - and plugged the cord back in.
Unfortunately, I neglected to flip the on/off switch when I laid the sander down in the gravel - right-side up, of course.
That thing took off (on a gravel driveway) and was across the parking area and climbing up the leg of the table before I could reach over and pull the cord out of the outlet - it travelled about 30 feet in maybe one second (or less.)

When I first posted those photos above here:
http://www.garagejournal.com/forum/showthread.php?t=310549
there was another member (Ricky Joe) who sent me a PM and offered to sell me his, but the shipping costs were prohibitively expensive. You might check it out and see if he still has it.

I had Econ-Abrasives (Frisco, Texas - econabrasives.com) make me up some 24-grit 3" x 27" belts for this baby. Amazingly, the aggregate cleared the housing and didn't damage the machine. Those belts made very short work of some end-grain on some 4" x 4" pressure-treated posts.

 

[bushmechanic]

Ahhh... Belt sander races. How much fun were those?

 

[Mohawk Dave]

My Stihl MS461 with a 36" bar, big cutters? Totally safe...

That roller blade wheel grinder saw race car is frikin gnarly.