Let's Make Robots!

Couplings or wheel hubs for cordless drill motors

I posted some design info and pictures of a robot I'm working on to the main LMR robots listing. You can check it out here

As I indicated in the post, however, I'm having trouble coupling or interfacing some cordless drill motors (the Harbor Freight 17v kind which I have read many people use in their bots) to some 1/4" screws, which are the axels of the wheels on my robot.

I'm wondering if anyone who has used drill motors in projects could share with me some ideas on how to interface their axels to the drill motors. I've seen a bunch of videos of various bots that use them, but rarely is there much explanation as to how the power from the drill motors is ultimately transferred to the wheels.

Thanks so much for any suggestions!

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ossipee's picture

To home Depot get some alum barstock cut it to the lenght you want, then bore a hole 1/4" all the way thru it, the bore the larger hole thru the other end 1/2 way. so the shafts each fit in one side, once it fit drill a hole at 90 degree's to the bar stock to lock each shaft in place and the tap[thread the perpendicular holes] and use a couple of allen screws to lock the shafts into place, a cheap simple coupler

 

http://onlinecatalog.tpa-us.com/category/rigid-shaft-couplings&bc=100|1006|1333

if you do not have of cannot get this stuff send me a drawing and I will make you a pair

Ro-Bot-X's picture

I made my own wheel hub for a power window motor that I used in a project at some point. I got a long hex nut from Home Depot and enlarged half of the hole to fit my motor's shaft and drilled and taped a set scew to be able to mount it on the motor shaft. At the other end I just screwed in a bolt with a couple of large washers to hold the wheel and a split washer to prevent unscrewing. 

birdmun's picture

Chris the Carpenter has a robot named walter. He/It is mobilized by a pair of 18v(?) cordless drill motors. They were too fast and didn't have enough torque. Chris had to double up on his gearing down to get them to be very useful. I have seen people here mention using windshield wiper motors or even some power window motors for moving robots.

birdmun's picture

With a flat on the rod, you could only tighten your set screws down so far. I am sure McMaster-Carr carries a left/right handed threaded coupler that would allow one to join two dissimilar threaded rods. Add a nut on each rod and use them to lock the coupler in place? I am just shooting from the hip here.

mpmumau's picture

I think I understand, and that was one of the ideas that had flashed through my head. You mean putting like a standard hex stop nut or something like that at the end of each thread, and then using some sort of hex coupler to join the two?

birdmun's picture

is exactly what I was thinking.

ChuckCrunch's picture

using the chucks that come with the drills is the quickest way . but not good for space , if the thread on the drills was not reversed it would be so much better , you could use some kind of nut  but one of these <link>

http://compare.ebay.com.au/like/160860377048?ltyp=AllFixedPriceItemTypes

look for something like this in your size

mpmumau's picture

I decided to give the chucks a try as per a suggestion on my main robot post as well by amando96, who has already built a bot very similar to this design (I'm used his kind of as the basis for the general idea of this bot). Tonight, I actually removed the plastic casing from one of the chucks from the drills I'd bought just to see what was inside, and if it would maybe reduce the size of the chuck, and it looks like that may just work. I'm going to experiment with that a bit, as it would be great if I could do it with just those chucks, although it still seems to me that maybe a coupling of some kind might be mechanically superior.

Thanks very much for the suggestion, and I'll be sure to let you know how it goes.

birdmun's picture

twss :D

mpmumau's picture

Parts THAT big just aren't producable by modern industry.