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Author Topic: How to Hax0r Cheap Cordless Drill Motors for robot uses  (Read 5022 times)

TeamTiki

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How to Hax0r Cheap Cordless Drill Motors for robot uses
« on: January 14, 2015, 10:33:55 pm »
Cordless drills have been a staple of combat robots from near the beginning.  Their high power to weight ratio,  Combined motor and transmission, and relatively low cost make them ideal as robot motors.  This thread does not deal with the "better" cordless drills, often featuring 2 (or more) speed gearboxes and larger, custom motors.  Instead, this thread is about low cost, single speed, cordless drill featuring a 550 size motor.   

In the past (circa 2000) the Harbor Freight Brand 18volt cordless drill was a viable budget minded robot motor, suitable for bots from 12-60Lbs.  It is my opinion, as of this writing (1/2015) the Hf 18v cordless drill is no longer suitable for combat applications.   Its further my opinion that remaining reliable brands of cordless drills are:  Sears Craftsman,  Ryobi, and Black and Decker.  These drills have the added bonus of lower voltage motors, as low as 7.2v and as high as 20V "max".

Below is a video showing how to strip the motor/gearbox from a drill case, this is a Ryobi drill, but they are all very similar. The one thing I think needs clarification from the video, The chuck screw.   The small screw that holds the drill chuck from backing off is LEFT HAND THREADED .  I use the mantra of "tighten" to remember to turn it the correct way.  Black and decker are superior in the screw department, as its a torx drive,  most others are phillips. also of note, the B&D is 10-32 LH, not the much more common M5 LH. 

http://youtu.be/gfxb4YmEBic

cheers,
Chewy

IanMcMahon

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #1 on: January 19, 2015, 09:15:33 pm »
Other notes:

-If the drill has a clutch, you will need to replace three or four of the balls with set screws. I remember 10-24's being the right size.

-You can order prestripped motors and gearboxes from ereplacementparts.com or other drill parts sellers. Just remember to order as many as you think you will need because sometimes replacement parts are discontinued.

-Pete sells hubs for mounting the gearboxes to Colson 7/8" wide wheels. If you want to make your own hub, I think the OD required for the hub is 0.610" and the thread of the shaft is 3-8"-24.

-The mount is a little funky. If you file off the little nub, it becomes far easier to mount. The clutch plate makes a great stencil for the mounting hole.

zacodonnell

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #2 on: January 30, 2015, 04:41:53 pm »
When he says "pete sells" he means http://www.kitbots.com.  It is for new builders after all!

-Zac

TeamTiki

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #3 on: February 19, 2015, 11:42:25 am »
Here is a short video showing how to lock the torque clutch of the "cordless drill motor" 


http://youtu.be/T3oKUL8h6bw

process takes about 10 min per motor.    Also shows the internal arrangement of the planetary gear stack.

next video will detail how I mount the gearbox to a bot frame, and a wheel on the threaded shaft.

Lucas Grell

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #4 on: February 25, 2015, 08:49:11 am »
How much does just the gearbox weigh, without the motor? Might be a good option for some of the newer guys at my school to use, probably a bit cheaper than the banebots boxes.

TeamTiki

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #5 on: March 07, 2015, 05:27:00 pm »
IIRC the gearbox is about 1/2 the total weight of the assembly, roughly 8oz motor, 8oz gearbox. However, I consider this a module, not a component.  That is to say, use it as it is, don't bother modifying it,  or just pay more up front and run the OMFGBaneBots.  These drills are all made in china for the lowest cost possible,  and no matter how much work you do to them to make them "better"  you are still polishing a turd. 
That being said, rebuilding the gearbox with good internals is a great project for learning how to use a machine shop,  but if the end goal is to make robots and make robots that don't fail... these may not be a good option.
THAT being said,  i still think these are about the best value for money.  They work, work well, are light and powerful, can be mounted with simple hand tools or off the shelf stuff from the hardware store.  Stick a small wheel right on the shaft,  run as close to nominal voltage as you can,  break in the brushes,  and have spares, they will serve you well.

Lucas Grell

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #6 on: March 07, 2015, 05:59:36 pm »
That's all they'd need to be, I'd just hook them to some more reliable motors, literally next year at proctor the last of the people who know what they're doing are gone. We're gonna need stuff that we can afford to get beat to hell.

seangcxq

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #7 on: March 09, 2015, 05:24:12 pm »
Don't worry about replacing the motors, I ran the stock 550 size 18v motors in the Harbor freight drills for nearly 5 years on 6S and never had a motor fail. Most common issues were the plastic gearbox casings cracking, or gears losing teeth. Always used full metal gearboxes.

Edit: Looking around on harbor freight, it looks like they may have discontinued the model with metal gears (may be repackaged), but I'd assume the point of failure to remain unchanged for pretty much all cheap drill gearmotors.
« Last Edit: March 09, 2015, 05:31:39 pm by seangcxq »

teamsandman

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #8 on: March 10, 2015, 01:04:43 pm »
I have never had a problem with the stock motors in my 6 pound, and they are supported only at the front of the gearbox..

I swapped out one gearbox in the past because a motor was loosening from the gearbox and it was quicker to put in a whole new unit than take it apart and re-loctite the motor screws. The only failure I had was when Ripto Ultimate slammed me into the ceiling, and one gearbox cracked, but it still worked (https://www.youtube.com/watch?v=1msLZhzH4cY). In the future, I'll have a small UHMW block to support the motor can if I can free up weight from something else.

TeamTiki

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #9 on: March 12, 2015, 08:49:54 pm »
the failure on the current stock (2015) Harborfreight 18v drill is now:  the pins on the last stage output carrier tend to loosen up.  Drill motors are still a viable option for bots, IMO,  but the HF variety are not.

roybrox

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #10 on: March 31, 2015, 09:42:13 pm »
On the other side of the scale of quality, I was walking through Home Depot and saw that they had DeWalts with brushless motors.

http://www.dewalt.com/tools/cordless-drills-drilldrivers-dcd790d2.aspx

Has anyone cracked one of those apart yet and tried to use it for a drive, or has the cost of each drill been too limiting?
DANGER 4 - Road Rash, BEST KOREA, The Cuban, Gracious Pipefessionalism and many more!

Lucas Grell

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #11 on: March 31, 2015, 10:51:52 pm »
At that point, I'd rather buy a custom setup, honestly. Also, 2000 RPM sounds too high, and 600 is too low.

TeamAstroBot

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #12 on: April 01, 2015, 08:03:27 am »
I've considered breaking one of these open!

http://www.homedepot.com/p/Milwaukee-M12-Fuel-12-Volt-Brushless-1-2-in-Drill-and-Driver-Kit-2403-22/203835499

even comes with a more reasonable sized battery that may be able to be modded for use.

mg4201

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Re: How to Hax0r Cheap Cordless Drill Motors for robot uses
« Reply #13 on: July 15, 2015, 07:01:16 am »
drilling it out with a carbide endmill works go slow and use oil. the downside is you will wreck the endmill. you need a mill to do this. I am a machinist and other than a sink edm this is the only way that has worked for me.
sorry gentlemen I stuck this post inthe wrong thread it should be in how to remove a broken tap
« Last Edit: July 15, 2015, 01:14:53 pm by mg4201 »

Sangeeth

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Help us with idea for motor mounts for cordless driller motors.
« Reply #14 on: December 30, 2016, 06:51:46 am »
Sir ....
I am a student in India .we were using some power windows motor for the drive.Now we have bought some cordless drill motor from the service centers.please do help   me how to mount these motor .At present we were thinking of using some steel pipe clamps .kindly help us.we do have a tension that the gearbox will break.we are thinking of using 6 motors for drive as we were building a push bot provided with a Flipper powered by 6/5 power window motor.   Hope that you reply me.....
If possible kindly mail me on " sangeethpmohan6@gmail.com"