Drills

hello, my name is glen and im an australian featherweight robot builder.

i noticed a few people use drills in their featherweights (the cheap brands). over here a few people are having problems with mounting the drills themselves and mounting wheels to them. the problem has mostly been overcome but i was just wondering how most of the UK competitors got round the problem.

thanks, glen.

With Micro-Maul I use some 40 quid (each) drills, because they give me the high quality I want:),
And I do this step by step to mount them:
1. open the case and take the wires from the trigger
2. solder some longer, high current wires from the motor.
3. Take the torque changer off and reset the gearbox for direct drive (no torque limiter)
4. fold some custom straps from 2mm ali (one around the motor, and the other around the gearbox) Drill some mounting holes.
5. Get your chuck and give it a good bashing with your hammer (this works) then unscrew it clockwise. The chuck will come off.
6. Slide the wheel of choice onto the axle and check that its how far you want it to be (up or down). Now glue it in place with super-glue.
7. Get a 3-4mm drill bit and drill through the wheels axle flange and the axle it-self in one long drill. Find a 3-4mm bolt, slide through axle + wheel, then you have an attached wheel.
8. (you can then bolt your assembly onto the base using your straps).
I hope this is the info you need
Cheers, Ewan

geezuz ewan i dont know where to start here,

first i know how to do it just wondering how you people did it. also why are you bashing your chuck with a hammer? that is totally unnescecary as if you turn on the motor it comes straight off.

glueing the wheel is a shocking idea. i would personally never do it but eh. it would have to rank among the weakest methods. is this why micromauls wheels fell off??

anyway my method. i mount the motors with 2 plates. the first one goes on the D-slot and has a D-slot cut out of it so the motor cant twist around. it also holds the little balls that disable the clutch down. the plate behind it goes at the front of the motor and just behind the gearbox. it holds the motor up and supports the whole assembly. it also has 3 holes in it through which the screws holding the gearbox and motor together poke through to stop it twisting as well. this setup is really strong - enough so that you can jump on top of it.

the way i mount the wheels is this, first i drill a hole through the back of the shaft. i then put a small length of 2mm steel shaft (roll pins work too) through this hole. i put a washer behind this steel shaft as well. then with the wheels (this works only with custom wheels) you cut a long channel in the wheel which the steel shaft sits. this stops the wheel staying stationary while the shaft spins which causes the wheel to fall off. then i use a new bolt that goes into the chuck as the left hand one isnt up to it. i just wrenched a new bolt in, works a treat.

is the way ewan said the way most others do it?? very odd if soo.

I dont use glue to actually mount the wheels, I use a 4mm bolt through the axle and wheel to hold it in place. The wheels in Mini-Maul (my previous bot, at robotwars) were just held in the chuck, and had custom made pillow block bearings at the end of the shaft.
The 2mm ali straps are keyed in the middle to actually hold the motor in place (and stop it from spinning).Oh and the hammer thing just happened beacause I had to undo some glue which the drill-maker had placed to hold the chuck onto the threaded rod. The hammer solved this problem:).
And I have no Idea how most other english people do this, but Ive heard most use the same bolt through the axle technique as I do...
Cheers, Ewan

As this is to do with drills, Ill post my question here.

Im going to use two 14.4v drills for drive in my featherweight, and got with it two 14.4v Ni-Cd batteries of course...
What I want to know what difference is there if I run each drill on 14.4v (one set for each drill), and running both drills on a combined 28.8v?

Thanks in advance...

If you use one battery per motor (at 14.4v) then youll get quite good drive out of the motors, and your batteries will (should) last a 5min bout.
But if you use both batts on series (28.8v) then youll have halve the avalible current, and Id be surprised if you lasted even halve a bout. And there is another problem, the motors can only handle 14.4v 18v at extreme max, dont even think of using drill motors too far over their starting voltage. I tried a 14.4v drill motor at 24v and it simply disintergrated when I put a load in it. Stick with two batts in parralel...
Cheers, Ewan
P.S hopefully this helps...

Ewans half way there :)

But if you use both batts on series (28.8v) then youll have halve the available current

No - you mean you will hold the available capacity of the 2 batteries combined.

Also the more voltage you give a motor - the more current it will pull. Hence why drill motors will fry when they run at a lot higher voltage; they simple eat the current and catch fire.

Like Ewan said - best to hook the 2 batteries together in parallel, you will get longer running time out of both motors.

As for not over volting drill motors too much - a simple guideline to make sure your drill motors are safe etc- is not to go above the drill motors voltage by 3volts.
9.6v drills on 12v is fine
12v drills on 14.4v is fine
14.4v drills on 18v is JUST about fine.

Mr Stu

So best to run each drill on 14.4v then... :)

Does anybody know where I can get cheep 7.2v drills (must be 7.2v) for my next project. By cheep I mean a max of 20pounds

Regards
Ian Mc Donald

hehe i always laugh when i see them figures stu :)

i always used to abide by them but now alot of people are using 12v drills at 24v WITH SUCCESS which is quite unusual. the reason for this is they use much smaller wheels, 95mm and the motors draw less current for a comparable torque so really they are drawing less current for the same torque (its just has more torque and draws more current at the top of its range now that its over-volted :)) its alot like the tornado principle, the gearing (smaller wheels) and higher voltage allows the motors to run cooler for a comparable power.

if you want to see some machines powered by 12v drills at 24v have a look at http://www.robowars.orgwww.robowars.org

on the subject of drill batteries, are you actually using the drill batteries chris bird? i have never had success with them. most of the time my batterys are unevenly charged and when in parrallel the just clag and stop the robot in its tracks. ive found the 1 battery per motor works the best, but if someone else has done it with success.....

ian, i know out here (Australia) new drills only come in 9.6, 12, 14.4 and 18v. the older versions run on 7.2v and so are pretty rare. the only ones ive seen are the makita drills and they are quite expensive, more than 20 pounds.

Does anybody know where I can get cheep 7.2v drills (must be 7.2v) for my next project.

at almost all cheap drill- gerarboxes you can add any standard RC -car Stock Motor. Just remove the pinion gear from the old motor and mount it on the new one. I have done this successfully with 2 LRP GT2 11 winders (41000 rpm at 7,2 V), 15 quid each. Works fine, the plastic planetary gearwheels of the 1´st stage don´t melt :) until now (after 10 minutes under full RPM).
Helmut

question for helmut; how do you remove the pinion gear from the drill motor and mount it on the car motor? In the past I tried, once, and couldnt, since it seems to be welded on and doesnt seem to have a grub screw holding it in place.
Any help would be very much appreciated.

Hi
It´s possible to remove the pinion carefully with 2 screwdrivers, but some people have bad experience with this kind of working. Better: a pinion puller, you can buy this tool for a ridiculous price. example
http://www.slotracer.ca/miva/merchant.mv?Screen=PROD&Store_Code=SR100502&Produc t_Code=H107000http://www.slotracer.ca/miva/merchan...100502&Product _Code=H107000

I made the tool by myself from a scrap piece of 15*15*1.5 box section, just slice one side ca 5 mm with a saw and cut a m 3 thread on the opposite side. Works sufficient.
Helmut

i use a butane torch (a mini one) to heat up the gear than just use a flat head screwdriver to lever the gear off, works fine :)

glen
i used the same method before, (well proven since more than 20 years :) )but another german builder told me, he had not removed the pinion by this way, but the rotor shaft :sad: .... IMHO its better using the tool, takes just a few minutes of preparation.
Greetings from Austria (the no kangaroos country)

thanks for the advice guys, i think ill get a pinion puller, seems the best bet; not got much in the way of workshop accessories for preparing metal etc. Next silly question then, whats the best way to keep it on the model cars shaft....

http://robotwars.00server.comhttp://robotwars.00server.com

thats simple. you can press the pinion on the shaft easily by using a vise. the shaft normally comes out a little on the rear side. all shafts of this 540 or 550 series have a diameter of 3,17 mm (must be some odd inch unit) and the same fixing holes. For more security you can add a drop of loctite (if you want to remove the pinon after glueing, you have to warm up the pinon with a lighter or so).

regards
Helmut

have many people had problems in the UK with the pinions in the gearboxes shearing and the gears shredding?? ive had really bad experiences with drills honestly.

also helmut, could you provide some more info on how you made that gear puller?

Thanks Helmut, just lookin for the right type of drills and Ill be sorted.

Thanks for you advice and have a merry xmas.

You could always buy just the drill type motor and make a gearbox.

thats what I did.

Glen, sounds like your gears werent correctly meshed. They tear up real quick if even 1mm out.

If anyone gets sick and tired of drills, let me know on info@jamesbaker.f9.co.uk and Ill tell you how much my custom made gearboxes cost. They are not as cheap as drills can be, but they are supplied with motors and ready to bolt in. Choice of ratios and module. I can even do a double trouble gearbox which uses 2 motors to turn 1 output shaft. Quite neat.

ill give you a quick email within the next day or two ;)

What is the average gear ratio for a cordless drill ...?

Chris - http://www.featherweights.org/forum

30-35:1

Problem.

I need to mount my wheels onto my drills but my wheels have a 12mm bore and my drill has only a 3/8th inch shaft. How am I going to get the wheels onto the drills? I have the chucks so can use them if needs be

Regards
Ian Mc Donald

there are a ton of ways to do it,

so to determine which way, a few questions -
1) can you put a shallow groove in the hub of the wheels? or are they plastic. if so try the method i described earlier, works 100%

2) how wide are the wheels? - if they are thin. try putting the wheel on the shaft, then the chuck over it and tighten it up, there *may* be some slippage but it shouldnt come off.

if you get a bit restless with other methods you can buy 95mm wheels that will screw straight on the shaft with no trouble at all.

you may be able to make a plug to go inside the wheel??

Thanks to Stu I know that drillmotors and gearboxes arnt a bad way, especialy with custom gearboxes, way smaller and stronger than the original plastic housing.
But latest discoveries(and I guess James did that aserious wile ago) let us think about mini gearboxes like Kos made for the heavies.
The KOSboxes, all of them are still functioning, some even after a serious mistreatment(Gravities for example)without any serious damage.
So RC motors are easier applicable in the feathers.

Hi

I found a cheep and relatively easy way of mounthing my wheels.

1. Take the wheel and put a M10 bolt through it. Secure it in place with e-poxy resin (If the hold is bigger than 10mm then use some packing to make it smaller. I used some 1mm H.I.P. that i had lying around. Is working well)

2. Cut the bolt to size.

3. Place the bolt into the chuck and tighten it by hand or by key as much as possible.

4. Take some duct tape or simular and wrap it around the chuck to provent it from opening.

5. Mount your drills in the usual way.

This was has worked well so far for me. I will report if it fails.

Regards
Ian Mc Donald

if you want ian i can send you a photo were a saw has just clipped the wheels and taken them straight off,

you should be able to get away with it for a demo bot though, thats about it.

Thats what most people already do Ian mate.

Mr Stu

back from australias first public event and ill say just this regarding drills.

you can use 12v drills at 24v. we had about 4 robots doing it and not one suffered a broken gearbox or burnout. they also have awesome power and speed, my 9.6v drills at 12v on 150mm wheels were quite pathetic in comparison.

just if you decide to use this setup use wheels smaller than 100mm and use a PWM speed controller, this helps alot in not breaking gearboxes.

i know what ill be doing next time....

im looking for some model monster truck type wheels. anyone have any idea where i might find some. (roughly cd diameter)

model shop?
just a guess.
more importantly though, they will squish (technical term?) under 12kg.
you can fill them with foam, but this gets heavy.
good luck though, it might work...

Electric Brick (Bob Colemans machine) seemes to work perfectly well with them.

really?
interesting....
how high a ground clearance does he have and does he ever get stuck on the floor? also, has he glued them on?

Electric brick had quite a high ground clearance but that is because of the design of the bot. As far as I noticed the tyres never squashed enough for the chassis to touch the floor nevermind get stuck, also he seemed to have a lot of grip on the nice shiny MDF floor at inspire while alot of robots were sliding around all over the place. They worked so well I was thinking of changing the design of my new robot (to be unveiled in aberystwyth) to incorperate them but i was already too far into the build.

Joseph Townsend

I know what the lack of traction is like on a slippery surface, our 12v 340watt winch motors couldnt get the power and torque to the floor due to our mower wheels being to hard in rubber compound

Does anyone know if the 14.4V challenge drill driver avaliable from argos has sealed gearboxes? or do they fall apart like the ones from B&Q?

Also if anyone knows of any drills that do have sealed gearboxes could they post here as a list of suitable (and unsuitable) makes would be useful

Joe Townsend

The challange 14.4v one so have a seeled gearbox

Does any one know if teh b&Q 6v one is sealed?

Regards
Ian Mc Donald

What do you mean by sealed, do you mean the bearings are contained within the case?

When you remove the motor and gearbox from the drill a sealed one will stay in one piece, some (like the B&Q ones) fall apart so need to be fixed together before you can use them

Joe Townsend