Drills

[glen]

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.

[ewan]

Drills

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

[glen]

Drills

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.

[ewan]

Drills

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

[karnage_cjb]

Drills

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...

[ewan]

Drills

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...

[stu]

Drills

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

[karnage_cjb]

Drills

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

[team_ireland]

Drills

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

[glen]

Drills

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.

[Guest]

Drills

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

[wardy]

Drills

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.

[Guest]

Drills

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

[glen]

Drills

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

[Guest]

Drills

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)