Drive motor options

Hi Ellis! You reminded me how slack I've been so I tried out some new drill on the drill gears. It worked brilliantly, see the details here: http://www.robowars.org/forum/viewto...?p=85652#85652

Nice work nick. Could be it was as you said Ellis, some type of sintered steel... strange material to work with!
It's also most probable my fault as well as I drilled them without coolant and the two that cracked clearly overheated!
That material has got some sort of case hardening tho, I could cut through the central part relatively easy with a black HSS drill and reamed to a good finish. The ends were a different story!

I was also drilling slightly larger holes than you were Nick, 6 and 5mm. The 5mm holes came out fine, but the 6mm holes were at the limit a 10T mod 1 gear can take!

Attachment 4322

My gears look different to the ones in your photo; they have a surface finish that couldn't have come from any milling or turning method I know of and they were definitely hard all the way thru. Your gears would probably benefit from the carbide drills as well; I had the lathe set for 200 rpm and used a slow feed as I don't have and data for working sintered steel with carbide. The gears only got slightly warm.

Quote:

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Originally Posted by overkill

My gears look different to the ones in your photo; they have a surface finish that couldn't have come from any milling or turning method I know of

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Originally they looked like this:

Attachment 4323
I couldn't drill through it at that stage so I turned it on a lathe and cut a new face, that took the hardened piece off and I could just about drill it.
What type of drills did you get Nick, there are loads of different shapes carbide drills around! What worked for you?

Ah, now your gear looks exactly like mine. I used drills like this: http://www.mcmaster.com/#standard-drill-bits/=ql6bw5 and I am sure you can find the same thing locally in the UK or Europe. I tried facing one of these gears and only succeeded in ruining a carbide insert.

Could be they are different materials then, as I did face it with a carbide insert. I needed the gear 5mm wide so I cut it off with a Dremel type cut-off disc, no problems there either.
Good choice of drill on that website, thanks...

Gearboxes almost ready now. Have not tried them out with the motor yet, but they turn freely by hand. Had to do some modifications to the original design, namely introducing thrust washers to reduce gear rubbing on the side plates. Looks good enough though, considering its a precision part manufactured using hand tools :-| a lathe milling combi would have come very useful! will have to wait a bit more for that...
Will try to find some time tomorrow to couple the motor to the box and give it a go...hoping it will stay in one piece - fingers crossed!

Attachment 4346Attachment 4347Attachment 4348

looks good!

For a gearbox made with just hand tools, that is fantastic work.

Is there any chance of getting a run through of how you got it so accurate with hand tools?

There is hope that mere mortals may be able to make something like this!

Well tbh I did use a pillar drill for the plate holes, and a lathe to machine the output shaft ;)

This afternoon I'm trying to rig it up and give it a go...and a video clip if all goes well!

Good news :D

In the afternoon spent a couple of hours with my brother setting up the gearbox and testing it - results are encouraging for now. The motor spins freely, no abnormal loading on the motor.

After ''running in'' the boxes we decided to load it a bit to see what happens, so I connected a 1/4" extension to the output shaft and held it in a keyless chuck (like in the photo a couple of posts above). The motor stalled so we increased throttle slowly...I was expecting something to fail but it didn't, the 1/4 extension started slipping inside the chuck.

Loctite 603 doing its job very well in keeping those gears glued on their shafts!

The only flaw I noticed till now is that the large gear on the output shaft wobbles a little bit...

Here are a couple of vid clips from this afternoon : Warning! its quite noisy!!

http://www.youtube.com/watch?v=arEgD...ature=youtu.be

http://www.youtube.com/watch?v=Yxy2JPsfRMI&feature=youtu.be

How does the esc handle full forward straight to full reverse?

If you give it a full fwd and then a full rev, the motor from full fwd will go to dead stop, to go to rev you have to repeat the rev input. That said we still have to program the ESC as I forgot place the programming card on the order. I'm not much into electrics and electronics, that's my brother's job...I only understand gears, metal and grease!
Through the whole test the esc and motor did not heat up or anything...

That's a Trackstar if I'm not mistaken.

If so,
With the programming card you can set about anything, but 1 thing will have to be done with the transmitter, setting the reverse @100%.

Yep its a trackstar SC120, reverse is at about 80% speed but brother said he can fix that, I think its as you said Mario through the transmitter - but I wouldn't know as I'm totally useless when it comes to electrics!

Still looks good tough, and we measured our 28-36 @16 amps 3S with burned rubber smell.
Those el cheapo motors and speedo's seem to deliver.