Relative power of different drive trains in comparison to each other

[overkill]

Like Gary said, Robot Marketplace sells the motor, gearbox and the mounting kit: http://www.robotcombat.com/products/0-DEWUT.html You might be able to get the motor & gearbox cheaper by buying a 'skin only' drill on Amazon or eBay, but I don't know what model you would need.

This is just one of the better options, there are plenty of others out there.

[knightrous]

Dewuts are a great solution and allow you to use any of the 3 speeds in the new dewalt gearboxes with a quick change of the selector bar. I've been running these for around a year now and have had zero issues with them. I sourced my Dewat kits directly from Charles @ e0designs and then bought the motors and gearboxes off eBay for US$30-40ea (There is a refurb place on eBay that does them).

The only negative of a Dewat kit is that they are a fairly big unit, being 63.5mm square and 200mm long, which might make them a bit bulky for some designs.

[Pinski1]

I was planning on trying to design up a metric DEWUT kit, unfortunately the CNC machines I have access to can only machine plastic so I was going to trial it with Delrin.

[mark_m]

I was planning on trying to design up a metric DEWUT kit, unfortunately the CNC machines I have access to can only machine plastic so I was going to trial it with Delrin.

I'd be keen to collaborate with you on that. I've got some old polycarb we could try too. I don't know how well it will machine or how tough it will be, but it might be useful whilst we tune the design.
I noticed Charles has released the IGES/Parasolid files for the Dewut kit, so it shouldn't be too difficult to get started. From a quick look through the files the smallest feature I've found needs a 2mm cutter, and I've got a bunch of those suitable for the CNC router.

[Pinski1]

My main reason for a redesign was that I need to learn how to use proper CAD software not SketchUp which is only just working for me currently. I wanted to make quote a few edits, my dewalt gearboxes seem to be different to Charles' and I wasn't happy with the clamp motor mount.

Unfortunately the hardest part to fix will be the funky shaft , I had the idea of using a shoulder bolt that has the head cut down but you'd need a shoulder greater than 20mm to get a large enough head.

(I'm on the phone, excuse the rampant spelling mistakes)

[mark_m]

Starting with an off-the-shelf screw is a great idea. I think an M16 cap head would just about do it, or a '16mm' (M12) shoulder bolt. The head wouldn't be as large as the Dewut one, but it should still sufficient to engage with the 'nubs'. Lets chat offline.

[typhoon_driver]

"nubs"? Do you mean shaft splines? If so, for any kind of reliable drive, you need to have a spline on the shaft to engage the gearbox. A fudged solution will work for only so long.

[mark_m]

The output carrier has both 'nubs' and an internal spline:
http://www.etotheipiplusone.net/pics...dw/dewut25.jpg
The 'nubs' originally interacted with an anti-backdrive' system:
http://www.etotheipiplusone.net/pics...dw/dewut24.jpg
But Charles used them to drive the output shaft:
http://www.etotheipiplusone.net/pics...dw/dewut29.jpg

An M16 screw head is large enough to have cut outs machined into it to engage with the nubs, but would have a little less engagement.

[daveimi]

How would 4x 12V drills compare to say 2x Makita's or Dewalts? Beginning to think the easiest way to more power would simply be 4WD drill pusher.

[overkill]

Generic drill motors are rated about 100W peak power while 18V Dewalt motors have 1100W peak power. To get the Dewalts pushing efficiently, you will need some very wide & grippy wheels.