Build Report - Pusher 12

[Kevin Berry]

I'm building a pushy hobbyweight for an upcoming ROBOT article. Thought I'd give those using the forum a preview, posting build reports & progress here. Plus this gives me a bit of accountability to actually finish it!

This is meant to be built using materials already in my bot shop. Low tech in some respects, but I'll be tossing in some higher end materials as I unearth them from the heap.

Basic specs: 4 hacked cordless drill motor/gearboxes; 2 12V ghetto packs built from the drill's NiCAD batteries; an old Vantec ESC; CNC Botparts hubs & Colson wheels; JR receiver and battery pack. Chassis is my favorite secret bot material, Kevlar covered Nomex honeycomb, with the vertical surfaces covered by titanium. UHMW motor mounts (like CNC Botparts but homemade). Frame also includes some really cool brackets that came with Plantation Shutters my wife wanted hung. Spare parts wind up in the "metal box". Current parts weight less frame & armor is 8 lbs.

Pic of layout on the Kevlar before cutting (its a bit pricey so measure twice, think three times, cut once is my mantra).

[TheDuck]

...Plus this gives me a bit of accountability to actually finish it!...
Well then, we'll be keeping an eye out for some more progress reports, Mr. Berry! :)

[Kevin Berry]

OK todays progress - virtually nil. Couldn't drill out axle supports 'cause my 1/2" chuck drill died, have to replace it. Couldn't figure out the rear motor mounts I'm "adopting" from the cncbotparts design, had to stop and look it up on their site, won't work, have to redesign.

Other than that, it was a really productive day!

[HarryBotter]

OK todays progress - virtually nil...Other than that, it was a really productive day!

Sounds like a pretty typical day in my robot lab too. :)

[Kevin Berry]

And for today's gradual creep forward ... went shopping for my new drill. No joy, the one I want is sold out. So had to come home, dredge the drill press out of the back of the shed. A 15 mile round trip fruitless shopping expedition, 30 minutes moving junk and a 200 pound tool to drill one 31/64" hole! Ah, the joys of bot building!

Hopefully tomorrow will be much more productive, when the planets all line up you can get an amazing amount of work done in an hour or two.

[Kevin Berry]

Well some progress. Got one set of motor mounts cut out of 1/2" UHMW. Used my newly inherited set of Forstner bits on the drill press to cut out an oval hole. Sweet, cuts like butter and perfectly smooth. Pics coming tomorrow.

Nice to make progress. I was going to go ahead and make all 4 sets, but decided I ought to mount the first set on the chassis, to make sure I don't waste a lot of work if there is an issue/modification needed.

In related work, charged on battery pack today. Since they were made almost 2 years ago, and never touched since I bought them, it was really nice to see it take a charge. Still have to cycle it a few times to make sure it is truly good.

[Kevin Berry]

OK got the beta version of the mounts finished. This is a copy of a sport-standard mount (made professional by cncbotparts) combined with a home improvement leftover plantation shutter bracket. The baseplate is the 3/8" kevlar honeycomb panel, not shown are 10-32 hex head button screws coming from the bottom into the UHMW blocks. The "rear" (left) block has a 1.5" hole, press fitted onto the motor can. The "front" (right) block has a slotted hole made from 2, 7/8" overlapping holes to fit the double half round nose of the drill gearbox.

With some tweaks, went into "production" on these, have a set laid out and drilled, just need to be cut out.

[Kevin Berry]

Realized I'd never posted the plans

[Kevin Berry]

Finally posting latest progress. Motor mounts done.

[spleenriper]

Looking good! I wish I had the tools and material to make my own motor mounts.

[Kevin Berry]

spleenriper said "Looking good! I wish I had the tools and material to make my own motor mounts."

Actually, thats the point of this whole project. The mounts were made with about $5 worth of UHMW, available at surplus scrap yards, or on line from Kenwood Plastics or McMaster Carr. The rear mount was made with a hacksaw and a regular wood cutting hole saw and a battery powered drill. The hole saw is one of those with the concentric rings, where you take only the one you want and mount it to the central drill bit. About $3.00 at red box http://www.redboxtools.com/product_images/1399.jpg.

The front mounts, again cut with a hacksaw, have an oval hole which I used an expensive drill press and forstner bit to cut, but also could have been done with that same hole saw set using a hand drill. The only other tools used were two "C" clamps. The whole thing was done on a picnic table down by the river, where I can work and watch the birds at the same time. I've also made this with only a coping saw, and a small drill bit to start the hole.

Give it a shot! These can also be made with 1/2" plywood, or even 3/4" fir, if they aren't going to be stressed by combat.

[spleenriper]

That is pretty cheap. I think I'll get one of those after I finish my current bot.

[Kevin Berry]

Got all 4 motors mounted, forgot the camera before I put it all away. The chassis with all parts except top and side armor weights 9 lb, 14 oz so that's always good news! Oops, forgot wire, nuts, bolts, a few brackets, .....

[Kevin Berry]

Heres the photo with motors mounted and other components just set in place. After some travel, will get back to this project. Also ordered the Anderson Powerpole connectors from www.robotcombat.com/store.html