THe pressed steel bearing housings come in today from an internet purchase from Brisbane.
They look pretty good and are very light. THe OD bearing size is 40mm with a 1/2 inch ID. Dont have these yet buts thats the size.

Pondering on the material of the shaft. As the wheels will be sticking out from the body they need to be very securely mounted so hence the overkill in the drive setup. 40mm bearings on a 150mm wheel sounds good I hope.

Glad somethings are finalised, have deviated a few times from comments I have made in ealier post about 4 motors and 200mm wheels so things are set in stone now.
6 inch wheels - 2 X 250watt scooter motors (24/36 volts?) with 3/8 roller chain running 4 wheels.
completely invertable design with a slight chance of bodyslamming smaller bots, hehe hopefully
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PIcked up some of the bearings today.
Really dig the self locking, self aligning features of them. It will make setups a lot easier.

Have taken a top view shot showing the final proporations of the weapon and body. Finally am happy with the size of the body to the weapon. Its going to end up one sweet super nerdmobile i thinks.

http://robowars.org/forum/album_pic.php?pic_id=223

Ideally the front half should be an axlebot but will be offsetting the front wheels back a bit to try to reduce its overall width.
The Main frame design is going to be extremely simple, 2 rectangular shapes will hold the complete drive train making it real easy to work on.

Originally with the thought of using 4 of these motors meant it was obviously going to be larger but in the end I would prefer small and chunky as there is a ratio I want it to have and thats basically big jaws on a compact body.

In reality the big scooter motors have thrown some proportions out, mainly the height but its a small compromse. At 150mm wheel height the body will be about 120mm centred so thats a 15mm ground clearance on both sides.
Ends up making this thing look more like a stocky bull terrier.

The bearing mounts shown in the pic are shown horizotal but will be mounted vertical which will reduce the lengh of the sides and make it rather easy to set chain tension simply useing a flat spacer behind the mounts.
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Why is it that just after you send an email to the states saying " where the freak are my wheels", the postie rocks up and delivers them. Doh!

The tyres arent exaclty what was in the pic but they are still cool.

http://robowars.org/forum/album_pic.php?pic_id=225

Really happy about a few things, firstly they are lighter than the wheels on Pinscher which is shown bottom left. (note tread pattern in Pinschers tyres thanks to an angle grinder, never again)

The wheel shown has had some grinding done to remove one side of the hub.
I know some would leave the bearings in the wheel and have a shaft welded to the body but I prefer a different approach.

Like the idea of deep dished hubs as its harder to get the hub smacked in when it is deeper in the wheel, looks cooler anyway.

Have adopted an approach of making everything easy to remove and service so all this stuffing around and planning now will make it easier later on when it counts.

Another bonus is that the wheels will work fine when they are flat, they have a capacity for 300 pounds (30psi) so only issue with that is working out method to stop tyre slipping on rim, probably fill them with something, have an idea for this, will test before sharing that tip.

All I have to find now is a 1/2 inch steel rod for the axles which hopefully shouldnt be too hard, so far the only place I have checked had metric so the search for rod continues. woohoo

If anyone knows a place local for imperial shafting let us know.
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To stop the wheels slipping on the hub, you may want to investgate the ways in which serious 4x4 & race car tyres are held on the rims. They use small screws & actuall screw through the rim flange & into the tyre. This stops the bead from slipping & popping off.

You can not use this method if you tyres are using tubes obviously

Mytqik is correct. Self tappers and foam filled wheels have been used with great success.

Have to admit would never have thought of that, sounds promising.

Was starting to think about araldyte but that gets messy.

So would 4 screws be enuff do you think just on the inside or should it be held from both sides?

Has anyone ever foam fill tyres before, was wondering if it adhere to the tyre when it sets and can it be ripped out of the tyre later if you want.
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Marauder has RC car wheels filled with foam. The tyre is glued on with CA. I tear it off when the tyre needs replacing and sand it flat.

quote:

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Originally posted by Philip Taylor:
The tyre is glued on with CA.

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Super glue is a CA or cyanoacrylate glue. It may work for you.

Cut up some aluminium today from a single piece about 160mm wide and 6mm thick. It wore out my grinder disk doing it so should be very hard to cut.

On the back corners i grinded half way through and bent it. Isnt that strong but a line of welding will finish that, only way I could bend 6mm without tools.

Have a few more pieces to make up and thats mainly the back end of it where i need it to be tuff and also have mounting brackets of sorts to add additional components or weapons.

http://robowars.org/forum/album_pic.php?pic_id=231

In the pics the body tapers up on the side, it shouldnt do that, I just run out of disks to cut with. The panels on top next to the wheels are going to be leveled horizontal and the centre piece is going to taper down towards the back. THis centre piece is also the removable panel to access inside.

Between the wheels need to protect the sprockets so will be lloking at mounting something there which can also be used to attach side panels for occasions where I would want to preotect the wheels.

The panel thats on top betwwen the front wheels is just out of a video and isnt that strong at all, it just looks cool for the moment, will get this part made from stainless stell from a sink. Probably use the rippled part of the sink for extra strength.

Bodys about half done which am happy about as it was an inpulse to get out the grinder and spend an hour cutting. Need some more al to finish it then prep it to get welded as one solid piece of 6mm.

My secret goal is to be able to stand on this and ride it so want it tuff but dont know if the high gear ratio is going to put a strain on this sort of hooligan behaviour.
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holy crap that looks awesome, the way you give your robots character would satisfy even donald hutson!

one question though, is this a lightweight or featherweight? (im guessing light.)
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

yeah seconding that "looks cool" sentiment

mmmm lotsa bits to grab n rip MUAHAHAHA

what was that glen was saying about charicter ;->
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Mechanical engineers build weapons, civil engineers build targets

Yeah pretty happy with wheres its at.

Dont mind if you want to smash it up, have been thinking of you all as I have been planning it.

Keep in mind the parts in the photo a just held together with some tape
Some more refinements will happen and I see some side armour thats mounted loosely like a shield.

Would prefer to run it with exposed wheels.
Rather than armour have optional wheels in progres that I will be keen to see how thaey perform against the spinners.

Have been designing this to basically have expendable wheels and still operate while there stuffed up.
Theres a few layers of things before any damage is really done.
Not that I intend to let you

And yeah Its a Lightweight but not that much more so will weigh it soon and see if I exchange some parts It might be a feather.

It might be a case of removing some weight from the sprockets, making a bracket and using Lighter motors. Removing some unessasary steel from the jaws and or removing the motors and actuators from the weapon using it just as a pivoting invertable wedge.

Wont really know till I get it a bit more complete and then weigh the components and do the maths.
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oh man,
George i have more respect for u everyday. that is so cool looking. I love robots that actually look like what your typical robot would be (mechadon, tripulta raptor, growler, disector and especially tazbot). Anybody can build a box or a wedge but it takes something else to make it look good and give it character.

I love that as it looks a bit like diesector (of course) but from the jaws back looks like devils plunger and sewer snake (minus the wedge).

Send a picture of pincher and this one to Donald, i think he will find it quite interesting.
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Andrew Welch, Team Unconventional Robotics

Its pretty obvious that Donald is an influence but look at this pic and see if theres a similarity in the weapon.

http://robowars.org/forum/album_pic.php?pic_id=233

Its a bit of a coincidence i think that I had designed something similar about ten years ago.

I was learning this 3D software and chose a robot as the subject. (Twilight Zone Music). End product was about 2 seconds of animation. The image is a scan of a printout from one of the frames, the white spots are from having it in a plastic sleeve and ageing. Software used was Swivel 3D and Pixars Renderman.

Didnt realise how long I’ve been a nerd.
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