Just a small question, at marayong 9 I noticed that most circular saw motors that you guys were using looked the same. Just wondering where you guys got it and what voltage it runs on. I was thinking along the lines of a batt powered angle grinder, but haven't yet seen such a thing. Thanks in advance! _________________ ( •_•)
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
All the saws are powered by car fan motors that you can pick up from most car wreckers. Some of the motors are very weedy and stall too easily, you want the largest one you can find (within reason). Euro cars are often a good source for larger motors. Prices vary upwards from $10 to $40 and pricier doesn't mean better, just rarer. Everyone runs the motors on 12 up to 24V.
The motor shaft is also important. Many fan motors have what's called a D shaft, which is about 6 to 8mm wide and has a large flat section cut into it. This is hard to mount a saw to unless you can make an adaptor on a lathe or use an expensive gadget called a Trantorque bush.
A better motor shaft is one with an adaptor already attached. These are a wide disk with 3 mounting holes. Its fairly easy to drill some matching holes in your saw blade and pop it straight on.
Another thing to consider with a saw bot is to use a smaller diameter blade with as many teeth as possible. This way, the motor is less likely to stall or over heat and you will be able to inflict more damage.
Finally, if you want a pre-made solution, Dewalt make a fantastic 18V cordless angle grinder. It could be adapted to a bot with very little work and if you have a spare $640 , its just the ticket! _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Dec 07, 2004 9:11 pm
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
Do you know how it was done on orbit? Was an adapter used? (sorry , i'm TERRIBLE at names)!!! But yours is easy to remember, nick.
Also, why woould a cordless anglegrinder cost so much, when cordless drills are so cheap? It would just use a different motor and gears, wouldn't it? (and mabey more batteries. _________________ ( •_•)
Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane
No one remembers little Hellbringer and its saw. Its a shame. It still works perfectly after 18 months. It cost me about $20 to make that weapon too. Just a air compressor motor (actually a drill motor is bigger), a rubber model plane wheel, some old bearings, some threaded rod and a circular saw.
I remember the first time we tested it at Chris's place and the coke bottle went over the neighbours fnce. Scared the crap out of me. Damn that was a long time ago. _________________ Get Some!!!
Secretary of the Queensland Robotics Sports Club inc.
Tue Dec 07, 2004 10:01 pm
ffej Experienced Roboteer
Joined: 22 Jun 2004
Posts: 595
Location: Kurrajong, NSW
Andrew is Orbit's owner
Comparitivly speaking, thats not that bad for a Dewalt grinder. Take a look at their cordless drills, there up there at the $300-800 range, there a bit better made than your typical XU1 though _________________ Jeff Ferrara
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Tue Dec 07, 2004 10:02 pm
Valen Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
one says "Dewalt" the other says "XU-1"
check out what a dewalt drill is worth for comparison _________________ Mechanical engineers build weapons, civil engineers build targets
Tue Dec 07, 2004 10:04 pm
andrew
Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W
Well orbits saw is a dewalt saw blade (good quality 33 dollar one) and the motor is a tr magna fan motor i think. Its a large one which i have discovered to have lots of torque and a awesome top speed. The motor already has a round funky sorta mounting plate to it with tapped holes already drilled all ready for the right size nut to pass through blade and mounting dealy.
I run it at 24 volts and so far very little has stalled the thing. the only time i can remember is once against cobra, It has taken on steel hammer on nicks ld thwakbot hammer cutting through 5mm ali and going slightly into teh wteel hammer head and cutting up the mounting arms, it has also grinded away (although not causing damage) on Ko's 3mm steel armour brick bot although it still didnt stall and produced some nice sparks.
Nick has some more of the same motors if u want to buy one off him maybe but i want at least one more i think for a spare.
AT the fun event if its happening on 18th or whenever ill bring the assembly along and show u in great detail how everything is done so u can have a look at how simple an effective weopon can be. Pitty the rest of the robot isnt as effective as the weopon hey. . _________________ Andrew Welch, Team Unconventional Robotics
Tue Dec 07, 2004 10:06 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
quote:
Also, why woould a cordless anglegrinder cost so much, when cordless drills are so cheap? It would just use a different motor and gears, wouldn't it?
Dewalt gear is considered to be about the best U can get - its WAY better quality than The budget chinese stuff like XU1 drills. I only mentioned it 'cause I'm lusting after one myself, but still haven't gotten over the price tag As far as I know, it's the ONLY cordless angle grinder available in Australia.
Another reason why builders use fan motors is that they are 'pancake' shaped (flat & wide) and are ideal for making bots with horizontal saws. If you were to make a vertical saw weapon, you could a wider range of ex-car motors. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Dec 07, 2004 11:46 pm
Spockie-Tech Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
An interesting point raised by Rick (Team Moth) the other day was that DeWalt has now been bought by Black and Decker who are (in his opinion) proceeding to "milk" the brand for its reputation of high quality allowing them to charge high prices, whilst significantly lowering the quality by phasing in their own production facilities and models under the DeWalt brand..
Translated, Dewalt is nowhere near as good as they used to be and rapidly getting worse..
I went to buy some DeWalt chuck-screws (to replace the crappy metal ones in the chinese drills) from their "service center" the other day, and sure enough the same service center is both a DeWalt and Black and Decker service center, and if the apparent competence level of the staff in there was anything to go by, there may well be some truth in what he says.. They certainly didnt appear to have any clue, interest or give a damn about anything..
Any other Tradesmen who use DeWalt products noticed this ? _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
Last edited by Spockie-Tech on Wed Dec 08, 2004 10:00 am; edited 1 time in total
Wed Dec 08, 2004 1:40 am
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
hey brett i went to that service center at ringwood i think?? its to buggery out in the middle of no where out past knox i believe and yeah black and decker and dewalt are in the same center.
the guy quoted me *$88* dollars for an 18v motor and had no idea what the left handed screws where for unless i gave him the part number (even after that he still couldnt chase them down..). hopefully the homebush bay one will be more competant.
as for fan motors the flat flat ones do have one problem, they use a spinning copper plate above a big flat magnet with like a 2mm gap. if you get a huge hit there going to bend into each other and cease working - which in case you didnt know is bad _________________ www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
Wed Dec 08, 2004 5:48 am
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
I've seen some petrol cordless angle grinders with little 33cc motors on them. They were only $450 IIRC. So Dewalt obviously arn't the only ones making them in Aus.
For saw blades, I would stick to a max size of 8inch and use 24v. Also, don't mount your blade on an angle, it cause problems. Our saw blade on Haemorrhage has survived a lot of pounding, from saw to saw impacts on Scoopy Doo at RoboWars breaking scoopy's arm and losing a tooth or two to cutting off Ball Peens batteries. With the blade mounted on a 45` angle, it causes a few problems to the bearings in the motor and the blade has come out a bit buckled afew times, but nothing that couldn't be fixed. Haemorrhage has had the same weapon motor in it for over a year now and is still going strong for a 12v motor. _________________ https://www.halfdonethings.com/
Wed Dec 08, 2004 10:36 am
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
Cool, thanks for all the help! Sorry andrew, I can't make it to the fun event on the 18th 'cause I'll be on holiday. (mabey next time eh?) And with petrol anglegrinders, I don't think their alowed in the sydney comp yet. (may be wrong). _________________ ( •_•)
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
tim - i got two saw blades at the markets.
one is 240mm and about 40t im guessing and is all mild steel im sure (seeing as its rusted all the way to the tips of the teeth and at a guess carbide doesnt rust?)
the other is about 235mm and has at least 60t same as before.
The Cheese wedge uses an angle grinder gear box with the 240 volt motor cut off and the origional motor shaft center drilled so that a 300psi compresor motor can be press fitted into it.
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