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Author Topic: Middleweight Metal  (Read 751 times)

18hvenhuizen

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Middleweight Metal
« on: November 03, 2016, 02:51:26 pm »
I am currently building a middleweight bot and I need to buy some armor for the outside. What width should I buy and where should I buy it? I should add that we need it to cover and protect a 3 ft. by 3 ft. square.
« Last Edit: November 03, 2016, 03:08:30 pm by 18hvenhuizen »

Coboxite

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Re: Middleweight Metal
« Reply #1 on: November 03, 2016, 07:09:26 pm »
Well, first off, its not helpful if we don't know the design. What size of metal you need to order greatly depends on your design(Spinner? Flipper? Wedge?), as well as the tools you have to cut it(An acetylene torch is a lot easier to cut with than an angle grinder, but angle grinders are easier to come about at home). Also remember that you do not need to make the entire machine out of one material. Choose the material to the needs of the part(External component in the line of fire need to be very hard and strong, but internal components don't need as much strength).


For an actual metal supply, McMaster-Carr and Online Metals are the best places to look. They have a large supply of metals in various sizes and thicknesses. Online Metals are cheaper, but McMaster has a better selection(They have AR400 steel and Grade 5 Titanium). Which is better the resource is up to you.


Also, 3ft squared is huge. That amount in 1/4" thick steel is roughly 93 lbs, or more than half your weight. What do you need that much material for?

18hvenhuizen

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Re: Middleweight Metal
« Reply #2 on: November 06, 2016, 01:02:09 pm »
We have a plasma cutter, acetylene torch, chop saw, and angle grinder. Our design is a KE drum spinner.

18hvenhuizen

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Re: Middleweight Metal
« Reply #3 on: November 06, 2016, 01:03:04 pm »
We are trying to completely cover our chassis with sheet metal to reinforce the armor.

rcjunky

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Re: Middleweight Metal
« Reply #4 on: November 06, 2016, 10:49:18 pm »
Check out chapter 3 in general, especially pg115

http://www.riobotz.com.br/riobotz_combot_tutorial.pdf
Andrew Burghgraef
Canadian Carnage Robotics

Great Hobbies- Canada's leading retailer of radio controlled models and related hobby supplies

18hvenhuizen

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Re: Middleweight Metal
« Reply #5 on: November 09, 2016, 09:51:58 am »
We have a chassis that is 28 by 29 on top and on bottom. It is five inches tall and needs to be covered as it is only pipes right now. What kind of metal should we use?

Coboxite

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Re: Middleweight Metal
« Reply #6 on: November 09, 2016, 08:54:31 pm »
We have a chassis that is 28 by 29 on top and on bottom. It is five inches tall and needs to be covered as it is only pipes right now. What kind of metal should we use?
This does not tell me anything, 28 does not tell me anything without context. Square inches? Square Centimeters? Some visual representation would be greatly appreciated, a photo or doodle would help wonders.


For a generic armor that can be acquired on the cheap, you can't go wrong with 4130 or 4140 chrome-moly steel. Its strong, easily weldable, can be hardened to further improve its strength, and is available at pretty much all steel supplies. As for thickness, well, as thick as you can make it and stay underweight.

AR400 is superior in terms of strength, and doesn't need to be hardened to obtain its maximum strength, and can be found at most steel suppliers(McMaster has it). Down side is that its much more expensive, is much harder to machine, and is harder to weld.


If you have money to burn, grade five titanium is ALMOST as good as steel, but is only about half the weight(Double the thickness to get more strength for the same weight). Downside is that its much harder to machine, very difficult to weld properly(TIG is pretty much mandatory), and is way more expensive per pound than steel.


Of course, you could always go the Beast route and not even bother putting on armor. As long as your tubing is big enough, your opponent can't stick its weapon anywhere near your squishy bits, short of a tacitly placed pointy stick. If you do want to at least deter this sort of approach, a few thick sheets of UHMW plastic will keep them out, at least.
« Last Edit: November 09, 2016, 09:32:27 pm by Coboxite »