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Micro Magnum, Team Magnum, NSW
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Nick
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Joined: 16 Jun 2004
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Location: Sydney, NSW


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Steel will always be more brittle as the hardness increases, it doesn't matter what the alloy is.

I haven't hear that about laser cutting but it could be true. My laser cuts the same radius corners in thick or thin materials; it just has to move slower in thicker materials. What I do notice is that small radius holes sometimes cut less accurately in thick material ( we are talking about wood, not metal here). When I get metal water jetted, I always specify small holes under size and then drill them out before tapping them - its more accurate and reliable.
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Post Wed Apr 26, 2017 8:10 pm 
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MoonSet416



Joined: 25 Sep 2016
Posts: 436
Location: Sydney


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Ah I see... I feel kinda lucky that the smaller radiuses in my chassis are all chamfers of lightening holes. Smile

As listed on action laser's website they only have 6061 ali in imperial sizes, which means my 1.5cm chassis probably cannot be made there. That being the case are there some other machine shops with metric ali stock?

Post Wed Apr 26, 2017 8:32 pm 
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Glen
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The laser cutter machine itself has to decelerate and accelerate into and out of sharp corners. because of that it will always have some radius but it should be insignificantly small. 3mm chamfers is plenty okay. Just things like the slots for tabs might not be perfectly square.

Any laser cutter should be able to cut out 15mm alloy, shop around, where are you located?

And yeah impact toughness drops as hardness increases. the two are hand in hand mostly.
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Last edited by Glen on Wed Apr 26, 2017 10:52 pm; edited 1 time in total

Post Wed Apr 26, 2017 8:45 pm 
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MoonSet416



Joined: 25 Sep 2016
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Location: Sydney


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Thx for the info...

I'm in Sydney btw. Probably should have my personal info updated. Smile

Post Wed Apr 26, 2017 9:37 pm 
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Nick
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I found that in Australia, most of the higher performance grades of aluminium are imported from the USA and are imperial. You might get lucky asking around the various laser cutting shops but you might have to adjust some parts for imperial dimensions.

When I order sheet material, it is almost never the exact thickness stated - you never know if it will be a little thicker or thinner. If you are planning to have tightly fitting slotted parts, you might want to either buy the material first and measure it, or to specify a slot size smaller than the material and add a shallow rebate on the other part to guarantee they fit.
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Post Wed Apr 26, 2017 9:44 pm 
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MoonSet416



Joined: 25 Sep 2016
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Yes you're right.
Only available 1.5cm plate I found was on Ebay, and it was selling for a pretty high price. (300*100*15 for 41USD)
So I guess there are two choices left for me. The first one is to reduce the thickness to 12.7mm, which might not be enough.
The second option is to go back to China in winter holiday (which I will do anyway), cut the plates there and bring them to here.

I'm now liking the second one a bit more, but I wonder if it would be hard to travel with a bunch of weird looking ali plates

Post Thu Apr 27, 2017 12:44 am 
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chunkulator



Joined: 27 Jul 2016
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I've had good experiences with a Sydney supplier called Calm Aluminium who were able to supply metric thicknesses of 6061-T6 plate.

Post Thu Apr 27, 2017 10:36 am 
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Knightrous
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Joined: 15 Jun 2004
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Location: NSW


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Action Aluminium have 6061 stock in both metric and imperial.
http://www.actionaluminium.com.au/Action_Aluminium_Catalogue_2014.pdf

I regularly drop into their Smithfield store to buy 6061, 5083 and 5005.
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Post Thu Apr 27, 2017 2:23 pm 
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pilleya



Joined: 31 Mar 2016
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Location: Sydney


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Buying aluminium plate in big thicknesses is expensive, instead find a flat bar of the size you want and design around that. It is much cheaper to buy flat bar then plate.

Post Thu Apr 27, 2017 7:23 pm 
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Nick
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Joined: 16 Jun 2004
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Good point - buying a length of flat bar is cheaper than getting cut to size plate. On the other hand, getting bar wide enough to fit some of those parts on is going to be difficult and sometimes its more space efficient to lay small parts out on a plate for laser cutting than on a bar.
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Post Thu Apr 27, 2017 7:54 pm 
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MoonSet416



Joined: 25 Sep 2016
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Thanks for the info guys.

Post Sun Apr 30, 2017 8:37 pm 
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MoonSet416



Joined: 25 Sep 2016
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Did some changes to the design.

The front wedge design is inspired by Whoops, the angled sides are meant to deflect horizontal spinners. The added bit sticking out of the side panel is basically a ball bearing on the end of a bolt, which is meant to provide support and lower friction during gyrodance. Don't know if these will ever work, but since they don't take up too much weight I might just try them.


Post Mon May 01, 2017 1:17 am 
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Nick
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The new wedge design looks good and will be stronger against horizontal spinners. The ball bearing idea is interesting and could provide a huge tactical advantage with faster turns - I might have to try that out on Mr Mangle Smile.
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Post Mon May 01, 2017 10:03 am 
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MoonSet416



Joined: 25 Sep 2016
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Yeah I think it will work well with your new wheels, might be able to let Mr Mangle rest on two wheels and a bearing during a turn.

Post Mon May 01, 2017 10:22 am 
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MoonSet416



Joined: 25 Sep 2016
Posts: 436
Location: Sydney


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Question: how many spare parts do you guys usually have? (Since I'm outsourcing the parts, I might want some spares because order more at a time might lead to less setup fees, but I also don't want to order a ridiculous amount of parts because that costs too.)

Post Mon May 01, 2017 5:30 pm 
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