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Creator Mat
01-14-2011, 11:18 PM
In the rules for the mini-bots it says that Aluminum sheet is allowed. So what is the definition of a Aluminum sheet. 1" thick, 1/2" thick, or 1/4" thick piece of aluminum? Or could we get a 12" x 12" x 12" block of aluminum machine it out and call it a "sheet"? Where does a sheet of aluminum stop being a sheet and becomes a block?

MrForbes
01-14-2011, 11:27 PM
wikipedia is always right...it says up to 1/4 inch

http://en.wikipedia.org/wiki/Sheet_metal

sounds good to me

dtengineering
01-14-2011, 11:51 PM
I don't believe melting and casting are disallowed by the rules... in previous years we cast and turned wheel hubs, and at least some of the aluminum in those hubs was... in a former life... sheet.

Now, I'd probably get a Q&A ruling on this, as I'd kind of suspect that "sheet" means that it starts as sheet and stays as "sheet"... but it doesn't say so (yet) as far as I know. I'd also be prepared to document the fact that whatever cast component you make started out as sheet.

Perhaps a better way would be to use a CNC machine to cut thin layers of your project from sheet stock and build up your mechanism layer by layer... you could use aircraft grade adhesives to hold the aluminum together and then go back and do a final machining pass to get everything exactly to size.

Jason

Chris is me
01-15-2011, 12:06 AM
Food for thought: Vex metal was once aluminium sheet. :)

DonRotolo
01-15-2011, 12:08 AM
you could use aircraft grade adhesivesThere are some very strong automotive (body repair) adhesives too, probably more readily available and less costly as well.

jvriezen
01-15-2011, 12:43 AM
I don't believe melting and casting are disallowed by the rules... in previous years we cast and turned wheel hubs, and at least some of the aluminum in those hubs was... in a former life... sheet.

Now, I'd probably get a Q&A ruling on this, as I'd kind of suspect that "sheet" means that it starts as sheet and stays as "sheet"... but it doesn't say so (yet) as far as I know. I'd also be prepared to document the fact that whatever cast component you make started out as sheet.

Perhaps a better way would be to use a CNC machine to cut thin layers of your project from sheet stock and build up your mechanism layer by layer... you could use aircraft grade adhesives to hold the aluminum together and then go back and do a final machining pass to get everything exactly to size.

Jason

Aircraft grade adhesive is not an allowable material, is it?

efoote868
01-15-2011, 12:48 AM
In the rules for the mini-bots it says that Aluminum sheet is allowed. So what is the definition of a Aluminum sheet. 1" thick, 1/2" thick, or 1/4" thick piece of aluminum? Or could we get a 12" x 12" x 12" block of aluminum machine it out and call it a "sheet"? Where does a sheet of aluminum stop being a sheet and becomes a block?

I'd say it stops being a sheet when you can no longer bend it with a normal shop setup.

Rion Atkinson
01-15-2011, 01:47 AM
I'd say it stops being a sheet when you can no longer bend it with a normal shop setup.

Now your question is what is a "normal shop set up." Take 148 the past few years. Sheet metal robots, just bent and riveted.

Creator Mat
01-15-2011, 02:26 AM
wikipedia is always right...it says up to 1/4 inch

http://en.wikipedia.org/wiki/Sheet_metal

sounds good to me

Its right until I change the entry... jk. Thx for the answer i couldn't find my answer on wiki I guess a search of "sheet" doesn't cut it I have to search "sheet metal", who knew?

sanddrag
01-15-2011, 02:45 AM
Generally speaking, I've always regarded anything over 1/8" thick as plate. Don't they also allow any aluminum bar stock though?

MrForbes
01-15-2011, 08:41 AM
I'd say it stops being a sheet when you can no longer bend it with a normal shop setup.

I can bend 1/4" relatively easily in my press, I can bend thicker metal too, but not in very useful ways.

Even if wiki is not always right (that was a little joke) I would say 1/8" is definitely sheet metal, and 3/8" is definitely not sheet metal. So it's somewhere around 1/4" thick that it changes.

Teched3
01-15-2011, 09:53 AM
ihave always taught the sheet metal was differentiated from plate by having a gauge number. Consulting the engineer's handbook, go to this link for clarification and documentation:

http://www.engineershandbook.com/Tables/gauge2.htm

Notice the difference between ferrous and non- ferrous metals.:) :) :)

dlavery
01-15-2011, 11:34 AM
Food for thought: Vex metal was once aluminium sheet. :)

Isn't it still?




.

Bob Steele
01-15-2011, 11:57 AM
Food for thought: Vex metal was once aluminium sheet. :)

What Vex metal are we talking about here?
Most of the metal in my VEX kits is steel

The FTC metal is aluminum...
Has VEX changed over to aluminum?

I have some VERY expensive aluminum parts that I got a few years ago from VEX that are aluminum... that is the only aluminum I see on the VEX product site. 99.95 for an aluminum chassis kit... Do they have sheet?

just curious