[Dan S]

I have been watching auctions on eBay for a few weeks; seeing what aluminum was going for, and I have some questions for the more educated amongst us.

1. What is the difference between flat, bar, sheet, and plate? Are they made using different manufacturing process? Is it the size of the piece?
2. what is tooling plate? It seems to always fetch a higher price per pound than the other stuff.

[metlmunchr]

Bar could be rectangular (flat), round, hex, or square. Generally extruded shapes in the smaller sizes.

Sheet is a rolled product, generally 3/16 or less in thickness.

Plate is ditto above, but 1/4 and heavier.

Tooling plate is often a cast product and treated for additional dimensional stability. Sometimes Blanchard ground for flatness. The cast variety is very brittle and doesn't like to be bent or formed.

[Dan S]

metlmunchr

So would tooling plate be better for building a machine because it’s more dimensionally stable?

[metlmunchr]

Dan, I think either can work fine. A big advantage to ground tooling plate is the flatness. As long as you can machine a square end on a mating part, you've got purpendicularity when you attach it to the surface of tooling plate. On the other hand, I wouldn't hesitate to use standard plate if it was more available in the sizes I was looking for. In the typical machine build you're generally not making the type of machining cuts in the components that cause plate to start walking around. I'd say if you're looking at building a bridge type machine like a typical router or plasma, and planning to keep the x-axis guides below the table surface (a very good idea, IMO) then using tooling plate for the uprights of the bridge and for the carriage which attaches the z axis drive components to the y axis guides would be money well spent. Otherwise, you'll need access to a mill so you can flycut some flat surfaces for mounting various components and keeping things square. It's generally easier to purchase flatness than to create it unless you already have some serious machining capabilities. For the remainder of components, it should make little difference which type material is used.

[biddaddyg]

Dan, I have given up on Ebay for Aluminum. By the time your bid is in and you pay shipping your not going to be very much ahead of the game. Enco (use-enco.com) provides free shipping on orders over 50 bucks most of the time. They have a full selection of 6061-T6 which is a very good aluminum for machine building. I have been designing and building automation for over 20 years. I have been purchasing aluminum from Enco and often get email offers for free shipping almost every month, not to mention they also have a great selection of end mills, tools etc and low pricing, but the free shipping is where the real savings come in. I often combine purchases with friends as well and end up getting great deals. Plus with Ebay, your getting cuts and scraps where Enco your purchasing 3' or 6' lengths of quality 6061-T6 which is one of the best for machining around, and except treatments and surface coatings if need be. They also sell a limited selection of steels, stainless and round stocks, etc.. Good luck!
Glen

[Dan S]

Metlmunchr, biddaddyg

Thank you for those words of wisdom and advice. I will keep them in mind for when it’s time to purchase some aluminum.

[TyRex]

I'm gonna have to disagree a little bit about ebay for metals. I admit to searching a long time on ebay for scrap metal, and coming up short. However, I've found an ebay store called "Speedy Metals" that actually has good deals(better than onlinemetals usually). The shipping is cheap, and sooooo fast i couldnt believe it.

http://stores.ebay.com/SPEEDY-METALS...enameZl2QQtZkm

keep an eye out for the "speedy specials"....I scored some 3" dia 6061, 2' long, for 35 + 9 dollars shipping......also 8 feet of 1" dia 6061 for 17.50 + 6.75 shipping.

[jeffs555]

I also had a good experience ordering off Ebay from Speedy Metals. I normally don't order metals because with the shipping, it is usually more expensive than buying locally. I did however buy some fairly heavy steel bars from Speedy and even with shipping, it was much less than it would have cost locally. It arrived promptly and well packaged.

[Dan S]

Here is a quote i got from http://www.metalsupermarkets.com/

the rule of thumb i have been think about is $2/lb with shipping included.

If i had bid i would have won some auctions and lost others. So basically just like everything else on ebay, timing is the key.

[biddaddyg]

Sounds like a wash. Some of the prices you listed above are good ones, but I like being able to go get it and not have to deal with someone new every time I need something. But yes, I guess if your looking and find a good deal from time to time, great! But for the everyday purchases from a very rep. company you still cant go wrong. I just offered it up as a way to get a good deal (and no, I dont work for them). Sign up and get the internet offers either way. I live in Fla, and when they ship from Atlanta, I get the stuff in a day or sometimes two. But I will check out the Speedy Metals site and keep it in mind. Good luck all.
Glen

[TyRex]

Originally posted by Dan S
If i had bid i would have won some auctions and lost others. So basically just like everything else on ebay, timing is the key.

They are all "buy it now"....no auctions

[cyclotron]

"Tooling plate is often a cast product and treated for additional dimensional stability. Sometimes Blanchard ground for flatness. The cast variety is very brittle and doesn't like to be bent or formed."


I'm thinking of using 5/8" Al mic 6 for my gantry mill, does any one know what the flex characteristics are of tooling plate vs. rolled 6061 t6? I would be using the mic 6 primarily for its parallelism and flatness, but I'd sooner fly cut
a huge plate of 6061 if I thought that the mic 6 would just snap. whats the deal?

[jc_eng]

Just a quick note.

You can purchase metals from the speedymetal website and still get good prices.

http://www.speedymetals.com