Tube Versus Channel

[MrForbes]

Originally Posted by Kevin Sevcik

In other news, while we're getting pretty good at the 1/16 tube and plates and 3/16 rivets construction,

wow, those are big rivets. We usually use 1/8 or 5/32" rivets on thin aluminum. We save the big ones for heavy stuff.

[Kevin Sevcik]

Originally Posted by squirrel

wow, those are big rivets. We usually use 1/8 or 5/32" rivets on thin aluminum. We save the big ones for heavy stuff.

We use aluminum interlock structural rivets. They only go down to 3/16". They're probably overkill, but they have good clamp-up and hole filling. And Allen Gregory from 3847 pointed out that they use the same drill as a #10-24 clearance hole.... So if you standardize on 3/16 rivets and #10-24 screws, you only need one drill bit for a lot of your construction. 3847 is doing that, and it sounds like a nifty idea to me.

[IndySam]

We love the 3/16 rivets and have also started standardizing on 10/32 after doing 1/4-20 for years.

We also use hysol for the gussets we don't plan on removing.

Our robots are also mostly constructed from 1x1 tube in both 1/16 and 1/8 thicknesses.

1/8 c-channel is also a great choice for many parts.

I love prototyping with 8020 but we rarely use it for anything other than pneumatic supports that need adjustments.

[Bill_B]

Originally Posted by Kevin Sevcik

Especially if it means I don't have to shear and break a bunch of corner brackets at work in my copious free time. So has anyone looked at or tried these tubing connectors yet? I swear I saw a team using something like this for their tube based frame, so I started hunting. They look a bit heavier than the plates we're using, but I think things would come out straighter and less complicated. And you could assemble your frame and test things before you put a screw or rivet into the connector to secure it.

Jumped over to their site. I admit the connectors look good for quick assembly, perhaps rivaling 80/20 in quickness, if you have a bunch of pre-cut "standard" length tubes. building a frame would be quick and you could set your tube pieces up to give useful outside dimensions for the assemblies.

No dimensions given for the connectors - but I infer from the tubing they're selling that there might be a problem with 1/16 1" tube. They list wall thickness for their tube as .065", so the connectors must fit inside there, snugly? Their other option has walls .060 and listed as "slip fit" for things you want to disassemble easily. This makes one wonder how the connectors will fare in the .0625" walls we're thinking about here. Loose-ish but not slippery? I guess I'd have to buy a few for a sample frame to get some hands-on trials.

Esto has quite a few tube profiles with flanges and such. Most are anodized since their target is the construction of static displays and machine guarding frames. They are also rounded edges for a more friendly handling feel.

[Kevin Sevcik]

Originally Posted by Bill_B

I admit the connectors look good for quick assembly, perhaps rivaling 80/20 in quickness, if you have a bunch of pre-cut "standard" length tubes. building a frame would be quick and you could set your tube pieces up to give useful outside dimensions for the assemblies.

No dimensions given for the connectors - but I infer from the tubing they're selling that there might be a problem with 1/16 1" tube. They list wall thickness for their tube as .065", so the connectors must fit inside there, snugly? Their other option has walls .060 and listed as "slip fit" for things you want to disassemble easily. This makes one wonder how the connectors will fare in the .0625" walls we're thinking about here. Loose-ish but not slippery? I guess I'd have to buy a few for a sample frame to get some hands-on trials.

Precut standard length tubes? I should introduce you to my new best friend, the Diablo Non-Ferrous Circular Saw Blade. Toss this into your favorite 10" miter/chopsaw and you'll be amazed how fast you can put out tube for frames. I CADed the frame for our shooter, wrote out a cut list, and we had all the tube parts cut and ready to go in less than an hour. With accurate bevels and clean square edges. I can't tell you how happy I am the I noticed it on a Lowe's trip a few years ago. It makes it easier to work with just about any long aluminum on the bot. In fact, I think it's so nifty, I'm doing this:

Teams, if you do any significant manual work with long aluminum tube, channel, the kitframe, pretty much anything aluminum, then you need to buy this Diablo Non-Ferrous Circular Saw Blade and a half-decent chop saw like this Hitachi 10" Compound Miter Saw. You will be amazed how much faster and better things go vs. your current vertical/horizontal bandsaw, hacksaw, or dull butter knife. You'll wonder how you ever managed without it.

Ahem. And now that that's out of my system... Yes, I'm a little concerned about the fit of those connectors in various aluminum square tubing. I think I'll be lucky enough to have it work for me, and my terribly cheap square tubing from SSS-Steel just so happens to be nominally 0.065" wall. So I should be fine, but others mileage may vary.

Also, 8020 actually has a similar line of tubing and connectors marketed as their Quick Frame series. No clue if it's better or worse, but it looks like it mates up pretty easy with the standard 8020 profiles for teams that want to mix and match.