strongest 80/20 fastener

[GMKlenklen]

Hey... what's the strongest fastener for most joints?

GMKlenklen,

If you are asking about the slotted 80/20, then you should use different connectors and biscuts depending on what forces the joint will encounter. With the slotted 80/20 that my former team used, we found that the connectors that can be purchased with the stock are more than ample in securing the 80/20.
Now if your question was about welds, possibly this site, and this site could be helpful, but I've little experience with welded frames/parts.
If you'd like more specific advice, I think I could be more effective if you described what type of joint you are trying to make and what, if any, unusual forces you expect to act on the joint.
Hope this helps,

Mike

[artdutra04]

Originally Posted by GMKlenklen

Hey... what's the strongest fastener for most joints?

Of all the options available for securing one piece of 80/20 extrusion to another, the corner anchors are the strongest; however keep in mind that you need a milling machine to bore these end holes. Team 228 used 80/20 extrusion frames from 2003-2006 and these corner anchors from the 80/20 catalog - although slightly on the heavy side in the weight and budget departments - were crucial to making these frames work.

I would also advise against welding 80/20 into a frame, as it its almost a self defeating measure. (Also, welding 80/20 would make it impossible to get additional component slide-ins into or out of the extrusion channel. Your only option would be the drop-ins, which are less preferable to slide-ins for mounting crucial components like transmissions or pillow blocks.)

[rfolea]

There is a great chart hidden in the 8020 catalog that outlines the performance of the various fastner options.

I say hidden because it is not in the fastener section, it is in the extrusion section section of the catalog (go figure).

In my catalog it is on page 40 about 5 or 6 pages into section 1.

It lists how each fastener performs under the different kinds of loads (direct, cantilevered, tortional, etc)

It says the double anchors are best, but they are very hard to use because you heve to mill every piece (we did that last year - ugh).

This year we are using the corners mentioned in the previous post - much easier, though a lot of tapping. (These are on page 127 of my catalog in the joining plates section)

[GMKlenklen]

Ok, sweet.
The reason I didn't specify the application was because net cut is at 12am... it was 12am.

Generally, most connections would be between two or more 10 series tslot excrusions(sp?) at 90* to eachother. Also there would be several bearing block attachments and the ocasional securement of 3/8" plywood or lexan.
no welding.

Thank you all for responding to my very general and poorly constructed question!

GMKlenklen,

In the case of 90 degree corners, I think artdutra04's answer is the best given the stock connectors. The triangular uppler/lower corner brackets (with 3 bolt holes on each leg) is the most secure option for bolting the two pieces together. Assuming the main forces will be pushing the two toward each other (i.e. if this is for your robot frame), then the second best option is using the inside corner bracket. If you need to put something close to the inside of this angle, then the outside corner bracket and an angle bracket may be the way to go.
Pillow blocks can either be bolted to a biscut in the frame, or if you're willing to give up the adjustability of the pillow blocks, they can be bolted through the frame.
In my expereiences with my former team, I think we may have used all of the methods above at some point or another, and our robot never fell apart (although we normally find a bolt or two lying at the bottom of the shipping crate each time we move it...)
My apologies if I seemed a little curt; I had just finished my statics homework, so I was still in that nit-picking state of mind. Best of luck this season,

Mike

[DonRotolo]

Extrusion connectors don't handle impact or shock well - although the gusset plates for corners are probably stronger than you need, and two of the barrel connectors (the ones they mill into the end) are probably good enough.

We used single barrel connactors on our chassis last year, and they were always coming loose. Gusset plates and the cheap T nuts fixed that.

Don

[=Martin=Taylor=]

Well I don't know if they will suit your application, but toilet bolts are by far my favorite 80/20 fastener.

They are a conventional size (1/4-20) and are very strong. I like them because they are longer then most 80/20 fasteners and are bolts rather then nuts (biscuits).



They can also be bought at any hardware store.

(Oh, and Happy Birthday )