Our team (FRC3548) is building a robot based on Dr Joe’s Boom Done design. One thing they did is to use a “gravy spoon” hoop for their ball support mechanism. They used 1/4 rod, soft steel for their design.
I don’t have any experience bending 1/4 rod steel. Based on discussions with some folks I am going in the direction of using 1/2 EMT conduit vs the 1/4 rod steel.
So here’s a gaggle of questions for CD:
Do you think the 1/2 EMT conduit is a satisfactory substitute for the 1/4 rod, soft steel in terms of expected performance?
Do you have tips for bending the 1/2 conduit? I went to the store and purchased a 1/2 inch tube bender (Klein) today for this task.
EMT is light but significantly more rigid than the rod. That could be good or bad depending on what you want it to do. Once it’s bent, I don’t think you’ll need to worry about it getting deformed.
I used to being the electrical trade, so I’ve got some experience bending that stuff. It is inexpensive, so I’d recommend buying several extra sticks and practicing your technique. Don’t try to bend a smaller radius than the bender allows; you’ll crimp it and it won’t hold it’s shape well. Just play with it for a while, and I’m sure you’ll get it to work.
Any competent electrician can bend your emt for you. If you don’t know one just be brave and bend it your self. emt is cheap and if you look at the side of the bender it will say for a 90deg. Bend add 6 inches and for a 45 add 3 inches. It might be minus instead of add. Just look at the side if the bender it will be there. But it is easy google it to see how its done.
So we had an EMT bender to do just this and have found that making the shape you want to bend it to out of wood (i.e. semicircle with correct inner diameter), screwing it down to a table, adding a block to hold it on one side, and then finding some friends to help bend, worked a lot better.
I’ve used 1/2in EMT (both straight and bent) on a number of FRC robots over the years, most recently on Team Copioli for Build Blitz. 1/2in EMT is a great solution when you need a rigid frame member that needs to be curved.
The pipe bender tool for 1/2in EMT is also relatively inexpensive, you can buy them starting at $30. The one we used for Build Blitz is McMaster #2424A5 with the #8754A11 handle.
We bought one from the nearby Ace Hardware for about $20, used a piece of PVC pipe to steady it in lieu of a handle (which I don’t think they had in hand), and still got good bends. Not saying I wouldn’t mind the real handle, but if you’re in a real pinch…
You might want to seek out some professional help on tube bending. Our team is probably going to use 3/4" EMT, to form a cradle, for both picking up the gameball and for holding during shooting, similar to Team 1114 , in 2008.
Thanks for your help. Last night I successfully bent my first stick of EMT rod into a ball hoop design using a newly purchase 1/2 inch EMT conduit tube bender from Home Depot costing about $35 (handle and foot together).
I owe this thread a picture… darn where’s my camera phone!
