small radius bender for "half inch" emt

Nov 27, 2013
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in a universal confluence I found a bucket of pulleys in the metals area at work while thinking about custom moped chopper exhaust systems.

I used two pulleys as bending dies. The rest is scrap cutoffs, hence the ugly shapes. Let me stress this is only a test, so i will prolly make a better system, but I just wanted to (quickly) see if this would work.

The flat stock on the back of the assembly fits the groove of the metal table. The big flange is to clamp the bender to the table. There is also a flange welded perpedicularly to the end of the flat stock- it holds the tube while bending - I will measure this next time. NBD, but could be improved.

The pulleys are configured so that one is fixed to the table and the other orbits it. I used the rectangle tube to attach the pulleys because I could insert a lever/handle in it, and my only real work was drilling holes.

I drilled one hole, mounted a pulley, positioned a cuttoff of EMT, placed the other wheel, and marked the center of the axle, before drilling.
 

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Nov 27, 2013
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the emt goes between the pulleys, the end past the flange.

I inserted a long-ish piece of bar stock in the rectangle tube and pulled. Hard enough to move the table, but not as hard as i thought i might need to.
 

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Nov 27, 2013
143
4
18
earth
www.Frankenbikes.com
a normal emt bend with a conduit "shoe bender " is about d10"

this bend is about d4.5"

the tube did not collapse, but it did wrinkle slightly on the inside diameter.

the outside is still round, but the inside diameter is shaped like the pulley channel. If you were to saw through the tube it would have a distinctly egg shaped profile.

I can totally live with this. it is still a tube and did not collapse.

in fact I actually want to find a bigger pulley, as this d is too small !

cool


el
 

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curtisfox

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Dec 29, 2008
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I welded a flat stock in the pulley so the tube didn't go so deep. It worked good and didn't flatten the sides, also my pulley was for wide belt...........Curt
 
Nov 27, 2013
143
4
18
earth
www.Frankenbikes.com
new idea -Re: small radius bender for "half inch" emt

it just hit me'

i am going to try welding/attaching a "handle" and stop to one of the pulleys and see if i can create a small radius "shoe bender"

advantages would be: one pulley, less set up, no bench or clamps needed