EMT Conduit Bender

Discussion in 'Shop Talk' started by Ed K, Apr 4, 2005.

  1. Ed K

    Ed K Well-Known Member

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    I'd like to make/find/scavenge a conduit bender that I could use to create semicurcular arcs of 3/4" diameter EMT. The purpose would be for forming smooth long radius arcs to serve as the framework for greenhouse/hoophouse structures

    Yes I could probably use a hand held conduit bender and try to evenly bend it but I think the results might be a little less uniform than I'm looking for.

    Anyone have any good ideas on this? Anyone know how the manufactures of hoophouses do this?

    I found a picture at this link that seems to make some sense what are your opinionso of that?

    http://bioengr.ag.utk.edu/Extension/ExtPubs/PlanList97.htm#Greenhouse Plans (click on the "greenhouse plans" then "plan 6217" to see the picture of the bender)

    Thanks
     
  2. farminghandyman

    farminghandyman Well-Known Member Supporter

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    looks like it should work

    on a large bend like that one may have to expement a little on the radius as the conduit will probly spring back some after bending so you will probly have a slichly smaller radius than the building is, (I see the jig is 7' and the building 9'6" to 10' depending on how you want to measure.)

    if you have a wood floor or deck you could jsut nail blocks on to the floor, and do the same thing, the key is uniformity of the pieces,
     

  3. moopups

    moopups In Remembrance

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    Laminate a couple of pieces of 3/4 inch plywood together, turn in a lathe to creat the concave surface shape needed. Attach this to a flat surface that will not move under pressure, hand bend the EMT to a predetermined stop spot. Add about 7% additional 'travel' to allow for the spring back. Bending around squared blocks will allow pinching and misshapes without the concave shape being present in the bending form.

    Adding a lube substance helps, ordinary pan spray, silicone spray, even wax helps.
     
  4. mikell

    mikell Well-Known Member

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  5. Oregonsparkie

    Oregonsparkie Well-Known Member

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    I would call local electrical contractors, I bet they would sell you a good used one fairly inexpensively.
     
  6. Ed K

    Ed K Well-Known Member

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    Mikell,

    how do you adjust the center distance between the wheels in your machine?

    Thanks
     
  7. mikell

    mikell Well-Known Member

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    You have 3 wheels 2 are fixed and the center one is on a slide moved by a screw the center wheel also has a crank. You force the center wheel between the outer wheels to bend the tube. It may take 3 or 4 runs to the proper arch you want. I'll keep looking for a better plan.


    mikell
     
  8. farminghandyman

    farminghandyman Well-Known Member Supporter

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    I personally think the idea the plan show will do you fine, if your building that plan,

    yes a roll bender may do nicer job but your are a 7 foot radius and I don't think you will have to worry about crushing the tube on that slight radius, to bend the conduit you may have to bend from both ends to get you complete bend (using the one shown in the plan) and my guess is it would be the cheapest rout to follow,

    if your wanting to make tight bends you will need a bender that supports the tube to keep it from flatting, like in electrical bends, or even in bends that would be smaller circle bends my guess is if the radius was less than 5' on 3/4" conduit, you would want to support the sides in some way in bending.

    but if your interested in a tubing roller that would handle the job here are a few more links,

    http://www.wikco.com/rbndr.html

    http://www.rdhs.com/products/htb4wayroller.htm

    this book may give you some ideas as well, for a small bender or how to make rolling wheels for a large radius bender,
    http://www.lindsaybks.com/dgjp/djgbk/pipe/index.html