June 22, 2021 3 min read

DIY Conduit Flange Strength Testing

Last week we rounded up 5 different flange designs for EMT Conduit that all use this off the shelf threaded plumbing flange.We had a lot of comments asking for strength testing on these flange designs and we appreciate the feedback! This last week we tested all of the flanges to see how much weight they could handle before pulling out or bending. We were surprised with the results and found out which method offers the best all around strength.

The Test Rig

Flange Testing Cable Rig


We've never done tests like this before, but this rig we built should give you a good idea of what to expect from the flanges. We used cables, pulleys, and a come along to add tension and force to the flanges. Also on the rig was a tester that allows you to pull from both directions and record the amount of weight being applied when it stops detecting force. The tester we used maxed out at 600 pounds because we didn’t think the flanges would handle that much weight, but we were actually shocked by the results.
DIY Tester Weight Readout Meter
Do not try this at home, this was simply a testing rig that we made for this video and your entertainment. We tested all five designs including the simple threading method, the two off the shelf coupler designs, and the community flange.
Flange Reinforcement Hack
We also tested the reinforcement hack that works with the first 3 designs. Most builds will require two different kinds of strength. Projects mounted to the ceiling need pull out strength and wall mounted builds like shelves need bend strength so we measured the pull out and bend strength of each flange. 

Pull Out Test Results

DIY Flange Testing Pull Out Test


 First we tested the pull out  strength and all but two maxed out the testers weight of 600 pounds. The threaded conduit and compression fitting flange didn’t reach the max weight of 600 pounds. However with the reinforcement hack they both handled the 600 pounds easily. We were expecting maybe one of the flanges to be able to handle 600 pounds, but the fact that almost all of them went above that number was really surprising and cool to see. 
Strength Test Without The Weight Meter
In the name of science we did remove the tester and cranked until something finally failed on the flanges. It took quite a bit of force to cause failure which is encouraging. (Play clip) if all you care about is pull strength then you could be confident with pretty much all of the methods except those too. However the set screw coupler with a self tapping screw did arguably the best when we removed the tester and cranked until failure.
Self Tapping Screw DIY Conduit Flange
So the method that I would personally use for pull out strength only is the set screw fitting with a self tapping screw into the conduit. Even though that design maxed out the tester I would recommend strengthening it with the hack because adding that extra security is well worth it.That’s for pull strength only. The bending test had far different results. 

Bend Test Results

DIY Bend Strength Testing Rig


We used a similar rig for bending that applied force upwards. This allowed us to see the weight it took to bend the flanges . All of the flanges except for one started bending pretty early around 40-50 pounds of torque.
EMT Conduit Compression Fitting Flange
The best results came from the flange that had the compression fitting combined with reinforcement hack. It had around double the force before bending. So again if you need strength in both directions I would use the compression flange reinforced with the hack. That flange design will give you the best all around strength. 

Keep In Mind

Flange Bend Strength Testing


A couple of things to remember when building with these. One is the fact that we were testing weight or force directly applied to a single flange. Most likely your project will have multiple flanges mounted and will have weight distributed evenly which gives more strength and security. Secondly I want to mention that we used a foot of pipe sticking out of each flange for the bend tests. If you do longer spans you will lose strength so for builds that need the strongest bend resistance possible you should add reinforcement where necessary, and remember to build within your limits. 


To learn how to put these flanges together and use them in your next project you can watch the tutorial video here. We are really happy with the results and are excited to see how you guys use them in your projects. If you need any help with your project don't hesitate to reach out. Thanks for reading and happy building!