Hey guys,
As some of you know, I recently tested a bunch of grinding discs. Well I just came out with a new video you should check out here:
As an inventor, I’m always looking for ways to improve the tools I use, and my latest project was no different. A problem I’ve faced is seeing many different takes online as to which flap disc is the best; I’ve read countless reviews and seen many videos people have done, but wasn’t convinced those testing methods actually matched real-world conditions.
So I set out to finally answer the question “which flap disc actually is the best?” and build a custom test rig for grinding discs, one that could test their performance, durability, and efficiency under these real-world conditions. The goal wasn’t just to run tests, but to create a rig that would provide reliable, consistent results to help me figure out which discs actually perform the best and under which conditions.
The first step was designing a rig that could handle different variables like weight, angle, and pressure. I decided on a setup with two grinders, each mounted on adjustable platforms. This setup would let me control how the discs were tested and make precise modifications, like if the disc was shaped in a way that needed to be placed at an angle.
One of the key features of the rig is the oscillation system I built. This system moves the test platform back and forth, mimicking the actual grinding motion you’d see in a real workshop. (You can see how I used the Monster squares and fixture table to align the rails in the image below) To track how much material was being removed, I added measurement markings to the test bars, so I could see exactly how much was ground off during each test.
The test setup included multiple cameras, positioned to capture everything from the contact point between the disc and the test bar to the amperage being drawn by the grinders. But managing the sparks created by the grinders was another challenge. Originally I didn’t have any guard on, and it made it very difficult to see what was going on in the captured footage due to the sparks flying everywhere. So I designed spark diverters to direct the sparks away from the test area. Keeping everything safe and visible while the tests run was also key to getting reliable data.
BEFORE
AFTER
The data that was captured measured multiple variables: 4 & 8 pounds of pressure, and room temperature steel and hot “freshly welded” steel. It wasn’t until after 134 tests were conducted, that I realized we needed another variable: slower disc speed. The problem was some of the high end discs weren’t performing well, so I figured turning the disc speed down would set them up to give better results. So I tested every single disc again with a slower speed, but only at the 4 pound pressure.
The results are being analyzed, and I’ll be posting all the data here on the Fireball forum. If you’re curious about how these flap discs performed, be sure to check back here!
Ultimately, this was a lot of work, but it was also a great dive in shop science and data collection. Let me know what you think.
Jason