- Joined
- Nov 16, 2012
- Messages
- 5,596
Folks,
I happen to have 3 methods of doing Rockwell testing. One is a stationary Rockwell tester; another is portable Leeb unit and the third is a plastic tube, ball bearing and a simple scale/chart. For items applicable to the simple unit, it gives results that are basically dead-on with the ones costing a couple grand each.
This only measures on the Rockwell C scale so, items need to be fairly hard for this to register. Also, the items should be at least 1/4" thick, must be flat, clean bare metal and must be supported on a heavy surface (such as the anvil portion of your work vise). Larger heavy objects can be measured provided there's a flat spot and the unit can be placed dead-on vertically. I've had this device for many years and it was store-bought but, I believe the manufacturer is out of business. It's very simple to make. See the picture and enclosed chart.
The ball bearing must be 3/16" chrome steel. There's a little lever that drops the ball inside the tube from a height of 25cm. As the ball drops and rebounds, the tube must be positioned so the ball does not touch the sides of the tube on the way down or up. Years ago, I made another one just like this with a wider tube and it worked just fine (but I'll be darned if I can find it now)... The tube is marked every centimeter and half-centimeter all the way up to the drop point. Don't try to drop the ball with your fingers. That will not work. It has to be dropped "cleanly" from a mechanism that just lets it go without influencing it. Look closely in the picture. That's what the little black lever accomplishes. Carefully drop the ball and watch how high it bounces and read the number. Use the chart and the sliding scale to look-up the Rockwell. Do multiple bounces in a row until you get 3 that read about the same. If you hear it touch the side of the tube, don't use that result. You'll get a feel for it after a while. Read the instructions on the chart...
Have Fun!
Ray C.
I happen to have 3 methods of doing Rockwell testing. One is a stationary Rockwell tester; another is portable Leeb unit and the third is a plastic tube, ball bearing and a simple scale/chart. For items applicable to the simple unit, it gives results that are basically dead-on with the ones costing a couple grand each.
This only measures on the Rockwell C scale so, items need to be fairly hard for this to register. Also, the items should be at least 1/4" thick, must be flat, clean bare metal and must be supported on a heavy surface (such as the anvil portion of your work vise). Larger heavy objects can be measured provided there's a flat spot and the unit can be placed dead-on vertically. I've had this device for many years and it was store-bought but, I believe the manufacturer is out of business. It's very simple to make. See the picture and enclosed chart.
The ball bearing must be 3/16" chrome steel. There's a little lever that drops the ball inside the tube from a height of 25cm. As the ball drops and rebounds, the tube must be positioned so the ball does not touch the sides of the tube on the way down or up. Years ago, I made another one just like this with a wider tube and it worked just fine (but I'll be darned if I can find it now)... The tube is marked every centimeter and half-centimeter all the way up to the drop point. Don't try to drop the ball with your fingers. That will not work. It has to be dropped "cleanly" from a mechanism that just lets it go without influencing it. Look closely in the picture. That's what the little black lever accomplishes. Carefully drop the ball and watch how high it bounces and read the number. Use the chart and the sliding scale to look-up the Rockwell. Do multiple bounces in a row until you get 3 that read about the same. If you hear it touch the side of the tube, don't use that result. You'll get a feel for it after a while. Read the instructions on the chart...
Have Fun!
Ray C.