Making o ring tool for lathe

I would grind one out of a high speed steel blank tool bit. Just make sure to to have some front and side clearance. With a little care and time one should be able to grind it by hand while checking the width frequently to hit size
 
I have hand ground many o ring groove tools. And the grooves I made were all straight sided. I have done thousands of parts with them. Also done o ring face groove tools. I have many special groove micrometers and depth gages to check them. And also have gages to check dia of grooves.
Jimsehr
 
Ideally, an O ring groove has a cross sectional area slightly less than the cross sectional area of the O ring. The amount of the difference depends upon whether the design is for a static or dynamic seal and runs around 10 - 15 %. O rings are incompressible but deformable so the actual geometry of the gland is less important than the actual volume of the gland. The actual dimensions of the standard O rings are given in McMaster Carr's catalog as well as those of manufacturers.

I have ground my own tools out of HSS. I generally grind a straight walled cutter with a width to match the design width of the groove. Internal grooves require some special attention as to depth as it is difficult to accurately measure depth without special tools.
 
I would encourage others to "look at the book" so far as O ring groove specs; I still have a spec sheet form Kaiser Steel of O ring groove specs, and they are not straight sided and are wider than the O ring itself. We made our own hydraulic cylinders and other hydraulic appauratus there, I still have a drawing of their hydraulic cylinder standards that they used, of the Ortman- Miller design.
 
I have seen the Parker o ring book, but don’t understand it. I am in calculus 2 right now, but I still find it hard to understand the machinist handbook o ring tables. I am making a pressure to force gauge, so I believe it is a static seal. I have tested it with a buna n O ring and I got 8,000 psi with a 1/2 inch with a 1/2 inch press ram. The bore is 1 square inch, so I get 1 psi per lb of force on the gauge. I used a parting blade to make the groove. The whole unit is made out of aluminum. This was for prototyping, but I’m not sure it will hold up for very long. The tolerances are not great and the finish is poor compared to what a professionally manufactured hydraulic cylinder would be. If I was far enough in my engineering degree I probably wouldn’t need to ask if aluminum is ok to be making this unit out of, but it was the cheapest option for prototyping. I wish my skills were high enough to do the math to see if the metal could handle the pressures and all the other calculations needed to make the right part the first time out of the right materials.

Does anyone have a diagram of the degrees the tool should be? I will look in the machinist handbook tomorrow for the rest in between work and class.
 
Jimsehr said:
I have hand ground many o ring groove tools. And the grooves I made were all straight sided. I have done thousands of parts with them. Also done o ring face groove tools. I have many special groove micrometers and depth gages to check them. And also have gages to check dia of grooves.
Jimsehr
Click to expand...
Sounds pricey.
 
You must log in or register to reply here.
Back
Top