How To Turn A Round Groove?

dieselshadow said:
I don't have the knowledge to actually grind my own tooling. This would be a handy skill to have. Clearly I can see the benefits and needs
Click to expand...

The way you gain the knowledge and skill is to just do it. ;) The cutting edged sticks out further than everything else, all of the other surfaces are just clearance. If you can sharpen a cold chisel, you can grind lathe bits.

A cheap bench grinder or belt/disk sander and a random piece of metal makes a pretty good practice platform. Useful tool bits can be ground from many different broken tools. Broken taps, broken drill bits, broken end mills. I save all of the broken bits and I tend to generate quite a few :rolleyes:.

BTW, I use my bench grinder with a standard aluminum oxide gray wheel for 99% of my carbide grinding, you just have to push a little harder. Grinds pretty fast once it gets red hot.:cautious:
 
Last edited:
I have never seen a radius form O-ring groove specified by an engineer in 25 years, however I do currently make parts as drawn by a Customer employing dovetail O-Ring grooves in large parts for high vacuum applications, this is a far more difficult task to accomplish, as mentioned above Kaiser makes such tools.

I have no relationship with Kaiser. I just use their tools.

http://www.thinbit.com/pdfs/thinbit_sec_2.pdf
 
dieselshadow said:
Well this project got passed by. I don't have any hand ground tooling, or a grinder setup to do it, and lastly I don't have the knowledge to actually grind my own tooling. This would be a handy skill to have. Clearly I can see the benefits and needs.

Is there any reason not to use carbide blanks and grind those?
Click to expand...

Now that you passed on it. I would get some scrap and try and cut the groves. Would be a good learning project.
 
Yup. That's a good idea. I'll order me up some carbide tipped tooling to grind.
 
If the part is not too hard, you can grind the back end of a 1/8" drill bit to a sharp edge at a few degrees off a 90 degree angle and make a holder if necessary from a piece of key stock with a 1/8" hole in it and a set screw to hold the bit. Quick, easy, cheap, and with a little care, accurate.
 
Shanks of drills aren't all that hard out where the chuck has to be able to get a bite on them, so cut off a little to get closer to the fluted area. It's harder there. Or, you can use a broken center drill, or on-size end mill shank. They're all hard. Carbide works great for that, but it's a little hard to get the set screw to bite into. But you can make a clamp type holder for that, and it works very well.
 
Bob Korves said:
If the part is not too hard, you can grind the back end of a 1/8" drill bit to a sharp edge at a few degrees off a 90 degree angle and make a holder if necessary from a piece of key stock with a 1/8" hole in it and a set screw to hold the bit. Quick, easy, cheap, and with a little care, accurate.
Click to expand...

Good idea except the back end of a drill shank is not usually fully hardened, use a broken drill bit. Broken centre drills also make great little cutting tools for various jobs, make up boring bars by drilling a suitable hole across the end of a suitable sized bar to take the brocken centre drill, also drill and tap an axial hole from the end fit with grub screw to clamp tool. Or simply weld a small piece of HSS to the end of a bar then grind it up to make a quick boring bar
 
If you order a Kennametal insert VNGA-434T 0820 It has the right size radius and shape to do that groove. You would have to set the 15 degree angle off a little as the v shape of the insert is 35 degrees and do one side of part at a time. I'm sure you could get other inserts to work also.
jimsehr
 
You must log in or register to reply here.
Back
Top