Snap ring groove cutter

[brian Rupnow]

My Grandma was right!! Idle hands are the Devils workshop!!! This week, I've been pretty darned idle. To the point where I have started building those tools that you only need "Once in a blue moon!!" I occasionally have to put snap ring grooves in small shafts, ranging from 3/16" up to 3/8". Up until now, I have "made do" by clamping a hacksaw blade to my toolpost in the lathe. Yesterday afternoon, I designed one which will fit into my AXA toolholder, which is a lot more secure and a lot safer. Hacksaw blades seem to be just the right width for this. I know I could have ground down an HSS toolbit and accomplished the same thing, however I have a lifetime supply of hacksaw blades so thought I would do it this way. Note that on the drawing there are a couple of dimensions with ### or *** after them. They are to remind you to measure your own hacksaw blade to use in this rig. My hacksaw blades are .027" thick x 0.458" wide--yours might be different.

[brian Rupnow]

These are the parts disassembled. The cut in the cover plate isn't supposed to be there. I was using up some stock that I had, and that little cut doesn't impair the way the tool works.

[Doozer]

Kaiser ThinBit for production.

-D

[brian Rupnow]

And here we are, all assembled.

[brian Rupnow]

And here is the tool in the lathe, and a couple of grooves cut into a piece of cold rolled steel.

[Rich Carlstedt]

Brian
Really cool tool. Thanks for posting

You can also use an Aloris Parting tool holder
This picture shows mine and I ground down the hacksaw blade to about .010"
for parting a 1 mm hex nut



Looks like you used a Starritt hacksaw blade ( yellow) .. good choice !
Rich

[PStechPaul]

Do such blades need to be ground slightly on the side surfaces to make a trapezoidal cross section and avoid jamming? It may not make much difference for shallow cuts for snap-ring grooves, but for parting I think it might be necessary.

[brian Rupnow]

At first I tried the hacksaw blade with no top-rake, like I would normally use for aluminum, but it didn't want to "bite" into the cold rolled steel. Then I ground a 10 degree +/- top rake on the top of the hacksaw blade, and it started curling out chips like nobody's business. I wouldn't dare use this for a cut-off, but it certainly has no problems going in deep enough for a snap ring groove.---Brian

[J Harp]

Good job Brian.

Now a question for Rich Carlstedt. Rich, what is the chuck you are using in that picture? Thanks.

[TGTool]

These are the parts disassembled. The cut in the cover plate isn't supposed to be there. I was using up some stock that I had, and that little cut doesn't impair the way the tool works.

RE: The small cut. Maybe too late now, but you could do like the software companies do in How Many Software Managers Does It Take to Change a Lightbulb? Highlight the cut and call it a feature of the tool.

[Rich Carlstedt]

Good job Brian.

Now a question for Rich Carlstedt. Rich, what is the chuck you are using in that picture? Thanks.

J, Its a Jacobs "Rubber Flex" collet and chuck , with a L00 taper, on my Atlas Clausing 6300 Lathe ( 12")
These are really good units that seem to have fallen to the wayside ?

Second answer:
I grind a side relief taper (top to bottom) by setting the Aloris tool holder on my belt sander, with the table
sloped at 90 and 1/4 to 1/2 degree. This give a .004 max taper from top to bottom of a 1/2" blade....per side !
Using the holder allows very precise handling of the blade for a parallel grind. And yes, I try to make the thickness
about .001 thinner inside. If you look at the photo, note the vertical lines that are in the first 1/8" from the tip of the blade .
This is my "controlled size" or ground width. Only make what is needed. parting the nuts requires maybe .025" penetration to .045 for facing

I finish with a 300 grit India stone stone , by marking with a sharpy ink pen and stoning the ink off
Rich

[Rich Carlstedt]

Even a cheap hacksaw blade will be made of carbon steel and that can handle most common alloys

[duckman]

J Harp that is a rubber flex collet chuck.

[1935Ron]

very slick holder!

[daveo]

Nice, You could use cut up circular saw blades in it too. Then you could have a nice parting tool!