I have difficulty with tiny stuff.
I want to cut a groove around a 1/8 inch brass rod, to accept a retaining ring. The specifications say the groove should be .020 wide. How do I do this? Should I just grind a regular tool bit down until it is .020 wide? Is there a better way?
I have to do 24 of these. This is on an old but pretty good South Bend 10K lathe.
Thanks for your help and advice.
Will
you only have to grind down one tool bit and use it 24 times if you want the groove to be done right.....
Hi Will,
I've cut grooves this size before, just grind a tool blank as you would for a cutoff tool. Have the skinny parts as short as possible, hone the final thou or two with a stone, and have a bit of side relief. No top rake for brass.
In steel I've also done snap ring grooves by clamping a dremel tool to the toolpost (el cheapo toolpost grinder style) and using the thin cutoff wheels. You'll break a few so stand to the side, but it works OK.
Cheers, Stan
Will Self wrote:
Normally you grind the tool a bit narrower than the groove you want and do the cut in two or more passes, measuring as you go. It's not easy to get a tool to cut exactly to width time after time and any chatter will scrap another piece. In high volume production there'd be time to play with the tool form and width until it cut to size in one plunge but for HSM it's easier to take more cuts. I'd try 17 thou and see how that works. Of course if the groove width isn't very critical as long as it's at least 20 thou then go for it with a 20 thou tool.
Dave Baker - Puma Race Engines
I had to cut some very narrow grooves recently. I made the grooving tool by carefully grinding a piece of bi-metal blade from my bandsaw. Let me know if you need more detail.
Ted
Or make it real easy and get a Thinbit holder & blades.
michael
Rig up a groover out of a piece of old power hacksaw blade and a chunk of keystock. MSC has tooling for this type of work but you don't want to know the cost...
Stan
Take a 1/32nd inch drill (.03125") and grind a flat on it the shank end of it (or break off the fluted part) until it is .021 or so wide. Then hone the flat and hone a little relief below the cutting edge, a few degrees is plenty. Clamp that in your tool post between a couple of pieces of softer metal, get the flat on the center line, and it will cut your grooves.
For brass this might work, but remember that most drills have soft shanks.
Jim
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