Internal Circlip Groove - How to machine?

I wish to machine a few dozen internal circlip grooves of around 3/8"
ID and about 40 thou wide in Acrylic, PTFE and 303 stainless.
For an external groove I could probably narrow down a parting off tool
to do the job but I have doubts I could grind up a carbide or hss tool
accurately enough for an internal one particularly with my eyesight.
Insert tooling seems very expensive for what will probably be a one
off job although having the capability in the future would be useful.
I was toying with the idea of mounting a dremel sized grinding wheel
in the lathe chuck and trying to grind the toolbit accurately in
position but I can't go faster than about 1500 rpm on the stone this
Is there is a better way to do this or is there something available
off the shelf for a tenner rather than a hundred quid?
Reply to
The Other Mike
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I doubt you'll find anything cheaper than these although they are in the USA so it's a bit more hassle.
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Any of the insert systems will cost a fortune so it's either the above or grind one up yourself from HSS.
Reply to
Dave Baker
For a one off / few can you not turn up a piece of silver steel to a Tee shape - ie a disk the width of your groove on the end of a bar of reduced shank, then file the disk into a boring bar cutter shape by removing three quadrants plus clearance. Heat, quench and temper and you have your tool.
Reply to
Andrew Mawson
He wants to machine stainless. I wouldn't go near that stuff without carbide or HSS. Silver steel is ok for light work on non ferrous and easily machineable ferrous but I'd bet it wouldn't last 5 minutes on stainless.
Reply to
Dave Baker
Just an idea, but what about thinning the end of a woodruff key / t-slot milling cutter?
Reply to
To get inside a 3/8" bore ????
Reply to
Dave Baker
I am experimenting with a damaged circular saw blade. The TCT tips seem to be ideal tool tips and separate with the application of a little heat.
Grind appropriately then braze onto the end of a bar.
I did learn to grind the tip before separating it, they are a bit small on their own.
Reply to
Process is much the same eyesight-wise - get a brazed carbide tip boring bar and thin and shape the end 'till it's as thick as/the shape you need.
Don't use a stone, use a 40mm diamond disc,
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They don't last long, but at £1.25 each .. they'll happily chew up and shape carbide for a bit, long enough to shape a boring bar anyway. They work better in a dremel, but they'll still do it in a lathe, I just tried. Keep them wet and they last a fair bit longer.
-- Peter Fairbrother
Reply to
Peter Fairbrother
A quick look on ebay reveals HSS WOODRUFF KEY CUTTER 3/8" X 3/32" (item: 350336708448) and they also do a 5/16's one, I'll grant you that some modification may be needed to the shank to make it work properly and I'm presuming that the groove is near the end of bore....
Reply to

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