Internal Circlip Groove - How to machine?

Question

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 way.

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?

Dave Baker · Accepted Answer

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.

Andrew Mawson · Answer

messageeyesight.useful.availableFor a one off / few can you not turn up a piece of silver steel to aTee shape - ie a disk the width of your groove on the end of a bar ofreduced shank, then file the disk into a boring bar cutter shape byremoving three quadrants plus clearance. Heat, quench and temper andyou have your tool.AWEM

Dave Baker · Answer

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.

Graham · Answer

Just an idea, but what about thinning the end of a woodruff key /t-slot milling cutter?Graham

Dave Baker · Answer

To get inside a 3/8" bore ????

rsss · Answer

carbide

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.

RSSS

Peter Fairbrother · Answer

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

Graham · Answer

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....

Internal Circlip Groove - How to machine?

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