Carbide Inserts in the Home Workshop

[Hopefuldave]

All of the above - HSS for the soft stuff / best possible finish / special form tools, inserts for harder materials when I can allow the less-shiny finishes, brazed carbide for nasties like hardened QCTPs (e.g. boring the base to fit a topslide spigot - something I find I have to do a few times a week at work...) - the hard skin seems to be a couple of mm deep, HSS won't touch it, inserts seem to just slide around under the clamp and "get out of the way"!

I almost always *sharpen* brazed tips, preferring to get the cheap ones and grind my own geometry, as cheap or expensive they still chip on hardened tool steel... A fine-ish green grit wheel and a diamond lap are good investments! Often the steel shaft needs grinding too - e.g. a lot of the cheaper brazed-tip boring bars are a bit clumsy as supplied, but grinding away some of the steel at the business end of a (f'rinstance) 10 or 12mm boring bar to get some heel clearance will let me get it into a 15mm hole *and cutting* and leaves the bulk of the bar at full size and rigidity, unless I need to go deep.

I've found the carbide parting inserts (in the fancy blade tools) are a wonder, but damn they're *fragile*! No interrupted cuts, any side load at all and the insert's gone and the blade bends, nasty noises! I go with HSS if I have a tricky job to part off.

Dave H. (the other one)