View Full Version : HSS toolbits

06-13-2005, 10:28 PM
I have to make some more tooling for interrupted cuts in tight places.

I've done this before, but always had a devil of a time making short pieces out of HSS square
tool bit stock.

How do y'all cut off pieces of HSS?


06-13-2005, 10:35 PM
I use a die grinder with a thin radiac blade. Works OK

06-13-2005, 10:38 PM
angle grinder with thin cutoff wheel

06-13-2005, 10:49 PM
Take it to a cutoff disc, score around the bit where you want it cut, then clamp it in a vice at that mark. Put a piece of steel up against the protruding part and whack it with a hammer. Chances are the break will be at some angle, and that's alright since you probably want some angle there. Grind it into your cutting tool shape.

Before smoking on it with the hammer, cover the protruding part and the steel bar you use with a shop rag or something. This will catch the part as it breaks off, and will contain any bits that will be flying off at mach 3 or so. Not kidding, bits of hss will be flying off at high speed, and the least of your troubles would be if you cut a finger or something. Imagine getting one of those bits in your eye-

Anyway, this works about the best, unless you have a cbn cutoff wheel and lots of patience. You could cut all the way through, but the bit will get hot and you shouldn't be cooling it in water. You could roll it in your hands every ten seconds or so to cool it, but it will take awhile to cut it through, and you don't really want more than about 3/16 or so of the cutoff wheel in the hss. If you're patient, you can cut it through at an angle, giving you a head start on the formation of two new cutting tools.

You could get creative and score it angled across, and hope it will break somewhat along the score mark. That can happen.

06-13-2005, 11:00 PM
A hacksaw works surprisingly well for small tools (under 1/2 x 1/2) if using unhardened O-1, A-1 or W-1. Also M42 cobalt.

Barry Milton

06-14-2005, 02:46 AM
What Darryl says is what I do. I grind a notch all the way around the bit stock. Wear your full face shield when doing it.


Try O-6 tool steel. Unhardened it machines like 7075 aluminum. Lovely stuff.

[This message has been edited by Evan (edited 06-14-2005).]

Your Old Dog
06-14-2005, 07:50 AM
I've used a Dremel with a nickle sized thin cutoff wheel to cut 1/4 inch M-2. It won't take any abuse though, let it flex and the little stone shatters (actually, evaporates might be a better word)

Spin Doctor
06-14-2005, 09:02 AM
Thin cut-off wheels work best but one does have to watch the ammount of heat generated. I really see no nedn to cut off HSS tool bits unless they are going in boring bars. I usually grind both ends in to the same general type of tool. Both threading, internal or outside radius, chamfer tools. Plus when they are longer they're a lot easier to hang on to. http://bbs.homeshopmachinist.net//biggrin.gif

06-14-2005, 06:11 PM
Thanks, Y'all. I guess I need to get a cutoff wheel for my die grinder.

Anybody ever make a mini chop saw out of an
air die grinder?


Your Old Dog
06-14-2005, 06:30 PM
If you do the cutoff wheel just make sure you got eye protection on. The ones I use vaporise with out a trace. Would really do a job on your eye. Hate to be one of those types distracted by safety to the point they can't function but I wouldn't get close to mine with out my face shield......

06-14-2005, 07:30 PM
Now I get it! I've wondered where those dremel discs go- so they're vaporizing are they- http://bbs.homeshopmachinist.net//smile.gif I've read that you can apply ca to the sides of them to strengthen them. I tried it, seems to work, but boy does it stink when it's being abraded away in a cut.

06-14-2005, 07:37 PM
I always coat both sides of the dremel wheels with thin ca on both sides.put on a couple of drops,then wipe across the whole disc to cover it.makes them last quite a bit longer.Still won't take big side loads though.As for cooling bits between grinding,lay them on your anvil.this draws the heat out of the toolsteel quickly.


Paul Alciatore
06-15-2005, 11:40 AM
Dremel with the reinforced abrasive disks. They are a lot sturdier than the plain disks.

I almost never use anything else in the Dremel since I discovered them. I have used them for a variety of other tasks that would have called for other wheels in the past. Sharpening small drills, web thinning on drills, special shapes on drills (split point and zero rake angle) and mills, other special shapes, even general (small of course) grinding.

Be sure to use eye protection.

Paul A.

Norman Atkinson
06-15-2005, 03:50 PM
For the benefit of the ones that the Pilgrim Fathers left behind, what is "ca"?


Michael C
06-15-2005, 04:25 PM
ca is abreviation for cyanocrolate sp glue, aka super glue. Buy the good stuff not crazy glue or super glue. Good stuff is found at model stores, Woodcraft, woodworking stores, tool stores. Comes in different viscosities and drying times. The fumes contain cyanide so show some caution.


Norman Atkinson
06-15-2005, 04:38 PM
Thank you Michael C.

I was stuck for an explanation.