Sharpening HSS

not too hot!

Andy in Raleigh

>I will let others with more experience fill in more details, but if you are itching to sharpen and turn, be sure you don't keep it in contact with the wheel very long and keep a wet sponge handy for cooling. Getting it too hot weakens it (de-tempering?).

Re: Sharpening HSS

Fred in NC

>Actually, a lot of what we hear about sharpening requirements is not quite so. It is true for CARBON steel tools, but not for HSS.

1. HSS can take a higher temperature than carbon steel before it loses its temper. You don't want to overheat it, of course. I have found that the couple seconds it takes to refresh the edge will hardly heat the tool.

2. A white "friable" wheel is best for any kind of turning tool, and I highly recommend it.

3. The speed we need to be concerned about is SURFACE speed of the wheel. At the same RPM a 8" wheel has a higher surface speed than 6". A 8" high speed grinder (3400 RPM) is a bit too fast for my liking. I use a cheap 6" 3400 RPM grinder with the white wheel.

4. I don't believe in water cooling HSS tools while grinding. I don't believe in getting them too hot either. It only takes a couple seconds to refresh the edge. The only time you run the risk of overheating the tool is when you are grinding a new shape on it.

5. The best investment I have made in grinding is the Wolverine jig. If you cannot buy one, it can be improvised easily. The tool rest that comes with most griders is a JOKE!

You can spend a lot of money in grinding equipment, which is fine if you can afford it. The most important item is the white wheel, and with a little care you can get by until you can get it.

Hope this helps. Please interpret the above as my own opinion.

Re: Sharpening HSS

Richard Allen

>Andy is incorect that HSS will lose temper if it gets hot from grinding.

One of the reasons I use HSS is because it will NOT lose temper by the heats generated sharpening on a grinder.

For sharpening the prefered system for sharpeing is:

8" half speed grinder (Woodcraft sells one at a fair price).

You need friable grinding wheels (white AO wheels are good for this and there are others that also work) One coarse and one a bit finner (60 and 100 or 80 and 120) BTW the Woodcraft grinder comes with suiatable wheels in place.

You need a grinding jig. There are several to select from and they all work okay. You can even make your own. The most popular grinding jig is the Oneway Wolvorine grinding jig.

This is the system most woodturners use. With a little instruction you can easly sharpen your turning tools using such a system.

Good Luck

Richard

Re: Sharpening HSS

Michael Stadulis, in Gloucester County, NJ

>Hi Joe,

Regarding the issue of what.... and what not to do w/ HSS, I would still suggest to you that you approach things this way: If you are radically modifying a grind profile on a wheel, I wouldn't worry too much about overheating the steel, but when you get to the point where you want to establish a cutting edge, take more care to keep a cooler edge. It is true that for our purposes, HSS will not lose it's temper, but other bad things can happen. When you get down to finessing a sharp edge......and then cool it rapidly in water because its too hot to hold, you can cool the thin metal at the edge so quickly that you cause micro fractures in the steel from rapid contraction. Those among us that study edges under microscopes could probably confirm this.

Technique for grinding an edge is much like what we've all noticed when learning to use a router bit to mill an edge. If you move the router too slowly, the router bit heats up and burns the molded wood profile. That's because it's barely cutting wood and needs the larger woodchips to contact the tool edge and carry heat away. Same theory applies with grinding to an extent when you reshape. Go at it until you finally get to really sharpening the edge, and then be careful. If you get a hot edge, let it air cool slowly.......and do not water quench.

Good luck,

-Mike

Re: Sharpening HSS

Dennis Peacock

>Joe,

All advice so far is good. HSS tools are more difficult to burn the tooling and loose it's tempering. Standard Carbon tools can very easily loose tempering during sharpening.

A couple of things I would like to add?

1. Use only a lite touch of the tooling to the grinding wheel. Unless you are regrinding a profile, a lite touch is all it takes.

2. I use a 6" Delta VS grinder ($39 at lowes) can it came with a white AO wheel and a standard crappy grey wheel. This grinder is both fast and slow speed and has a light on it. An excellent grinder as I have used mine for about a year now.

3. I also use a Tormek for sharpening. It is water cooled and turns at a whopping 90 RPM. For the hobbiest, this is the most expensive route to go. The Tormek and all the jigs needed ran me almost $600.

What's the difference in the cutting edges between the Wolverine and Tormek? Not much.

The Tormek sharpens/grinds at a finer grit than the grinding wheel and gives a more "honed" grinding patteren when compared to the AO wheel. Does it matter to turning? I don't believe so.

Any way....a lathe and turning tools is just the beginning of accessories having their hands in your wallet!!!!

Happy Turning,

Dennis

Yep

TD

>

Right on Fred!

TD

>

I would add

Bill Howatt

>a diamond wheel dresser to smooth out the surface of your white wheel from time to time. The white wheels groove quicker than the grey ones; this is because they are friable.

Bill