Grinding HSS tools

[Tinkerer58]

I have read a number of conflicting thoughts on grinding your own HSS tools all relating to over heating the HSS during the grinding process stating that it ruins the tool. To avoid this I am considering using my other grinder that I use for sharpening wood turning chisels. It has an ali oxide wheel that has a water bath under it to keep the wheel wet. I was going to modify it and make a suitable tool rest. The water bath should prevent the HSS from over heating. I would love to know your experiences and thoughts please.
I just hope this subject doesn't set the cat among the pigeons as it looks like it has potential for heated debates. Sorry about the pun LOL.

 

[Swifty]

Should work well, most of the bench grinders that we use to grind our HSS toolbits have to also do day to day grinding of everything else. The grinder that you propose to use is dedicated to grinding hardened tool steel.

Paul.

 

[Hopper]

Been grinding HSS toolbits on ordinary bench grinders for 40 years or more at home and at work and never a problem. Usually keep a tin of water next to the grinder and when you feel the toolbit getting hot on your fingers, dip it in water and swish it around a bit.

 

[Tinkerer58]

I'm just wondering the problems some are experiencing is to do with the crap Chinese and Indian stuff we tend to get a lot of here. Every foreigner that lands on our shores want to start a business importing their crap from their home country, seen an Indian run shop selling cooking pots, I think they were made from re-enforced tin bloody foil with with brass gilding on handles, absolute sht at premium prices.

 

[Mainer]

If it's decent HSS you will have to work really hard to anneal it. HSS's big advantage over carbon steel is "high red hardness," i.e. even if it gets hot it won't anneal. Annealing HSS requires a temperature-controlled oven and a specific heating-cooling cycle. You won't come close to what is required by grinding it.

In other words, don't worry about it.

 

[Swifty]

As tinkerer58 already owns the water cooled grinder, there is no loss in trying it out. I believe that most of the wood turning chisels are made from carbon tool steel, hence the care needed when grinding them. Made my late father a HSS tipped wood turning chisel years ago, really held an edge well.

Paul.

 

[gus]

Been grinding HSS toolbits on ordinary bench grinders for 40 years or more at home and at work and never a problem. Usually keep a tin of water next to the grinder and when you feel the toolbit getting hot on your fingers, dip it in water and swish it around a bit.

Hi Tinkerer,
I agree with Hopper. Been grinding HSS till it turned blue and yet cut OK.
Been doing this as a 18 year old lad doing his Trade School in 1961.
Been using the Chinese HSS. They are not too bad though not as good as Swedish HSS. Too cool faster between grinding,I use cold water with ice cubes thrown in.
Now started using HSS inserts from Warner,USA.They are good stuff and worth every cent paid for though very expensive.

 

[Paulsv]

If your water-bath grinder is anything like the Tormek grinder I use for my woodworking tools, it'll take all day to grind a lathe tool from a blank. It is a slow moving wheel, with, at its roughest, a 220 grit finish. I can use it to touch up an edge, but it is too slow for any shaping. The little bit you can take off in a reasonable amount of time with it could be done on a bench grinder in a lot less time than it takes for the steel to heat up.

 

[Tin Falcon]

Hmmm I would say there are a number of factors in keeping tools cool when grinding.

M-2 tool steel is the standard.
added cobalt helps with red hardness but is also harder to grind.
Quality of the steel - in general a name brand better than Chines import.


The wheel
IMHO norton is the standard for brand.
I expect less from imports from asia.
Gray alox is a general purpose wheel and the least desirable for HSS
but gray alox works fine .
I used import gray wheels for years.

White wheels are made for HSS and not terribly pricey.

The latest and greatest but IIRC 2-3 times the price is the new blue wheels designed to keep the tool cool and last 3x as long as a white wheel.

Green wheels are for carbide .

wheel binder one does not need to worry about this just read above.

wheel grit. Rough with a course grit like 40- 60 and finish wit 100-120 then stone with a oil stone.

IIRC all whet stone grinders I have seen are for fine finishing at low rpm fine stone and water cooled. Some have a second high speed roughing stone.

So advice buy the best tooling and grinding wheels you can afford.

Will Chinese tools ground on a Chinese gray wheel work ? yes of course. will a Chicago Latrobe tooling or blanks from Warner tool ground on a Norton blue wheel work better . Again yes of course but also expect to put out several times the cash.


What I use? I used import gray wheels for 12 years. that is what came on my jet grinder. IIRC about a year ago upgraded to white Norton wheel.
Vast improvement but one needs to keep other famy members for uing them for general grinding. DAMHIKT
Bits I use everything from Chinese import to top america brands.

If I had to pick one vendor for HSS it would be the Warner Company Latrobe PA. My favorite but more money than imports.
Tin

 

[gus]

A freshly ground HSS cutter will not give a good finish.Diamond honing file removes the rough
edges and sharpens to razor sharpness.
Together with dobbs of Tapmatic Tapping Fluid.at 600 rpm,1---3 thou depth cut and fine feed,I get good surface finish even if material is SAE Grade 5 Bars.

Just bought a couple of Japanese Diamond Honing Files from TokyuHands,Osaka,Japan.TokyuHands is fatal to my pocket if I hang around too long. Just bought some quality four facet Nachi Drill bits.

 

[lennardhme]

I use a bench grinder to shape the bit, then my wetstone Tormek to finish & sharpen. Dont need to hone as you wont get a sharper finish [ a boon on smaller lathes & for a top finish ] repeateable, & removes the min. of material.
Wouldnt use anything else.

 

[robcas631]

Well said Tin

 

[n4zou]

The trick is never allowing the tool to turn any colour while you are grinding it. Grind a moment and then plunge cool it in water. Don't get in a hurry and take it slow and easy. If you do give it some colour while you are grinding it you'll need to grind that colour away as that coloured metal will not cut properly. Free hand grinding tool bits is an art that must be learned through practice and experience. While I was in trade school we were given 1/2" square, hot rolled steel which we ground into tool bits. If you ground it properly it would cut aluminium as well as real HSS bits would cut steel. We would grind our hot rolled "tool" bits and then cut aluminium with them. After the instructor certified our ability to grind tools we received real HSS tool blanks to use from then own. To this very day I still use hot rolled steel for cutting aluminium instead of HSS steel for several reasons. It cuts just fine, it costs a lot less, and it's so much easier and faster to grind than HSS.

 

[Tinkerer58]

Thank you guys for all the input it's really appreciated. The wet grinder does have a smaller grey wheel that runs at higher speed, the large white wheel is run through a gearbox. So with a few tool rest mods I'll use the grey to shape the tools and white to finish. I'll have a play with it all to see which gives the best results. I have noticed that the HSS from India is just crap, the Chinese is far supperior, but obviously US, European, JAP and Aussie HSS is just soo much better. They just seem to keep their edge longer.

 

[gus]

Hi Lennard,

A wetstone is a good idea. Diamond files will wear off. Please advise wetstone vendor.

 

[Tin Falcon]

Gus I believe Lenard is using one of these he will have to tell you the model.
the Japaneses water stones are dear at $250 each but with care should out last the operator.

IMHO Sharpening supplies.com offer good value and ships fast htis is the place I purchased my Norton white stones.

Tormek Sharpenter
This one pictured is about $380 plus shipping.

Tin

 

[cidrontmg]

Hi Gus, the Tormek sharpener is top quality, Swedish and pricey, but there's also a German Scheppach "wet whetstoner", at
http://www.scheppach.com/en/produkt...-2500/backPID/werkstatt.html?cHash=cc0c7f0e79

 

[Tin Falcon]

sears has the 8" version for $124 wtih free shipping to the lower 48 i expect. not bad.

http://www.sears.com/shc/s/p_10153_12605_00935878000P?sid=IMx20120601x002000-Tools-active
Tin

 

[Niceonetidy]

I have been told by a commercial grinding house where I get special form tools that you can get hss steel very hot, but never quench. Aparantly it's not recommended for some reason.

Then fine finish the edge using an Arkansas stone. They are super hard, and very fine grit

 

[Tin Falcon]

The idea is to keep the tool cool while grinding through the methods that were listed. getting it hot then quenching can shock the metal.

we do not want to get it that hot. like others have said hold in your bear hand when it start to get warm cool the tool.

Tin