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Tamper84
09-18-2012, 04:08 PM
At school the instructor says since hss is pretty much out dated, and we wont be covering it. :( All we use at school is inserts. Anyway, I would like to learn on how to grind them. Besides the south bend book, is there any other resource or how too? I do have some un ground hss out in the shop that I can play with here at the house. Any tips would be greatly appreciated!!

Thanks,
Chris

small.planes
09-18-2012, 04:24 PM
Somewhere on the Sherline site is a good guide.

Dave

Mcgyver
09-18-2012, 04:36 PM
just look around, all old machining texts will have it. Lots of posts here. all you need to understand is rake and clearance angles....then get some and have it. Take a piece 1/4" square mild steel if you want to practice. I would advise to stone them after grinding, sharp tools work better

If find the instructors comment either very lazy or indicative of a certain category of intellect. Cutting tools aren't milk, the don't go bad. A more precise statement might be "in most commercial circumstances and almost all production circumstances there are better materials to use than hss; since that's what you're here for we won't spend time covering hss"

They still work wonderfully and are the right tool much home shop work. The different economic paradigm from commercial shops and the lighter equipment benefiting from the lower cutting forces are obvious reasons....and sometimes its only way to get things done.

Forrest Addy
09-18-2012, 04:44 PM
Your instructor is an idiot for making this one remark. Don't get me wrong. Carbide is 2 to 6 X more ptoductive in a production setting than HSS even when the higher cost per cutting edge is considered. Carbie is a no-brainer for most applications. However HSS should be discussed an hour or and used for a lab session. Not addressing HSS is like teaching grade school pencil and paper math justifying the omission by ubiquitous calculartors or dissing home cooking because everthing is available at the deli.

HSS has a number of advantages for small lot manual machining, applications where where work is slender or unsuported, or where time is more plentiful than tooling budgets like home or small maintenence shops.

Grinding HSS tools is well treated in South Bend's "How to Run a Lathe" and similar older beginner's texts. The grinding wheel commonly used for off-hand bench grinding is generally well suited for free-hand grinding HSS lathe tools. The usual spec is is A-46-O for amuminum oxide, 46 grit, O hardness - V for fitrified is in there someplace too. There may be many numbers and derignations before and after this core spec but they relate to specific refinements to the abrasive, bond, shape etc.

It should be noted that HSS comes in several grades some that are easily ground but less durable as a cutting tool and some damn difficult to grind that last well in long cuts in abrasive materials. HSS is quite a topic for a couple hundred words in a message board. You really should dig out a couple older texts and study for your self.

HSS may be obsolescent but not obsolete. It still has many uses in manual machining. My home shop is quite complete and until recently hummed several nights a week making home projects and small lot machine work for local people. I have a couple dozen HSS tools I use on my home shop lathe as well as a full complement of carbide tooling. My HSS is used about half the time usually for detail finishing: radii, grooves, threads, reliefs, funny shapes like seal entries and hose barbs.

As for your nay-saying instructor, be diplomatic; he may not knw how to use HSS advanatgeously so he scoffs. I doubt if he will be flattered to be exposed as a hopeless duffer for denying HSS as a machine shop resource. Maybe in lieu of confrontation you could submit an extra credit paper or study up and become a HSS resource for your classmates.

Hal
09-18-2012, 04:48 PM
There is a guy on utube that uses a piece of wood 2"x2" , it is large enough to see what he is doing.
It worth a look.

Hal

customcutter
09-18-2012, 04:58 PM
There is a guy on utube that uses a piece of wood 2"x2" , it is large enough to see what he is doing.
It worth a look.

Hal

MrPete I think

Dr Stan
09-18-2012, 05:08 PM
Well I understand how the instructor would come to his opinion as he must meet the demands of local industry, not the small job shop or HSMer. Its unfortunate that some of the skills of yesteryear have virtually disappeared. Drafting by hand for example is virtually gone. So what happens when someone needs to make a quick sketch on the plant floor or the construction site?

At one point scraping was taught to everyone in the trade, but that went away a long time ago so there are very few who can really do it justice. All that aside, I too recommend SB's How to Run a Lathe along with some of the older textbooks. The Oklahoma Department of Vo-Tech (now called Career Tech) produced some excellent manual machining books that included hand sharpening HSS.

Last, but far from the least is my favorite the Machinery Repairman's Handbook published by the US Navy. Chapter 5 is the "OFFHAND GRINDING OF TOOLS AND SELECTION OF CARBIDE TOOLING". You can find the entire manual for free at: http://www.instructables.com/files/orig/FJR/1XC1/HK7EP282OTX/FJR1XC1HK7EP282OTX.pdf

Bookmark the location and print out a copy. You'll find it full of valuable information.

dp
09-18-2012, 05:18 PM
The best way to learn to grind cutters is to use plain steel or wood, or both. Once you learn the basics of shape and function, and assuming you take the time to make jigs, you can apply everything you learned to HSS. The advantage is cost and time.

Forrest Addy
09-18-2012, 05:23 PM
Ah Yes! YouTube. Lots of HSS lathe tool action.

Start here: http://www.youtube.com/results?search_query=metal+lathe+tool+grinding&oq=lathe+tool+grinding&gs_l=youtube.1.1.0j0i5.2828.15016.0.19235.18.15.0. 0.0.0.1297.6079.3-2j1j1j1j3.8.0...0.0...1ac.1.N56vv4dSBeQ

Dr Stan
09-18-2012, 06:00 PM
The best way to learn to grind cutters is to use plain steel or wood, or both. Once you learn the basics of shape and function, and assuming you take the time to make jigs, you can apply everything you learned to HSS. The advantage is cost and time.

steel yes, wood no as it will load up grinding wheels

dp
09-18-2012, 06:04 PM
steel yes, wood no as it will load up grinding wheels

I use a disk sander.

Dr Stan
09-18-2012, 06:29 PM
I use a disk sander.

that will not produce as sharp of an edge as a grinder

loose nut
09-18-2012, 07:59 PM
HSS should be stoned (the tool bit not the guy doing it) after grinding to get the best out of it.

Dr Stan
09-18-2012, 08:05 PM
HSS should be stoned (the tool bit not the guy doing it) after grinding to get the best out of it.

that is correct

elf
09-18-2012, 09:06 PM
that will not produce as sharp of an edge as a grinder

I've found the exact opposite to be true. Why do knife makers finish an edge with a sander?

Dr Stan
09-18-2012, 09:07 PM
I've found the exact opposite to be true. Why do knife makers finish an edge with a sander?

The good ones do not. They use a stone or a steel just like my Dad the meat cutter taught me.

Or even better yet, a leather strop like a barber uses or a leather wheel like a wood carver uses on a chisel.

J. Randall
09-18-2012, 09:23 PM
The best way to learn to grind cutters is to use plain steel or wood, or both. Once you learn the basics of shape and function, and assuming you take the time to make jigs, you can apply everything you learned to HSS. The advantage is cost and time.

I disagree, we had to do that in a votech class, when you are through, what have you got? A look alike that you can't prove out. HSS is not that expensive, start with it, and modify it if you need to, till it works to your satisfaction. When you get the basic grind down where it cuts to suit you, then you can start experimenting with chipbreakers, easily ground in with a small grinding disc, even a dremel tool.
James

vpt
09-18-2012, 09:48 PM
HSS should be stoned (the tool bit not the guy doing it) after grinding to get the best out of it.



I agree. For some stuff (finishing hss) I use diamond stones, nice neat clean finish on the hss = the same on the part.

http://www.horizonsltd.com/images/sharpener-diamond-EZE-LAP.jpg

Chuck K
09-18-2012, 10:20 PM
At school the instructor says since hss is pretty much out dated, and we wont be covering it. :( All we use at school is inserts. Anyway, I would like to learn on how to grind them. Besides the south bend book, is there any other resource or how too? I do have some un ground hss out in the shop that I can play with here at the house. Any tips would be greatly appreciated!!

Thanks,
Chris

I took a machining course at the local junior college and one of the things you had to learn was grinding hss. You had to make the tool before you could use the lathe. I remember thinking what a waste of time it was because I planned on buying and using carbide. I now have a lot of carbide, but I enjoy using hss a lot more. I'm not in a production environment, so time isn't an issue. The biggest loss I see from not learning how to grind your tools is the understanding of the effects of the geometry of the tool. That and the personal satisfaction you get when the c's are dropping off the end of your tool. As the others have said...the books are good. I found a lot of info on grinding and grinding wheels on http://www.chaski.org/homemachinist/. Just don't invoke the wrath of Harold while you're there..im joking.

Chuck

oldtiffie
09-18-2012, 11:31 PM
At school the instructor says since hss is pretty much out dated, and we wont be covering it. :( All we use at school is inserts. Anyway, I would like to learn on how to grind them. Besides the south bend book, is there any other resource or how too? I do have some un ground hss out in the shop that I can play with here at the house. Any tips would be greatly appreciated!!

Thanks,
Chris

The instructor is a bit bigotted and "one-eyed" as while carbide is the major tool of choice for "production" there are plenty of times where "special" and "form" tools made from HSS are best as they can be made and "touched-up" in a matter of minutes.

But many small(er) HSM-er's machines are not robust enough to get all (any?) of the benefits of using carbide tools and so in those circumstances, HSS is the tool medium of choice.

dp
09-18-2012, 11:55 PM
I disagree, we had to do that in a votech class, when you are through, what have you got?

What have you got when you're done? You have an education and jigs. But if that doesn't float your boat then for God's sake, man, don't do that! :) I found I could quickly develop the technique for work holding, angles, and visualizing for a wide variety of tool forms faster because HSS is slow to grind, but obviously it isn't for everyone.

ogre
09-19-2012, 04:25 AM
One of my favorite books that will cover this and much more is Audels machinist and tool makers handybook. About 800pgs. of great info and theres one on ebay right now for $25!!

J Tiers
09-19-2012, 08:25 AM
I've found the exact opposite to be true. Why do knife makers finish an edge with a sander?

The average sanding setup will round over the edge due to flexibility of the sanding belt or even the disk. The very slight "give" of the grains in the disk, or the obvious flexibility of a belt make getting a sharp edge difficult on a cutter, where the edges are closer to 90 deg.

The edge pushes the grains away as they come in contact, moving away slightly from first contact to full contact, which puts a small rounding on the edge. Very difficult to get a true "intersection of planes" finish.

A knife is different.... depending on how sharpened, as it is possible to "strop" an edge with a very flexible "belt" and get a keener edge.

A vitreous wheel is simply not flexible in the same way

vpt
09-19-2012, 08:31 AM
The instructor is a bit bigotted and "one-eyed" as while carbide is the major tool of choice for "production" there are plenty of times where "special" and "form" tools made from HSS are best as they can be made and "touched-up" in a matter of minutes.

But many small(er) HSM-er's machines are not robust enough to get all (any?) of the benefits of using carbide tools and so in those circumstances, HSS is the tool medium of choice.


I agree. I find about 25% of the time I am looking for some sort of "special" grind to fit in a tight spot or down a small bore or something along those lines. I have a few carbide bits and only use them on very hard materials otherwise they stay in the box.

I even used valves for boring bars. ;)

http://img684.imageshack.us/img684/4333/boringbar001.jpg

Tamper84
09-19-2012, 11:34 AM
Thanks guys! I will look into all of the resources that you all have told me about. And I didnt mean for this to turn in to a bashing fest on the instructor lol. He does seem pretty knowledgeable. Thank you all for the help!

Chris

Dr Stan
09-19-2012, 12:53 PM
I even used valves for boring bars. ;)

That's an interesting tip. I'll have to drop in on a local auto machine shop and score a few. They could also serve as a bar to braze/silver solder on a piece of carbide.

Mike Burdick
09-19-2012, 01:34 PM
...I would like to learn on how to grind them [HSS tool bits]. ...


Chris, here's an interesting web page article to read....

http://conradhoffman.com/advancedsharp.htm



.

lazlo
09-19-2012, 04:03 PM
I've found the exact opposite to be true. Why do knife makers finish an edge with a sander?

Custom knifemakers finish their edges a lot like the Conrad Hoffman page that Mike posted: set the bevel angles with a belt grinder, refine the edge with a ceramic stone, and then polish the edge with either a buffer or a strop loaded with abrasive.

Euph0ny
09-19-2012, 04:14 PM
Somebody already mentioned Tubal Cain (Mr Pete) and his four toolbit grinding videos on youtube. Here are direct links:

http://youtu.be/hrDr4rYLiAk

http://youtu.be/dRyqIm5JR5s

http://youtu.be/HTQ46NMMc88

http://youtu.be/rZbr7Sh8jQw

vpt
09-19-2012, 08:02 PM
That's an interesting tip. I'll have to drop in on a local auto machine shop and score a few. They could also serve as a bar to braze/silver solder on a piece of carbide.



When I first showed the valve some one mentioned to just watch out for the sodium filled valves. I guess very unlikely to get a sodium valve however. I was able to cut 4130 with the bare valve. However I do have a bunch of these valves and I already ground another one down but left a shelf on it which I thought I would get some carbide inserts for.

Tamper84
09-19-2012, 08:28 PM
Just a quick question on the valves. How do you know the difference between a sodium valve or a regular one? Just courious. And I have to look at mr.petes you tube again.

Thanks,
Chris

dp
09-19-2012, 08:30 PM
Somebody already mentioned Tubal Cain (Mr Pete) and his four toolbit grinding videos on youtube. Here are direct links:



He likes wooden training tools, too. :)

boslab
09-19-2012, 08:39 PM
At school the instructor says since hss is pretty much out dated, and we wont be covering it. :( All we use at school is inserts. Anyway, I would like to learn on how to grind them. Besides the south bend book, is there any other resource or how too? I do have some un ground hss out in the shop that I can play with here at the house. Any tips would be greatly appreciated!!

Thanks,
Chris
Thats got to be one of the dullest things i have heard today!, i suppose if he needed a form tool he would commission sandvick to produce an insert and holder, he must have deep pockets!, i would love to see his shop, thousands of dollars in tooling!
just follow Forrests instructions they are spot on
mark

justanengineer
09-19-2012, 08:53 PM
HSS should be stoned (the tool bit not the guy doing it) after grinding to get the best out of it.

That depends upon the situation. As with everything in life, there are exceptions to the rule.


HSS is not that expensive, start with it, and modify it if you need to, till it works to your satisfaction. When you get the basic grind down where it cuts to suit you, then you can start experimenting with chipbreakers, easily ground in with a small grinding disc, even a dremel tool.


+1. The scarey part about HSS bits like most tooling is that you can buy a few new for the same money as a bucket bought second hand. If the OP keeps his eyes open via ebay, PM classifieds, craigs, auctions, fleas etc, you can find plenty of deals on HSS toolbits to experiment with. I would second simply using HSS and experimenting as you work on other projects.

To me, offhand grinding HSS is a "must have" skill simply bc of the versatility of it. You can build all of the fixtures you want for a grinder, but eventually you will need to free hand something. Carry that over into sharpening mower blades, chisels, drills etc, and you will find almost endless possible uses for skill in this area. Even with carbide, you still need to understand the fundamentals of cutting tool geometry so that you properly use and regrind it as necessary.

sasquatch
09-19-2012, 09:21 PM
AMEN!! Well said!!

J. Randall
09-20-2012, 12:15 AM
What have you got when you're done? You have an education and jigs. But if that doesn't float your boat then for God's sake, man, don't do that! :) I found I could quickly develop the technique for work holding, angles, and visualizing for a wide variety of tool forms faster because HSS is slow to grind, but obviously it isn't for everyone.

Did not comment on your use of jigs, that is a good idea, stand by my comment on grinding the tool out of mild steel, all you can do is look at it and you still have to grind the real one, the way I look at it you are adding extra time, but my all means as you advised me do it to your own choosing.
James

dp
09-20-2012, 12:20 AM
Did not comment on your use of jigs, that is a good idea, stand by my comment on grinding the tool out of mild steel, all you can do is look at it and you still have to grind the real one, the way I look at it you are adding extra time, but my all means as you advised me do it to your own choosing.
James

Just remember this suggestion is for the student grinder, and even the advanced grinder working on a one off or perhaps two or three off form grinds that will need to be refreshed later. That requires practice practice practice to get repeatability. Another case is grinding involute cutters, for example. Not everything you take to the wheel is going to be a lathe cutter.

vpt
09-20-2012, 08:12 AM
Yup, when I was in school you had to grind your own hss or no turning for you. One guy spent the better part of the first day grinding up one hss bit (3 hour classes). Towards the end of the class I saw him finally making his way over to the lathe. It was quiet for awhile while he set up the lathe to make a pass on some sort of steel we were using to make screw drivers. I heard the lathe turn on, then a little chatter, then BANG, broken hss. lol

Anyhow, I wanted to mention that I will use anything I find that will do the job at hand. This router bit was perfect for the velocity stacks I was turning up for a intake manifold.

http://img37.imageshack.us/img37/4088/porsche003.jpg

Mcgyver
09-20-2012, 12:29 PM
The biggest loss I see from not learning how to grind your tools is the understanding of the effects of the geometry of the tool. That

Now that is an excellent point.

Once the tiny effort is made to understand 1) tool geometry, 2) how speed affects tool life and 3) how cutting force and rigidity work, the return on investment is amazing as these things are the basics of every machining operation. Everything just makes more sense and what's going on in most situations becomes almost intuitive

I started at 12 with a Unimat. As it was the only way to get a cutting tool, every machinist did so, all the books I collected made nothing more of it than any other shop function....and didn't occur that I might not be smart enough, I (like everyone else) just did it. Much the same as no one starved to death before instant breakfasts. Today it sometimes takes on the air of the difficult with beginners sometimes avoiding it. If for no other reason than Chuck's point, it should be where they start.

I think it's just like tying your shoelaces. It's no more difficult and that too once seemed formidable.

Good on you Chris, you'll be a better machinist for learning tool geometry.

Doozer
09-20-2012, 02:00 PM
It is the difference between giving someone a fish,
and giving them a fishing pole. Learn to grind HSS.

--Doozer

J. Randall
09-20-2012, 03:39 PM
Just remember this suggestion is for the student grinder, and even the advanced grinder working on a one off or perhaps two or three off form grinds that will need to be refreshed later. That requires practice practice practice to get repeatability. Another case is grinding involute cutters, for example. Not everything you take to the wheel is going to be a lathe cutter.

Totally agree, practice is what will get you there, no matter what form of tool you are grinding.
James

michigan doug
09-20-2012, 04:29 PM
Why do you suppose there are companies still today, who make high speed steel inserts?

Because sometimes, hss is better for the application. Under some circumstances, you can get a better finish, etc.

Please carry on,

doug

darryl
09-20-2012, 11:05 PM
I've wondered also about how to identify a sodium filled valve, without grinding into it. I have some stellite valves that I've used for making custom cutters. Seems to work as well as some of the hss cutters, maybe better. With this kind of thing it takes time to prepare a cutter, since there's often a lot of slow grinding to do.

sch
09-21-2012, 03:04 AM
HSS does not mind being ground hot, so some color change in the bit will not damage the steel. It is designed to cut at 1000F without loosing its hardness, not that you would want to grind it
at any where near that temp. There is a school of thought, bolstered by a reviewer on the old rec.crafts.metalworking site that spiralled into oblivion >10 yrs ago, that dipping really hot HSS into
water to cool it can induce microfractures at the thin edges, a POV supported by metallurgists at Carpenter Steel, a tool steel specialty company. YMMV, but be not concerned by a little
heat induced coloring near the tip. Another consideration is that smaller bits are a lot easier to shape, ie 1/4 to 3/8" is easy compared to 1/2" or above, especially for threading cutters.
It helps to have a threading gauge and a set of ID/OD radiuses for shaping tool bits for same. A good sharp cutting wheel of high quality ALOx, reduces cutting heat significantly and can make
short work of shaping a bit. A bad or inappropriate wheel will cut slowly and burn your gloved fingers. A tool holder is a nice thing to have along with an easily calibrated angled tool rest.

Mcgyver
09-21-2012, 08:04 AM
There is a school of thought, bolstered by a reviewer on the old rec.crafts.metalworking site that spiralled into oblivion >10 yrs ago, that dipping really hot HSS into
water to cool it can induce microfractures at the thin edges, a POV supported by metallurgists at Carpenter Steel, a tool steel specialty company. .

I remember that, and while he didn't seem to have a lot of support it also seemed an informed and well reasoned view, and he carried on despite the mob reaction it generated.

.....perhaps we would be better to hold the bit with vise grips and let it turn blue...and maybe dunk the other end to draw off heat but not shock the business end

I've not embraced the well reason view into practice because 1) its so much easier to sharpen the bit hand held and you need to cool it to hold onto it and 2) if I was inducing micro cracks I can't say I've noticed it in performance. hss bits last a long time in my experience...then again I don't how long they could last without the quench....or maybe these micocfractures are so shallow they get stoned out.....or maybe i'm cooling it before it gets too hot and avoiding micocfractures.

good to be aware of in any event.

lazlo
09-21-2012, 09:51 AM
that dipping really hot HSS into water to cool it can induce microfractures at the thin edges, a POV supported by metallurgists at Carpenter Steel, a tool steel specialty company.

We've discussed that rec.metalworking thread here many times. My recollection was that when he asked the guys at Carpenter Steel, they told him to dip the tool steel.

The amusing part was when several folks pointed out that all grinders have dip pots, and that most machine shop books, including Moltrecht's Machine Shop Practice, tell you to dip the HSS to cool it between grindings. He said he was going to track down Dr. Moltrecht and ask him why -- the thread stopped there :)

I agree with the point about HSS having red hardness in the 1200°F range, that should make it immune to as much heat as a bare hand can handle.

Boucher
09-21-2012, 10:06 AM
Freehand grinding is good but simple guides produce better-looking results without a bunch of facets. This is one that I made from some HDPE.
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0073.jpg

John Stevenson’s recommendation to use the diamond wheel on HSS and view it as an expendable has improved the quality and sharpness of my tools.

With these grinding guides I Don’t use the overhead water pot but I do wet the table and guide which removes a lot of the heat and prevents the bit reaching a troublesome temperature.

I rough out the bits on the 2X72 belt sander and finish on the grinding wheels.

For grinding good threading tools using HSS cutoff blades I copied this setup from over on the PM Gunsmith forum.

http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0267Small.jpg
The wheel shown is CBN that Evan’s wife got for me.

lazlo
09-21-2012, 04:17 PM
Freehand grinding is good but simple guides produce better-looking results without a bunch of facets. This is one that I made from some HDPE.

Nice job Byron.

Evan
09-21-2012, 04:46 PM
At school the instructor says since hss is pretty much out dated, and we wont be covering it.

That is a ridiculous statement. HSS tools are a part of the arsenal and will address cutting problems that cannot be solved any other way. You should print out this thread and take it to him, privately.

I use everything from carbon steel tooling to diamond, ceremet and CBN cutters. They all have their advantages and disadvantages, uses and limitations.

I'm just waiting for the Russians to start producing tooling with the trillion carat stockpile of superhard diamonds that they just declassified. The diamonds are a different crystal structure created by a meteorite impact and twice as hard as regular cubic diamonds.

customcutter
09-21-2012, 05:24 PM
The good ones do not. They use a stone or a steel just like my Dad the meat cutter taught me.

Or even better yet, a leather strop like a barber uses or a leather wheel like a wood carver uses on a chisel.

Or a paper wheel loaded with buffing compound. Or a 3M belt in the 5-10micron range.

Ken

Doozer
09-21-2012, 08:39 PM
http://i109.photobucket.com/albums/n50/boucherbyron/IMG_0267Small.jpg
.

O.T. -- But,
I had the same problem fitting a box end wrench on the compound nuts
when I had my Nardini. Nice fix.

--Doozer

vpt
09-22-2012, 10:31 AM
Many times I hear the best possible edge is from snapping a bit in half. Like when you shatter a endmill or break a bit off in the lathe. The edge of that break is normally razor sharp.

I know nice formed angles aren't possible this way but has anyone ever tried making cleanish break and turned with it?

Dr Stan
09-22-2012, 07:05 PM
Many times I hear the best possible edge is from snapping a bit in half. Like when you shatter a endmill or break a bit off in the lathe. The edge of that break is normally razor sharp.

I know nice formed angles aren't possible this way but has anyone ever tried making cleanish break and turned with it?

Sounds similar to the process of napping flint for spear & arrow heads. I just do not know how one could control it enough to create the necessary clearance angles.

Evan
09-22-2012, 07:48 PM
The sharpest edge obtainable by any process is the edge of broken glass. The actual edge is one molecule wide. The standard for cutting exceedingly thin sections of tissue for microscopy is the broken glass microtome.

Boucher
09-22-2012, 09:11 PM
The cutting edge left from finishing with either CBN or a fine Diamond wheel is very good (almost like a mirror finish). If one is set up with guides and the table is left at the correct tilt, it only takes a second to refresh an edge. Try it , You will like it. The fact that the Tangential tools cut so good is related to the simple accuracy of their sharpening fixtures.

RLWP
09-23-2012, 04:23 AM
The sharpest edge obtainable by any process is the edge of broken glass. The actual edge is one molecule wide. The standard for cutting exceedingly thin sections of tissue for microscopy is the broken glass microtome.

You can make some splendid scrapers for wood that way too

Richard