Stephen Myhre´s Tools Question

[Sebastián Urresti]

Dear TCP folks:

As I am not an english born speaker I am having some problems with the descriptions made in Stephen Myhre´s book on how to make two bone carving tools. So, here is the question: Does any one made one of these? Could be possible to have some extra pictures, beside the ones that Janel posted, with other angles of these tools? I am not capable of making them and "see" the shape and each face. I see the pictures and I can´t figure them out.

Thank you very much,

Sebas

[toscano]

Sebas,

I made two of these tools recently. I have some pictures of them, but I would be more than happy to take more if the shapes are not clear. I took these pictures right after rough-shaping them so there's a lot of colouration and roughness there. Janel, do these look about the same as yours? Myhre's book was a little unclear for me too, so these are what I believe he was talking about, but I may be wrong.

 

-t

[Sebastián Urresti]

Dear Toscano:

THANK YOU VERY MUCH!!!! That was the third face of number one that I couldn´t see!!!!! The one that unite the other flat faces!

Phew, that was a fast answer!

One question, could you solve number two? Getting greedy here

Thanks again,

Sebas

[Janel]

What is the second question?

 

Tassos, those are useful tools! My version has a more rounded third edge. The Stephen Myhre tools that were gifted to me are more like what you made. There is no right way really, the uses will vary with the shapes and sizes of the tools. The initial inspiration was from stone-stonecarving tools. We get to grow from that beginning.

 

Sebas, try this description: Make the round stock as a triangle, three flat and equal faces. Choose one face to angle or curve, and use the whet stone or grinding wheel to change that angle. My tool's third face is rounded, so that I have a rounded scraper edge to use, and a pointed edge for undercutting, and a flat and slightly curved edge opposite the rounded bottom face. Oh dear, it is getting tricky now.

 

The third face, the one that connects the left and right faces, can be flat or rounded. Different shapes and sizes make handy tools. I have tiny ones, using 1/16" stock, to 1/4" stock. Very handy.

 

Does this also help?

[Sebastián Urresti]

Dear Janel,

When the student is ready the master appears...

OF COURSE THAT HELPS! But I am a slow reader, tomorrow I will follow your instruction on the faces´ use. I finished mine and I´ll post you a picture, it´s exactly as you describe it and exactly as Toscano´s photos.

The second question is about the number 2 tool... Still working on that one.

Hughs,

Sebas

[Joe Aimetti]

Hello all-

 

Those were nice pictures of making those tools Toscano. Kudos to you.

I am fortunate enough to have a Sherline mini lathe and milling machine, although still teaching myself to use them. I can see where this might come in handy if I wish to make small, precision tools like that, although I have made some out of sewing needles by hand with one of my Dremel tools(BTW- Did you ever mount them to a handle and try them out Janel ?) Sewing needle steel is not the best material for cutting tools, but will work when used on a smaller scale. I also buy pieces of spring steel round stock from the hobby store and grind away what I don’t need on them . ;^) Trimming down exacto knife blades work good also. I use old drill bits I get at flea markets as a source for tool steel to grind up.

 

I do have a question though: On the picturers of the last tool you made, you showed the discoloring of the steel due to the heat of the grinder. I know you are using HSS, but would getting the steel hot enough to discolor it degrade the hardness and edge holding abilityof the steel?

Just curious.

 

Again, thanks for the instruction.

[toscano]

Joe,

From what I understand about HSS, a little colouring shouldn't affect the edge.

It's best to avoid it altogether of course so a small container of water where you regularly dip the tool is advised.

I may have been a little too impatient with mine though the cutting edge does not seem affected.

 

Any metal workers out there with a more learned view?

 

cheers

-t

[Joe Aimetti]

OK , I might have found the answer to my own question. Here is a reply from a metal working forum answering a question of grinding HSS until it gets too hot. I believe I was thinking of tool steel but read on:

 

From: "Ed Huntress" <huntres2@optonline.net>

Newsgroups: rec.crafts.metalworking

Subject: Re: Flycutter from hell?

Date: Fri, 18 May 2001 02:51:53 GMT

 

Never, ever, ever. Change your thinking on this quick. High speed steel is

tough stuff, but it can't tolerate that kind of thermal shock. Neither can

most other high-alloy tool steels -- and the low-alloy and straight-carbon

types (O-1, W-1) can't take the heat to begin with.

 

I use water to cool mild steel when I'm grinding it, and I'll do it on

woodworking chisels and plane-iron blades, which I never let get hot enough

to show color, anyway. My good ones are never allowed to get too hot to

touch. At those low temperatures it's not much of a risk and water dips

speed the operation a lot.

 

But you can't grind HSS very well without getting it hot. It can take the

heat, right up to a low red glow. What it can't take is thermal shock.

 

OK, Jack, let's take a closer look at this. You're grinding a material

that's designed to *cut* at temperatures as high as 1,000 - 1,100 deg. F

(higher for cobalt HSS). It won't be damaged, annealed, or otherwise

affected by temperatures below that. But it will develop surface cracks like

crazy if it's cooled too quickly, even from temperatures well below its

annealing temperature.

 

The material contains 10 - 15% carbides: chromium carbide, iron carbide, and

tungsten carbide. If you grind it slowly, those carbide particles stand

proud of the matrix and grind your grinding wheel. It's a tug-of-war. Your

absolute rate of wheel wear will be low if you grind gently, but your

relative rate of wear will be higher. In other words, you waste grinding

wheel by grinding HSS slowly.

 

To grind HSS effectively you have to use enough pressure to work on the

matrix that holds the carbide particles. That's what it takes to grind HSS

quickly and efficiently. Because you're applying a lot of local pressure

when you do that, it's hard to avoid gouging the wheel locally. Its relative

wear rate will be better, but it will lose shape, and the net effect is a

toss-up, in terms of how much HSS you can grind with a given amount of

wheel.

 

If someone has told you to grind HSS this way, he or she never learned about

the properties of the material or of the results of 100 years of shop

experience. I see absurd recommendations on this and many other subjects on

the web and sometimes in print, by people who have done things some odd way

for 20 years and who claim to be "experts". They were never taught right,

either.

 

So, grind HSS slowly if you want to. As you say, one of the pleasures of

doing this for a hobby is that we don't have to worry about production

rates. But be careful about the implications of what you're saying. To

water-dip HSS between grinding passes is not a wise thing to do. If you're

grinding so slowly that you're not heating the steel beyond the temperature

at which you can hold it, you probably won't have any problem. But that's

not the way HSS is usually ground. If someone heats it up by grinding with

firm pressure, and then dips it in water a few times between passes, he'll

wind up with a lot of chipped and broken tools. And he'll never know why,

because someone told him that the books say to dip it in water between

passes.

 

Ed Huntress

[Phil White]

Hi Joe,

 

You did answer your own question, more or less. HSS was designed to be used on high speed cutting tools, such as drills, milling machines, and tool bits for lathes, where friction will heat the tip up well past the tolerances of most carbon-based tool steels. It will hold an edge at a very high heat, without loosing it's temper.

 

I would add a further note, if you are using recycled tools (drills) to make tools. Usually the shanks of the drills are not hardened, and if re-ground into small tools you won't be getting the benefit of the toughness of the steel. Same thing with the spring steel you find at the hobby store. However, spring steel can be easily hardened and tempered after you have ground (or filed) your tools to shape, whereas HSS can't, at least unless you have a furnace.

 

You might check out the tutorial that I posted on hardening and tempeing steels, in the metalwork section.

 

Best regards,

 

Phil

[Joe Aimetti]

Hi Joe,

 

You did answer your own question, more or less. HSS was designed to be used on high speed cutting tools, such as drills, milling machines, and tool bits for lathes, where friction will heat the tip up well past the tolerances of most carbon-based tool steels. It will hold an edge at a very high heat, without loosing it's temper.

 

I would add a further note, if you are using recycled tools (drills) to make tools. Usually the shanks of the drills are not hardened, and if re-ground into small tools you won't be getting the benefit of the toughness of the steel. Same thing with the spring steel you find at the hobby store. However, spring steel can be easily hardened and tempered after you have ground (or filed) your tools to shape, whereas HSS can't, at least unless you have a furnace.

 

You might check out the tutorial that I posted on hardening and tempeing steels, in the metalwork section.

 

Best regards,

 

Phil

 

 

Hello Phil-

 

I will be sure to check that out, and the info on the surplus tools. I have a mini lathe and a selection of blanks for making my own cutters , which I have done so in the past. I would guess from your answer that they are HSS.

Well, I learned some more today!

Thank you again for the info.

 

Joe

[Don The Carving Glove Guy]

Stephen, I use a bench belt sander to sharpen with. I use the back side of the sander where the belt goes up away from the tools not down into the tool being sharpened. I altered the back side in a couple of ways. First I added a surface on the back under the belt to push against. Second I mounted a wood block on the long base that maded a point that other items could be mounted to. In my case I took a small pc of 2 x 4 and bolted it to the base. I then drilled a hole thru the block a added two links that went to a second pc of 2 x 4. The links were hooked with threaded rod and wing nuts so that I can adjust the second block to the sanding belt. I mounted a small ketchen funnel into the surface of the second block and now when any tool is put into the funnel I find the center and am able to rotate the tool and set the sharpening angle. ( I wish I were home to send a picture.) With this set up I can sharpen any surface to any angle I want. I can remove the tool from the sharpner, inspect and replace without changing the angle. When the tool looks sharp I buff the surface to a high luster and test for sharpness. This method has worked great. I use 20 deg for most tools when carving bass wood. 25 degrees when carving harder woods. You can try anything you would like.

I will send a picture later (end of march when I get home)