what type of steel for making woodturning tools?

I want to attampt to make a wide scraper for woodturning. I figure I'd obtain a blank of tool steel about 1 1/2" x 3/8" x 6". I'd weld on a handle, and carefully grind (without overheating) to get the shape I want. I want it to hold a cutting edge as long as possible, obviously.

My question is- what type of steel blank should I use? Since I can buy the tool I want for about $80, I'm looking to spend far less! I have a mig welder, abrasive chop saw, and oxy-acetylene torch. And lots of suitable stock for a handle

I see suitably sized blanks on ebay- there is "low carbon steel", O6, O1, S7, A2, 4142 HT, 4140, etc..

Will I need to heat treat whatever blank I get? If so, what would be the process?

Sorry for the naive questions- I just don't know a thing about types of steel, or treating. I'm sure this is a very complicated topic, but perhaps someone can give me a guideline.

Lynn, the first thing I'd do is see if my local library has any metalurgy books. As far as welding a toolsteel end on to a mild steel I wouldn't. The amount of untempered martinsite in the weld zone would scare the crap out of me on a scraper that I would be using on a wood lathe. Plus are you talking about the width being 1-1/2" or 6". One option you could try is get some 3/8" High Speed Steel Tool Bits and Sliver Solder them on to the handle. The amount of heat really shouldn't mess up the hardness to much and you won't have to screw around with heat treating. Besides if you make the tool and heat treat it the only options that I would assume you would have are a Water or Oil hardening tool steel. If you really want to do that I'd say go with O-1. You can buy O-1 in the widths and thicknesses that are right in the ball park that your talking about. Oh screw it if you can afford the tools you've got and the computer/internet and every thing else just buy the damn thing and be done with it.

Lynn, here's an idea that might work for you.

Buy a larger HSS cut off blade, T type that is used for parting metal, and cut into the width you need. Then make a metal holder with a slot cut across it that will allow the "T" part of the blade to fit snug and a top (tap and bolt) that will act like a clamp - you get the idea . Note that the slot for the "T" will prevent the blade from moving side to side. Then sharpen the other side to whatever shape you want. One cut off blade will make a number of "replaceable" shapes!


Just a thought.....Mike

[This message has been edited by Mike Burdick (edited 01-21-2003).]

Use an old dull file of good quality,grind to suit. Temper most of the length toward the handle. (polish brite, and heat slowely to first straw , then quench)Ross

[This message has been edited by AlfaGTA (edited 01-21-2003).]

Hey Lynn
I do the same thing as you. Here is how. I buy A-2 tool steel in what ever size I want. Cut it to the proper length, grind a tang on it and rough in the shape that you want on the end. Send it our to the local heat treating company and ask for 55-60Rc and a vacuum process. They will come back to you a pretty gold color. If youdo several at once you will come out ahead of the game.
Good luck
Fred t

If you are more interested in turning wood than in making tools you should buy the tool for the $80 or shop around for a used item. If your time is worth anything you will cost yourself more than that to make the tool. If you make the scraper I think you should use "high speed" steel which has tungsten in it among other things to give the edge strength and hardness even when very hot. This is the reason it is called high speed steel. In my experience it is easy to overheat wood chisels since you are not using coolant and unless you like sharpening things the high speed steel is worth the cost. Silver soldering the high speed steel to something softer to serve as an extension and a handle will not hurt the high speed if you do a good job with the silver solder. If you have a way to grind tungsten carbide you can silver solder a piece of that to a mild steel bar and have a very long wearing wood scraper. The cost of a pretty big piece of tungsten carbide is not outrageous and if you are going to build a tool you might want to build a super good one. Another idea with tungsten carbide is to do the solder/braze onto the handle and then take it to someone with a wire EDM and let them put on any fancy contour you want. You can probably get that done for the minimum charge. You might be out more than $80 but you will have something to be proud of.

Get a leaf spring, 3/8 thick you better check out the truck shop, odds are they have a broke stack that's free for the taking. Odds are this steel will be either 1095 or 5160.

Torch off a chunk, grind back from the torched ends about 1/4", preheat to dull red and weld it onto shank. I'd use 6011 but the mig will work. After welding let cool out and heat to full red, hotter than dull red but not to austenitic and let cool out again.

This weld zone can be improved by forging, when steel is heated above it's austenitic point grain growth occurs, forging helps refine the grain structure. Packing is another name for this.

Shape tool, mill it, file it, grind it or reheat and forge it out. Getting it blue won't hurt since it is soft yet, not hardened.

Once tool is shaped then comes the hardening part. These leaf springs are going to be oil hardening, but you aren't going to know the exact hardening temperature nor have a thermocouple built into that torch. There is an old trick of using a magnet, steel looses magnetivity when it reaches the austenitic point, so have a magnet handy. Quench this steel in HOT oil, and don't use motor oil it will flash, used motor oil is worse. There is commercial heat treat oil, hydralic oil also works well because of it's higher flash point. I would probably not harden the complete tool, just a few inches of the end. Selectively hardening is easy when using a torch, not so easy with a furnace.

Once hardened this steel needs tempered, purple is the color I would heat to, might go a bit more and go full blue, just depends on the shocks this tool will be subjected to.

Lots of books on blacksmithing and heatreating to be had for the purusing.

Used leaf springs are cheap, a bit of gas for the torch, if the first one breaks make another. Practice makes perfect, and I'd suggest some practice runs on the heat treat. Stick the result in the vice, check it's strenth, hit it with a hammer, see if it breaks. If it breaks temper at a higher temperature.

Do the practicing with some scrap pieces, not with the finish shaped part.

Have fun and work safe.

Great info here!

Yeah, it would probably be more cost effective to just buy the scrapers I need, but the real point here is that I want to learn how to make tools and heat treat steel. I like halfnut's approach- free materials, and experiment until I get it right.

If I can figure out how to do this, there are a number of lathe tools I'd like to make. After looking, it is more like $120 for the kind of scraper I want, so making one looks more and more appealing.

I am definitely guilty of working on my shop and my tools more that I work on actual furniture...

Mike burdick: "Buy a larger HSS cut off blade, T type that is used for parting metal"- I don't follow. What sort of HSS cut off blade are you referring to?

[This message has been edited by Lynn Kasdorf (edited 01-22-2003).]

AlfaGTA- I've heard of grinding an old file for this purpose, but it is also regarded as dangerous, as the file can shatter.

Is your suggestion of tempering to make it less prone to shattering?

And I wonder if you could elaborate a bit on the process:

Polish brite: how? wire wheel?

Heat slowly to first straw: heat with a torch until it turns straw colored?

Quench: in water? oil?

After all this, would it be a good test to whack it with a hammer to see if it shatters?

Thanks

Lynn,

I kinda got long winded with technique and such. You asked a question about files and tempering and such. Here's a breif on heat treating and steel.

Some grades of steel are heat treatable, some are termed alloy steels and have numbers behind them such as 1095 and 4140. Others are in the tool steel class and have names as such, O1, W1, D2, A6, etc. These tool steels have been standardized and thus classed. Used to be that the various steel companies sold steel under there own names, such as Vega, Hampen, Oil Tough, etc. these by the way are the old Carpenter names.

Each of the tool steels has it's own particular charactaristics and are used for specific purposes, while one steel might suffice for all purposes, another might have better charactaristics for the job in hand. Some are tougher than others but not as abrasive resistant, others keep their shape better during the heat treat process, others maintain hardness at higher temperatures, and on and on.

Steel furnished from the steel mill comes in various states of hardness, usually it is unhardened.

Hardening consists of heating to a critical temperature and then quenching in a medium of some sort. Some steels harden in air, others in water and others in oil. Once hardened steel is stressed and brittle, can break like glass. To relieve an amount of these stresses a process called tempering is done, often called drawing. This tempering is achieved by again raising the temperature of the steel, how much softening is done is determined by how hot you heat it. Different steels are affected by tempering differently. A temperature which will soften a high carbon steel won't affect a High Speed steel, different alloys etc.

Steel changes color when heating, this is actually an oxidation, certain colors emerge at certain temperatures. To see these colors best it is necessary to remove previous oxidations, buffing with a wire wheel won't quite do it, need to polish with some emery paper or grind with a wheel.

A file is left in nearly as hard a condition as posible, thus they are brittle. Usually you need to draw the temper some more, straw emerges about 375 degrees, gets darker and turns brown, then to the shades of blue as the temperature increase. How soft you want to draw the temper to just depends on the application.

Get thee to a library or find a local blacksmith to converse with. Look in the library for a book such as Shop Work on the Farm, older books such as this often had a good basic simple section about heatreating of simple tool steels.

Outstanding!

Halfnut, you have cleared up a great deal. I'll see if my local library has any related books.

Thanks

old dull worn out files are great, it can be ground and forged to shape tempered and harden as good as anything and will do wonders in wood.
i worked in a foundry pattern shop for years and thats what i used.