Making Plane Irons for wood planes?

[Karl Krauter]

I've been lurking for a while now, decided to get a user name last fall sometime. Anyway I've done some searching on making irons and haven't come up with much, I did find one thread about making irons for students but it wasn't what I am looking for. I apologize if I am asking something that has been answered.

Ok so here is the question, has anyone made irons and chip breakers for krenov style planes? I'm not to worried about the metalergy portion (read further), mainly looking for design and any pitfalls issues.

I have 2 friends that are blacksmiths, one of which is a machinist and blacksmiths professionally. Both of them are very interested in the project and have dealt with with O1 steel. Actually they really want to make there own planes too. I have not built a plane before, but after reading David Finck's book am not intimidated by the prospect.

One last thing, I'm not a complete newbie to woodworking, I'm maybe an accomplished newbie. Mostly have worked with poplar and pine, and a little with western juniper. I'm just trying to build up my tool collection, since my friend who got me into woodworking and hand tools moved away with all his tools. Hence wanting to build some wood planes.

Again sorry if I am out of line on the question.

Karl

[Brian Kent]

Karl, welcome. I've made a few planes but certainly don't have the tools or skills to make the irons. Good luck on that one and post along the way.

Brian

[David Gendron]

There is a few Creekers that did post about plane making involving irons as well... I f can remenber, they mostly used thick steel and didn't bother with a chip braker. An other option would be to get a set of Hock iron/chip braker assembly and go from there, his stuff work realy well, so I'm sure you could use that as an idea!!

[Larry Williams]

Why a cap iron? They cause more problems than they solve. When those who repeat the mantra about cap irons being an improvement, they always fail to mention the fact that cap iron planes were historically always common pitch planes. Try and find an old double iron plane that isn't common pitch, if you doubt what I'm saying. The only old double iron planes at a steeper pitch I've ever been able to find are a very few Slater infills. Slater made custom planes as well as offering kits and I suspect those I've seen were craftsman made kits. The traditional cutting geometries of York pitch, middle pitch or half pitch are far more effective at dealing with difficult or figured grain than cap irons. The British double iron planes were almost always bedded at 47.5º while American double iron planes are 45º. I consider them both common pitch.

[Michael Faurot]

If you, or your friends, all ready know how to do the metallurgy for O1 tool steel, then making blades is pretty straight forward. As others have mentioned, you don't need a cap iron, just use a thicker piece of steel. This simplifies both the construction of the plane and its use. So now all you're dealing with is a rectangular piece of metal with a bevel on one end.

[Steve knight]

yes chuck the chip breaker. I have made over 3500 planes and never had anyone say they needed one.
but 0-1 irons don't take much to make. cut to length grind the basic bevel get them hot enough so a magnet does not stick dunk in oil and throw in an oven at 300 for a hour or so and your done. use 1/4" for less warpage problems.

[Bob Glenn]

Karl, I made three plane irons from A2 steel, (see A Plane is Born in Neander). If I had to do it again, I would use O1 steel since heat treating A2 requires a special oven. I used 1/4 steel a chip breaker is not needed. One other tip, if you grind the bevel on the tool steel, be careful you don't over heat the steel because you will work harden it and it will get harder and harder to grind. I ended up cutting the section I ground off then milled the bevel. You could also cut the bevel with a hack saw.

[Karl Krauter]

Thank you everyone for the information. Looks like I will be ordering some .25" O1 and ditching the chipbreaker. I was just going from David Finck's book, so that is why I was worried about chipbreakers. I will try to do some photo documentation for the project, at least the metal end of the plane. I'm sure you guys have seen plenty of newbies hack up some wood and call it a plane.

Again I greatly appreciate everyone's input.

Karl

[Sam Takeuchi]

Yes, pictorial will be greatly appreciated. Just be careful when you heat treat your blade. Safety first!

[Karl Krauter]

Yes, pictorial will be greatly appreciated. Just be careful when you heat treat your blade. Safety first!

I'll be watched carefully by the pro's, I'm sure we will do a test run with a couple pieces. Then go into production. Hopeing to make around 20 blades. One of them would like to laminate some blades, as he had watched at a blacksmith conference. We'll see how that works too.

karl

[Karl Krauter]

Are there any preferences for length. For the krenov style plane it looks to be kept short. Any reasons for not doing this?

[Kevin Lucas]

I just checked Wooden Planes and How to Make Them by David G Perch and Robert S Lee and I cannot see any thing for length. From most of the drawings it SEEMS to be body height, plus wedge height and add about 2 inches? That should give enough room for a hammer to tap the iron for left and right alignment.

I have a relative that wants to give me a forge and so tempted to try my own irons. Can't wait to see how yours turn out )

[Andrew Recher]

This is something that I've been wanting to do for a while (planes and plane blades). I've forged a number of knives in the forge I'll describe below but haven't gotten around to the plane blades.

Your doing the right thing by going with purchased O1. There's a lot of scrap carbon steel out there but you can't always tell what you have and it sometimes requires a little experimenting to get it to harden properly. If you can harden it at all. The couple of plane blades I did try to make I used old lawnmower blades for the steel but I couldn't get them to harden. In my opinion it just isn't worth the time using unknown ( though I have had pretty good success using some old rotary hoe tines from old ag. equipment. From my experience, Steve Knight's advice above is pretty much right on the money.

I built a small forge that works really well. It's based on a design by Tim Lively. It uses all readily available parts from the hardware store. The tub is filled (sloping down to the pipe to form a v shape) with a mixture of hardwood ash and clay (soaked kitty litter, unused preferably) and allowed to harden. I used a hair dryer for the air source for a while but I now use a small squirrel cage from a bathroom fan. I usually buy 20 lb. bags of hardwood lump charcoal for fuel (not the presssed briquettes) though when I started out I used wood and just made my charcoal as I worked (it's a lot smokier that way though).

It gets quite hot, too hot in fact, if you blow the air too hard or walk away too long you can burn the steel pretty easily. It does take some practice to get a nice even heat over the entire piece. Some smiths will bury a piece of iron pipe in the coals to place the blade into. That helps to even out the heat.

Hope you'll be able to share some pics, so that those of use without much extra time for our hobbies can be jealous.

Andrew

[Jonathan McCullough]

This may seem too simple, but has anyone tried taking two inexpensive store-bought plane irons, and epoxying them together?

I'm serious. Think about it. What makes a plane iron work is that it uses two surfaces--the back and the bevel--to create a single cutting line. That's true whether the plane iron is 1/32" thick or 5" thick. What makes the thinner plane irons disadvantageous is that their lower mass takes less energy to make them resonate, i.e. vibrate, in other words, "chatter." You can reduce this chatter in one of two ways--add mass, or find a structural way to pre-stress the iron. Using a thicker blade adds mass, and using a chipbreaker not only adds mass but also puts tension on the iron itself.

All things being equal, nothing would beat the mechanical adhesion of o-1 tool steel to itself. But two plane irons epoxied together would add mass, wouldn't interfere with the business end of the cutter, would provide a slot for the chipbreaker screw if you wanted one, and would cost a whole lot less ($6 where I live for two irons) for an experimental wooden plane.

You could silver solder them together using the technique Bob Smalser used for his high-angle smoother, but at those temperatures (700 degrees?) you may be messing with the temper of the steel. So why not epoxy? Why not?

[Sam Takeuchi]

Even before going into epoxy stuff, the main problem with those cheap blades is that they are soft and don't hold edge well. I suppose heat treating them prior to epoxying them together may be necessary. Especially considering the fact cheap store bought replacement blades nowadays are made from suspicious quality steel.

But if heat treating is required, then it's not too much more expensive to buy a bar of O1 to make solid blades, and even have choice over the kind of steel you use.

That aside, I don't know how well epoxied blade would perform. Personally I wouldn't bother with junk quality blade. For $6, you are probably better off buying a tapered laminated blade for wooden planes.

[Alan Schwabacher]

The chip breaker is fairly effective at making a thin blade behave almost as well as a thicker one. It essentially allows two thin blades to pretend they are one thick one by pressing down near the edge to hold it steadier, without epoxy. That seems to be the major role of a chip breaker: allowing cheaper blades to behave better. But if you are making your own, they might as well be thick.

[george wilson]

We got the blacksmith's shop to make most of our plane irons. They were,however,in the habit of using 1070 carbon steel for the welded on bits. It was better to weld with than the more premium 1095.The Cooper's shop had a hard row to hoe. They always used white oak for barrels,and had no heat in their shop. They came and asked me if I could help them out with a longer lasting blade for their long cooper's planes. their blades were 4" wide.(we had already made some long cooper's planes for them. Their old planes suffered quite a bit from white oak being shoved over the same spot year after year.)

I made them some A2 steel blades. They held up MUCH better,and we hand forged them. They were undetectable from more authentic bitted blades.

A2 will get a soft skin if gotten hot and exposed to air,so I had to work out a way to forge a tapered blade without ruining the steel. We just heated the top end of the blade and hammered it into a taper. The last 2 1/2" was not gotten to any glowing heat. Then,we wrapped the blades in stainless steel foil with a little piece of brown paper inside to burn off the oxygen in the envelope. Put in too much,and the envelope would burst,ruining the A2. You had to be careful. We put the wrapped up blades into our electric furnace to get the optimum temperature. Steels have optimum hardening temperatures,and you lose some durability if you are more than 25 degrees off.

We'd heat the blades up and remove them. We had a 400 degree oven waiting to draw the temper as soon as the blade got just cool enough that you could pick it up. This is another important step. Let it get fully cool,and the life of the blade suffers. About 130 degrees F is when you should temper the iron.

The blades worked very well. I never signed them,only stamping a 1/16" A-2 on the side of the blades to remind them what steel the blade was made of. I didn't want flack from the blacksmith's shop as the irons weren't made of authentic metal!!

I had also warned them that they'd have to come to the toolmaker's shop to grind them on our blue zirconia belts. Sandstone wheels weren't going to do much to them!!!

I knew these irons weren't made of authentic steel,but those poor guys had to work that tough wood all day in the cold or heat,and I wanted to make their lives a little easier. The irons were hand forged,with round tops. No one could tell they weren't bitted unless they could remove the iron and have a very close look,for they were left black,except down at the cutting edge.

When we started to think about planes,my director told me that he didn't have a problem if we made the blades all 1 piece anyway. That was surprising,since everything else was niggled over for hours!

[Jonathan McCullough]

@ Sam: I got a Buck Brothers Made in China special 2" plane iron to put on a jack plane for horking off big chunks of wood. It most reminds me of a chrome-vanadium iron I have from an old Sargent. It's not bad actually, and for that purpose it's great. But as to whether the steel is suspect, you've got to consider whether that just about any international player can make O-1, and the fact that just about anyone does. As far as I'm concerned, all steel is suspect, and anyone anywhere can flub it. Ooops, did some old 1950's SS brightwork get into that batch? Oh well, we'll still sell it as O-1. Consider also that more and more steel in anything you buy is coming from China.

Although I might disagree if it were my livelihood, $40 seems a lot to pay for any plane iron. I haven't tried epoxy with two plane irons yet, but if I make a little woodie, I'll probably give the diy "lamination" a try.

[Sam Takeuchi]

I actually have more faith in the steel industry than that. After all, that's what they make, and that's why they have so many variety of steels as well as grades of steel. If they are so sloppy as to sell botched batch that are out of order specification, they have much bigger and serious problems than complaints from blade manufacturers. I'm not saying that they are all honest and reliable, but manufacturers and companies that sell quality blades do spend a lot of time and money to find firm that can supply quality of steel that meet their requirement as a part of whole manufacturing process. And it shows in the end product.

As far as stock blade from the past century goes, they weren't that great, even the early to mid 20th century laminated type. Those blades were produced in the cheapest manner acceptable at that time. They work ok on softwood, but couldn't hold edge for reasonable amount of time on hardwood. I wouldn't hold them up as standard of bench mark for anything, though. I say this, because something like material removal with jack plane is actually heavy work. You can ignore dull blade or tear out at this time, but if you have to remove 3/8" (or even 1/4" for that matter), it should be done in the most efficient and least tiring manner. Trying to get that much with a blade that wouldn't hold edge reasonable well is extremely tiring, especially on hardwood.

While $40 for a blade seems expensive, remember, the blade is the heart of a hand plane. Entire plane is actually built around this piece of steel. And $40 seems like a lot, but for that price, you can make several blades by buying quality steel, cut, grind, heat, temper and flatten. Yes, a lot of steel is produced in China, and I'm sure there are a lot of crappy quality steels are available, but if you were serious about quality of steel, you wouldn't pick the cheapest steel of unknown origin, would you? Even if quality and specification is as good as or better than what you seek, but don't want one out of China, you can find suppliers who sell steels made locally, Sheffield, Sweden or elsewhere. Also if you want to go extreme, there are level of quality control within steel production with paperwork for every single step of the way going all the way back to the mine. Though, don't expect that sort of quality control in plane iron production, though. All in all, what I mean is quality steel isn't made with bunch of buckets on the floor (even though I have seen documentary about China's backyard steel production...literally with buckets). Blades sold by manufacturers and companies today, who knows? Maybe they were made in China, but I guarantee you, reputable manufactures and companies do pay attention to quality and grades of steel before they produce and sell.

[george wilson]

Many machinists on another forum have complained about the messed up tool and mild steel they have bought from their suppliers. It's getting to the point where most of the steel is coming from China,I guess. Machinists have ruined expensive milling cutters from running into half melted ball bearings( VERY hard),and various other junk they find in the steel.

Quality control is very sloppy in China. That includes the pieces of soccer balls some of you have found in Chinese plywood,and other stuff,like it delaminating,or not staying flat,having big voids,etc.

[Ron Petley]

I bought a bar of 3/8ths 01 steel, no cap iron, cut it to length with a hack saw. length would be long enough to stick up above your wedge so you can get at it once it is installed in your plane. Width would be a little less than the inside widt of the plane you are going to build. Cut ir square it makes it easier later.
I flat ground one end to 27degrees leaving about 2mm thickness at the point. If the point is to thin it overheats in my home heat treating.
Once heat treated I ground the point to 25 degrees, and flattened the back and sharpened like any other plane blade.
Thats about it heat to non magnetic, hold for 5 min, quench in oil, I have olve oil at 135F I did a interuped quench, quench and remove when it is just hot enough to somke the oil, about 400F.
Heat treat in a oven at 400F in a sand filled container for 2 hours.
Grind and sharpen and you are good to go. Not much metal working mostly quench and heat treating.
Hers is a post with my set up in it.
http://www.sawmillcreek.org/showthread.php?t=94494&highlight=Petley

http://www.sawmillcreek.org/showthread.php?t=96540

Cheers Ron.

[george wilson]

I just plain quench till the blade is cool enough to have passed through the "hardening gate" as it is called. Interrupted quenches may not fully harden any steel. If you have a toaster oven,it should be pre heated to 400 degrees(I put a high temperature thermometer's long shaft into mine ( can't trust the toaster's thermometer).

As soon as your iron is quenched,and you can barely manage to hold it(about 130 degrees),place it at once into the toaster oven after hurriedly wiping off the oil.

This is THE BEST WAY to get the most durability from your blade. If you have no toaster oven,and let the metal fully cool before tempering,you won't kill the quality of the blade,but it is better to do as I have written,to get the absolute most out of it.

[Ron Petley]

I am not sure what the process’ and purposes are for other smith interrupted techniques, but here is what the concept is from a metallurgical point of view and why I would do it.
Austenite is FCC (face centered cubic) which is a most efficient atomic stacking arrangement. All the other transformation products that occur on cooling are BCC (body centered cubic)or body centered in nature like the BCT(body centered tetragonal) of martenensite, which takes much more space for the same amount of atoms. So while we do get simple thermal contraction as metal is cooled it is fairly small compared to the massive expansion you get when you have a BCC transformation. This all seems academic, but some folks may not realize this. I recently read an article that stated that steel contracts when martensite forms, this is so completely opposite of the facts that I was shocked the editors let it get by them, it is quite basic and fundamental that the martensite transformation is one of the most expansive.

So when you cool a blade and one part cools quicker than the other it will reach a body centered (hopefully martensite) transformation sooner. If this happens you could have expansion on one part of the blade while another is still contracting, it is obvious what the dangers of this may be, and since the part that has not yet transformed is still very plastic austenite, there is plenty of room for permanent shape change. If you interrupt the quench just before this transformation and allow the entire blade to equalize in temperature before continuing, it becomes very obvious how advantageous it can be to have the entire blade hardening evenly at the same time.

It is best done as near the transformation temperature as possible without beginning it. In oil I like to pull the blade out at the point where there is just a few wisps of vapor coming off the steel and the oil is able to coat the blade without burning off or flashing. Many oils have a vapor point that approximates 400F. so that can be helpful.
I think it is splitting hairs, whatever works for you is the best and sticking with it for repeatable results is what it is all about.
The basic method is sound and full quench is easier and has less room for error, so good point George.
Also getting the blade into the oven as soon as you can is also a important point I missed, thanks for pointing that out.
Cheers Ron.