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Does anyone have a good idea of the best/most efficient way of how traditional wooden single iron plane blades were forged? They were tapered from roughly 1/4 inch on the cutting side down to 1/8 or less on the top pretty evenly and the sides were parallel, Ive been scratching my head as to how the smiths of yore did this!

 

All ideas welcome!

 

Josh

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well there are a number of ways that could be accomplished.  Some can do it with no real extra tooling.  Eye trained and all.  You can use a flatter and side blocks.  Calipers to check till it is right on.  Filed after forged to specific dimensions.  I know there are some still forging them today.  I heard at the last guild of metalsmiths meeting and got to see a plain iron that a japanese man did durring...I belive it was durring abana or some other large gathering.  

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I disagree with Stefflus.  I think that the heavier the blade the better!  The only caveat is that the blade weight makes the whole tool heavier too.  Heavy blades will vibrate or chatter less with any depth of cut and any speed of planing... they are just more rigid!  My own view is that the tapering is better discarded in favor of a heavier flat blade.  This is the way that cheaper planes can be tuned to superior performance.  IMO most planes will perform better with more weight/momentum and thus will be improved by thicker and untapered blades.  Of course if you have a plane that cannot be refitted to take a flat blade you will not have this option.  With modern steel costs there is no point in being chintzy about the amount of steel used in a plane blade.  At least not for handmade blades... maybe different if you are a manufacturer making several thousand blades at a time.

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yes, well i was thinking perhaps they started with a bar, drew it out and drew it out thinner in one direction, maybe used a flatter to help, and maybe cut the sides straight off with a hot chisel before grinding, some appear to have no grinding, with flat hammer marks the length, which was apparently what made bedding an iron so difficult "n the day". Perhaps I'm over thinking the process, and it was just a very skilled smith drawing out by eye with years of practice....

as to the thickness, most plane with no chip breaker were as thick at the cutting edge as possible and cost effective, and of course bigger and thicker for the rougher bench planes than the molders, Ive seen a few nearly 1/2 thick!

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OK first the *old* ones were forged from real wrought iron with the high carbon edge forge welded on.

That out of the way:
Before mechanization: well after you forge a thousand or two you get *good* at it.

After mechanization: (and we're talking water wheels!) You could use a die for shaping.

More modern still: you might use roll forming or closed die forging.

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The blade taper is important for a single iron held in place with a wooden wedge. The tapered blade will hold without slipping even when the wedge is gently tapped in. If you use a constant thickness blade the wedge will need to be knocked in hard and then you can't adjust the blade position left and right as easily. Lots of old wooden planes have cracked sides from someone knocking the wedge in tight then whacking the side of the blade hard to adjust it.

 

If it was me I would make the blade first and then make the wooden wedge to match the blade. That way you can concentrate on making nice smooth surfaces and don't have to worry about getting a particular angle for the taper. Shaving down the wedge to make a perfect fit is easy compared to fooling with calipers on a red hot piece of steel.

 

The blade width just needs to be narrow enough to clear the sides of the plane with some clearance for adjustment. The most efficent way to get the width right is probably cutting a tapered blank so that you can draw it out width-wise and end up with a roughly constant width blade. Grinding or filing could be optional if the forge work was neat enough.

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The Woodwrights shop had an episode on Japanese planes and they showed how the laminated iron was scalloped on the HC side to reduce the metal in contact with the grind stone thus reducing the time spent honing the flat side.  They said it was scraped out not ground out and it looked it too.  The same technique was used on their chisels as well for the same reasons.

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He said it was tapered pretty evenly. And it should be for proper bedding of iron in bed and wedge against iron.

But how do you do it with minimal or no grinding, and what is side blocks?

 

I would however like to see some math on the need for thickness in the cutting end.

If you are going to take a see-through whisp of a shaving, and the iron is properly bedded, then the blade could be very thin.

Are you taking a heavier cut, then the blade needs to be thicker. But if the blade is thicker than needed then you get vibration because of the momentum applied on the long bevel.

In other words there is a sweet spot for every situation.

Thin cut, thick cut, the blades the same, its adjusted to give the thickness/depth of cut required.

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Fellows,

 

New here, as I have interests far and broad! Anyway, i just happened to read an article today about tapered irons. My understanding is that they were drop forged. You may ask what about the planes of the 18th and early 19th centuries, before drop forging. The question in return, should be, did they have tapered irons at that time?

 

http://www.planemaker.com/articles_plow_n_skated.html

 

Here is the article, took me a couplr fo minutes to dig it up.

 

Regards,

Albert A Rasch

The Rasch Outdoor Chronicles

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from what i understand the early irons where done the old fashion elbow grease way with hammer and file, while the post industrial revolution ones where drop forgings. I personaly feel that the thicker a blade the better. the japanese use planes that are equiped with a quarter inch thick plus blade that is extremely hard, and a wooden body of secondary importance, very different from western style planes.

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  • 4 weeks later...

I have a book that I just pulled out after years of not looking at. The book is out of print and is  " Restoring, Tuning & Using Classic woodworking tools" Author...Michael Dunbar...ISBN o-8069-6670-x...copyright 1989. The focus is on refurbishing and using hand planes...wood, iron and transitional planes. Talks about the taper, frogs and chip breakers and how to adjust them without damage to the tools. The first irons were made of wrought iron and forge welded tool steels.

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I have forge welded high carbon steel to wrought to make a japanese style blade. I tapered it by hand in the forge and cleaned up with a grinder. As noted above, you then make the plane to fit the blade. I am sure a Japanese 7th generation plane blade smith could find fault but I have gotten some very thin shavings using the blades.

It is pretty straight forward. This wouldnt work in a stanley plane but make a few and go to the" Daiku Dojo" web site and look up the "Kanna making " demonstrations to learn how to mark out the plane. It is a doable project for the avg. smith who has done a little woodworking. Good luck and PM me if you want more info. I will help but dont claim to be an expert.

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