Replacement iron of old coffin wood smoother

[Wilbur Pan]

If there is concern about the edge heating up too much, and I agree that this shouldn't be an issue, you could always just grind the edge square, heat treat the plane iron, and reestablish the bevel.

[Jim Nardi]

DL Barret and sons are making reasonable priced new tapered irons. Writen up in PWW a month or so ago.

http://dlbarrettandsons.com/index.html

[Casey Gooding]

Lee Valley makes nice replacement blades for woodies. Fair price and the backs are nice and flat.

[george wilson]

Cooking ovens do vary in temperature. It is safer to do it like I said,starting behind the cutting edge,and letting the colors creep towards the edge. You can't see the iron inside an oven,but can on a burner,or hotplate. I have a high class knifemaker's electric furnace,and it's a whole different deal from a kitchen oven. I CAN rely on it doing what I set it to do.I've done my best to do things like put on a consistent fire blue finish on a flintlock pistol barrel in a kitchen oven,even using a 1000 degree Brownell's thermocouple thermometer with it,set ostensibly to the right heat to produce a dark blue,even according to the extra thermometer. The thin end of the barrel would get too hot,while the breech end would get blue. With a proper knife oven,that is not a problem. I think a household oven must be configured to let air currents develop,making some spots hotter than others,as well as not being accurate enough.It could be that the electric coils down below he work let real hot air drift up. When you turn on the kitchen oven to 400 degrees, the coils in the bottom get red hot. They must be about 1200 degrees or more,and are below the work. There is very hot air coming up from them. My electric knife furnace has the coils in the sides. Hot air from them goes to the top of the furnace,where its temperature can stabilize,and gradually drifts down to the furnace floor where the work is. Maybe that makes for more even heating performance. All I can say is that these are real experiences I have had.

Wilbur,about the prospect of rehardening: What you say about grinding the bevel off is good advice,but,of course wastes the blade's length some.But if a person isn't experienced at hardening steel,or may not have proper means to do so,it is best just to keep it simple. Besides,there are 2 different steels on the faces of the iron,which could also lead to warping. I have seen blacksmiths blister and destroy tool steel,though they might be o.k. at the more usual work of hammering metal out. Obviously,they should have known better,but it just shows that special experience is needed,even if one already works metal. I do not refer to the blacksmith shop in Williamsburg !!

Adam,if you read my rather long posting,I said that it would be better if he didn't have to quench. The reason to quench is,I repeat,if the colors go too high,and must be arrested. That is what good quenching does. He is a first time person at this,and things can get out of hand.I do not recommend him to wait till the blade goes to purple and THEN quench. The idea is to quench before things get out of control.If the blade shows signs of going TOO dark brown,quench.

There is much not covered. I have advised Berl about some other info: For one thing,we don't know the carbon content of the blade. We don't know how hot it was when it was hardened. These things can affect the color you need to draw to. I have had antique tools that were so hard that I actually did have to draw them purple to get them to hold an edge. I've advised Berl,at his request, in a PM how to test at each color level,and if not softened,to go to another color.The set of Addis chisels I may have mentioned were so hard I had to resort to purple.

The iron in question is bitted with crucible steel,also called cast steel,as it was made in fairly small crucibles about as large as a big pretzel bottle,and cast into ingots. Unless the plane was made very early in the 18th.C.,it is crucible steel.Before that,they had shear steel,and double shear steel made from case hardened blister steel bars welded together and hammered out. It had layers of hard and soft steel,not homogenous enough.Tool steel in the old days was hand made. Everything was done by experience of the operators. Exact chemistry was unknown until more modern times.Tool steel was made in small batches,and samples were hardened,cracked open,and classified by an old hand as to 3 basic grades according to the size of the grains in the fractures: The lowest grade was spindle steel,probably about .70 carbon,or less,to our modern understanding. The next grade was knife steel(I could be wrong about this name,I'm getting tired),it was possibly like .85-.95 carbon. Highest grade was razor steel,probably 1% carbon,or a bit more.

That was the extent of control.An old plane iron or other tool can be quite variable,even among the best makers,like Addis,Witherby,and others. I've had to reharden,or draw temper in a number of antique tools in use by their private owners,that chipped,or rolled edges.

The point of this long posting is to show that tool steel,or other metals,even in the 19th.C. was not exactly controled. Now,we live in an age where exacting chemistrys are known,and windows of only 25 degrees can make a significant difference in hardening or drawing steels to obtain maximum life from them. When $250,000.00 is not uncommon for a complex die,that extra life is vital to industry.

Re:Triple,or double quenching. This process does any good ONLY if each retempering is close to 25 degrees below the prior tempering. There are books you can get that describe the finer points of heat treating.

[Zahid Naqvi]

Berl, I thought I'd post a link to the LV blades Casey referred to earlier.

http://www.leevalley.com/wood/page.a...182,43698&ap=1

Or the Hock Blades. These blades can also be used in wooden planes, although you may have to make minor modifications to you wedge (depending upon the type of plane).

[george wilson]

Zahid,those irons are not taper ground. He'd have to change the wedge. other than that,they are probably excellent orons.

[Berl Mendenhall]

Zahid and others, I appreciate all the response to my thread. I never expected this much interest. This just goes to show what a great forum SC is. I've learned a lot. Through this thread I've found top of the line makers making woodies, what a great resource. Not cheep by any means but they're out there. I know using woodies isn't for everyone but they do it for me. I've got a couple of Stanley # 4's. They're good planes and will work just fine, but not near as much fun as woodies.

I didn't expect to find makers that made blades that would fit these old planes. I've got my bases pretty much covered now. If the tempering thing doesn't work out, I'll just convert the plane to a single iron plane (all my woodies have chip breakers). Making a wedge is no big deal, I've make em before. I believe it was David Keller NC that said "it's not rocket science". I chalk fit em (blue sidewalk chalk). In violin making we chalk fit some of the joints. Anyway thanks for all the information.

Berl

[Ron Petley]

I would tend towards the oven treatment over the torch.
Your oven temp might not be very close to reality. So error on the low side. Pre heat the oven start at 350F, place the iron in a tray of sand and place the whole try in the oven, cook for 2 hours, turn off the oven and let it cool. Read this in the voice of Julia Child. Try your blade if it is still chippy re do it at 375F. Knife makers do 1 hour cool and repeat for another hour, but 2 hours straight should do the job.
This way the edge will not over heat no mater how thin it is. The sand will help the oven temp swings as the element comes on and off. I figure if the blade is no good you have little to lose trying this. but go low to start with if you over cook it you can not go back, but if it is under done you can always go up a little.
Cheers Ron.

[george wilson]

Repeat,only 25 degrees lower on successive tempers does any good. the sand sounds like a good idea.