Thread: Chipping Norris Blade

Hi All

Thanks for the advice. On the good news front after sacrificing a centimetre and half of blade I hit steel that doesn't shatter the moment the blade hits timber. Blade is keen and does a nice job .

If the above failed, I liked Robs idea of grafting a new tip onto the Norris blade, so at that point I gave up on trying to sort the brittle bit and ground the away to see if there was better steel further down. I reckon I could get away with mig welding an extension in appropriate jig with no porosity if I was careful - the tip is a fair distance from the joint . If I make make small weld pools each hit confident that will minimise heat input

If I had needed to grafting a new tip, I guess, would have committed me to making 2 may be 3 blades - One for test, one to replace a blade in box chamfer plane, I am a tad dubious of - and reharden the tip of the Norris plane - but for now that is delayed.

Cannot be sure that the blade will not start notching again, but best not to fret about what is not a problem.

Cheers M

Hi Rob

Also - was wondering how your plane project was going. Whichever choice you make for your plane blade I am sure it will be interesting.

Am rather partial to nibbed irons.

Regards

Ian - if I still had one of those old norris blades, I'd dent it and see what it says!!

I've got a spreadsheet of a few of the things I've hardness tested:
DW - Hardness Testing - Google Sheets

I don't know if that's readable. The big surprises have been a few laminated blades that are hard tempered showing up at 65 or so, but none from a good make has behaved like that. Looking at my list, DR Barton is a plane blade I tried to use in a jack plane and was always chipping. When I got a hardness tester, I found it to be 65 hardness.

The other surprise is a stewart spiers original panel plane iron at 59. the plane is ok to use, but it's not great, and I never really used it that much as I got it more to have in hand if I want to make one like it. I replaced the iron with a sharon 50100 plane iron that landed at 61 (toaster oven got away from me and the temper got to 415 or 420F - it's still nice to use, but 62 would be my magic number target in plane irons in the 0.9-1% carbon range and some alloying, and 64 for something like 26c3 (1.25% carbon) and 63 for W1 or 1095 that are right at 1% carbon.

1084 for me lands around 60/61 with a double 400F temper, but these are two long tempers. I have but one example in my chart double tempered at 360F and 61.5. Alpha knife steel's chart says 60 at 400F (which would be without grain growth. Hardness increases with growth, but obviously the performance effect is still negative due to the grain growth). If we do everything right with forges and quench, we can generally beat the schedules by a point.

if you're snap tempering (tempering to color only a short period of time), you can preserve a little more hardness than two long double tempers.

1084 grows grain *really* easily, but if the grain isn't bloated, it's really tolerant of a huge range of tempering temperatures. O1 with a double 360F temper, or 1095, both would feel biting sharp but lack toughness. 1084 and 80crv2 (plan and alloyed of about the same thing) seem to me at least to be better for planing if tempered shy of my pet regime (two careful double tempers at 400F).

Hardness is so critical if fine shavings are to be taken, but something like the aforementioned 59 hardness planes make great irons for penultimate work where the shavings are never really thin. What I don't know is how many people actually do that kind of work. Jack and try plane irons a click short of high hardness can be very mellow and pleasant, though - sharpening is almost done just by thinking about it.
---------

forgot - two ward parallel irons that I tested - 62 and 63 hardness. IH sorby parallel iron was 62.

Ward's taper plane irons averaged around 60/61. Buck bros of old varied stuff based on use - most of their tools are soft, but the patternmaker's tools aren't. marples can be more of a puzzler, but it's usually on the softer side for plane irons - never could figure out why.

Lots of intent in stuff made back then. As much as we hear talk about how inconsistent they were and that they were guessing, I tested two pfeil gouges - one was 60 and the other 61.5 and their edge condition coincided with hardness. 60 is just barely getting it done with a carving tool. Two LV V11 chisels I've seen tested are 61 and 63.5 hardness (I no longer have them, or I'd dent them, too, and see what they show).

Originally Posted by MartinCH

Hi All

Thanks for the advice. On the good news front after sacrificing a centimetre and half of blade I hit steel that doesn't shatter the moment the blade hits timber. Blade is keen and does a nice job .

that's a good conclusion! A lot of length to lose, but it is what it is.

Originally Posted by MartinCH

Hi Rob

Also - was wondering how your plane project was going. Whichever choice you make for your plane blade I am sure it will be interesting.

Am rather partial to nibbed irons.

Regards

Its good Martin.
Its sitting on the bench waiting for attention. I had to get some woodwork done so it was put aside. I also need to just find a time where I can make the blade and use the kitchen oven when I'm the only one here.

Originally Posted by auscab

..... I also need to just find a time where I can make the blade and use the kitchen oven when I'm the only one here.....

Yep, saves a minor interrogation & having to reassure the significant other that it won't do the slightest harm to the oven. I make sure I clean all the scale & any residual oil off so it doesn't stink the place out...)

Cheers,

- always remember "no japanning in the kitchen" , like really, never..

On the bright side my significant other burnt down the kitchen boiling out the tannin from a piece of wood - try explain what you were cooking to firies with that one,.
At least one get out of jail free card...

Cheers

I want to put in some timber treated pine posts and extend a lean to roof out the back for my blacksmithing stuff. Sheet iron it in for walls. Then do more blade making and planes in that space where I can also do other metal and welding activities . I almost had a $50 electric oven the other week off FB market place for that workshop. To heat treat stuff. The seller ended up giving it away as it sat there for a week before I asked about it. They show up so I'll see if I can get another one.

Originally Posted by MartinCH

- always remember "no japanning in the kitchen" , like really, never..

On the bright side my significant other burnt down the kitchen boiling out the tannin from a piece of wood - try explain what you were cooking to firies with that one,.
At least one get out of jail free card...

Cheers

gilsonite you'd probably get away with, but the baking turps and linseed would really stink. But caveat here, I would never do it in the kitchen without steady air movement.

if my wife wasn't here for a week, I'd consider japanning a long plane in the oven, though.

I was using a very steady heat shielded toaster oven that I'd used for years tempering steel. It would hit temp target and stay within 5F or less in a "metal sandwich" (extra blades or flat stock to put the item being tempered between), and I had no issue with gilsonite japanning in the shop until....

...one day I walked in, and my toaster oven that had done probably a thousand heat cycles lost its temperature control, and the shop was full of smoke. I didn't figure out why right away and felt sick for the day just from being in it and thinking about what was going on and opening the garage door. Not like deathly sick, just like a little tired.

I mention gilsonite powder because it has little hydrogen sulfide in it compared to bitumen, and a known point that it will melt and link into a varnish on a tool, and aside from malfunctions, it will not create really nasty smoke like I encountered.

Regardless of guessing on toaster oven functionality though, I will only do it outside now....except I'd make an exception for a big plane, but with closing off the area and establishing circulation with outside air. And using a thermocouple to be able to observe temp.

Rob mentions finding an older oven. I've always been kind of shocked how easily people will just throw out an old oven without thinking much about it. They're usually working, sometimes just needing a thermostatic probe or couple or whatever, or maybe an element replaced, and as a kid, the new oven was upstairs, and the last one was in the basement to do things you didn't want to do with the old one (canning, cooking dog food, whatever).

will comment on a "bummer" in a separate post

japanning bummer - when I learned to cook varnish, suspected cold japanning is just a varnish that is cooked and also cured right after on the plane. we cook varnishes ahead of time since baking the item they go on usually isn't possible.

True varnish (that never separates or settles again) gilsonite japanning is the easiest varnish I've cooked - it links together in the pot at 400F or so instantly and "pills" with a sticky feel rather than oily. When the resin links with the oil, the oily feeling is replaced by a sticky feel.

.......

in reading old texts, this is considered a cheap japanning. Stuff like you see on a sewing machine is more generally layers of varnish, with color on the bottom and clear super high quality varnishes like a copal varnish on top. which is why a lot of the old turn of the century sewing machines still have a lot of finish on them. They must've looked absolutely brilliant brand new.

Cheap could be a relative term, though - like this kind of japanning we're talking about using went on ford's cars and got baked, and the wood parts appear to have gotten baked finish in some cases, and rosin varnish with pigment in other cases. A sewing machine that costs two weeks' pay and is relatively little is going to get more attention than a car that will have the finish fail by sun exposure at some point no matter what.