Thread: Making my own moulding planes

Thanks Paul.

While there are lots of special-purpose steels out there (an infinite number of the darn things, it would seem), I would find it strange if generic mower blades were other than a pretty basic carbon steel, but who knows, they might be! Anyway, the particular blade I cut up for my tap cutters turns out to be ideal for the purpose, water-quenching the small bits I used did no damage that I can see, and produced a hardness that seems perfect for purpose. Not sure if it would be so for a plane blade, though, it may be a bit too soft, but I'm tempted to give some a try. I'll put it on the list, along with a few dozen other 'gunnadoits". I may get around to it before I shed the mortal coil...

Cheers,

Originally Posted by Mountain Ash

Hi again all. Had my very first go at blacksmithing the other night. Used the open fire to get the plane blade tip up to my approximation of cherry red and then quenched in Canol oil (not pre heated though, sorry Doug).

Hopefully it may have gotten it hot enough to work. Did you test to see if it was non-magnetic? The way to test if it has quenched correctly is to run a file over it. If the file skates over it it is hardened, if it bites in it has not hardened. If it's not hardened the next step is to heat and quench again - no point in tempering if it's not hardened.

Originally Posted by Mountain Ash

Cleaned it up and popped it into the oven for close to 2 hours on 220°. Came out looking straw coloured and quenched in same oil again.

No need to quench it after tempering. Better to leave it in the oven to cool down slowly.

Fingers crossed for you that it's worked. You have taken the first step - there's no going back now.

Hi Doug. I did think of the magnet.....well after tempering was done I sharpened up the blade yesterday and didn't notice any difference with that process but the plane isn't finished yet in order to test it. I'm assuming that I can repeat the process if the edge fails to stay sharp

Originally Posted by Mountain Ash

I'm assuming that I can repeat the process if the edge fails to stay sharp

Yes you can but there's always a cost of some kind.

Each time you heat the blade in the forge/blowtorch/fire or whatever you lose a small amount of carbon content in the steel. Probably not a real big issue here but something to think about if you start doing more high-end work.

The real cost here is redoing all the work - something that could be avoided by doing the right tests at the right time and fixing things before investing more time and effort.

Always:
- test for non-magnetic before quenching
- After quenching test that a file will skate over the surface. If not reheat to non-magnetic and quench again, rinse repeat.
- Check your temper coloring is appropriate when it comes out of the oven. If you take the temper too far it will be too soft so go back to the start again.

If we were not in lockdown in Melbourne right now I would invite you over for an afternoon and show you how it works. When I was starting out I really had no idea of how some things were supposed to look. It was not until I did the process with an expereinced bladesmith that it all made sense.

Originally Posted by doug3030

Yes you can but there's always a cost of some kind.

Each time you heat the blade in the forge/blowtorch/fire or whatever you lose a small amount of carbon content in the steel. Probably not a real big issue here but something to think about if you start doing more high-end work.

The real cost here is redoing all the work - something that could be avoided by doing the right tests at the right time and fixing things before investing more time and effort.

Always:
- test for non-magnetic before quenching
- After quenching test that a file will skate over the surface. If not reheat to non-magnetic and quench again, rinse repeat.
- Check your temper coloring is appropriate when it comes out of the oven. If you take the temper too far it will be too soft so go back to the start again.

If we were not in lockdown in Melbourne right now I would invite you over for an afternoon and show you how it works. When I was starting out I really had no idea of how some things were supposed to look. It was not until I did the process with an expereinced bladesmith that it all made sense.

Doug

Thanks for mentioning the "cost."

My own thoughts are that the biggest potential for "carbon migration" is during the annealing stage and if we use our fire for this purpose the slow cooling does make the steel susceptible to such a loss. However, for our purposes it is both inescapable and probably inconsequential at our level of operation: Different if you were selling commercially and also offering a high end product.

When tempering the light straw colour comes up very suddenly and I find you have to watch for it very carefully. One moment there is no sign of it and in the next instance it is dark straw or even verging on blue. Ok if you were forging a cold chisel, but otherwise a trip back to the hardening step is called for. I should point out that I do these steps using an oxy torch, although I would like to try tempering in SWMBO's oven (when she has gone shopping). I will suggest to her that she needs an accurate oven thermometer.

I know you mentioned tempering without quenching (ie: a slow cool) but I have never tried that. I have always quenched in oil and I don't "hold" the steel at temperature. As soon as it hits light straw I quench it. It has worked well for me without any failures, but that is not to say a slow cool would have worked too. Additionally slow cooling is relative. It could be done either inside an oven or outside in still air or even outside under compressed air. All would still come under the definition of a slow regime. It would be interesting to do a comparison, but pointless without a hardness tester to measure the results (where are you Rob Streeper ?) I have never considered or tried it. Perhaps the 1070 leaf spring is very tolerant of our backyard antics and as such is ideal for purpose. I don't absolutely know this of course: Just surmising.

Regards
Paul

Originally Posted by Bushmiller

My own thoughts are that the biggest potential for "carbon migration" is during the annealing stage and if we use our fire for this purpose the slow cooling does make the steel susceptible to such a loss. However, for our purposes it is both inescapable and probably inconsequential at our level of operation: Different if you were selling commercially and also offering a high end product.

Yes, yes and yes. no arguments there at all.

Originally Posted by Bushmiller

When tempering the light straw colour comes up very suddenly and I find you have to watch for it very carefully. One moment there is no sign of it and in the next instance it is dark straw or even verging on blue. Ok if you were forging a cold chisel, but otherwise a trip back to the hardening step is called for. I should point out that I do these steps using an oxy torch, although I would like to try tempering in SWMBO's oven (when she has gone shopping). I will suggest to her that she needs an accurate oven thermometer.

Now it is getting confusing because we are now talking about two different and equally valid methods of tempering. My comments in the post above were directed at Mountain Ash, who said he tempered his in the oven. No quench is required and it is best to ensure that the blade is left in the controlled, gentle heat for a while to heat right through. I put it in a toaster oven with a timer which turns it off after an hour and then it cools down overnight (usually two cycles of this. I do not know why the two cycles other than that's what people who know a lot more about it than me do. )

Paul, you then introduced tempering with an oxytorch, which would require quenching to stop the steel overheating and becoming too soft. I have never tried doing this probably because I learned from a knife-maker and getting an even temper along the length of a big blade with a blowtorch would probably take a lot of skill.

Toaster ovens are not expensive. In fact you can pay a lot more for an accurate thermometer to put in your toaster oven than you paid for the oven itself. If it maintains domestic bliss by keeping steel out of the house oven its a great investment, even if tempering a blade does absolutely no harm to an oven. For the wives who complain about that sort of thing - what do you think your baking trays are made of? But having a toaster oven in the shed is also handy to heat up a pie for lunch too.

My arrangenent with Jools is that if I want to use something from the kitchen, I just take it. If I render it unsuitable to return to the kitchen I buy a new one for the kitchen and keep the old one for the shed. I have not had a single argument with that lady in the 17 years whe have known each other.

Originally Posted by Bushmiller

I know you mentioned tempering without quenching (ie: a slow cool) but I have never tried that. I have always quenched in oil and I don't "hold" the steel at temperature. As soon as it hits light straw I quench it. It has worked well for me without any failures, but that is not to say a slow cool would have worked too. Additionally slow cooling is relative. It could be done either inside an oven or outside in still air or even outside under compressed air. All would still come under the definition of a slow regime. It would be interesting to do a comparison, but pointless without a hardness tester to measure the results (where are you Rob Streeper ?) I have never considered or tried it. Perhaps the 1070 leaf spring is very tolerant of our backyard antics and as such is ideal for purpose. I don't absolutely know this of course: Just surmising.

As I said above - two different methods of tempering. both have their advantages. Your way the job is done in a few minutes of intense concentration. My way it takes a couple of hours but it's set and forget, walk away and have a beer and come back and get it in the morning.

1075 steel is very forgiving and a great steel to learn with. I just placed an order with Artisan Supplies yesterday for three bars of it in different sizes.

As for Rockwell hardness testing - my knife making mentor has a rockwell tester. Artisan supplies gets a container-load of them in occasionally and they all sell out on pre-order every time at over $2000 each. While I am happy with what I am getting that's $2000 I can use for something else.

Doug

I can imagine that a long thin surface would be much more challenging. A sword, for example, being an extreme. However, on items like plane blades and chisels it is child's play as the heat is brought in from the the tang end in the case of chisels and the blunt end of the plane blade. This way the more precise tempering at the sharp edge is easily controlled as you can see it start to come in and if the other end is over heated a touch that is an advantage rather than a disadvantage. Again the narrow edge of such tools make them easier to deal with than a long knife blade.

The only real issue is that as the mass of the blade increases the amount of heat you are able to deliver becomes more of a problem. For smaller objects I use a 15 tip, but for larger tools I grab a heating head. The largest blade I have made (for a froe) really battled to get enough heat for the hardening step. The technique, as I am sure you will realise, is constantly waving the torch back and forth as if you were spray painting in the same strip.

I don't think I will be rushing out to buy a hardness tester just yet either. I have used the oven in the kitchen too, but at this stage I have only ever dried off my handsaws after cleaning them up. So far I have not been banned.

Regards
Paul

Originally Posted by doug3030

Toaster ovens are not expensive.... But having a toaster oven in the shed is also handy to heat up a pie for lunch too.

Smart

Originally Posted by doug3030

If we were not in lockdown in Melbourne right now I would invite you over for an afternoon and show you how it works. When I was starting out I really had no idea of how some things were supposed to look. It was not until I did the process with an expereinced bladesmith that it all made sense.

Thanks Doug. When things get back to "normal" maybe we could revisit the idea.

Hi all. As promised to Soundwave and encouraged by others interest I have finished my #4 rounding plane AND finished the iron that belongs in it. As I make each one I improve my process and end up with a better result. I am understanding more about the relationship between the iron and the body and particularly how the iron dictates design (sort of obvious really but each of us has our own path to take). Funnily enough though it took me 2 try's to make the wedge. And of course no point if it doesn't work. You can be the judge (see moulding made in photos)

Ta dah!
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The blade revealed
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The #4 hollow I tried to pair with
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The numbers courtesy of a new stamp set (original stamp much nicer than modern equivalent)
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Moulding profile (snuck in a 1/8 bead at the top)
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Sorry about photo rotation