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  1. #61
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    Thanks Ian. I will also have a look at my local timber mob.

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  3. #62
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    Quote Originally Posted by doug3030 View Post
    Damn - now I will have to post a pic of mine when the epoxy is dry and the handle is oiled
    So here's my marking knife complete, along with the kitchen knife, the blank from which yielded the offcut for the marking knife. My partner, Jools, made the kitchen knife. That was the main project, I just picked up the scraps and made something useful.

    2knife.jpg
    I got sick of sitting around doing nothing - so I took up meditation.

  4. #63
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    Quote Originally Posted by doug3030 View Post
    So here's my marking knife complete, along with the kitchen knife, the blank from which yielded the offcut for the marking knife. My partner, Jools, made the kitchen knife. That was the main project, I just picked up the scraps and made something useful.

    2knife.jpg
    Doug

    Nice job by both of you. Have you stained the marking knife as I would not have picked it as the same timber? I also note the rivets look as though they are custom made. Are they a cutler's rivet or solid and have they been made using multiple small rods? I seem to recall that Dai Sensei was experimenting with a technique along those lines.

    I am a big fan of the Santoku shape for kitchen knives. Did you or Jools make the blade too?

    Regards
    Paul

    Ps: I just enlarged your pic after posting and saw the splayed pointy end of the marking knife, which was not obvious in the thumbnail size, (reminiscent of arrow heads designed to resist withdrawal from soft tissue ). I like that touch and it looks as though you could place index finger pressure on that region if you wished.
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  5. #64
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    Quote Originally Posted by Bushmiller View Post
    Doug

    Nice job by both of you. Have you stained the marking knife as I would not have picked it as the same timber? I also note the rivets look as though they are custom made. Are they a cutler's rivet or solid and have they been made using multiple small rods? I seem to recall that Dai Sensei was experimenting with a technique along those lines.

    I am a big fan of the Santoku shape for kitchen knives. Did you or Jools make the blade too?

    Regards
    Paul

    Ps: I just enlarged your pic after posting and saw the splayed pointy end of the marking knife, which was not obvious in the thumbnail size, (reminiscent of arrow heads designed to resist withdrawal from soft tissue ). I like that touch and it looks as though you could place index finger pressure on that region if you wished.
    Thanks Paul.

    The two knives both started out as a flat piece of 1075 bar stock. I cut it to length for Jools's Santoku. She cleaned the light rust off of the billet and painted it with marking fluid, traced out the blade shape of the knife she was copying then cut it out with the angle grinder. I picked up the offcut from under the handle of her knife and decided it was just what I needed for my marking knife (inspired by the Vesper Tools marking knife, which I have always admired)

    After rough cutting with the angle grinder Jools ground the profile to the marked lines with the belt grinder. I ground the bevels on the blade for her as that required a bit more experience and confidence than she has right now but I think she will get that in the future. She hand-sanded it to the mirror finish, glued on the scales and shaped the handle.I sharpened it. Basically she did 95 percent of it with some guidance. The "rivets" are called Mosaic Pins and are available from Artisan Supplies, same place I get my steel stock as per the link I posted earlier. They can be copper, brass or stainless tubes filled in with various things to make pretty patterns. A google search will reveal heaps of such treasures. You can make them yourself but I see little point unless you wanted something specific.

    The handle of he marking knife is still the same unstained piece of Queen Ebony from the earlier pictures, the colour came out with the application of U-Beaut Aussie Oil. The same finish was used on the sheoak scales on Jools's knife.
    I got sick of sitting around doing nothing - so I took up meditation.

  6. #65
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    Quote Originally Posted by doug3030 View Post

    The handle of he marking knife is still the same unstained piece of Queen Ebony from the earlier pictures, the colour came out with the application of U-Beaut Aussie Oil. The same finish was used on the sheoak scales on Jools's knife.
    Doug

    I understand now. I mistook the "blank" as the timber not the steel. A silly mistake once it is explained to me .

    Please pass my congratulations to Jools for such a good result and thank you for the additional explanations.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  7. #66
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    Default The Riddle Of Steel.....

    Steel for plane blades is something that interests me. I've been reading the thread as it goes. I'm not too knowledgeable.

    Below are some pix of knife projects I was involved in (boxes, mounts, linings, handles). It was fun. The actual blade-work was done by Matt McVicar of VicarForge. He's a mate of many years.

    For the steel, Lawn mower blades are usually 1085. Food for thought!.....

    I need to make a new blade for my Japanese marking gauge.... it BROKE!!! (goddam Chinesium)


    Knife making must be crazy fun. If you want any tips, Matt is a forge master with his own studio plus an instructor at Tharwa Forge here in southern Canberra.

    Woods were from my own collection and gidgee from The Timber Joint. That gidgee was so amazing to work with, but by Zeus it was hard!

    stiletto box 2.jpg AFP knife 3.jpg

  8. #67
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    WP

    Those knives and boxes are superb. To date the knives I have made (kitchen type) are all for purpose, but I can see where your knives are just beautiful in themselves. I feel an unreasonable addiction coming on ,

    Also there are several disciplines involved there. Blacksmithing, woodworking and leathercraft just to name some.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  9. #68
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    Hi WP. Thanks for the lawn mower blade tip

  10. #69
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    Quote Originally Posted by Mountain Ash View Post
    Hi WP. Thanks for the lawn mower blade tip
    Be aware that not all lawnmower blades are 1084. I have quite a few which are made of some mongrel steel that warps dramatically after forging.

    I love the ability to recycle junk into something beautiful and/or useful but sometimes you need to balance out the cost of known steels against the hours you put into making something only to have recycled steel crack or break along a stressline or something and result in all you efforts being for nothing.

    Not trying to discourage you from experimenting - I do it all the time - but for things that a lot of work is going into it is often better to pay a small price for new,unstressed steel of a known type, that you know you can heat treat with the equipment you have.
    I got sick of sitting around doing nothing - so I took up meditation.

  11. #70
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    I've accumulated a few spent mower blades over the last 15 years and kept a few of the less beaten-up ones to see if I could re-purpose them.

    Just a few days ago, in fact, I dug one out to make some cutters for the threadboxes I was working on. First I checked the hardness by filing, & it seemed a bit harder than saw-plate, but not much, a file would cut it fairly easily (but it quickly wrecked a hacksaw blade!). Out of curiosity, I cooked a sliver up & dunked it in oil. It had no effect, so I repeated the exercise & quenched in straight water. It came quite a bit harder, but not brittle-hard, I could still cut it with a file (just). I reckoned that it was just perfect for that particular job.

    So I'm guessing, but does that indicate a fairly low C content? If I quench thick saw-plate in water, it's far too hard to use without tempering...

    Cheers,
    IW

  12. #71
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    Quote Originally Posted by IanW View Post
    I've accumulated a few spent mower blades over the last 15 years and kept a few of the less beaten-up ones to see if I could re-purpose them.

    Just a few days ago, in fact, I dug one out to make some cutters for the threadboxes I was working on. First I checked the hardness by filing, & it seemed a bit harder than saw-plate, but not much, a file would cut it fairly easily (but it quickly wrecked a hacksaw blade!). Out of curiosity, I cooked a sliver up & dunked it in oil. It had no effect, so I repeated the exercise & quenched in straight water. It came quite a bit harder, but not brittle-hard, I could still cut it with a file (just). I reckoned that it was just perfect for that particular job.

    So I'm guessing, but does that indicate a fairly low C content? If I quench thick saw-plate in water, it's far too hard to use without tempering...

    Cheers,
    My (albeit limited) understanding is that the response to quenching medium is less to do with the carbon content than the other elements in the steel. O1 and A2 are fairly similar, for example. But one prefers oil and the other air.

  13. #72
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    Quote Originally Posted by IanW View Post
    I've accumulated a few spent mower blades over the last 15 years and kept a few of the less beaten-up ones to see if I could re-purpose them.

    Just a few days ago, in fact, I dug one out to make some cutters for the threadboxes I was working on. First I checked the hardness by filing, & it seemed a bit harder than saw-plate, but not much, a file would cut it fairly easily (but it quickly wrecked a hacksaw blade!). Out of curiosity, I cooked a sliver up & dunked it in oil. It had no effect, so I repeated the exercise & quenched in straight water. It came quite a bit harder, but not brittle-hard, I could still cut it with a file (just). I reckoned that it was just perfect for that particular job.

    So I'm guessing, but does that indicate a fairly low C content? If I quench thick saw-plate in water, it's far too hard to use without tempering...

    Cheers,
    Ian

    I'm not sure of the implications. While I am very comfortable in my treatment of high carbon steel as found in leaf springs I have no experience of heat treating other metals with significantly different carbon content. I have not ignored your comment, but have been short on time to research. I will see what I can do.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  14. #73
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    For what it's worth, I'm a very amateur steel worker... All the above routes are possible, but when I started plane making I was concerned that too much variability in steel would prevent me from understanding what was caused by a steel problem, and what was faulty design or execution in the plane body...
    I went the purchased tool steel route: Steel - Page 1 - Creative Man
    the 35 mm by 1 meter lengths, in 3.5mm or 6mm thickness, are a good price, and come through the post ok. It's annealed on receipt, so you have a known steel in a known state, that's easy to work. $45 for a meter of 3.5mm steel gives me at least 5 plane blades to play with.
    I heat with a mapp torch in a 'forge' made from 2 aircrete bricks from bunnings, using a magnet to check for the phase change. dunk in canola oil once non-magnetic, and then temper at 200 degrees in the oven for 2 hours, twice. Easy, cost effective, fun.
    Plus one for not worrying too much about the taper on a blade. Good if you can do it for 'historical accuracy', but I've not found it necessary in practice.

  15. #74
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    Quote Originally Posted by IanW View Post
    So I'm guessing, but does that indicate a fairly low C content?
    Hi Ian,

    Like Paul, I have my areas of comfort when it comes to heat treating, but I am still on the steep part of the learning curve in metallurgy/ heat treating overall.

    My gut feeling is that you are right, because high carbon steel SHOULD become extremely brittle when given a rapid quench in water. The fact that it has hardened at all when quenched probably indicates that it has at least some level of carbon though so "fairly low C content is probably an apt description.

    Trouble is that metallurgy has gotten well beyond the realms of the amateurs now with so many specialist alloys being made for so many diverse uses. And the steel used in some applications is not the one that is best suited for the job but rather the cheapest one that will "just do the job" and so the "junkyard steels" chart I posted earlier in the thread (which is already decades old) is becoming more and more dated as 21st century cost cutting through cheaper technology continues. They would put plastic blades on lawn mowers if they could get away with it.

    When I quench 10-series carbon steels (the only ones I have used so far) I use canola oil, heated to 80 degrees C, which provides a more gentle quench than room-temperature canola oil and way gentler than any water quench. I heat the canola oil up by heating a piece of re-bar in the forge to cherry red and dropping it in the quench tank. I have a piece just the right size to provide the approximate right amount of heat. The re-bar heats up with the forge and once I drop it in the tank I know the forge is up to temp and put in whatever blades I am heat treating then take them out and quench them smallest to biggest as they reach critical temperature.

    A fast quench such as water can be very hard on the blades and increases the chances of warps or cracks, particularly with recycled steel which may already have hidden stress fractures. It can be heartbreaking to see the blade you have spent ages making out of an old leaf spring crack on quenching. Sometimes time is more important than dollars.
    I got sick of sitting around doing nothing - so I took up meditation.

  16. #75
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    Quote Originally Posted by IanW View Post
    I've accumulated a few spent mower blades over the last 15 years and kept a few of the less beaten-up ones to see if I could re-purpose them.

    Just a few days ago, in fact, I dug one out to make some cutters for the threadboxes I was working on. First I checked the hardness by filing, & it seemed a bit harder than saw-plate, but not much, a file would cut it fairly easily (but it quickly wrecked a hacksaw blade!). Out of curiosity, I cooked a sliver up & dunked it in oil. It had no effect, so I repeated the exercise & quenched in straight water. It came quite a bit harder, but not brittle-hard, I could still cut it with a file (just). I reckoned that it was just perfect for that particular job.

    So I'm guessing, but does that indicate a fairly low C content? If I quench thick saw-plate in water, it's far too hard to use without tempering...

    Cheers,
    Ian

    A very cursory glance into the possibilties indicate it was not a carbon content issue, but a hardenability issue. It is a little like male/female relationships - complicated!

    Some steels need to be qenched quicker than others to achieve hardness and I think your mower blades are in that category. Water is the fastest medium for quenching (but can lead to cracking), followed by oil, compressed air and finally still air. The speed at which a steel should be quenched has to be determined. This, I have read, can be performed by a Jominy test, (Understanding the Jominy End-Quench Test | 2015-05-07 | Industrial Heating ) but that is mostly beyond the backyard exponent's capabilities. We rely on that information being supplied and therein lies the issue with recycled steel: We don't really know, although the chart Doug supplied elsewhere ( Making my own moulding planes ) on post#19 in this thread is helpful in determining the type of steel content but not the preferred method of hardening and tempering.

    This link is a bit wordy, but might give some useful information at least in principle.

    How Fast Do You Have to Quench? Hardenability of Steel - Knife Steel Nerds

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

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