Head Knife....i Want To Make One

[klickitat]

What grind do these knives have on them? Flat, Scandi, Convex?

[walter roth]

You will find the description of "Lea-Compound" in my tread page 2 or 3.
http://Leatherworker.NET/forum/index.php?showtopic=49437&page=17
so I'm doing that. http://www.Lea.co.UK/help-and-advice/reference-charts/greaseless-abrasive-compounds.php
greeting
Walter

[StrigaMort]

Great thread, thanks much. Answers a lot of questions for me. I have been saving my old blades for just such a purpose. As for the cost/benefit ratio, there are those of us who just get a kick out of making stuff.

I've never tried it, but I have read that a regular kitchen oven will get 1080 steel to the proper 430 degrees or so for heat treating the blade to proper temper. Maybe some of you who actually know could comment on that process.

Switzforge, that little hole in the blade is for inserting a nail or screwdriver to lock the blade in place so you can loosen the spindle nut while changing the blade. Some grinders and saws don't have a locking mechanism.

A household kitchen oven can indeed temper 1080, or most any steel. That, however, leaves the hardening step out. 1084, 1080, 1075, 1070 etc... steels are usually worked in an annealed state, that is, soft. After grinding away whatever is not what you want to keep (in this case, a head knife) the steel needs to be hardened. The above mentioned steels are great for the home enthusiast because they are easily heat treated. It's worth mentioning that "10xx" series steels numerically higher than 1084 become more difficult to heat treat (ht) without specialized equipment. With eutectoid steels like 1084, the requirement is fairly straight forward for ht. With a very small blade you can use a torch to get the steel hot enough to become non-magnetic (actually using a magnet to check for when this occurs, it'll be bright red hot), then allow the steel to get about two shades of red past non-mag. This is all that is required to get the carbon into solution. Immediately quench in "medium fast" oil, or canola oil is fine. At this point a new file should skate on the freshly hardened steel. If it doesn't most likely you didn't get it hot enough. You can try a few times without damaging the steel. That hard steel now has all kinds of stress in it. The hardening process is not kind! So! It must be tempered. Tempering cuts back on the hardness, increases toughness and relieves some of that pent up stress. It should be done right after the oil quench. THIS is where your oven can come in handy. I'm greatly simplifying all of this, but you aren't creating a super high end custom knife... 400° (f) for two 1 hour cycles in the kitchen oven is fine for tempering.

Hope I haven't been too technical.

Heat treating is a bunch of processes, for stainless, it gets very technical. But ultimately ht is:

Annealing

Normalizing (if you hammer forge, if you just use belt grinders or files to remove steel you can skip this)

Hardening

Quenching

Tempering

If that doesn't answer your question, or adds more, I'll do my best to explain further.

[StrigaMort]

Oh, I should point out that if you need to ht a larger portion of steel than what you can keep at a constant heat using a torch (a head knife, or most any aside from a very small blade falls into this catagory), you'll need a way to evenly heat it. This can be done many ways, but one of the easiest is to build a small forge. I can help with that if need be.

Otherwise, if you don't mind (this hasn't been mentioned), you can always send the blade out for professional ht. Going this route, you can use super high end steels and not have to deal with ht at all. Arguably, the best, most practical way to go about it.

[KWosnig]

Haven't been on for awhile and so I decided to make a couple after reading this.

I had a damaged ten inch table saw blade, round and I made a pattern from info in Stohlmans leathercraft tools.

I just finished cutting the blanks for a head knife and a round knife. Attached a photo of them.

After I finish them, I will make handles out of oak and most likely rivet them on.

I did attempt to flex these pieces, I couldn't get any flex. I did not measure thickness, but I estimate a little over a sixteenth.

Tomorrow I will grind smooth and prep for handles. After handles are on, then I will set bevels and sharpen.

Later.

[KWosnig]

I have the sharpening process to perform on the head knife yet, however this is what I came up with. I used oak for the handle and screws and nuts to attach. Next few will be what it is now.

[KWosnig]

This is what the Head knife looks like now.

[switzforge]

Looks like you've got a good tool there

[KWosnig]

Thanks, I haven't finished sharpening process yet. I wanted to avoid cutting myself while braiding handles, after I finish the head knife handle(about 1/2 way now)I will wrap handles in plastic wrap and tape over that, then proceed with sharpening. I am using a vixen to cut the chamfers, then a three stone process and final stropping, then use it.

I started with some simple handles and then decided I needed better ones. The screws make changing it simpler. I went with a full tang, I thought about just driving a tang into a file handle or something, but I am partial to full tangs.

I have a couple of Japanese bayonets from 60-70 years ago and they were the examples I had in mind.

I am originally from Pueblo. Been in NW since 1972.

[Ole South]

I already had a circular-saw blade head knife roughed out when I first ran into this thread back in '13. I was just beginning my leatherwork adventure and thought $90-150.00 for a blade I'd seldom use was an unwise investment (silly me). So.... armed with pictures of round-knives and ancient brain surgery implements I went rooting around in my tool junk. I emerged with probably one of the first 5 1/4 carbide toothed skill saw blades (note the diamond arbor in the pics), my Grandfather gave me, ever sold (bear in mind I'm a grandpappy myself) more'n 25 years prior.

Like Switz, never expecting this to be more than a utility knife, I carefully roughed out the blade profile (minding the temper) by-guess-and-by-golly with an edge grinder, a bench grinder and finished with a belt and disk sander. More by luck than good planning it turned out almost the same as our beloved Osbornes. Note: the Osborne has a more elliptical curvature whereas the diy has an almost perfect arc.

Version 1.0 got equipped with an Oak handle from a salvaged 1" dowel rod. You'll note the wicked pointy tips. Thinking these would facilitate tight inside curve cuts I thought they would be a good idea.

They are not.

They stick you in the wrist at the most inopportune times.

Version 2.0 corrected this and got a new handle (Rosewood). By this time I had procured and rescued a vintage Osborne and had a better idea of what fit my hand.

The third picture shows the Osborne sbs with my diy saw-blade round knife. The other two.... ummm, edged implements(?!!?) were made with scraps left over from the saw blade. The little skiver is tang-less unfortunately, but it works very well. The weird pocketknife/straight razor looking thing was just for fun. It's dangerous but cuts well, I use it for trimming edges. I may one day re-profile it into a single bevel fold-up skiving knife,

Okay... so how do they work???

Pretty well. The head knife when struck, rings like a chime. It sustains a ring longer than the Osborne ( if that matters).

Holding an edge:

The diy Round blade is a little more robust than the Osborne (both are mol .060" (+/- .001) at the handle but the Osborne tapers to about .046" (+/- .002) at the meat side of the bevel while my diy is .055". Both are convex beveled. The diy is better balanced.

I find I don't sharpen the diy Round as much as the Osborne but do sharpen the little diy skiver (same metal) more than my right handed Al Stohlman English skiver (which has nearly 2.x the cutting edge).

Usage:
I use the diy Round for heavier weight / stiff leather and the Osborne for thinner 2-6oz veg tan and most all the chrome tanned stuff. The Osborne works best when guiding around a template but the diy rocks free-hand thick work.

Net-net... they all hold an edge well and don't lose them when not in use. Considering there has been no heat-treatment applied... I'm very happy with the results. I've ended up with three knives from one worn out circular saw blade that I use as much as my store bought knives.

Edited October 28, 2015 by Ole South