Sword dynamics

Nice video, and a fine response to the "Swords were heavy!", etc., BS.  The people making and using these needed speed and fine balance, and they got them.

Be warned the closed captioning isn't very good.

I may not be able to smith much anymore, but I still like reading about discoveries

like this.
A study and excavation led by University College London (UCL) and published in the Journal of Archaeological Science, found evidence of chromium steel production in Chahak, southern Iran, dating back to the 11th century.

Up until the discovery it was widely accepted that the practice was a 20th century innovation made in the West.
Our various ancestors were not stupid(that they didn't die and we're here is some of the evidence), and produced a lot of things.  For instance, after reading about part of the Anglo-Saxon method of making a sword in England, I've said "If you asked them about carbon migration they wouldn't know what the hell you were talking about, but they could use the idea to help produce fine blades."

History.  You wonder just how much we do not know.

Wound up with something I've wanted

A real military kukri

Early one, has no British markings, does have Nepali markings on the spine.  This sucker is BIG, 19" overall.

I'll post some more on this later. 

Making two knives, the grips

When we left this the knives were being tempered in the oven.  Once they'd cooled completely, they went back to the belt sander to clean off the fire scale and oxidation.  Came out pretty well.

Those lines are to lay out the holes to drill.  I'm going to use brass pins and epoxy to hold the scales on.  I used the centerpunch to mark the hole locations, then drilled them on the press.

See that clamp on the left?  It's there as a safety: if the bit grabs- when it happens, usually just as it's breaking through the far side- it can start the piece spinning.  This is Bad; unsharpened, that point can rip you, and even with the back of the blade in the lead, it hits you it's going to hurt.  Some things I clamp in a drill press vise; can't do that here, so you put something in position so it's out of the way but will block the blade if it starts to spin.

Put a bit of cutting oil in each punch mark, use light pressure, and drill through.  When they're all done, you can take a larger bit and turn it in the face of each hole by hand to deburr the edges.

For the larger one I'm going to mark and drill some smaller holes(1/16") for more pins, so it'll match the big chef's knife already made.

By the way, on a knife like this I try to make sure the tang does not harden; makes drilling the holes a bitch.  Which is why I prefer to drill them before heat-treating.  If you plan to harden the entire thing, you WILL drill the holes before, or you won't drill at all.

Now we need the grip materials.  I've got a piece of walnut I'm going to use

Make sure the piece is thick enough, then on the side lay out the size you need to fit the tang, and cut it.  Remember, it has to be thick enough that, when you split it, the wood removed by the saw won't leave the scales too thin.

At this point you need to split the piece lengthwise.  Remember that the side you marked is not where you want to split; turn it 90 degrees and use that edge. 

Draw a line down the length and across one end(a square helps here), then clamp it in the vise.  If you start the saw at a diagonal on the corner, and keep it centered on both lines it'll make sure you're cutting straight down the center; once well started it's easy to keep it straight with just the one lengthwise line.  That gets you two scales.

To the belt sander, or to a flat surface where you can put down a sheet of sandpaper and sand the inside of each scale smooth.  Don't try to get it too fine; you want it flat to fit the tang, but that's it.  Say 100 or 120 grit will do fine.  That leaves a surface that's flat but still a touch rough, which means more area for the epoxy to get into and grab hold of.

Back to the drill press.  Line the tang up on one scale, and drill an end hole. 
Then stick a pin in that hole(I'm using 1/8" brass rod) to keep it from shifting, make sure the tang is lined up on the wood, and move down and drill another, preferably at the end, at least in the middle.  Then stick a pin in that one and drill the rest.  That'll give you holes nicely lined up.  In the case of the larger blade, I changed to a 1/16" bit and drilled those holes.

Take that scale off, and do the other.  That gives you the set.

Next step is to, one at a time and using a couple of pins to keep it aligned, mark around the tang with a fine-point pen or pencil. 

That will allow you to cut the excess off each scale right down to the line with a saw, or knife, or the sander.  You'll notice the front of each scale is a bit further forward than you'd want it to be, and that's deliberate; I'd rather sand it back a bit to fit than be looking at it a bit short and engaging in language practice.

Shape the profile of each, then use a couple of pins

to hold them together and shape the front as you wish it.  Go slow, check it frequently  so you don't overdo it.

At this point you can either glue the scales on as-is, or do a bit of sanding and shaping on the sides first.  I generally leave them pretty flat, as that gives a better surface for the clamps.  Also, if the clamps make any dings it doesn't matter, as they'll be sanded off.  I'm using a 'sets in an hour' epoxy, as I like to have enough time to get everything together before it sets, and if I can't do it in that time...

That's if all is ready.  Get all your pins cut, and use the sander or a file to bevel the ends a touch so they'll go in smoothly.  Make sure they're long enough to go through both scales and the tang and either be flush or stick out just a touch on both sides.  Count twice, be sure you've got enough(of each size in one case).  Get a place ready, have your clamps ready, and something to mix the epoxy on and with.  Note: if you're worried about time, get the 1 or 2-hour-setting epoxy; works just as well as the faster setting, and takes some of the time pressure off.  If you're confident, you can find 30-minute-set epoxy.  Be very confident before you do that...

Try the pins in the holes and make sure the damn things fit, no matter what the label says.  If they're a fraction large, now's the time to find out and either get some other material or sand these down to fit.

One more thing while setting up: either have some waxed paper to put between the clamp surfaces and the wood, or give them a coat of paste wax and let it dry first.  You do NOT want to find that one of your clamps has formed a bond with the wood.

Make sure the tang is clean, no traces of cutting oil, sweat or anything else on it.  I flushed these off with brake cleaner, and it wouldn't hurt at all to take some sandpaper and rough the surface just a bit.  Same as for the scales, more area for the glue to get into and grab onto.  I'd also suggest wearing some gloves, as you'll get the stuff on your hands if you don't.

Mix the epoxy. 

Take two pins and dip one end in the stuff and stick them in one of the scales.  Coat one side of the tang, the one matching the scale with the pins, put that scale in place and push the pins through the tang.

Coat the other side of the tang.  When I say 'coat', I mean it, don't be stingy.  You can mix some more if you need it.  Fit that scale on the two pins and push into place against the tang.

Dip each pin in the epoxy and push into place.  You can also use a toothpick or piece of wire to pick up a little and put it into the holes, then the pins.  Ideally a little epoxy will push out the far side as the pin goes through, you want the pin and hole to both get a dose.  Look everything over, make sure all's as it should be, then clamp.

Make sure the clamps are holding the scales snugly to the tang, but don't try to crush-fit it; you want there to be a fine film of epoxy in there, so don't squeeze all of it out.  Wipe off all the excess you can, especially on the blade, and then set it aside.  Whatever the label says, unless you're in a desperate hurry for some reason, let it cure until the next day.

Next day, take the clamps off and look it over.  Check for any cracks or splits in the scales, any actual problems with the fit.  If all's well, time to start sanding.

Yes, this is the smaller knife; I didn't trim the scales as well as the larger, and for some reason forgot to shoot a pic of the larger as it came out of the clamps.

If you cut the length of the pins so there's quite a bit sticking out one or both sides, no worry, just use a hacksaw and trim them flush.  Remember, when you start sanding those pin ends they'll get hot, push it and it'll be 'hot enough to make the epoxy soften' hot.  So use a light touch, and give it time to cool between cuts on the belt or disc.

Or, you can use a coarse file to do a lot of the shaping.  Wrap something around the blade to protect it from scratches, clamp it in the vise, and file away.  Completely removes the heat problem.

On the sander, I use a fairly coarse belt first so it does the gross sanding fast with less heat, but be careful not to take too much off.  Round the corners off, and remember you can use the belt at the rollers as well as on the flats or disk.  Keep trying it in your hand, and when it's close shut off the sander, and go to the vise and start using sandpaper.  'Close' being very subjective: when you get the hang of this you can get it very close on the power tools, until then I'd suggest leaving enough that you're certain of not removing too much.  Remember, power tools not only make a job easier, they make it possible to screw things up REALLY fast.

At this point I'll clamp the blade in a vise(use some padding, but not anything that'll give and let it move on you; it'll shift a bit just from the springiness of the steel, you don't want to add to that.

You can start off with a file(half-round here) or fine rasp where you have a lot to remove.  Then to to the sandpaper.  Or  abrasive strip.  It's 1" wide cloth with the abrasive on one side.  You can get it in just about every grit and different widths, just tear a length off and use it shoeshine fashion, or where you want to keep a surface flat wrap it or a piece of sandpaper around a fine file or a flat stick and use it that way.  Smooth the shape, and keep going until it suits you.  I'll throw in, it doesn't HAVE to be rounded; you can make sure the scales are even in thickness and just sand the corners off so you have a octagonal shape for the grip.  Works nicely for kitchen knives.

I'd suggest taking it to 220 grit for the finish, though you can go as fine as you'd like.  Remember, the finer you sand, the smoother the surface will be.  In the ase of a kitchen knife like this, I don't want it slippery, so I stop at 220.  For that matter, you could just go to 120-150 or so and stop there, though it'll take more finish to fill in the grain.  When all's done, the shape and finish are as you like it, time to finish it.

That can be as simple as linseed oil, getting some of the 'knife handle oil' from one of the kitchen supply companies, or a gunstock finish.  If the wood's pretty dry, might try a combination. 
For linseed, get some boiled linseed oil and wipe it heavily onto the wood.  Let it sit a few minutes; if a spot starts looking dry, put another dab on.  You want the stuff to soak in, so no rush.  When you think there's enough(I'd say ten minutes tops for thin pieces like this), wipe off the excess and set it aside for the oil to dry, I'd suggest either clamping the blade in the vise or otherwise security it so the wood is not in contact with anything.  Depending on weather, it can take a week or more to dry completely.  One thing I have known people to do is put the linseed on, give it plenty of time to completely dry, then do the other finish over that.  I'd not suggest it if you won't/can't give it the time to be absolutely dry, as if the linseed isn't when you put the other stuff on it can cause problems with the finish over time**. 

For the other stuff, follow the directions.  What I like best is Minwax Antique Oil Finish.  Doing it right will take a week or so(multiple coats, each needing time to dry), but it soaks into the wood, dries hard and is a good protectant.**

What happens if you check the work over and find a real problem?  A big crack, or split, something that can't be fixed in place, something that means you have to replace the wood?  Remember I mentioned heat making epoxy soften?  Turn the oven to 350F, when it's at heat put the knife in on a piece of foil or something and leave it a few minutes while you put on some gloves.  When the stuff gets hot enough it starts to soften, and you should be able to pull or pry the scales off.  Clean the epoxy residue off the tang and pins, and do it over.

And that's it.  Start off with good steel, take care while you work it, and you can produce a knife better than that available to most of humanity(including royalty) through most of history.


Note:
For sanding a truly flat surface, you can use either a surface plate, or, if there's a glass place around, get a piece of thick plate glass about a foot square.  Use a piece of plywood to make a base for it, maybe a piece of rubber tool-drawer or cabinet liner under it.  Stick a piece of suitable sandpaper on and start sanding.

*Same with gunstocks.  Linseed is often used as the first treatment on the stock, but if you're going to use something else to seal the surface, make damn sure the stuff has had time to dry.  I'd suggest a full two weeks, more if the weather is cool/cold and/or humid.
**First heard of this stuff on a thread at The High Road
http://www.thehighroad.org/showthread.php?t=240961
which had the procedure for gunstocks.  You basically do the same with knife hilts.

A couple of knives, beginning to end

I'd mentioned making some kitchen knives for the offspring & wife.  I got the big one done in time for them to take back with them, but the smaller, no.  So thought I'd go over how I'm making them*

I'm starting with a flat piece of O1 tool steel, 2" wide and 1/8" thick. 

 Use the hacksaw to cut an appropriate piece.

 Mark the point(a bit oversize), and the tang(where the grips go),

 and cut them, leaving the rough blank.

 Go to the grinder and clean up the profile.

Here I had taken it to the anvil to straighten, as it had a bit of curve in it.  Then I hit it with the belt sander to clean up the sides a bit.  Which could've been done on the grinder as well.

 Next step, grind** the edge area to a little over 1/16" thick. 

I work back from there, grinding material off, cutting deeper toward the edge, on both sides.  Light pressure, and keep it even.  Keep a bucket of water handy so you can cool it off when it gets uncomfortably hot.  In this case, the steel being in an annealed state, you can't mess up the hardness by getting it too hot, but you can burn the crap out of yourself.

When it looks pretty even on both sides,

 make sure the face of the grinding wheel is even, and work it lengthwise.

 This lets you see if you have any high or low spots to deal with, also if you need to change your angle a bit.  I'm grinding this so it's a straight taper from back to edge, so if I do this step and find the bevel is a bit off, I can correct that. You can make the bevel run from the back, partway down, wherever you choose for the blade shape/size/steel you're using.

 When that's done and all looks even, I go to the belt sander.  This is a 6x48" model with a 9" disc on one side(same one I used in crowning that barrel).  Keep that water handy, and start with a coarse belt(in this case 80 grit).  Work both sides, and clean up the marks from the grindstone.

You can also clean up the profile now.  When you have all the coarser marks gone, go to a finer belt. 
Note: they make a eraser-type block to clean the dust out of the grit, I highly recommend it.  I used to have a tube of a belt lubricant as well, you used it on the belt before you started cutting and it helped keep the grit from clogging.  Wish had some of it left.

Work each grit at a slightly different angle, which makes it easier to be sure you got rid of all the previous scratches.  And make sure the tang is flat as well.

A word on belts, this size or any other: locally I can find 80, 100, 120 and 180 grit.  If ordering, I can get anything from VERY coarse(as in 36) up to 400 grit.  If I were working on something I wanted a very fine finish on, I'd get a selection up to 400, then use buffing wheels for a higher polish.

But not right now.  We'll be going to the forge to harden these blades, and taking it beyond 180-200 would be a waste.  Much like polishing a gun you're going to rust-blue beyond, say, 320.

One more note here: the steel is as soft as it's ever going to be, so get the profile cleaned up and the bevels correct now.





Here's my forge.

  It's an old Champion portable, cast-iron bed and a hand-crank blower(I did have a bigger forge, different design; it gave up not long after I had to stop forging).  I used to use coal for the fuel(more heat per pound), and I still have a five-gallon bucket left, but to keep the smoke down here, since it's now available, I'm using charcoal.

NOT briquets.  They make those by grinding the charcoal to dust and mixing it with a binder, usually clay, wetting it and forming it into those nice, uniform pieces.  But the binder generates a LOT of ash, and causes it to spit badly when you start pushing air through.  Now, happily, raw charcoal is easily available, so I'm using that.

This odd-looking piece is for heating longer blades than these; piece of iron pipe cut in two with a bunch of holes drilled through.  Allows you to have a longer, narrower fire when needed.  In this case did not use it, blades not that long.  Do note that you need to either use a piece of brick or something to block the ends so the air doesn't all take the easy way out.

 I use some fire bricks to form a narrow channel(Yes, I forgot to take it out for the pic). 

A barbeque fire chimney works nicely to light it,

just let it sit until the coal is all burning, then dump it into the firebed.

This is my quenching trough.  Since these are small blades I'll prop one end up and just use the other end, that'll be plenty of oil.  As the fire is burning in, I'll stick a piece of heavy steel in- in this case a railroad spike- to heat, then I'll drop it into the oil to warm it.  Warm oil flows more easily, and gives a more even quench.  And if it's cool or cold outside, that'll also mean a bit less thermal shock to the steel.

As to the oil, more years ago than I care to remember I dug around and found a industrial oils company in Tulsa(they're still there) and called them.  They put me through to a salesman who listened to what I was doing and suggested a light quench oil, and sold me a five-gallon bucket.  I've still got about half, and if it hadn't been for some spills there'd be more; it doesn't wear out, just cap it tightly when not using it to keep moisture out.

When the fire is ready, what I do is put the blade in back down for a couple of minutes,

with low air blast, to warm the piece slowly.  That does two things:
I can pull it out and see if the blade warped any as it heated(and can straighten it now), and
I think it acts as a stress-relief heat.

Then it'll go in edge down. 

Low air blast at first and move it back & forth to heat it evenly, then stronger air when you're ready to bring it up to critical temperature.

You don't have to get the whole blade up to critical temperature, I like to get the area from the edge back to the line

up to full heat.  Keep it moving to keep the heat even, get it to that shadowless red I wrote about before, then into the oil, edge down.

Why only that part of the blade?  It's called differential hardening: the part that does the cutting, both now and as it wears down over time with sharpening***, is fully hardened, and the area behind that, since it's below critical temperature, will harden some, but not completely; more of a spring hardness.  I started doing that quite a while back, and especially for big blades and need to be able to take the shock of heavy cutting and chopping, it works beautifully.

You can get some of the same effect from getting the whole blade up to heat, but only lowering the 2/3 to 3/4 of the blade from the edge back into the oil; the rest will cool much more slowly and not fully harden.

I do two quenches.  While the first blade is cooling, I heat and harden the second.  By the time that's done I can look the first over, see if it warped and needs straightening.  If all's well, back to the fire with the same procedure as the first time, then same with the second blade.

This is out of the oil and cooled. 

No, no pictures of the heating and hardening, I'm not going to try to do those things and juggle a camera. 

Once cooled, or if you're impatient after it's been in the oil at least 30 seconds(preferably a minute), check the edge area with a sharp, fine file; set one side of the blade on something to steady it and slide the file across.  In the case of good medium and high-carbon steels, if they fully hardened the file will slide right off, doing nothing more than cleaning the surface a bit.  With a medium-carbon steel it might be more of a sensation of the file almost biting.  If the file actually bites, you didn't get it quite up to full critical temperature and it'll have to be heated and quenched again.

Wash the pieces thoroughly to get rid of the oil, then into the oven at 400F**** with a wire rack to keep them edge up.  They're also sitting on either a cookie sheet or baking stone(another reason to do a good job washing) to even out the heat.   At this point, remember: those hardened blades are hard.  Brittle hard.  Drop them on a hard surface and they may well crack.   So handle them carefully.

Leave them in for an hour, then pull out and let air cool.  At this point I'll take them to the belt sander and shine them up, then back into the oven.  Yes, I could do this before the first tempering heat, but remember that part about brittle?  I'm more comfortable doing this after the first heat.

Another hour in the oven, this time at 425F, then let them cool and look at the color.  With this steel and for this purpose, I like a medium-bronze color, which corresponds to a tempering heat of 425, if you cleaned all the oil off and have a shiny surface to start with.  Hard enough to hold an edge quite well, not so hard that you'll chip the edge hitting a bone or something.  After it's cool, back in the oven for one more hour, at the end of which turn the oven off and leave them to cool inside.  In this weather, and tired as I am, that means I'll start the finish grinding, drilling for pins and polishing tomorrow.  Which will be another post.

Just to cover everything, while the blades were cooling I scooped the remaining charcoal out and into the water bucket, poured the oil back into its bucket, and generally cleaned-up and put-away.

You DO have a water bucket around while doing stuff like this, don't you?  Uses are wide, from putting out the charcoal afterward, to 'Guess I better put that grass out', to "OW!  HOTHOTHOT!"





*Because I didn't think to do this on the big one.
**You can do the whole thing on a belt grinder.  I like to do the heavy work on the wheel, and save the belts for flat-grinding and polishing; they're not cheap.
***Use good steel and heat-treat it right, it'll last longer than you'll live before it gets past the hardened area.
****I know this steel, the second temper will be at a higher heat but I like to start here with O1.