Knife 49 – Hunter – EDC – Testing the Knife’s Hardness
Blade – 4 3/4″
Overall – 9″
Scales – Stabilized Spalted Beech
Handle Finish – Hand Rubbed Oil
Testing the Knife’s Hardness
Up to this point Testing the Knife’s Hardness has been to chop a hardwood scrap, roughly 2” x 2” by chopping at it as hard as I could. A used knife I had folded on the test and I couldn’t get it heat treated so it would not harden. I was still researching trying to find a better way without buying expensive equipment.
Then I stumbled on the “Brass Rod Test”. I think this test
is a little more reliable and I’m not sure why it’s not documented with more knife
I did find a couple different processes, both basically the
same. On way is to just hold a brass rod in a vise, the other you mount it in a
block of wood. I decided to mount a piece in a block of wood.
You don’t want the knife completely sharpened yet, but the edge
geometry needs to be close to sharp. The idea is to fold the edge. If the edge
returns to the original shape, the knife has the proper temper. If it folds and
stays folded, it not hard enough. If it chips, it is too hard and should be run
through a tempering cycle at a higher temperature than before.
Hold the knife at slightly more of an angle than the sharpening
angle and put pressure on the edge enough that you see it fold. A light shining
directly on it helps. As the edge folded, the light will change. Now drag the
edge across the bar watching the fold slide. If the edge returns to its
original geometry, you’re good to go finalize the sharpening. If the fold stays
folded, the knife edge is not hard. If it chips, temper again at a higher
You can also force the edge to deform while checking the weight
required to force a deform. If you can push at 30 pounds or so you know you’re
ok. This is a good test once in a while, but until I bought the file set Hardness Testers
on page 74
I did the test on every knife I made.
After a while, I began to become more interested in a serious test for hardness. I decided to order the “TTC 6 Piece Hardness Tester File Set”. This will allow me to get the hardness within the 60-65 Rockwell hardness which is ideal for a knife.
These file help measure Rockwell hardness. It’s measured as HRC,
or Sometimes RC. An abbreviation for Rockwell Hardness measured on the C scale.
The abbreviation usually appears after a number, e.g. 22 HRC. See: Rockwell C
Hardness. Rockwell C Hardness is a designation of hardness, of steel or Corrosion
A typical knife will usually be around 62RC, although some
knives such as cleavers may be as low as 55 HRC as will machetes. Hatchet would
also be 52 – 55RC. Some like a softer steel in the 54-56 RC range their knives.
Softer steels require sharpening more often, but they are much easier to
sharpen than harder steels. They are also less likely to chip. The edge is more
likely to roll over, rather than chip, which is a much easier fix than a
To use the file to test my knives, I file the heat treated and
tempered blade with the 55RC file. If it skates off, the blade is harder than
55RC. I then try the 60RC file. If this one almost bites or bites a little (a
metal shaving shows up or there is a visible scratch) you are around 60RC.
Moving up to the 65RC. This should skate over the steel. If it doesn’t another
temper cycle may be in order.
One of the questions I’m sure you’ll ask is what kind of tools do you need. I’ll tell what I use, and possible substitutes as well. A lot of the equipment is the same as you will will find in other types of metal and wood work, so a lot of it I had at hand. You may to. If not, I will tell you my opinion on what is a must have to start and a nice to have as you go.
A few basic metal working tools and supplies would be hack saw, an assortment of files, wood rasp are handy for handle forming, a scribe at (which can be made). Don’t forget clamps. I use quick grips, Pony spring clamps and C clamps for most of my knife making.
You’ll want to pick up some sand paper and sanding belts. The kind will depend obviously. Flat sheets from 60 to 2000 will be used. Belts for whatever belt sander or grinder you plan to use. If you’re only going to made one or two knives, I suppose it’s possible to do every thing by hand sanding, but I really don’t believe it’s realistic.
For forging I just use a cross peen hammer I bought at tractor supply. I sanded the finish off the handle for a better grip, did a quick polish on the face. This is for general forging. Any type of hammer will work for the stock removal method. Just something to tap pins in and out and similar task.
If you plan to forge you will need something for an anvil. A real anvil is the obvious best choice, but not a requirement starting out. Almost any heavy flat piece of iron will work.
I mentioned a vise in part 1 as well. Every shop will benefit from a good vise. Most shops wind up with multiple vises. You probably won’t need one at first, but you’ll want to keep it on the list. Eventually you’ll want one, and once you have one you’ll wonder how you lived without it.
Mallet. – Make yourself a wooden mallet. It will come in handy and in some cases, a metal hammer is not the best tool for the job.
Pliers. You’ll want a pair of pliers and/or vise grips. I think we can assume if your reading this you’ll have these, if not get some.
After I built my belt grinder, I built the follow jig for creating the edge bevel on a knife. In a lot of YouTube videos a lot of the bladesmiths like grinding the bevel by hand. This just didn’t work for me. If you can start right out of the gate doing a nice job by hand, then do it. If not, build yourself a similar jig. I couldn’t find one online i liked as it was shown. Some were to an extreme I didn’t need nor did i have the metal working skill to make. Some I just didn’t like for multiple reasons. I made this and I haven’t seen one exactly like it, although there may be. It works well for me.
It’s worth noting that a belt sander or angle grinder could be used in place of the belt grinder or even the belt sander mentioned in Part 1. It will take a bit more patience and a steadier hand, but it is completely doable.
I also found that finding the center line speeds up the grind. It allows you to grind almost to the line on each side, which eliminates the alternating from side to side. I made this one in a few hours with some scrap metal. It should be pretty self explanatory, but feel free to shot me an email or post the question on the forum.
I also have a metal cutting bandsaw. I have had this a long time, so it comes in handy. However, I don’t believe it’s something you need day one. A hacksaw, or a cut off wheel in a grinder, or jewelers saws, etc. can all be used instead.
Drill press – I think a drill press should be considered a must have. I’m sure you “could” get by with a hand drill. Even a small benchtop drill press would be a great addition beyond a hand drill. Drilling the handle material with a hand drill is not bad, but drilling the handles would be much better and easier (along with safer) with a drill press.
I mentioned the forge in Part 1, and as stated, it’s not really a requirement unless you want to heat treat, and you don’t want to sink the funds into a heat treat oven.
Heat Treating. – I will do a post about my journey into heat treating in another post, but I wanted to do my own, so I’m still learning and will be for a long time.
Square. – You will want some kind of square. What kind really doesn’t matter much to start with.
Dremel tool. – A Dremel tool is by no means a must have to start. It will come in handy when and if you have one. For those that go on rust hunting journeys, they can often be found at flea markets and second hand shops.
A Dremel tool is by no means a must have to start. It will come in handy when and if you have one. For those that go on rust hunting journeys, they can often be found at flea markets and second hand shops.
Drill bits. – Drill bits are an obvious must have if you plan to pin your handles. To start, you’ll just need the size or sizes of the pins you plan to use.
If you will be making your knives with hidden tangs, you may need to expand the sizes a little.
Taps. – I use tap and dies a lot in Tool making, but for this, you’ll only need them if you plan to use screw to hold your handles on.
Leather working tools. – I’ll cover this more in a separate post, but if you’re going to make leather sheaths, you need to think about leather tools.
Saw. – I use a bandsaw to rough out the handle scales. A coping saw would work just fine. I image you could find creative ways to use almost any kind of saw for your first knife or two, but I’d recommend at least a coping saw to get you going.
Epoxy. – You’ll need epoxy for setting the scales. I’ve tried both the 5 minute epoxies and the slower set epoxies. The shower set is stronger, so it’s what I typically use. I’ve also found the 5 minute stuff can rush me from time to time. I’ll go into more detail in my handle making post, but I am currently using WEST SYSTEM 650-8 G/Flex.
Sharpening. – You’ll need to figure out how you’ll sharpen your knives. There is an endless number of jigs and processes and techniques. If you have nothing today, you can start with sandpaper on pieces of metal. Oil stones, water stone, diamond stones and systems like this all work well.
Scales. – Hard wood scales are probably the easiest for most to have on hand. They work well, look fantastic, and are easy to work with. As of this writing, it’s all I’ve used. The modern composites are worth looking into however and look for a post as I drive into that pool.
Finish. – If you’re going to use wood scales, you’ll need a finish. I recommend tru-oil. It’s traditionally for gunstocks, but I have used it for everything from gunstocks, to hand planes, to knives. It will serve you well. I also like a good hand rubbed BLO finish, but then almost any oil based finish should be fine. I’m typically a “use what’s on hand” kind of builder, and this is no exception.
Layout Blue. – Layout blue is handy to have. Probably not what I would call a must have, but it is something to keep in mind as you want your layout to become more precise. Here is what I use.
A way to make a makers mark. I didn’t mark my first few blacksmithing and bladesmithing projects, and I kick myself for it, especially the ones I gave as gifts. It doesn’t have to be elaborate. Think about it.
I do not have a lot of trouble Sharpening knives, bit I wanted something with a consistent and repeatable edge from knife to knife without spending a bunch of money. This seems to be doing the trick.
I made the sanding sticks from hardwood. They’re 1″ wide. Sandpaper is glued on. Note the leather strip is on a 1″ metal bar. I tried metal for the sanding sticks but liked the wood better. I found the metal to heavy and a bit unforgiving. I’ll probably remake the strop on wood to.
I made the layout by clamping a knife and marking 17, 20, 25, and 30 degrees. I then drilled the holes so the top of the rod is at the bottom of the line.
When I built my belt grinder i used a 2 hp single phase motor I had on hand. I wasn’t exactly sure how much I’d use the grinder, and I wasn’t sure how necessary variable speed would be. I since discovered it is one of the most used pieces of equipment in my shop, and almost invaluable for making knives. I also found myself wishing I could slow the belt down quit often.
So I decided to upgrade. I purchased these two items.
Unfortunately for me, I did’t order the VFD from Amazon. It came and I hooked it up and it didn’t work. The status light was doing a slow red blink. A search on the internet suggested a bad unit. I called KB and sure enough, they said the unit was shorted. I could return it to them, they would assess it, and fix it or send a new one. I was not a happy camper and did not want to wait that long.
I called State Motor and Control Solutions where i had ordered it online and they immediately sent out a new VFD, but I had to pay the $30 return shipping on the bad one (I would have had to pay this anyway). Not ideal, and not perfect customer service, but better than the manufacturer. I should have ordered from Amazon I guess.
I’m not sure what the U,V, and W stand for but they get connected to the 3 lines on the motor. When i connected mine, the motor was running backwards for my grinder. Another quick search and I discovered changing two wires on the motor changes direction. It worked like a charm.
Being able to control the belt is a big help, especially grinding bevels. It’s also helpful for sanding wood that’s prone to burn. I’m finding the variable speed a huge help and use it almost every time i use the grinder now. It’s well worth the extra effort if you’re thinking of building a grinder.
Two things prompted me to get a different quench tank. First,
I discovered that it was better to heat the oil by heating the tank instead of
dropping a piece of hot steal in it. The oil doesn’t break down as fast. To be honest,
I didn’t even think about the oil breaking down.
I plan to add a block heater to the quench tank but for now
I’m just sitting a torch beside it until it hits a little over 120 degrees.
And the second reason was I was starting to think about making longer
It only takes a couple minutes with the torch to heat the
oil to approximately 130 degrees.