Lakeland Public Television presents Common Ground made possible
by the Minnesota Arts and Cultural Heritage Fund and the
citizens of Minnesota. Production funding of Common
Ground is made possible in part by First National Bank
Bemidji. Continuing their second century of service
to the community, a partnership for generations.
Member FDIC.
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♪ Welcome to Common Ground
I'm your host, Scott Knudson. In this
episode Curtis Olson of Bemidji uses high
tech steel to create a classic hunting
knife.
♪
♪
Hi, I'm Curtis Olson
welcome to my workshop. I make knives and I'm happy to show you what I do.
Basically I make custom hunting knives.
Drop point hunters, maybe three and three quarter inch, four inch blades.
And this one happens to be CPM 154 steel
it's stainless steel with a high molybdenum content.
And it's a great carbide. The steels that I
use are some of the best steels ever designed
by human kind. And part of it is
technology, part of it is knowledge, part of it is ability to
heat treat it. But steel I really like to use is CPM
154 or CTS HXP. Both of those steels
are particle metallurgy steel. And one's made by
crucible steel one's made by carpenter steel. But the
particle metallurgy differs from regular steel
in that regular steel is hot rolled and they
form it into bars and then they let it cool.
CPM technology is they take the molten steel, the molten alloy,
and they run it through a very fine nozzle and
they blast it with argon and they make it dust.
And they carbide the chromium, the carbon is
all evenly distributed throughout the blade, throughout the steel.
And that's what CPM technology is. I make the sheaf
to fit each knife. This one happens to be
stabilized walnut and the finish on the outside is super
glue finish. I begin making a knife by purchasing
the steel and I get that from knife supply
houses. Also specialty steel supply
houses. I buy it in six foot bars. I'll show you
that. This is what a six foot bar of
CPM 154 looks like.
It looks like that.
And then the first thing I do is I paint it with Dykem,
which is layout dye. Then make it look blue so if I
scratch on it with a carbide scratch I can see what I'm doing.
And I take one of my patterns
and see my patterns are over here, I got some patterns over there. I paint
them red if I use them quite often. I take this pattern
or whatever pattern I'm using and I put it on the steel with
the Dykem on it and I clamp it down...
and I push pretty hard. And I take the carbide scribe and just
scribe around the top, the blade,
the handle, the back end and then it's scribed.
Then I take that six foot bar and I cut it out and it looks like
this. Using a cut off wheel you can see the slag on
the side. And I have to remove that and get closer to
the lines, you can see the lines are there. So you can see the line is not
very close, I do that on purpose so I can be more accurate with a
grinder rather than a cut off wheel. So that's it with
the slag on it. Rough cut.
Next step is to get rid of that
slag. And here I've gotten rid of the slag, it looks a lot smoother
on the edges, it won't cut you. And the lines are cut very much
closer to what they should be.
And also, once I get the slag off and I get
really down to the line, I will then set up my
grinder to be very accurate at the 90 degree
angle from here to there. And then I'll make it
you know as perfect as I can get it all the way around. Cause I
like to start with as perfect as I can get it
90 degree everywhere. That's what it looks like
with the slag removed. The next step is to square everything
off. I...want to get everything as
accurate as possible so I set my machine up
with right angles and really get them very accurate.
And I make the right angle here, at all the edges.
So I know both sides are the same. And I've done that with this one.
So this ones already done, so it's pretty accurate.
The next step that I do
and this might be necessary, it might not be. But I like to make it
very clean. I surface grind
the flats so they're dead flat. So you can see what it
looks like, how the...shiny there.
But it's dead flat from top to bottom from front
to back. So now when I grind it I know that
if I mess it up it's my fault it's not the blade. [laughs]
The next step after surface ground
is to put lines, ascribe lines
very acute lines, where you're going to grind the blade.
And because I taper all the tangs of my hunting knives
I also have to put these very clear lines on the
back end of it, on the tang part. I put the lines here,
here and on the blade where I grind it.
And these lines are between 20 and 30 thousandths apart.
And I use a granite surface plate that keeps
it dead flat and dead straight.
[loud clank] The next
step is to plan the handle. The handle holes. You
can't drill the handle holes once you harden the steel. You have to
plan it out beforehand. So, the next step is to take that
piece that has scribe lines on it and paint the back end of it
with Dykem, layout dye. And mark it. I use
a caliper to mark it, to make clear lines on either side of
it so they're very even from top to bottom. And then I
take a center punch and I punch over here
and I punch in the back. And then I take my caliper
again to find out where the middle is and I just scribe a line there
there, flip it over...and then
put the center hole right there. And that thing is ready to drill.
[loud clank] The next step
is drilling it. And that's nothing
nothing new, you just drill holes. This is a different pattern.
But the holes here are for Loveless bolts
and for a stainless steel line thong hole.
So the next thing I'll do, I'll show you how I grind the blade.
But first I need to put my respirator on because
knife making is a dangerous activity.
And breathing is one of the
fundamental things that we humans do.
And I don't want to breath steel dust for too long.
So I put my respirator on.
Safety glasses
and I'll go
start to grind.
[switch]
[motor running]
[motor running]
[loud screeching]
[loud screeching]
[loud screeching]
[loud screeching]
[motor whirring]
[motor whirring]
[motor whirring]
[loud screeching]
[loud screeching]
[loud screeching] This grinder is a grinder that was
designed and patented and made
by Mike Leech. Mike Leech was my teacher in Michigan who showed me
how to make knives. He was also a tool maker for GM
in Flint. So he had all the abilities and all the
tools at hand. So he designed this machine. He's made
seven of them. There's only seven of them in the world, and I have one of them.
And to make a knife you have to have some way to
put a grind in the blade. And then he said, this is what you have to do. You have to get
something to grind the blade and this is probably the
one of the better ways to do it. For a flat grind.
Now this is what it will look like
when it gets ground. This is a flat ground blade.
And you can see it right here.....
flat ground on both sides. The next step
is to taper the tang. So what I'm gonna do is
first cut down to the lines here
that I've scribed 30 thousandth inches apart
just make a little cut there. And then I'll
go ahead and hollow grind both sides. And then
taper it from there.
[loud clank]
[puff of breath]
[puff of breath]
[tool clank]
[puff of breath]
[tool sliding]
[machine running]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring]
[loud whirring and grinding]
[loud grinding]
[loud whirring]
[loud whirring]
[whirring softer]
[whirring softer]
[whirring softer]
[whirring softer]
[whirring softer] [puff of breath]
[puff of breath]
[motor running]
[motor running]
[loud whirring]
[whirring]
[grinding]
[grinding]
[grinding]
[grinding]
[grinding]
[grinding]
[grinding]
[grinding]
[motor stopping]
[puff of breath]
[rustling]
[puff of breath]
Next thing we'll do is
to sand these course scratches off cause I don't
want to have a hardened steel blade with that course scratchin
it's hard to get the scratches out of a hard blade. Much easier now.
And I'll sand it at 320 grit on this flat
wheel that was made in the GM brake
lathe.
[motor running] [grinding]
[smooth whirring]
[smooth whirring]
[smooth whirring]
[smooth whirring]
So what I'm trying to do, these scratches here
are 120 grit scratches, they're pretty course.
I want to take those out and I also want to flatten this part over
here, take those scratches out. So, I have the scratches out on
this flat part here. Now I'm trying to take out the scratches on the
blade itself. And replace the 120 grit
scratches with 320 grit scratches.
And also make the plunge cut a little bit smoother.
Cause it gets pretty square on the machine over there
I round it off a little bit.
[smooth whirring]
[smooth whirring]
[smooth whirring] [switch off]
So, the scratches are now out. And it's kinda
warm there so I'm not gonna touch it. But it's ready for heat treat.
So I will take this
309 stainless steel foil and I've already
pre-cut it to 12 inches by 6 inches. It comes in 50 foot
rolls, 3 feet long. And you take the steel
that you want to put in there. This is a knife that's been ground
taper tanged, holes drilled, blades sanded
and the holes chamfered so they don't crack in the heat treat.
But also you put in the piece of brown
paper, doesn't matter if it's brown or white doesn't matter. But you put it in there
so when you heat it up to the temperature this
will be sealed. And the burning consuming that
sucks the oxygen out of there. And that will burn it you know, much
lower temperature than the quenching is. I'll start wrapping this
up and what I do is I just do this....
I fold it.
And I also mark it. I want to mark what
steel it is so I don't get it messed up. But I also aim
I put an arrow on here, so I know which goes in first.
Because
when it gets hot enough to...quench
the steel gets almost fluid, it gets soft.
If you grab it by the point you can bend it real easily. So the back end is
here. I always put it in point first so the pinchers
that I take it out of will grab the back end which is thicker.
Anyway, that's...what it looks like.
And then I fold it up and here's where you have to be careful because this
stuff is so sharp it will cut you a good one.
[loud pounding]
[loud pounding]
[loud pounding]
[crinkle]
[crinkle]
[crinkle]
[loud pounding]
[loud pounding]
[loud pounding] That's a double seal on that end on that side.
[crinkle]
[loud pounding]
[loud pounding]
[loud pounding]
[crinkle]
[crinkle]
[crinkle] [loud pounding]
[loud pounding]
[loud pounding]
[loud pounding] And this packet is
now ready to go into the furnace.
This is my furnace. It's an even heat oven made
in Michigan. And it has places inside
to put
six or seven blades so they're vertical.
So the heat acts on the steel evenly. So I put
here's the arrow, I know where the point is
it goes in this way. So the thickest part of the blade
when it's so hot it'll be almost fluid
I will grab that and it won't bend the point.
There's that.
Ok here's the
numbers. I turn it on [beeps] this is a computer controlled
furnace. And....[beeps]
it has four sets. I'm using
the first set. There's
two segments to this heat treat.
I ramp full on the first segment
I ramp full to
1450 degrees. And I will hold it
for seven minutes while it equalizes in temperature.
And then it'll ramp full up
to 1950 degrees which is the
austenitizing temperature, that's the quenching temperature.
And we'll hold that for 25 minutes.
[beeps] And it's ready and
it's on.
Time to take the blade out of the oven and
quench it. So I take the tongs and
I take it out and I make sure to hold that blade vertically
if you hold it, if you tip it sideways, it's so soft
that it will bend. So you hold it vertically. You take it out
and set it on the plate, the aluminum plate vertically. And then you
flip it down sideways so it's always touching the
spine of the blade. And then you put the other aluminum plate on top of it
and put some tension on it. Let it cool
and you can feel the plates are warm. So the blade's getting
cooled nicely.
[heavy slide]
[metal pop]
[tools clanking]
[metal pop]
[clunking around]
Still warm.
But not bad.
[metal crunching]
[metal crunching]
[metal crunching]
[tools clanking]
[metal bang]
Here's what it looks like when it comes out
all those colors.
Now what I do, is I will
take my Rockwell hardness tester, Aimes
hardness tester. And what it does is it will
measure the distance that this diamond penetrator
goes into the steel at
150 kilogram pressure.
So I put it on there, I'm finding a good flat spot,
I put it in there.
I get...
right to a set mark which is zero.
Right there. I move this
wheel to the acrylic
and then I put the 150 kilogram force on it.
There's 150
kilograms. Now I back it off, back
to the set mark to the zero mark.
And I read directly
right on 60.
A lot of factory knives are 55.
Custom knives are usually 60-62. Some steels can
go 62 but files are usually
about 59 or 60 so this will not be
cut by a file. It'll skate right over it.
Now, I will quench this in liquid nitrogen
and I let that soak for over night.
And I expect the numbers
to go up maybe two. So this is right now 60
hopefully when it gets done, cyrogenically being treated
it will be about 62. It completes the austenite
to the martin site transformation and it does all kinds of
other good things. Stress relieves it.
And grain structure the whole thing. It benefits the steel in many
ways.
[tank sliding]
[clanking]
[clanking]
[clanking]
[metal sliding]
[metal sliding]
[muffled whirring]
[muffled whirring]
[metal sliding down]
[shuts lid] And there it is.
So now it comes from
the cryo and I temper them twice. Every knife has to
be tempered twice to make them not brittle.
To make them resilient to make them tough to make
them more resistant. And I temper each of them twice for two hours.
After that it's time to polish it. Here's what it looks like
when I start off, when it comes from
all the tempering and the cyro and the whole
quenching thing. And I'll show you what it looks like when I get it polished up a little bit.
[motor whirring]
[motor whirring]
[soft whirring]
[soft whirring]
[soft whirring]
[soft whirring]
[soft whirring]
[soft whirring]
[soft whirring] [switch off]
So there it is at 320 grit.
Now what I typically do is I'll go to 600 grit.
[sandpaper smoothing]
[sandpaper smoothing]
[machine turns on]
[soft whirring]
[soft whirring] [grinding]
[grinding]
[soft whirring]
[grinding]
[grinding]
[grinding]
[grinding] [switch off]
And there it is
to 600 grit. You might not be
able to see much of a difference, but there is. I go back
to 400 grit and I go this way.
To make sure all the scratches at 320 grit are gone. And then I go
to 600 again and then I go to 800
and then I go to 1000. I want to make sure all the scratches are this way.
And then I buff it.
Next thing is to polish this with
a flat block.
I always sand with a block.
So you keep things flat. And I use, I start...I go back
this is 600 grit now. I go back to 400 grit to
make sure there's nothing in there that's going to surprise me later on.
[scratching] And this
probably takes more time than anything.
In my thinking, if you want to make a highly polished knife
this is how to do it. [laughs] And you just have
to sand it until, sand it and look...
and be honest with the
the scratches that you see in there. Sometimes I
wish them gone so I don't see them.
They'll come and bite you later on. Guarantee. Soon as you get to the next
finer grit, they're there.
[scratching]
[scratching]
[scratching] The next step
would be to take 600 grit
and ok, so I'm making everything go this way because I'm
taking more of the scratches out and this is more of an inspection thing.
600 grit would be then this way....
800 grit would
be then this way...90 degrees to what you just did.
1000 grit would be this way...
again. So you can see exactly
what you're doing. If you go parallel you
can't really tell anything but if you go opposite you can tell everything.
Well this is a completed knife right here
and you can see that
starts out in this piece of steel.
And we grind it, we drill it, we plan it.
Shape it. Heat treat it. Polish it. Put a
handle on it. And this one has bolsters on it. These are stainless steel bolsters
and it has Loveless bolts on it.
Which are basically brass nuts and a stainless
steel screw. So this handle is glued
on there but it's also mechanically held on with those bolts.
Tapered tang and the red line
spacer that Bob Loveless so loved. Bob Loveless was
one of the premier knife makers in the world.
He lived in California for many years and he
championed the use of high alloy
stainless steels. This is actually a
copy of Bob Loveless improved model.
It doesn't have a guard that sticks out much but it has this
curve here and has this finger groove right here and it feels really
good in the hand. When I make a knife I try to
first pick the best steel I can possibly find
on the planet. And I try to heat treat it
the very best I can. And then when I grind it I try to make
every line exact as I can. I try
to make the plunge cuts absolutely even. I
want to put the handles on I try to make the fit perfect.
And I try to make the handles whether they're wood
antler or micarta I want those handles to last a long
time with heavy abuse. So I try to treat them
with stabilization and super glue.
And I like to see my knives in the field being used and
roughly. [laughs]
Thank you for watching
join us again on Common Ground.
If you have an idea for Common Ground in north central Minnesota
email us.
♪
♪
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♪
♪
♪
♪
♪
♪
Production funding of Common
Ground was made possible in part by First National Bank
Bemidji. Continuing their second century of service to the
community. A partnership for generations. Member
FDIC.
♪
♪
♪
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