Tuesday, March 31, 2015

HT1 HIDDEN TANG - INITIAL LAYOUT AND PROFILE

I've always wanted to make a hidden or "stick" tang knife. After watching some videos on YouTube, I thought I would give it a try. I worked up a pattern for HT1, which is a striking trailing point design.

I glued the paper template on to some thin plywood. Cut this out on the wood band saw.
I am finding the oscillating spindle sander to be coming in handy. Much faster than changing tools on the belt grinder.
 Here's the pattern.
 I am laying it out on some 1/8" CPM 154
 Cutting the tang with the table mounted portable band saw.
It's going to save some belts to get close to the profile before heading over to the belt grinder.
Grinding the profile on the belt grinder. I like a ceramic 60 grit for this. It goes quickly.
 Profile is close.
 Comparing against template. Pretty good so far.
 I use the 4x36" belt sander to work the faces. A good magnet comes in handy here.
 Work the faces until the inclusions are gone.
I think we are ready for grinding the bevel.

HT1 HIDDEN TANG - HEAT TREAT & SCREW

I cut a slot in the tang to hold the screw and drilled a 3/16" pin hole with a #12 bit. Then wrapped it up in a foil envelope and took it up to around 1060°C (1940°F) and air cooled it with compressed air.
The blade right before hitting the tempering oven. I tempered at 200°C (~400°F) for two hours then cooled. Repeated two times.
After tempering I scrubbed the blade a little with some sandpaper.
Here I am working the inside of the choil with the 1/2" drum on the oscillating spindle sander.
Pressed the stainless steel machine screw into the tang slot. I used an 8-32 x 2" screw that I'll cut off later. It's purpose is to hold the pommel and squeeze the parts of the handle while the epoxy cures. It's is very important to note that THE SCREW MUST BE THINNER THAN THE BLADE IS WHERE THE GUARD IS LOCATED.
Ready to hit with the welder.
This is pretty light stuff. Here is how I set the welder.
Cooling. Notice how I clamped it in the vise to dissipate any excess heat that my travel down the tang. We don't want to ruin the temper of the cutting area with too high of heat.
Now I can grind off the excess weld.
Good penetration and no cracks showing. Fingers crossed.








HT1 HIDDEN TANG - GRIND & SANDING


I used an old 60 grit belt to knock off the sharp corners and then put a new 60 on. Pulling across each side and dipping in the blade in the water bucket after every pass or two.
The basic shape of the grind follows the arc of the belly.
This is what the rough grind looks like.
Now to some sand paper to clean up the bevel. Wet the sand paper to lubricate, keep the paper from clogging and galling the steel and keep the dust down.
This is after some hand sanding. I'll true up the bevel and match the two faces as closely as possible.


HT1 HIDDEN TANG - BLADE FINISHING

Hand sanding is always a bit of a chore, so to speed things I am a finishing with the Scotch-Brite belt.
Scotch-Brite on 10" contact wheel. Nice and slow and dipping in water. This will get hot!
Then a buff with black compound.
Once a near mirror finish emerges, any little scratches are evident.
Back to 220 grit, then 400, then 600 for a satin finish.
Now time for the maker's mark. I electro-etch this with an etching power supply, pad and electrolyte intended for stainless steel.
Here is the mark on the blade. Ready to apply some tape to the blade and get on with the guard and handle components.

HT1 HIDDEN TANG - HANDLE ROUGH SHAPING

After the bulky handle parts were set, I traced the arc that I had in mind on with a permanent marker.
Going at it with an old 60 grit belt.
Here the profile arc is close.
Now to start rounding the handle. I have to keep hitting the water when I pass over the stainless parts. Too hot and it will melt the epoxy.
Oh nice! An inclusion in the very rear of the wood. I guess you never know until you get inside if these things are going to show up.
Some finer shaping on the 1-1/2" drum.
This is the handle roughed. It will take some more shaping and finer grits to polish the stainless and sugilite composite up to a shine.

HT1 HIDDEN TANG - FINISHING

To finish the handle I worked it with 150 grit sand paper. In some areas a small length of dowel helps get in the inside curves.







I then move up to 220 with some Windex. Then on to 400.








After 400 I move over to the buffing wheel. Using the black compound to reveal and scratches that need to be sanded out further.

Once it's very shiny, I hit the stainless steel with some green Scotch-Brite pad to give it a brushed look.


Once the blade is revealed, scrape any excess epoxy off. I like to clean the blade with Mother's Mag and Aluminum polish.

This is close to done.



The only things remaining is to sharpen and buff some Renaissance wax on the knife.



HT1 HIDDEN TANG - GUARD FITTING


For this version of the HT1, I want to make a guard of 416 stainless steel. I have some 3/8" x 1-1/4" bar that I will cut just a bit longer than the depth of the blade.
Cutting on my Porta-Band.
Here I marked a centre line and will mark the tang right up at the ricasso.
Marked. Now I measured the thickness of the blade right at the ricasso. It's a hair over 0.13", so I will use a 0.125" (1/8") bit and drill a series of holes on the centre line.
Here the aim is to stay on the line no matter what.
Once the holes are in, I go to the "back" of the guard and enlarge them with a 1/4" bit. This is only done part of the way. Do not go all the way through to the front or you will be tossing this piece of stainless steel in the scrap bin.
Clearly marked the front. We're going to be focusing on this face much more the the back as it will be exposed. The back will be hidden and requires much less attention.
Here I am using an old 1/8" drill bit in the cordless drill. Running a slow RPMs, I am riding the flutes to remove the steel between the holes.
Once I can get round needle file in it's a matter of working this up and down to create the slot.
Test fitting the slot. I had to grind some of the tang. It is very important to know every part of the screw and tang must be smaller than the final position of the guard. Otherwise, the slot will have to be unnecessarily enlarged to pass over this spot and this will leave a gap then the guard is in place.
A square needle file helps to make the slot fit precisely. This is a trial and error process. Always filing small amounts and test fitting.
Once the guard will pass almost to position I stopped filing. The last bit of interference will hold the guard tight and close any very small gaps.
Now the roughly shape the guard on the band saw. This saves on belts a little and is cooler on the hands.
I hit the guard with the Scotch-Brite belt for a brushed look. The rest of the guard shaping will be done after the handle components are epoxied and set.