How to Build a Knife

Step 4 Finishing the blade (first time, no joke)

Before heat-treating the blade you'll need to finish it. Of course it's fitting that after the most fun part of the process, you need to endure the least fun part. Nevertheless, it's important. Why? To ensure you put out a quality product, of course. I also decided to add some simple filework to my blade during this step. To finish the blade, you'll need:

Sandpaper, grits ranging from 60 to 220. I use a sanding wheel and power drill to save time.
A sanding block, even if you're also using a sanding wheel.
Time. Lots and lots of time.

This step is fairly self-explanatory. The first picture below is early in the process, sanding with a rigid sanding wheel. These things aren't necessary, but I do recommend them for rough finishing. I saw 'em at the hardware store and thought I'd give them a spin. Ha-ha, I made a pun.

Work through through the successively finer grits until you reach about 220 grit. There's definitely a technique here--first of all, don't skimp. You'll regret scratches you don't take the time to remove during this step. Always work each successive grit perpendicular to the direction you worked the one before; so if you sand the blade lengthwise with one grit, sand across the blade for the next grit. Also, be sure to cover all the visible surfaces of the blade. Give special attention to the ricasso (the area where the blade meets the handle) and the spine/handle edges of the knife. It's better to sand part of the blade that will be covered than to leave a visible part of it unfinished. I'm sorry I don't have more pictures of this bit, but it's boring and I guess I forgot to take them.

Now, for that filework. You can see the process in the last three pictures below. First, choose your design and mark out even spaces on the part of the blade to be worked. Second, draw the pattern on the knife, using the marks as guides. I chose a pretty simple zig-zag pattern, but you can see a couple other possibilities on picture three. There are literally infinite possibilities for filework, but I'd try a very simple one on a first project. Bad filework can ruin an otherwise good knife. In the last picture you can see how I filed out the pattern. Use needle files. It's pretty simple; just be careful not to scratch the side of the blade. I did in one or two places, but later sanded the scratches out.

Once you've finished sanding and you've done any other ornamentation, you're ready for the next step: heat treating.

Comments

[knibbles]

Why do you finish the blade before you heat treat?

[thedingwing]

Heating steel creates oxidation, or scale as it is known in blacksmithing. If the blade is rough and scale forms, the scale sticks to the blade and it is hard to get off. If it is smooth before heat treating, you can usually knock it off with some steel wool or 220 wet/dry sand paper.

[spenfisher12]

well first i think it should have been annealed first (soffened) but befor tempering it is softer

[knibbles]

Please answer as I would like to make a knife and don't know why you would finish the blade before you heat treated it.

[GriffithPage]

I would imagine it is because the steel is easier to work with before heat treating.

[Basta]

It makes it easier to finish the second time. Plus, it was how I was taught. Next time I make a blade, though, I'm leaving it rough-ground during heat treating and then doing the final grinding while the blade is hard. I saw a tutorial online where the guy hardens the blade blank and then does ALL his grinding before he tempers. This makes sense to me, because it would reduce warpage in the hardening quench. So in short, you don't need to and probably shouldn't. If you use power tools after heat-treating, be careful and keep a quench bucket handy, because the friction can overheat the blade and ruin the temper.

[punkhead58]

Actually, I usually, depending on the steel's hardness, do all of my finishing (fine grinding, filework, and rough sanding) after normalizing and annealing, but before hardening. It makes it easier for me. But I suppose it is a personal preference.

[knibbles]

Thank you very much!! I'll post pictures of my knife when I finish. P.S. You are the first person to ever answer one of my comments.

[Basta]

Sorry it took me a year. I usually try to answer all the questions people have for me, which is probably why I have 700 comments so far. Some just slip through the cracks.

[fragmaster4]

Sorry apod13, that looks more like a serrated edge for sawing rather than an extra grip to me ;) I'm pretty sure if it was meant as grip it would be on the handle itself. Correct Basta?

[Basta]

The serrations are actually decorative filework and not sharp. They could probably provide a grip for your thumb. Step 4 shows the top view if you're interested.

[Southpaw_Jim]

I like the file work. It adds a little extra to it without being too much like so many commercial blades nowadays.

[sharpsword7]

what is the filework for

[sharpsword7]

respond fast

[z-man6233]

it would probably work with a flint but it might just be for looks

[apod13]

basically looks, but it also adds some grip for ur thumb

[seanerdeaner]

do you have 2 have file work?? and how can u use a rubber grip instaed of wood???

[knifepyro]

how long does it take to sharpen the blade

[opolskafani]

how long have you been making knives and how many have you made

[Basta]

I don't know, maybe four years and some where between a couple and a dozen. Depends what you call a "knife." Keep in mind I don't have four years of experience. I have four years of sparse instruction, great interest, and constant hobby work, only some of which is in knives.

[danoliveri]

where did u learn to make knives just wanted to know where this coming from

[Basta]

I learned from a blacksmith I know, as well as a few knife-making books.