Knife Grinding Jig-design and fabrication

Handmade Knife Grinding Jig

Grinding perfect knife lines by hand is hard. There’s no doubt about it. The purists will tell you that it’s the only way to be done , but I’m not a purist… I can’t afford to be. Some guys have the CNC machines to cut out their knife blanks perfectly, and high end fancy belt sanders to profile like a pro, but I don’t..unfortunately. I have to use what’s at my disposal and its limited. I have a basic belt sander and a small shop of goodies to use. So for the people like me who aren’t pumping out blades like a production shop, and who have a smaller budget to work with, a jig can go a long way. Let’s keep in mind as well that a jig will get you your bevel, but there’s always a fair bit of hand sanding and profiling to do too.
Jig design is all up to you. It depends on what materials you have to make it with, what kind of tools are at your disposal, what kind of grinding method you use, and what kind of knife you’re making.
In my case I have mostly SS and mild steel to work with. I have a small stick/TIG welder to make it with. I’ll be using my little 42″ belt sander to do the stock removal, and I’m focusing on small length blades like oyster knives and small hunters, carvers, skinners, etc.
Do your research. There’s a lot of designs online that will help you get ideas about your options. My belt sander has a relatively small backrest and toolrest, so I needed a jig that fit those rests. I researched some small DIY knife jig designs online and found some options that used materials that were easy to scrounge up at the local hardware store.
Here’s what I made. With a couple heavy duty door hinges, some angle iron, and some ready rod, we’re in business.

First lets drill and tap a hole in the angle to support the ready rod. I used 1/2″. Overlap the hinge plate on the angle piece and weld together. Now you have a u-shaped bracket with one side of the hinge plate still able to move. Now cut a piece of ready rod that fits the jigs needs and weld a nut to one end to make a bolt out of it. Insert the bolt into the jig and line up the last hinge right on top of the bolt and butting up to the other moveable hinge plate. See the pictures to get a better sense of whats going on here. Now weld the hinges together, making sure you’re centering everything on the bolt. Finally the last step is to complete the points that need to be secured. The bolt still needs to attach to the last hinge in order for the jig to be able to adjust as you need it. Thread a nut onto the start of the bolt and line up a flat of the nut with the hinge plate on top. Adjust the bolt as you need to get the whole jig at right angles. Now weld the nut and hinge plate together.

Ok you’ve got a working jig now! The picture above shows an oyster knife I’m grinding with the jig. I’m still using a couple of small c-clamps to clamp the blanks to the jig during grinding but I’ll probably incorporate a welded on, low profile bolt-and-U clamp when I get some extra time to design and make one. There you have it! I hope you enjoy it. If you’re having difficulty with adjusting to the perfect angle of grind, don’t hesitate to modify the design as you see fit. Like I said, I’m using this jig for small profile knives only. If your belt sander tool rest adjusts, you can also tune that in to fit the perfect angle of grind. I hope this helps in designing and making your own knife grinding jig!

Knife scale smorgasbord!

I couldn’t be happier about the latest haul! A big thanks to Tyler at WolfeandtheNarwhal  (etsy) for these pieces. It looks like I’ve got enough materials to get me through a couple months…I think.  

Here’s some pics of the haul. The Purpleheart stands out beautifully and I’ll be saving these pieces for a matched pair of skinning knives or something in that vein. The thin piece will be for some nice inlay work where a knife really needs to “pop”. 

On the bottom is a good sized piece of Walnut, and on the right is 2 nice planks of American Cherry. I’ll be using these pieces for a while and experiments with dyes and finishes will ensue. 

Now for the real beauties. The good sized block on the left is Cumaru (Brazilian Teak). Very, very hard and not so easy to come by, I’ll have to decide carefully where this wood fits. I’ve already produced 10 or 11 fillet knives in this wood and I love it! It finishes beautifully caramel with a simple finish. It also takes well to dye and ebonizer for that “aged” look. 

The centre pieces with the sweeping grain is Iroko. These blocks are already earmarked for some beautiful oyster knives I’ll be producing, but if there’s extra then I’ll be obsessing about the right knife. 

The only problem is that these pieces seem too beautiful to use! I hate to think of risking the loss of a nice piece because of my own foul up, but that’s how it is. Ordinary knives require little risk of fouling up, but the extra-ordinary ones sure do. I guess I’ll be risking it. 

       

Fillet Knife No.1 – part 1.

I’ve started working on the first Fillet Knife. I’m looking forward to trying out different design styles and materials! For the first knife, I’m going with cast bronze bolsters. I’ve wanted to incorporate some dyed bone into the handle as well. The design is simple and clean. I’m keeping the bolsters small and lightweight. I’m inlaying a piece of dyed bone below the bolsters and above the Cumaru scales. Using surgical steel (5/32″ pins),  I’ll double pin the bolsters and double pin the scales to the blade blank, with a custom mosaic pin added for good measure, support, and. It’s a bit tough to support the bone scales without pinning them. Make sure that they don’t separate from the knife while the epoxy is curing! I used a vice to support the bottoms, and vice grips to support the sides to the knife. I cut some uneven ” snaggle tooth” serrades about 1″ up the spine above the bolsters to add versatility and a bit of ” edge ” to the design (no pun intended). I’ll let the whole thing sit and cure overnight while clamped, and wait to start the sanding and finishing another time.                       

sheath-to-go

This morning I had a conversation that went a little like this..

Me: “Good morning!”

– ”  Morning! Hey I’m going fishing this weekend and I need you to make me a sheath for my fish descaler/bone saw.”

Me: ” Sure. When do you need it?”

– “In a few hours would be great.”

Me: “Yowza! ..well okay. ”

So begins the Sheath-to-go. An ultra quick sheath made ASAP, but durable enough to make it worth while.

First I quickly dyed the leather with ebonizer. I used enough to soak the leather which means the dye also assists in the wet forming. Since the knife is double edged, I can’t use a pocket sheath. I’ll need to freehand sketch a 3-piece sheath and incorporate a dangler to boot.
No time to measure really. I trace the knife out on some leather and cut 2 mating pieces and a welt at the same time. I cut a 10″ by 1/4″ strip and soak it too. I twisted it into the Puukko style dangler that I know my friend likes. I leave about 1″ untwisted on each end to secure inside of the sheath. After I dry the pieces out for a while on top of the coffee percolater, I use contact cement to glue it all together. I’ve left some leather unglued at the handle end for support.

A quick sanding up and shaping to get the proper profile. I stitch the sheath at the “high wear” areas only. I use a saddle stitch and I incorporate a whip stitch, especially at the dangler connecting point.
Next up is burnishing and a second dye. I apply a couple quick coats of acrylic resolene and we’re done! The Sheath-To-Go is complete and doable in a few hours when needed.

                  

Vinegaroon and Ebonizing

This dye can be used to control age and weather scales. It can also be used to dye leather a rich black through oxidization. I look forward to applying this technique to the knives I’m working on right now. 

I’ve wanted to recreate, on my fillet knife sheaths, the black spotting that you find on trout. This all-natural dye seems to work well for that. I also have some exotic hardwoods coming in, and I plan on dying some samples to test for nice colour combos. 

To make Ebonizer: submerge a fistful of steel wool in a mason jar full of white vinegar. Leave the lid loose so that the pressure increase doesn’t pop the lid off. Leave the jar with the steel wool submerged for 4 days approx. or until the steel wool corrodes entirely. The remaining coffee coloured liquid is the Ebonizer. 

Try experimenting with different vinegars to create the dye that works for you. 

   
         

new projects

Here’s some new pieces I’ve acquired. I’ll be working on these over the next few weeks and months. I think I’ll design the drop point hunter and the skinner knife as a pair. They will be fun knives to design handles for, and to sheath. For the trout fillet blades, I’ll probably try different bolster and handle materials. Stay tuned to see these pristine blanks become beautiful knives.  

 

step 8 – finishing

step 8 –  The sheath is formed, stitched, and dyed to your liking. Now it’s time to seal the leather with a waterproof finish and add any hardware/fittings. To finish this sheath I’ll be using an acrylic resolene wash and adding a snap to the handle securing strap.
To seal the leather with acrylic resolene, first rub the leather with a cloth to remove any excess dye. Mix the resolene with water using a 1:1 parts or 1:2 parts mix. The resolene needs to be diluted to created the desired effect and finish. Use a cloth to apply the wash in even swirls. Do not use a brush as the brush strokes will show once the wash dries on the leather.
The point here is to use many coats of diluted finish to produce a natural looking finish on the leather. Too much too quick, and the finish looks like nail polish applied in a hurry. I try using a rule that if the wash shows up on the leather as “milk”, spread it until the leather appears only wet with a thin coat of water. Do not let “milk” stand on the leather. Let the sheath dry between applications. I usually spread out this step over 2 days.
Once the sheath is sealed properly, and to your liking, you can add the hardware. I’m only adding 1 snap to the handle strap with this sheath, but “to each his own”.
The sheath is complete! I hope you enjoyed this series of posts. I have plenty of projects coming up, so stay tuned! For all your leatherwork and knifemaking needs, Skid Road Leather is here for you.

                          

step 7 – stitching

step 7 – It’s time to stitch the welt. Like I said in an earlier post, I like to keep my stitch line about .200″ or as much as 1/4″ (.250″) from the welt edge. I’ll use my vernier calipers to gently scribe that line all along the sheath edge. Dividers or any number of other leather marking tools can scribe the stitch line as well. Once the line is scribed then it’s time to mark the leather.
I use my leather stitch punch (fork) to mark the stitch pattern because then I know the holes will be evenly spaced. Once marked, I use my awl to puncture and enlarge the stitch marks as prep for the drill press. I use a 1/16″ or 5/64″ drill bit to carefully drill each hole on the press. Then I run the bit thru each hole on the back side of the leather as well, to clear the holes of any remaining leather bits.
The drilled sheath is ready for stitching! I use a chocolate brown waxed thread with the saddle stitch method. Make sure to give yourself plenty of extra thread so you don’t run out mid way thru! Starting at the tip of the sheath, I stitch and back-stitch about 1/2″ and then carry the stitch all the way to the end, tightening the stitches as I go. At the end of the stitch, by the knife handle, I back-stitch 1″ to secure the thread and strengthen the stitching at a crucial area. I run both thread ends thru the leather to the back of the sheath (belt side), and shear them off close to the leather.
Now that the sheath is shut and stitched, there’s no harm in laying a bit more dye to touch it up.

          

step 6 – shape and dye

step 6 – The sheath is functional and starting to look good now. But before we jump to stitching we’re gonna take our time cleaning it up and shaping to our design.
Trim off any excess leather from the extra welt material that sticks out of the sheath. I like to use a brand new blade in my box cutter for this.
Now profiling. Gently scribe a line along the face of the sheath that makes our finished profile so that there’s a guide line for the final cuts. Remember to use the paper welt and knife cut outs to determine how much welt/sheath material we can afford to cut off! If you cut off too much welt to support your stitch line, or right into the pocket itself, then its time to start over.

Now be careful! I like to keep the knife in the sheath and gently squeeze it in a padded vice while I cut. Keep the box cutter edge pointed towards yourself while you slowly trim the leather to size.
Once the sheath is trimmed to the profile we want, use a power sander, or hand sand the edge of the leather to break it slightly. I prefer to finish sand the welt by hand, as the power sander tends to burn or “gloss” the leather too much. Use rough sandpaper to clean it up, and get progressively finer paper to finish. Once that’s done it’s time to burnish. Burnish the welt and welt edge, and all sharp leather corners.

Now let’s lay on the dye. I’m using olive oil. Its my go to dye. It makes a nice rosy/caramel finish and it doubles as a conditioner. Use a cloth, not a brush, to rub the oil in evenly, in a circular swirl. Apply several coats and let the leather breath between applications. Once the colour reaches your liking, let the sheath sit overnight in a hot, dry spot or bake it on low heat (50 deg C) for several hours.

Step 5 – the welt

step 5 – Now that the belt loop is stitched in and secure, it’s time to close up the sheath and stitch in a welt. The welt is the piece of leather that the knife edge bears against when sliding into and out of the sheath. It protects the stitching and ensures long sheath life if done properly.
First things first. Fit the knife comfortably into the sheath ; where it would sit in the sheath. With the knife in place, hold it steady with one hand, and with the other place a sheet of paper into the sheath, right along the spine of the sheath. With the paper on the bottom, and the knife on top, trace along the knife edge onto the paper. Now you have a tracing of how the knife looks while in the sheath. Cut the piece out of the paper and now it’s up to you how big a welt to create. I typically cut a welt from 3/4″ to 1″ from the knife edge line to allow some room to cut the sheath down to size.
Now put the knife back in the sheath where it sits nicely. Use a pen to trace the knife edge right onto the leather inside. This will help to guide contact cement placement and laying the welt.
Do one last check to make sure you haven’t missed anything. After the welt is in, it’s a headache to make changes. Paste the contact cement along the welt on one side and the sheath where that side mates (only do 1 side at a time). Once the cement cures, place the welt in and compress by hand. Do the same for the other side. Now that the sheath is glued shut, place the knife in and make sure it fits snugly. Now use a soft mallet to gently hammer the welt to compress the glue into the leather fibres. Place the welt edge in a padded vice and any welt left exposed can be gently clamped between padded wood pieces. Once the glue sets up, take the sheath out of the clamps and leave it to cure overnight.