Shop made marking knife

Darren Wright

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Springfield, Missouri
I did a little research on knife blades that are available on the market and with the help of this article (http://www.wkfinetools.com/contrib/cSchwarz/z_art/markKnives/markKnives1.asp) I felt I had a good grasp on what I wanted to make.


I got further inspiration from Derek Cohen’s article at:
http://www.inthewoodshop.com/ShopMadeTools/A Knife for Marking Dovetails.html

Derek’s method re-purposes jig saw blades for the marking blade, something many of us have around our shops. Benefit is that they are cheap, hardened, and thin for getting in tight spaces (like shown on the last page of that first article).


I picked out a couple of used blades from my jig saw box and decided to start with them. In the end, both turned out well and didn't feel I needed to use a new blade.


I started out on my oscillating belt sander with the teeth pointing in the direction of the belt rotation I grasped the blade with some vice grips and began sanding the teeth off.


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Next, after a bad attempt to get a 55* to 60* bevel by eye, I chose to use my thread gauge as a template and mark off the correct angles (I think the thread gauge is 60* if I remember correctly)

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A little more trial and error I finally got some rough angles and bevels I was happy with, then went over to the bench and started hand honing the cutting edges. I got them close and decided I'd have more control if the blade was in it's handle, so I moved on to making the handles.


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I started with some tiger maple I've had around for a few years. I got lucky a few years back and bought a 1/2" x 10" x 84" piece marked at the same price as regular maple at the local yard, been using it for special projects over the years and have about 3' of it left. I was able to use some scrap for these.

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I started by measuring the width and thickness of the blades, both measured about .05" thick and .25" wide.

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I setup a spiral bit in my router and setup the router table for about .055" - .06" in depth. Using a single piece of my stock cut to length, I routed a groove in both sides to accommodate each blade, then split each from the main stock.
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I also drilled a 5/16" recess in each groove to accept a magnet, which will help keep the tip from sliding off the knife later.
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I then separated each handle from the original stock and marked a center line down the middle.
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I then ran each piece through the bandsaw and flipped the cut side to the outer side, which matched the grain pretty closely. I probably could have flattened the cut edge then routed the blade groove, but it probably wouldn't have looked much different.
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I then chose a spot to cut the tip half of the handle loose from the body and did so on the table saw
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Time for the glue up, I mixed a small amount of epoxy and glued in the magnets, let that cure, then very lightly coated the tip half of the handle. You can use wood glue on this half, just don't let much if any squeeze out into the cavity for where blade slides in, otherwise it's a bear to get cleaned out to slide the blade into it. It may be easier to wax the blade well, then glue up with the blade inserted to help keep squeeze-out from blocking the blade. The wax should help act as a release.

I missed pics of the gluing process since I had gloves on and didn't want to get my phone covered with epoxy. Lastly I filled the void for the blade with epoxy and the mating surfaces and clamped the two pieces of the handle together. After wiping off the squeeze-out I slide the tip half of the handle over the blade to align it with the two parts of the handle. From here I shaped the two pieces of the handle together on the sander mostly. I had planned on a more ergonomic handle, but my sander gave out part way through, so much of the shape was done with a round-over on the router table.

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Here is before the finish is applied and everything sanded to 320 The finish was using Dave Hawksford's technique of using dark walnut stain, wiped down with alcohol, then finished with golden oak. I used a BLO finish with a paste wax over it. I did do some final honing before mailing it out to Ken, but may not be as sharp as some of you would do.

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Very nice work Darren, but I have to ask why the tip guard? I guess if they were going in a tool box and could rattle around then fine, but in a work shop I figure you would have them in a set place, no real danger of having the tip damaged. I also wonder if the thickness of the handle down near the blade will get in your way?

In any event, very nice work, isn't it a joy to make something useful out of stuff just hanging around in your workshop!

PS Love that Tiger Maple! :thumb:
 
Thanks Guys. I thought it would be something that many of you may be interested in building since most of us have old saw blades laying around

why the tip guard?

So I don't end up with a bunch of holes in my pocket...or me for that matter. :D I've gotten where I wear an apron when working on projects, so planned to keep it in the front pocket with a pencil. I'll probably be looking for the darned cap all the time, may make a small leather sheath at some point for it though.

One thing I wish I had done was inlaid another piece of wood on one side to keep the cap direction straight as they are not quite centered.
 
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