Drawknife sharpening

When I was at the Wooden Canoe Assembly I met Robert from the Chocorua, NH chapter and he had made a jig for holding a drawknife to make sharpening easier and more accurate. We had quite a brainstorming session and continued with phone conversations after the assembly. I loved the idea as a lot of the woodworking forums I follow there are often threads on how to sharpen the drawknife. His idea could be reproduced by anyone. But the jig was sized and configured for the one knife he owned.
This is a pic of his.


The knife is held at the appropriate angle, the abrasive (diamond plate) is on the underside of that mahogany board and you just move it front to back and side to side.
Over at the paddle carving area there were several different drawknives and I have at least 6 or seven in different lengths, flat and curved. I needed something adjustable. This is what I came up with.
First a couple plywood discs to test my thought processes.

Then headlong into the first prototype that I doubt I will change.







The discs allow for setting the angle for the bevel. Adjustment is very easy, slack off the wing nuts and rotate the handles. The discs and clamps can spread to hold my 12” plus knife or my 6” or 8”. An added plus is if you rotate the handles 180° you can rest the stone on the back of the knife to align it to easily flatten the back of the blade which the original one at the show couldn’t do. I found it to be safer than any other method I’ve used in the past and worth my time to make. The two holes in the base hold the clamping discs when in storage and the hex/allen key to tighten the set screws is held to the board with a rare earth magnet, so everything I need is included on the board.
There is a commercially made sharpening jig called a Draw Sharp but I haven’t tried it for two reasons cost is over $100 and more importantly it guides on the back spine of the knife. I’ve seen many knives that had the back all beat up by someone using a hammer so those back imperfections would have to be dealt with first to use the Draw Sharp.
Anyway I thought I would share my latest diversion. The aluminum discs I bought from McMaster Carr, and I bought more than I need just to have extras to experiment with. So if anyone is interested I can make up a set of discs with the set screws for a very nominal cost. If you just have one knife just make the jig to fit your knife as first shown.You could just make plywood discs, thread the hole as I did and use a set screw instead of that oversized screw in my test of concept. I’m not planning on going into business making the discs or creating a kit with all the metal parts but who knows.
What are your thoughts, improvements?

Jim

Thank you for posting this. It's simple, safe, adjustable, and I bet produces a really nice edge. The discs for angle adjustment is clever. I like how both the flat and bevel surfaces can both be worked with minimal fuss. How is the diamond plate abrasive secured to the underside of its wood holder?

Thanks Rick. It’s just a simple clamp. One leg of an aluminum angle was cut down. The carriage is shorter than the abrasive plate so there is a clamping action. A happy accident was that the edge of the angle holding the plate is tipped up a bit (sorry no pic) so the edge of the drawknife doesn’t hit a corner but instead goes under a bit if you are not paying attention. A threaded insert is used for the knob to screw into instead of trusting tapped wood threads. Another unplanned but great feature is three layers of wood to make up the carriage is less that the width of the plate so when holding the wood there is a stop so your fingers don’t drift below the plate. Once sharp it would easily slice off the end of a finger. Hope that answers your question. I could do a step by step build description if anyone wants it.
Jim

Ingenious, and one of the unpredictable benefits of attending the WCHA's annual Assembly.

True words Glenn.
My next project for the assembly is some sort of paddle carving station. Those picnic tables were poor at best, so much movement. Plus I have a cheery paddle blank so I have a project to test it out, not to mention sharp drawknives.
Jim

That is nifty.
I made and used a more crude but effective, jig to sharpen planer knives.
This is far superior !
Thanks for posting. I have a few draw knives to sharpen.

Jim

cool idea but in my case I'd need a stack of jigs for my more than 1/2 dozen drawknives, plus my spokeshaves and other implements. I use the method an old timer taught me- clamp down a scrap of softwood, hold the knife at the desired angle (he never used a protractor) whack it with a mallet ONCE to get the desired angle transferred to the wood, Cut another small scrap (about 1x1x3") to match the angle, clamp it to the blade as a skate and go for it.
It takes less than a minute and is within 1-3° of accuracy, when done it goes in the kindling box.

Not sure I follow you method but there are many ways to do a job that’s for sure. This jig with the discs would handle all your drawknives, it does all of mine.
I developed a different jig for spoke shave blades and it works for everything from slicks to little thumb plane blades. I’m still trying for find a way to get it manufactured.
Jim

Thanks Jim for the timely post about sharpening drawknives! I just so happen to be using mine at the moment to shape garboard strake ends on my new canoe project.

You’re welcome Pat. If there is one group likely to use a drawknife it’s the boatbuilders.
Jim