Making a Knife Filing Jig for Perfect Bevel Grinding
In this video I am going to make a knife filing jig. That’s a simple device that helps you file perfect bevels onto knife blanks when you don’t have a belt grinder. It’s also really easy to make out of some plywood boards and some assorted hardware you might have lying around. This knife filing jig will be used in one of the upcoming videos to bevel the Sheepsfoot knife from the Build-A-Knife Box that I got from the Alec Steele Co. Have fun watching!
Video transcript:
Well hello ladies and gentlemen, didn’t see you there! Welcome to Tony Needs Hobbies. My name is Tony and in this video I am going to show you how I made this knife filing jig as well as what I will be making with it in one of the upcoming videos. Have fun watching!
The jig will be build out of 18 millimeter thick plywood. I had this precut in the correct width at the hardware store since I don’t have space for a table saw. I have two pieces of 10 centimeters and two pieces of 15 centimeters wide. They’re 60 centimeters long but I still have to cut the pieces to size. I will also need a piece of steel to guide the file, and some assorted hardware:
- T-nuts
- An M8 eyebolt
- Some M8 bolts
- Two hose clamps
- A wingnut
- Some M8 washers
- And screws
The jig will be built guided by this sketch that I made. The dimensions are guidelines that I will change as I go to make sure the jig fits on this workbench. Once the video is complete I will put these building instructions on my website, www.tonyneedshobbies.com.
Let’s start by marking where to cut the wood according the drawings that I made. And when all the dimensions are marked, I will cut the wood on my new miter saw. When that’s done, I bring the wood back inside to mark the locations where the T-nuts will go.
This jig is inspired by one built by Gough Customs but it’s different in a sense that I am going to put T-nuts in between the two layers of plywood. This allows for a more durable connection between the eyebolt and bolts with the wood – instead of just screwing the bolts in the wood. I’ll post a link to the video that inspired me in the description and now I’ll show you how I put the T-nuts in between the pieces of wood.
It’s not too difficult. I start with drilling a large and just deep enough hole on all the marked locations using a 25 millimeter forstner drill bit. In the center of each hole, I drill a hole through the wood where the threaded part of the T-nut fits through. In my case, it requires a 10 millimeter hole for the M8 T-nut to snugly fit.
When those holes are drilled, I lay out the pieces again, to mark the locations for the holes on the other pieces, so the bolts can go all the way through the wood. I flip the boards to double check the holes are at the correct location and then it’s time to drill again, this time using an 8 millimeter drill bit so that the bolt doesn’t jiggle too much.
When all the holes are prepared, the next step is to fit the T-nuts into the holes. This is really easy. Just hit them with a hammer until the flange is level with the wood. I use a round hammer with the same size as the hole to guide the T-nuts in and give it a few good hits with a heavy hammer. It’s no rocket science…
Then, before gluing it all together, I pre-drill some holes for screws and countersink them. This is going to be the back of the device, so the screws will not be visible in the end. I apply a generous amount of wood glue to the boards with the T-nuts in, working around the holes. Then I lay out the jig again and put in the screws to secure everything tightly and let the glue cure overnight.
The next day I prepare the jig for varnish application by sanding all the rough edges and corners to make it feel and look a bit better. I apply two layers of this tough, transparent varnish with light sanding between the application of the first and second layer.
I applied two layers of varnish and let it dry overnight. Now it looks good, feels smooth and is protected for a long period of time. The next time is making and adjusting the hardware. And I will start by making the file guide.
The guide will be a 70 centimeter steel rod. Any diameter will do as long as it fits through the eyebolt.
This will be more or less how the final thing will be constructed. Out of this scrap piece of wood, I will make two spacers to fill the gap between the rod and the file. It has to be the same width as the file with a hole in the top to fit the rod in. Luckily I have a round file with the same diameter. Then, I round the top and make the spacers look good on the small disc sander.
Before putting it all together, this next step is important. When filing a knife, you want to get a nice plunge line. That’s difficult since a file has a 90 degree angle. In this step I grind off the edges of the file so it’s a little bit easier to get a good plunge line on the knife. At least, that’s what I hope…
And with that done, everything is ready to be assembled and tested. The file and rod go through the hose clamp with the spacer in between. Then it’s secured tightly after which the same is done for the other end of the file. A quick look to see if everything looks OK and I can move on to testing this device on a scrap piece of mild steel.
In the next video I am going to put this jig to the test by building this build-a-knife-box that I got from the Alec Steele Co. It’s a sheepsfoot knife and I’m going to have a whole lot of fun trying to build it. If you don’t want to miss that video, then please subscribe to this channel and also let me know what you thought of this video either by dropping me a comment or hitting the like button. That’s it for now. I would like to thank you for watching.
Bye, bye!
