Intro: How to Make a Cutting Gauge
Step 1: Materials
1" x 2" x 24" Red Oak Board (craft/hobby area) - $2.24
Knurled Screw - $0.92
Wood Insert Nut - $1.24
Junior Hacksaw Blades 5 pack - 2.88
1/4" Dowel rod (Optional if you have a Dowel plate)
small files (I just had a set of cheap ones I bought at a cheap local tool store, pretty junky but they work ok)
Combination square (or try square)
Spoke Shave (optional)
Crosscut saw or Dovetail saw
Flat head Screwdriver
metal cutting disk for Dremel
metal grinding cylinder for Dremel
Dowel Plate (Optional, if you don't have one just buy a 1/4" dowel)
Drill (or hand drill)
Drill Bits (1/4" and 3/16")
3/4" Auger bit (or paddle bit if you have a electric drill)
Step 2: Cutting the Backstop
Taking your Dovetail saw cut a 3" long section of the Red Oak off. Then take a Block plane and smooth off the cut lines carefully ( it's easy to tear out the corners).
Step 3: Chamfer the Corners
Make a mark at 1" and 2" on the top then another mark at 1 1/2 " on both sides then connect the dots. This should be 1/2" down from the top edge. Cut it out with a Coping Saw then smooth it out with a spoke shave. This step isn't essential its just cosmetic but it does look nice.
Step 4: Cutting the Square Dowel
This step is optional if you decide to just buy a square dowel but it's really not too hard. The wood is already 3/4" thick you just need to make a cut at 8" length then cut the height down to 3/4". This will leave you with a 3/4" x 3/4" x 8" square dowel. The last photo has a 3/4" Auger bit and a 3/4" chisel for proportion and because they are needed next.
Step 5: Cutting a Mortise in the Backstop
Measure 1 1/2" over and 1" up to mark the center of the face. Next measure 3/8" to the left and 3/8" to the right, then 3/8" up and 3/8" down. This should give you the rough outline of a 3/4" square. Take the combination square and draw lines to form a square in the middle. Repeat this process on the other side so you will have a square on both sides in exactly the same spot.
Now take a piece of electrical tape or painters tape or duck tape and mark your auger bit at 3/8" from the cutting edge not the screw tip. This will help you see when you have reached the halfway mark. Now carefully drill halfway then flip over and repeat. If you drill all the way through it will blow out on the other side (it happened to me).
Take your 3/4" chisel and remove the rest of the waste in the same manner as you cut the hole. Only go about halfway down then flip over and repeat. Clean up the waste with a chisel and then a file. I used a 3 sided metal file.
Step 6: Check the Fit
Snug is good, loose is bad. If it's too loose you might need to start over, otherwise keep filing till it fits pretty good.
Step 7: Installing the Knurled Screw
Remove the square dowel and mark off the center of the top. Check the bit against the wood insert nut to make sure it's the same size (on mine it was 3/8") then drill a hole (check to make sure the drill is straight, I didn't do this and my knurled screw is leaning forward). Next screw the wood insert nut into the hole to thread it. Then remove it and cut it in half with a dremel and notch the top with a dremel so you can screw it back in. This way there will be room for a dowel pad to protect the square dowel from the force of the knurled screw.
Step 8: Making/Installing the Dowel
I decided to make my 3/8" dowel this way I wouldn't have to go to the store again and I guess I'm a bit of a cheapskate. You can purchase a 3/8" dowel if you want from the store and just cut it down to about 1/16" height then install it if you want or you can do like I did and make your own.
To make a dowel you will need a dowel plate. In my case that is a 1/4" thick steel plate with various sized holes from 1/16" to 1". I work in metal fabrication so I had one cut at work on a CNC laser. I then etched the hole sizes so I wouldn't have to check each time. Making a dowel isn't too hard, cut a small piece of wood 3/8" x 3/8" x 1 - 2 " then the fun begins.
Remember how they used to scold you for trying to put a square peg in a round hole? Now's your chance to prove them all wrong! Drive that square peg down with a mallet. Beat it till it fits! If it really won't go at all just go up a size, knock some of the corners off and try again. It does help to take a pocket knife and round off one end to help it start off.
After your dowel is complete carefully take a chisel and scribe all around it at about 1/16" height then push a little harder on the chisel and roll it around pushing a little harder each time till it breaks off. Be gentle on this step because its really easy to destroy your dowel by smashing it too hard with the chisel.
Step 9: Making a Cutting Blade
Now I know you've been wondering 'Just what are the Junior hacksaw blades for?' What a good question. I couldn't find any cutting blades and those were only 2.88 for a 5 pack so I reasoned I would make my own. Take your dremel and cut off about 1 inch worth of saw blade. Remove the barb on the end you won't need that. Next cut a rooftop shape by making two 45 degree cuts. Change the cutting disk out for the grinding cylinder and grind off the teeth (you won't be needing them) and sharpen to a general blade shape by using the grinding cylinder to bevel the edge.
A word of caution here. As with all power tools wear Safety glasses. Cutting metal WILL cause sparks and grind dust to go flying. Grind and cut away from your body so that the grind dust and sparks will preferably go to the ground. Use pliers or a vise to hold the saw blade while you cut it, the metal will be very hot and will burn you if you try to hold it in your hands. Gloves are good too. Just use common sense when handling any and all power tools.
After you have ground a rough bevel to the blade use the sharpening stone to put a better edge on it. Remove any remaining burs and measure the width of your new cutting blade. Mine is 1/4" so you will need a 1/4" drill bit for the next step.
Step 10: Mortise for the Blade
Make a mark about 1/2" inch down from the end and 3/8" from either side this should be center, repeat on the opposite side. Drill a 1/4" hole halfway then flip it over and repeat to prevent tear out. I don't have a 1/4" chisel so I cut it roughly square with a coping saw then took a small file and cleaned it up. You want to make sure the blade lays flat against the back side.
Step 11: Wedge for the Blade.
The wedge to hold the blade in needs to be about 1/16" - 1/8" shorter than the blade. It should be 1/4" x 1/4" square. chamfer the bottom with a file. Then I would take a block plane and shave it down till it fits snugly with the blade in as well. The blade and the wedge should be very snug. On my gauge you have to tap it slightly with a mallet to set it.
Step 12: Enjoy!
Now you have the satisfaction of saying 'I made that tool!'