How to make a Cutting Gauge

Step 1 Materials

Supplies:

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)

Tools:

3/4" chisel
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)
Coping saw
Spoke Shave (optional)
Block plane
Rip saw
Crosscut saw or Dovetail saw
Flat head Screwdriver
Dremel 
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)
Pencil
Permanent Marker
Drill (or hand drill)
Drill Bits (1/4" and 3/16")
3/4" Auger bit (or paddle bit if you have a electric drill)
Tape measure
Sharpening stone

Comments

[technofossil]

Nice project. Anyone who considers themselves a woodworker should have several marking gauges.

As a retired woodshop teacher, I have to comment.

In step 1, before you round off the top, mark the diagonals on the face. This will give you the center and account for any vagaries in size.

Also in step 1 you use a spoke shave to round the top. Someone less skilled may find it easier to use a file to shape the top. It will give more control. (You may like the result better yourself.)

Last. You spend a lot of effort converting a saw blade into a cutting edge and then cutting the mortise to fit it. If you drill a small hole instead, you can use a sharpened nail to do the job. Some sharpen the nail like a pencil, I prefer to grind the end of the nail at a 30 degree angle it gives a nice edge and is easy to keep sharp. Old drafting compasses were sharpened this way. (http://en.wikipedia.org/wiki/File:Cyrkiel_RB1.jpg) You said you were a bit of a cheapskate, so am I. I just saved you $2.88 :)

I like that you use a lot of hand tools. Less noise and more skill required.

Again, nice job.

[vincent7520]

I had also the idea of using a ball point stuck into the hole instead of a sharpened nail. Actually it is very practical for long markings and not too fine jobs in "crude" carpentry. This way you're sure to see the marking on wood that is barely planned. Of course this shouldn't be used for normal carpenter or cabinet making.

[technofossil]

Use a pencil not a pen. The ink may bleed and make the mark harder to follow. It may also stain the wood making finishing harder. The nail will give you a cleaner line to follow. I use both.

Get into good habits even if it is only for rough or practice work. As you start to do more intricate work, it will pay to have the right habits.

[vincent7520]

You're right !
Actually I used it to mark long pieces of wood to shape into a mast for a boat. Stains were not really a problem at this stage and the benefit was I didn't have to worry about the lead being used and not marking in the middle of the process.
For the rest you are perfectly right and it's a pleasure to talk to people like you.

Congratulations for you name too : I love technofossils ! …Although I have almost the whole paraphernalia of modern times (mac, ipod, ipad, etc…) I am quite one myself : some of my friends call me a luddite !…
My belief is that NASA technology is not as great as one may think as you can't plank a boat properly with it !!… LOL

[technofossil]

There is something about working with wood that can't be explained to an outsider. I've never meet another woodworker who wasn't eager to share. I tried to build a canoe once but never a boat.

I'm a Technofossil because I started as an electrical engineer in the early days of the computer explosion. I made a career change to teaching woodworking in high school. Never looked back.

Be well.

[vincent7520]

thank you
you too

[pfred2]

OK you convinced me I'm going to have to make some. Although usually I just mark off with calipers.

[splazem]

Very cool!

[Cheiron]

Thank's for noticing the problem on step 3 baustin,I fixed it. It should have read 2" not 2 1/2".

BTW very nice work PS118 that looks great!

Thank you all for your comments and suggestions I especially liked the ones about preventing tear-out. It's so frustrating when you have put time in on a piece only to have it ruined by something so simple.

[PS118]

Thanks. :)

[Cheiron]

I double checked ... you were right 1 1/2" LOL Sorry it's been a long day.

[Cheiron]

Thanks!

You are definitely right about the layout. Marking the diagonals in step one would have been a better way to find the center on the top and the front and back face. Drilling the hole in the top for the knurled screw would also have been easier before rounding off the edges.

A nail would have been easier and cheaper than making a knife blade, however I wanted to challenge myself to make a wedge to hold the blade in tightly. I figured it would be good practice for making a wedge for a tusk tenon (which will be part of my next project building a workbench hehehe).

[MadBricoleur]

Oh, wow! I first saw this because it was featured on the front page... I had invented (or so I thought) something similar to aid in making my ukulele, marking an offset perimeter from a curved piece of wood. Never knew there was a name for it! I guess the idea wasn't original after all.

[espdp2]

Just think, all by yourself, out of necessity, you invented a tool for a job that has been successful for millennia. Congratulations on being a secret genius!

[MadBricoleur]

haha, true dat. thx!

[PS118]

Thanks!!! Reading your instructible gave me the ideas and inspiration to finally build my own! (see attached image)

I used a 1/2" oak dowel and a piece of 3/4 oak scrap. I also had the 1/4"thumb screw laying around, so I just tapped the oak and screwed it in. The pad underneath is just a piece of 1/4" pine dowel I cut off thin with a utility knife.

It is 7" long overall, and I should be able to mark up to 6" wide with it.

Since I had no tiny tot hacksaw blades, I originally intended to use an xacto blade for the marking point. Since I couldn't come up with a way to not have part of the blade sticking out the top, I reluctantly decided to spare the inevitable accident and went with a grabber screw.

Actually that gave a few advantages:
1) super easy to do -- just drill a pilot hole and screw it on in!
2) Easy depth adjustment -- screw it in or out.
3) Easy sharpening -- take it out, screw something together with it, put in a new one.

[Endante]

This is Awesome Cherion! Great tips on how and why you did what you did. I already have the parts in my shop and am going to make one.

I am building a celtic harp and had the same "blow-out" issue you mentioned earlier, when drilling for the tuning pins in the neck. Wated alot of good wood.

I looked around and found the answer as to why it happens and what to do about it. This wont work with the auger bits because the force themselves through is why i didn't mention this earlier.

-- this is what I found--

The WHY is that the drill bit creates a pressure cone in front of the cutting surface as it bites into the wood. as you near the far side that pressure cone can "explode" outward ripping the underside surface.

the WHAT to do is: slow way down as you near the far edge, pause and even back the drill up to let the drill clear the material it is removing out of the hole. and MOST importantly keep your drill bits extreemly sharp and ground the the proper cutting angle.

Hope this helps

[baustin]

You could also add a knurled screw to the end of the square dowel to make it easier to change/adjust the blade.

[baustin]

This is great! On step 3 I think you meant to say mark both ends at 1-1/2 inches instead of 2-1/2 inches.
Also, to prevent breaking out the backside of your piece when drilling through, use a piece of scrap wood to back it up and it will prevent the bit from pushing through and breaking and splintering your work. Also, if you are using a brace and bit or a paddle, you can drill just until the tip of the center of the pit protrudes through the bottom of the work piece, then you can turn the piece over and your center point will be marked for you!

[Ortzinator]

It's called a mortise gauge.

[dnaman]

No, a mortise gauge has two blades or scribers that can be independently set to mark out both sides of the mortise or tenon.

[Cheiron]

This was the first time I have done a through mortise and also the first time I have had to make a wedge to secure anything. I try to challenge myself with at least one new thing in every project. Hopefully this will help some other people who want to get into woodworking but are on a tight budget like me :-)

Thanks for the comment

[Phil B]

Congratulations. The more you think about it, the more you will find other tools you can make, or adapt to a new purpose. All of this saves you much money and allows you to do better work.