Buying a Mortise Gauge
Now that we’ve discussed marking gauges, let’s move onto a very similar gauge, called a mortise gauge. In fact, some gauges double as both a marking gauge and a mortise gauge. Mortise gauges have two pins, or two cutters, instead of just one.
Why? To lay out the shoulders of mortises, like for this table leg mortise and tenon joint. Now let me tell you up front that if you’re on a tight budget, you can most certainly get along with just a marking gauge. It’s a lot less convenient to mark half of the lines on all of the parts first, and then go back and set the marking gauge for the other wall of the mortise, but it can be done.
I just don’t want you to feel like you have to go out and buy every single hand tool before you can start making furniture. But, a dedicated mortise gauges saves time, and makes it a little easier to prevent making a mistake.
The options for mortise gauges are just about the same as with marking gauges, so I won’t cover all of that again. But there are a couple of important points I want to mention.
Antique mortise gauges like those pictured above are my favorite, because they tightly hold the measurement that I take from my mortise chisel. But if you’re buying antique wooden marking gauges or mortise gauges, just make sure that the gauge is sturdy when tightened down and that the wooden or metal screws aren’t broken. If the mortise gauge doesn’t have cutters, but pins, that’s okay. Because, just like I mentioned with the marking gauges, you can also use a file to convert the pins into cutters. Here’s a video where I show how to do this:
Which Mortise Gauge is the Best?
I’ve had really had good luck with these antique Stanley “mustache” style mortise gauges (pictured below), and they are pretty affordable, at about $20-$30, in good condition.
Aside from nice rosewood and brass materials, they double as a marking gauge on one end and a mortise gauge on the other end.
They come with pins, but I converted them to cutters quite easily. You can find these Stanley No. 77 mortise / marking gauges here on Ebay.
This Veritas wheeled mortise gauge (pictured below) is made by Lee Valley, the same company that makes the wheel marking gauge that I mentioned earlier. You can find it for sale here.
It can be used as a mortise gauge, or it can hold two separate measurements simultaneously if you’re just using it as a marking gauge. This is important for when you’re repeating multiple measurements on multiple furniture parts. This is an appealing gauge for someone just wanting to purchase one gauge, rather than a separate marking gauge and mortising gauge.
However, it also slips, though not as much as their normal marking gauges. If it weren’t for the slipping issue, and one other issue, this would be the absolute best mortise gauge ever made (in my opinion). Here’s the other problem. When I use an antique style mortise gauge, I can easily move the fence, while keeping the cutters from moving, because the independent pin is advanced by a screw mechanism.
You would do this when you move from marking your mortises to marking the tenons, and you want the cutters to absolutely not move, but you have to move the fence. But as you can see on this wheeled mortise gauge, it’s very difficult to keep the cutters in place when you move the fence.
Yes, Lee Valley later released a shaft clamp to solve this problem (see it here), but on their website they charge an extra $11 for it if you just need the clamp, like I do. That kind of bothers me. In my opinion, it should certainly be a feature that’s included, especially for a part that certainly costs under 50 cents to make. The gauge costs about $55 plus shipping without the clamp, and an extra $7 if you want it to come with the clamp. If you don’t mind paying a little extra for the shaft clamp, and if you’re careful to keep the shafts from slipping, then this mortise gauge is a really fine option. And it can certainly double as a normal marking gauge, so you wouldn’t have to buy both.
And that leads me to a modern style of mortise gauge that I would strongly caution against buying, due to a similar issue as the previous gauge. This style (pictured above) is very common among cheap, new tools sellers. I have tested out this model, by Crown Tools, and here are some similar ones to avoid. The gauge looks really pretty (brass with Rosewood or Ebony), but when you loosen the thumb screw to adjust the fence, it is very, very difficult to keep the pins from moving. So I would not recommend that you buy one like this.
But if you’ve already purchased one of these, don’t throw it in the trash. It is inconvenient, but you can grab a quick-grip clamp, or a piece of painter’s tape, and tighten the sliding bar in place before you loosen the thumb screw. But it sure is inconvenient and awkward.
Lastly, if you find an antique wooden marking gauge or mortise gauge at a tool swap or at a flea market, make sure you test the gauge out to see if it moves smoothly, and is sturdy when tightened down. Also check that the screws aren’t broken or the pins missing.
Quick Links to All of My Recommended Marking Gauges & Mortise Gauges