Marking Gauge Stability Tweak

Back when I made this marking gauge, I thought I pretty much had it all figured out with the mistakes I made there (see the bottom of the post). But it turns out that one of them was kind of unresolved; how to get the arm to have no play whatsoever (as it was, the arm would swivel a little horizontally because its hole wasn’t a perfect fit). I’d thought of a bunch of stupid ideas, from making the arm trapezoidal to mounting the tightening screw diagonally, but mostly, I forgot about it because it still “kinda” worked and that’s all I cared about.

Then when I was milling the frame components for the new nightstands v2 project, I needed more than one gauge, so I grabbed one of my old Stanleys and noticed that the arm didn’t budge at all. Neither did my other old Stanley. Both of these were rectangular-like arms tightened with a screw from above, like the one I’d made. What did they do that I didn’t?

I flipped them over and found the answer.

The bottoms of the arms are slightly convex and the hole in the marking gauge stock is slightly concave. The gauge on the right is a Sweetheart-era Stanley and is a really good fit.

Upon realizing this, I immediately knocked the wedge and blade of out the arm of my shopmade gauge, pulled the arm out of the stock, and used my Taiwanese shave to put a slight radius on the bottom of the arm. Then I put a rasp into the stock and made a mating surface, and the result looks like this:

The fit doesn’t look terribly appealing to the eye, but doing just this much instantly solved the problem, and I’m really lovin’ this gauge now. At that point, I figured that I’d better get back to milling rather than try to make this dorky tool look better. That was a couple of days ago. I finally got around the taking the photos today. It took about five times as much time to take the photos and write this post than to actually fix the problem. Peh.

(And maybe someone else out there has already figured this out and posted something that I haven’t read.)

[Edit (17 June 2011): OK, so I finally bought The Anarchist’s Tool Chest by Christopher Schwarz, and unsurprisingly, on page 118, he talks about this problem. His solution is to do the wedge-jams-the-arm-into-a-corner thing. That works, but he gives short shrift to thumbscrew-tightened models, which is, of course, an injustice, because they work fine after you do what Stanley (and whoever they stole the idea from) did. Also, he says that the thumbscrew is knurled brass. Well, I couldn’t source any brass for mine, and a lot of new ones sure aren’t solid brass, if they contain any at all. I think a wooden thumbscrew is best (Stanley used these), but I don’t have a tap and threader, so I couldn’t do this. Anyways, it’s another datapoint.]

Making a Mortise Gauge

I’d like to say that I’ve been off designing a new project for the last three weeks, that I’ve made a new workbench, or that I’ve been moving, or something like that.

But no, I’ve been making a new mortise gauge, and yes, it took me nearly three weeks (mainly because I haven’t spent much actual time in the shop due to an acute case of laziness). This is based on the marking gauge I made a while back, but I wanted to solve some of the deficiencies of that one.

I should also mention that the whole reason I wanted a new mortise gauge was to correct an irritating problem in the two-armed Asian-style gauge that I have now: there’s only one thumbscrew to secure the whole thing, and the two arms are separated by a little metal plate. When you’re trying to adjust one arm, the plate moves, moving the other arm slightly. It takes a lot of dorking around (at least for me) to get both adjusted to the correct length. So I resolved that I would fix that by making a two-armed version with two independent thumbscrews.

I started by making the stock out of some of that pacific madrone that I’ve got hanging around, using the same technique as in that earlier post. This is the view after I’d cut the mortises, drilled the small guide holes, and shaped the top:

When I set about making the arms (out of beech, for whatever reason), I fine-tuned them to fit the mortises tightly using the old “plane clamped upside down in the vise” trick that was featured on what I think was a fairly recent episode of St. Roy’s show:

Just watch that you don’t plane your fingers! When the arms were fit, I had this:

Then it was time to put in the screw inserts for the thumbscrew securing mechanism. Sometimes this can be a real pain, and it was a really big pain this time. I started by enlarging the guide holes with a #5 auger bit:

The problem was, however, that a #5 bit was too small for an insert (seen behind the vise above), and a #6 was too large. Furthermore, the screw inserts were brass, which means that they are very easy to mangle. I used a round file to enlarge the holes slighty, then gently drove in the inserts with a bolt. (Prayer may also have been involved; I do not remember.)

With that part done, I made the holes for the blades, the wedges to secure the blades, and finally, the blades themselves (out of spring steel again). Remembering my goof from the previous marking gauge, I put the wedges on the outsides of the blades this time. The wedges were also fine-tuned using the clamped-plane method described above.

Then I made the “saddle pieces” that I described in the marking gauge post. This time, I bought a thinner strip of brass so it was easier to hammer to shape. Then, to design around the problem of the saddle getting in the way, I marked where the blades hit the saddle:

Then I sawed and filed out a notch in each saddle so that the blades could be brought flush to the stock:

At that point, there was nothing left to do but trim the thumbscrews and wedges down to size, and call it done:

Initial tests seem to indicate that it works.

[Edit: If you’re thinking about making a marking gauge, see this post for an important tweak that helps resolve a certain annoyance in this style of marking gauge. This one doesn’t have that issue, but bigger ones tend to.] I’ll restore this link some day, maybe

Making a Marking Gauge

I made a marking gauge a while back, complete with captive wedge and everything. For a long time, I didn’t have a cutter for its arm, so it wasn’t very useful. Then at some point, I made a cutter out of a section of an old saw, and it was then a working tool. The problem was that I never used it, and after a while, I realized that I never used it because I was always reaching for my gauges with thumbscrews. I guess I didn’t like the captive wedge.

To fix this, I decided to ditch the wedge and retrofit a thumbscrew. I bought all of the hardware necessary and immediately proceeded to bore too small of a hole for the screw insert, and this ultimately ruined the fence part of the gauge. I removed the screw insert, gave up for the day, and sulked:

The next day, I milled a new piece of beech to thickness, cut it to size, and mortised a new hole for the fence:

Standard through-mortise procedure applies: Cut halfway through on each side. Easy enough; then I roughed out the fence shape with my new saw (I’m using it more than I thought I would):

I finished the shaping with my saw rasp and some sandpaper–nothing new there.

In all of the thumbscrew-model marking gauges I’ve seen (the metal screws, that is), there’s a piece of metal acting as a guard between the screw and wooden parts. I don’t know what to call this, so I’m calling it a “saddle,” because it’s usually a U-shaped thing that fits over the wood.

I cut off a piece of brass from some stock I had lying around, put it in a vise, and smacked it with a hammer to try to form it. I guess I was expecting it to be a lot softer, because nothing much happened when I did that. So I took out my little sledgehammer and gave it a pounding. I don’t know if this is the way you’re “supposed” to do stuff like this, but it worked:

After some filing, it fit perfectly.

Then I turned my attention to boring the hole for the screw insert. I had already drilled a small pilot hole before shaping, so keeping the bit straight wasn’t a problem, and I’d also learned from my previous hamfistedness that I needed to use a #7 bit, not a #6 bit. Fortunately, I had one:

Notice the finished saddle piece at the right here.

After going to the correct depth with the #7 bit, I finished going all the way through with a #5 bit, then I used a large furniture connector driven by a ratchet to drive in the screw insert:

To finish it, all I had to do was hack the thumbscrew to a proper length and put everything together:

Immediately after putting everything together, I realized that maybe the marking gauge with a thumbscrew and wedged cutter is not as simple of a tool to make as it seems. That’s because there is a limitation of this particular configuration that I hadn’t thought about before, namely, that the cutter can’t be set less than about 3/16″ away from the fence. There are two causes here:

  • I put the wedge on the inside of the cutter rather than the outside.
  • The saddle introduces yet more buffer space. That wouldn’t have been a problem if I put the saddle on the side, like some other marking gauges, but I didn’t like the fact that the arm had a little play in that configuration.

How interesting! I know how to overcome both of these issues, but I’m not going to bother for this particular gauge. It’s done and ready to use.

[Edit: See this post for how I fixed the second problem listed above. Also, see this post for a more advanced approach to the problem.]Links not available at the moment, but they are the tweaking and panel gauge links, which might not be restored yet.

[Edit: Bob Rozaieski has put up a video of making a French style marking gauge. Check it out here.]