This pattern has the advantage over other wedged types in that you can
adjust the gauge by tapping one end or the other of the the stem against the
bench top. With other types, there is a risk of loosening the wedge. |
This
gauge was made to work inside a rebate (rabbet) where the end of the usual
stem would catch the rebate wall. The cutter is made from the end of a hacksaw blade, ground to shape and inset with its outer face flush with the stem tip. To reach to the face of the rebate wall, you'll need to ensure that the screw head does not project, but since the blade will be hardened, don't try to countersink the hole with a drill or countersink bit. Ideally; you'll need a conical grinding stone for the job. Since you would otherwise be screwing into end-grain, use a small-diameter wall plug to receive the screw. File a comfort chamfer for your thumb. Give a professional finish by slightly cambering the remote end of the stem and the ends of the pin. Of course, there's no reason why you should not make a conventional point by grinding the end of a broken drill (or perhaps a fine masonry nail). |
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Make the stock 1in to 1-1/8in thick (25 - 28mm) | ||
The drawing first appeared in Good Woodworking magazine and is reproduced with the kind consent of the Editor. | My stem was
European beech, the stock was some Hawthorn from the garden. Rosewood for
the dowel pin made a nice contrast.
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A
panel gauge gets across those panels that other gauges cannot reach. Since
the leverage from the drag on the point is greater than usual, a wider stock
is needed. When used one-handed, the drag can also cause a slender stem to become quite whippy, so I've shown a stock that is wider for most of its length. Common marking gauges are tilted in use but in this case the point has been tilted instead. Panel gauge stocks are usually provided with a rebate (rabbet), just why, I'm really not sure. Unusually, mine is shaped to allow some tilt that helps you to see the cutter when starting the mark. Note that the pin need project no more than 1/16in (1.5mm). |
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The drawing is
slightly simplified. Because of the small bearing area between the stock and
the stem, there is a tendency for the stock to tilt out of right-angles. My
own gauge has been shaped to increase the thickness of the stock in the
region of the wedge. You can adjust the gauge by the usual method of tapping one end or the other, but with this model there is a chance that the wedge will be loosened. |
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How many of us use
more than a couple of sizes of mortise gauge? These gauges, while often nice to look at, are expensive, and apart from the Ultimum (Ultimate?) pattern, can't be satisfactorily adjusted by tapping one end or other of the stem against the bench end. (The screw that bears on the brass slider tends to move the slider as well, usually taking up the backlash (lost movement) in the collar at the thumbscrew end. The Ultimum pattern has the slider inside a cylindrical stem operated by a screwhead inset in the far end). The diagram should be self-explanatory. Some people arrange that the mortise chisel should just be able to fit between the points at their extreme tips. This marks a tenon very slightly wider than the mortise. If anything, aim to make the separation slightly too small. If you don't get the distance quite right, you can adjust the pins by filing or abrading with a hone. Shanks of broken drills make good points (fine masonry nails less so, but possible). Grind them by using an egg-whisk type handrill to rotate the pin. Finish by hand to form a polished surface. From experience, I have learnt that it is not a good idea to follow the earlier tip by filing vertical faces to the pins |
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A
Grasshopper Gauge I got a screw adjustment by fixing a facing to an old on |