I think it could be used for laying stone steps. The end flat part would
rest on lower step and the adjustable part would be set to the height of the
step. Then it would be laid on top of the step with adjustable part standing
up and the end flat piece against the front edge. To measure the depth of
the step by using the marks on the strait edge for the next step.
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If so -- the steps would be rather shallow. 100mm is only 3.937
inches. Not serious steps if that small -- but perhaps ones which one
can flow up without breaking stride for some ceremonial purpose. But a
tool like that would certainly be made to have a range more suitable to
the extremes of step sizes.
If you use a string, normally you measure for your end bricks first. A
typical brick with mortar is 75mm, but they can run up to about 100,
like this gage.
I haven't laid brick on my own, but I know I don't like chalk lines for
shingling. It takes time and energy, makes holes in roofing felt, and
is a potential source for error. If you mark a good chalk line, you
still have to eyeball as you place your shingles. The feel of a gage is
easier and surer. If you've put your felt on straight, those lines can
be used to double check.
In bricklaying, a string would have to be properly adjusted for each
course. If you're looking down at it, it won't be a precise guide.
Besides measuring end bricks, the gage could make it easy to lay every
9th brick, for example, then fill in the other 8. If your level were
2m, your bricks 200mm, and you wanted mortar 10mm wide between them, you
would cut a gage board to 1690mm, lay that along the wall with one end
against the corner brick, set a brick at the other end, and put the
board aside. Use the gage as you tap the brick to the right height,
then check the level against the corner. Then slap the other 8 into
place and use the level as a straightedge to check by feel as you tap
the bricks down to level. It sounds quick, and people will worship you
for having courses straight and level to the mm.
It looks as if my reply several hours ago did not propagate.
I think when one uses a string, he starts by measuring to set the end
bricks. With mortar, a typical brick is about 75mm high. Some are up
around 100mm, the limit of this gage.
Because the gage is adjustable in mm, it could be useful if a mason
found he was building on a course that wasn't level. He could add a mm
or so to each course at one end and subtract a little at the other end
until the ends were level.
Youtube shows a several masons not using strings, which would have to be
reset for each course and could be hard to eyeball. If a mason buttered
the wall for five bricks, then used the gage to set the height of the
fifth brick, he could use his level as a straightedge as he tapped the
others down into line. That could be quicker and straighter than using