Johnson-level-tool-mfg RAS-1 Bedienungsanleitung PDF herunterladen (Seite 32)

Theidealinchriseis7or8(or30°to35°)butmaybefroma

5-inch rise to a 14-inch rise depending on the circumstances. The

step rise or run may be modiﬁed if the run becomes impractical

oriftheminimumheadroomisunder61/2ft.Checkthehead

room by measuring down along a plumb line dropped from the

lowest ceiling point to where the tread beneath would be. To ﬁnd

the tread height, count the number of steps necessary to get

under the plumb line and then multiply by the step rise. Another

considerationistohaveaminimumof4"fromtheinsidecorner

ofthesteptothebottomedgeofthestringer(SeeFigure18).A

quick test is to use the square as you did for the common rafter

topplumbcut(usingthestepinchrise)andmakeaplumbline

the distance of the step rise, then measuring from the end of the

plumb line directly to the edge of the stringer.

The tread length depends on available room and intended use.

For instance, for two-way trac a length of 36 to 42 inches is

needed, whereas one-way trac doesn’t require over a 24 inch

length. Also, the calculated tread width does not include a nosing

width(1-3/4"beingmaximum).

FIG. 18 Stringer Layout.

1 2 ... 27 28 29 30 31 32 33 34 35 36 37 ... 66 67

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Johnson-level-tool-mfg RAS-1 Bedienungsanleitung Seite 32