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Home → Publications → Tree Planters' Notes → Tree Planters' Notes Volume 19, Number 2 (1968) → A Useful Homeade Plastic Tree Caliper for Seedling Inventories

A Useful Homeade Plastic Tree Caliper for Seedling Inventories

A handy and useful tree caliper for measuring seedling diameter for nursery seedbed inventories can be constructed from scraps of plastic. One square foot of Plexiglas about 1/10 in. thick will produce about a dozen of these calipers. The pattern for the caliper is similar to that used on many wire gages. Rectangles of an approximate size 1-1 /2 in. x 5 in. are first cut out with a fine-tooth coping saw, holding the plastic firmly and evenly on a table with a large wood clamp or heavy weights. However, this size can be varied to suit individual needs. A long narrow vee slit is then cut in to an intersecting point. A small hole (1/8 in. diam. or less) is then drilled at the point of intersection to help prevent splitting. Also a hole can be drilled at or near the back for a string. A slow speed drill should be used for all drilling operations (375 rpm or less) . The right-angle corners can easily be worked off with a fine grit wheel on a bench grinder. Calibration is made in 32nds of an inch, from 2 to 10, to fit any particular inventory system but again could vary to suit individual needs.


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Author(s): Alan R. Peaslee

Publication: Tree Planters' Notes - Volume 19, Number 2 (1968)

Volume: 19

Number: 2