Shop math
The arithmetic that comes up at the bench, so you can do it on your phone instead of on a scrap of plywood. Inch fields take fractions: type 1 3/8 or 3/8 or 1.375.
Every shop
Inch fractions, decimals and millimetres
1 3/8 in = 1.375 in = 34.92 mm
Wood shop
Board feet
4 board feetRough lumber is sold by its thickness before surfacing: 4/4 is 1 in, 8/4 is 2 in.
Wood shop
Frames and segmented rings
Cut each end at 22.5° from square. Each piece is 4.142 in on its long edge (4 5/32) and 2.899 in on its short edge.About 33.14 in of stock before saw kerf and waste. “Across the flats” is the largest circle you can turn from the ring. Small angle errors add up: 8 pieces make 16 cuts, so a tenth of a degree off leaves a 1.6° gap. Dry-fit before glue.
Wood shop · Craft room
Resin pour volume
87.77 fl oz (2.6 L) in total: 1730 mL of A and 865 mL of B.This is a BY VOLUME ratio. Some resins are mixed by weight at a different ratio: use the one on your bottle, and check its maximum pour depth before filling a deep void in one go. For a river with wavy edges, measure the width in several places and average them.
Sewing room
Circle skirt
Waist radius 4 3/4 in (4.77), hem radius 26 3/4 in (26.77).Both are measured from the same corner point. Cut in one piece it needs a 53.55 in square, wider than most fabric, so full circles are usually cut as two halves. Add your hem allowance to the length.
3D printing
Filament cost of a print
$1.06 of filament.Your slicer shows the gram estimate after slicing, supports included. Failed prints cost the same as good ones.
These are calculators, not instructions. None of them tells you how to set up or run a machine: that is what checkouts and the people in the shop are for.