Tool type
Bench planes are the metal planes with a tote at the back, a knob up front and an iron bedded bevel down under a cap iron. Stanley numbered its Bailey line by size, from the 5½-inch No. 1 to the 24-inch No. 8, and used fractions like No. 4½ and No. 5½ for wider versions. The smoothers (Nos. 1 to 4½) take the final shavings, the jack and fore planes (Nos. 5 to 6) flatten rough boards, and the jointers (Nos. 7 and 8) true long edges and faces. Stanley changed the design every few years from 1869 into the 1960s, and the collectors' Type Study turns those changes into a way to date a plane from listing photos.
10 models we cover.

Stanley · Bench plane
No. 11869–1943
$1,350–$2,600 typical ask
3 on eBay

Stanley · Bench plane
No. 21869–1961
$360–$430 typical ask
13 on eBay

Stanley · Bench plane
No. 31869–1984
$45–$70 typical ask
97 on eBay

Stanley · Bench plane
No. 41869–1984
$55–$90 typical ask
159 on eBay

Stanley · Bench plane
No. 4½about 1884–1961
$95–$150 typical ask
42 on eBay
Stanley · Bench plane
No. 51869–1984
$65–$90 typical ask
161 on eBay
Stanley · Bench plane
No. 5½1898–1958
$110–$200 typical ask
26 on eBay
Stanley · Bench plane
No. 61869–1970
$80–$120 typical ask
134 on eBay
Stanley · Bench plane
No. 71869–1970
$130–$210 typical ask
68 on eBay
Stanley · Bench plane
No. 81869–1961
$200–$290 typical ask
34 on eBay