Knowing when a machine was built tells you which parts fit it, which accessories it should have and whether the listing's story holds up. Most of the old makers numbered their machines in ways you can decode, and VintageMachinery.org has collected the tables. The volunteers who built them say they aren't the last word, so treat a date as a good estimate and check it against the plate, the paint and the details.
Delta and Rockwell
Start with the address on the plate. Delta's Milwaukee plant closed in 1952, so a Milwaukee address means 1952 or earlier and a Pittsburgh address means 1953 or later (a few 1953 machines got leftover Milwaukee tags). Delta didn't put serial numbers on its machines until 1941, so a Delta with no serial plate is likely older. The first Unisaws had their serial stamped on the tilt scale instead, starting at A-100 in 1939.
After that, a Delta serial comes in one of three kinds.
- Numeric serials from Milwaukee (1941 to 1952) and then Bellefontaine, Ohio (1953 to 1982). The table gives a range per year, so 1950 runs from 82-5501 to 91-5950 and 1960 from 125-9708 to 127-9999. A 37-315 jointer with serial 1279864 in the photo index is a 1960 machine.
- Two-letter prefixes from Tupelo, Mississippi, starting at AA-100 in 1951. CY is 1963, DS to EF is 1968, EP to EW is 1971 and GZ to HR is 1975. Some prefixes weren't used, and a few late ones can't be tied to a year.
- Eight-digit date codes from July 30, 1982 (and a few earlier), made of two digits for the year, a month letter and five digits. Rockwell used its fiscal year, which started in October, so A is October and 83B is November 1982. Shortly after Pentair bought Delta in April 1984, the letters switched to the calendar, A for January through L for December. By that rule a Unisaw 34-802 numbered 89E26173 was built in May 1989.
Plate styles help too. Early aluminum plates were 1/2 x 3 in, wartime ones were brass, steel or oilboard, and from late 1947 Delta used a 1 x 4 in aluminum plate, so the screw-hole spacing can identify a missing one. From 1973 machines carry the Rockwell International logo. On the Unisaw, running changes narrow it down further: the Jet-Lock fence arrived in 1960, T-slots in the miter slots in 1961, a sheet-metal motor cover replaced the cast-iron one in 1967 and a sheet-metal base replaced the cast-iron one in 1977.
Delta's Homecraft machines from 1946 to about August 1951 used letter serials from A-xxxx to Z-xxxx. Canadian Beaver and Rockwell machines are the gap, and nobody has found a way to date them yet.
Powermatic
Powermatic's serial numbers carry the year and a two-digit model code, and VintageMachinery.org's table comes from a late-1970s Powermatic document. From 1948 to 1953 there were no serials, and from 1953 to 1955 they were plain numbers. From 1955 to 1964 the format is one year digit and a number (N-nnnn), from 1965 to 1968 it's 6N-nnnn, from 1968 to 1977 it's one year digit and the model code (N66-nnnn), and from 1978 it's two year digits and the model code (NN66-nnnn).
The model code is usually the model number, but not always. The Model 60 jointer uses 61, and the Model 1200 drill press uses 20 followed by V for variable speed or S for step pulley. Powermatic was also inconsistent with dashes and leading zeros and sometimes went back to old formats, so check the date against the paint.
The paint is a good second opinion. An owners' study puts gray through 1958, a pea green from 1959 to 1969, metallic green from 1970 to 1981, two metallic golds from 1982 to 1995 and mustard yellow from 1996. A Model 66 serial that says 1985 on a green saw deserves a question. The badge is a red-on-aluminum oval reading Quality Machine, Powermatic, McMinnville Tenn., and from 1966 machines are labeled Powermatic Houdaille.
The table doesn't cover the imported Artisan machines, like the Model 64 saw and the Model 54 jointer. Date those by their manual, fence and paint.
Craftsman
Craftsman model numbers aren't serial numbers. The three digits before the decimal are Sears' source code for the maker: 113 is Emerson Electric, 103 is Central Specialty (King-Seeley's division), 102 is Walker-Turner, 101 is Atlas and 315 was Diehl and later Ryobi. The digits after the decimal are a Sears catalog number. It hints at which catalog years an item appeared in, but only roughly, and on the 113 table saws it mostly tells you the package, saw only or with legs, extensions and a motor.
So date a Craftsman by its manual. Sears printed a manual for its machines, and VintageMachinery.org hosts many of them with their dates. The source code helps too, since 103 items run from 1933 to 1963 and Emerson took over Sears' line in the 1960s. Some later Emerson serials appear to start with the year and the day of the year, but that's a pattern owners have noticed, not a documented rule.
Walker-Turner
Walker-Turner used several serial systems, which a 1961 service bulletin decodes. Type 0 machines have no serial. Type 1 numbers from 1939 look like model numbers and often end in the year the model started. Type 2 serials from April 1950 start with the two-digit year, then a letter for the machine (A saw, B band saw, D 15 in drill, E 20 in drill, P jointer, S shaper), a model letter, the quarter and a variant, like 52DA2A. Type 3 serials from April 1953 to September 1956 are plain sequence numbers, and Type 4 from October 1956 add a two-digit type prefix. After that, Rockwell badges date by Delta's tables.
Badges help as well. Walker-Turner Co. machines predate 1948, Kearney and Trecker plates run from 1948 to 1956, and Rockwell plates come after. An 8 in Walker-Turner jointer is always 1958 or later, because that was the first one.
Oliver
Oliver is the easiest of all. From 1907 every Oliver machine shares one serial sequence, starting with serial 1 on a Type B table saw. Serial 36,000 is about October 1928, 50,000 about November 1940, 74,000 about February 1950, 93,000 about March 1960 and 99,000 about October 1967. Then the numbers jump to 200,000 in October 1968, because 100,000 to 199,999 went to Oliver's food-equipment company. 202,000 is about May 1972, 205,000 January 1978, 207,000 January 1985 and 207,600 February 1989. So a serial dates any Oliver 88 or 232 to within months.
When there's no plate
Plates fall off and get painted over. Look for casting numbers, paint, the motor's own plate and the style of the switch and guards, and compare them with photos of dated machines in VintageMachinery.org's photo index. Then use the model page's checklist and our guide to checking a used machine to make sure the parts match the year.
