Dating
How to Date a Stanley Plane in Five Minutes
A decision procedure for dating a Stanley bench plane from the castings, adjusters and handles, using the features that actually discriminate between eras.
- updated 2026-02-14
- 5 min read
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Most people trying to date a Stanley plane start at the wrong end. They look up the number stamped on the iron, or they search for the patent dates, and they end up either with a range a century wide or with a confident answer that is wrong.
The reliable procedure is short. It works because a handful of Stanley's changes were permanent: once a feature appeared, it never went away, so its presence sets a hard earliest date and its absence sets a hard latest one. Chain four or five of those together and you have a window of a few years.
Rule one: date the body, not the plane
A hundred-year-old plane is a collection of parts, and the parts have different ages. Knobs split and get replaced. Totes crack at the horn — that is the single most common breakage on any bench plane. Irons wear down to a stub and get swapped for a better one. Lever caps get lost.
The body casting is the part that does not get replaced, because replacing it means buying a different plane. So date the casting first, get your answer, and only then check whether the other parts agree with it. When they do not, you have learned something useful about the plane's history rather than found a contradiction in the type study.
Rule two: patent dates are a floor, never a ceiling
The dates cast into the bed behind the frog are patent dates, not manufacturing dates. Stanley kept casting the same patent dates for years after the patents were granted, and in some cases after they had expired.
A plane reading PAT. AUG-19-02 was made in 1902 or later — possibly two decades later. What the patent dates are genuinely useful for is counting. The number of dates behind the frog changed over time, and counting them is the fastest single check in the whole procedure.
The five-minute procedure
Work down this list in order. Each step either sets a bound or narrows one you already have.
Step 1: Is there a lateral adjustment lever?
Look behind the frog, above the brass depth-adjustment nut, for a flat lever that swings left and right.
- No lever — 1884 or earlier. Stop reading the rest of this guide and go and look at the early types properly, because you have something unusual.
- Lever present — 1885 or later. This is the case for the overwhelming majority of planes you will meet.
Step 2: Read the toe
Look at the flat area of the casting in front of the knob.
| What you see | What it means |
|---|---|
| Nothing at all | 1901 or earlier |
BAILEY | 1902 or later |
BED ROCK | It is a Bedrock, made 1898–1943 |
Step 3: Look behind the frog
Take the iron and the frog off. Look at the bed casting where the frog sat.
| What you see | What it means |
|---|---|
| Nothing, and no adjusting screw | 1906 or earlier |
| A frog adjusting screw, but no patent dates | Roughly 1907–1909 |
| Three patent dates | Roughly 1910–1918 |
MADE IN USA | 1931 or later |
The frog adjusting screw is a small screw at the rear of the frog that engages a fork, letting you slide the frog forward to close the mouth without unclamping anything. It arrived in 1907 and never left.
Step 4: Look at the knob and its seat
| What you see | What it means |
|---|---|
| Low, squat knob | 1924 or earlier |
| Tall knob, flat seat | Roughly 1925–1932 |
| Tall knob, raised cast ring around the seat | 1933 or later |
The raised ring is a collar cast into the body around the base of the knob, with the knob bored to fit over it. Once you have seen one you cannot miss it.
This step is the one most likely to mislead you, because knobs get swapped more than any other part. If the knob disagrees with the castings, believe the castings.
Step 5: Check the lever cap and the finish
| What you see | What it means |
|---|---|
| Kidney-shaped hole in the lever cap | 1962 or later |
| Blue or grey paint instead of black japanning | 1962 or later |
| Plastic knob and tote | 1962 or later |
| Stained hardwood handles, steel depth nut | Likely 1942–1945 war production |
Worked example
A plane on a table at a flea market. It has a lateral lever, so 1885 or later. BAILEY on the toe, so 1902 or later. Three patent dates behind the frog, so 1910–1918. The knob is low, consistent with anything before 1925 — no contradiction. No MADE IN USA, consistent with pre-1931. No raised ring, consistent with pre-1933.
Everything agrees, and the tightest bound is the patent dates: 1910–1918, a Type 11. The iron carries a Sweetheart logo, which was not used until about 1920 — so the iron is a later replacement, or was fitted from stock at some point in the plane's working life. That does not change the date of the plane; it just tells you the iron is not original.
That whole chain takes about ninety seconds once you know where to look. The identify-by-marking tool runs the same logic interactively if you would rather tick boxes than remember tables.
What this procedure cannot tell you
It cannot give you a year. Stanley used up old stock before opening new boxes, so features from adjacent types overlap constantly, and a plane assembled from a two-year-old casting is completely normal. Anyone who tells you a Bailey plane was made in a specific year, from the plane alone, is guessing.
It also only covers bench planes. Block planes, transitionals and the specialty planes each have their own sequence of changes, and the bench plane type study does not transfer to them.
Where the dates come from
Every date here traces back to the published type studies, which were themselves reconstructed by collectors from dated catalogues and observed planes. Stanley never published any of it. The full type study lists the features type by type with a confidence rating on each, because some of them are far better attested than others.
Sources
- reference-site
Stanley Bench Plane Type Study (Types 1-20) — Patrick Leach - book
Stanley Tools: Guide to Identity and Value — John Walter - primary-patent
United States Patent and Trademark Office full-text and image database