Stanley · No. 21
Stanley never sold a No. 30 combination square. In its 1937 catalog the No. 30 is an angle divider, and the combination squares are the No. 21 and No. 22. The No. 21 came with a 9 or 12 inch slotted blade and one level glass, and its blade reverses face for face so you can read the graduations from either direction. The No. 22 has a 12-inch grooved blade and two level glasses, which made it a 12-inch plumb or level, and its handle slides to any point on the blade. Both have a cast-iron handle, machined on its working faces and finished in black japan, with a scratch awl held in a brass bushing. The blades were roll-tempered steel graduated in 8ths, 16ths and 32nds. One square works as a try square, miter square, level, depth gauge and marking gauge.
Identify and date it
Stanley's No. 30 was an angle divider, so a listing for a No. 30 combination square is mislabeled. One level glass and a slotted blade means a No. 21, and two glasses with a grooved blade means a No. 22. Goodell-Pratt and Starrett also made combination squares, so look for the Stanley name.
Level glasses crack or cloud, the scratch awl goes missing and rust can eat the graduations. A blade that's bent or worn at the end won't read true.
Buying guide
For a square to use, buy a complete No. 21 at $25–50 delivered, where most of the 23 or so listed sit. Check the photos for a clear level glass, readable graduations and the scratch awl in its brass bushing under the handle, and look for the Stanley name, since Goodell-Pratt and Starrett made combination squares too. Stanley's 1937 catalog lists the No. 21 with a 9 or 12 inch blade, so ask about the 6-inch ones, two of which share one title across different sellers. A Sweetheart logo dates a square to about 1920 to the mid-1930s, and the one we picked asks about $28 delivered, no more than plain ones. Skip the $138 listing, nearly three times the band top with no reason in the title.
$18.14est. delivered
The lowest delivered No. 21 without a copied title, about $18. The title gives no blade length or condition, so ask for photos of the level vial, the awl and the blade end.
Stanley No 21 Square
$27.10est. delivered
A 9-inch No. 21 marked Made in USA for about $27 delivered, near the bottom of the $25–50 band. Zoom in on the level vial and check the awl is under the handle.
Vintage Stanley 9''No 21 Combination Square Made in USA, Pat No. 1984951
$35.00est. delivered
A 12-inch No. 21, the longer of the two catalog blades, for $35 delivered in the middle of the band. Ask whether the handle locks firmly on the blade before you buy.
VINTAGE "STANLEY" #21 U.S.A. 12" COMBINATION SQUARE WITH 1" X 12" BLADE
$27.74est. delivered
Titled with the Sweetheart logo and the 1-23-17 patent date on a 9-inch slotted blade, for about $28 delivered. The heart logo puts it at about 1920 to the mid-1930s, so look for it in the photos, since the seller sells it as pictured.
VTG STANLEY NO. 21 PAT 1-23-17 SWEET HEART 9 IN SLOTTED COMBO SQUARE AS PICTURED
Delivered prices include shipping as eBay quoted it to a US address on Oct 11, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Snapshot
Checked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 11, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Used$18.14est. delivered
$10.00 + $8.14 shipping
Buy It Now$10.00
Good buy
Cheapest we'd trust. No size or condition in the title.
Seller: mvflaim
100% positive
Used$27.10est. delivered
$15.00 + $12.10 shipping
Buy It Now$15.00
Good buy
9-inch blade, Made in USA.
Seller: bla-henr
100% positive
Used$35.00est. delivered
$22.00 + $13.00 shipping
Buy It Now$22.00
Good buy
12-inch blade.
Seller: jackpatton2012
100% positive
Used$27.74est. delivered
$19.99 + $7.75 shipping
Buy It Now$19.99
Good buy
Sweetheart logo, 9-inch slotted blade, sold as pictured.
Seller: power.eagle
99.8% positive
Used$17.09est. delivered
$10.00 + $7.09 shipping
Buy It Now$10.00
Check the seller
Same title as another seller's listing. Compare the photos before you buy.
Seller: jack-bg_20200123
99.5% positive
Used$34.52est. delivered
$27.00 + $7.52 shipping
Buy It Now$27.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Check the seller
Same title as another seller's listing. The 1937 catalog lists only 9 and 12 inch blades, so ask about this 6-inch one.
Seller: lewisclark5000
100% positive
Used$35.15est. delivered
$27.45 + $7.70 shipping
Buy It Now$27.45
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Check the seller
Same title as another seller's listing. The 1937 catalog lists only 9 and 12 inch blades, so ask about this 6-inch one.
Seller: secondtimearound2021
100% positive
Used$137.70est. delivered
$125.00 + $12.70 shipping
Buy It Now$125.00
Priced high
Nearly three times the band top with no reason given. The seller lists it twice.
Seller: vitalbodies
100% positive
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