Martin chain #25 · E-16
25B21
Exact stock sprocket record from Martin's official Roller Chain Sprockets catalog.
Published catalog evidence
Exact source record
- Catalog number
- 25B21
- Chain designation
- 25
- Chain pitch
- 0.25"
- Number of teeth
- 21
- Material context
- all steel
- Sprocket style
- single stock sprockets
- Published row text
- 21 25B21 1 .809 B .25 .875 1 .375 .625 .28 A 25A21 .375 .04
Verification boundary
What still needs to match
Chain and strand countConfirm ANSI/ISO chain standard, pitch, roller width, and simplex/duplex/triplex arrangement.
Bore and hub systemVerify stock/finished bore, QD or taper-bushing size, hub style, keyway, setscrews, and shaft fit.
Material and teethConfirm steel/stainless material, hardened-tooth suffixes, corrosion requirements, and tooth count.
DutyCheck speed, horsepower, alignment, lubrication, shock loading, and current manufacturer limits.
Related catalog parts
Same chain family, nearby tooth count
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