120 Chain A Plate Sprocket Size Chart

Posted on August 11, 2026 in FAQ, How To, Size Chart

When you get into #120 roller chain, you are no longer dealing with light-duty drive parts. These sprockets are built for larger equipment, heavier loads, and applications where chain alignment and proper tooth count make a real difference. A 120 Chain A Plate Sprocket gives you a strong, flat sprocket option for custom mounting, fabrication, and industrial repair work.

120A plate sprockets are flat, hubless sprockets designed for use with #120 roller chain. A Type A sprocket does not have a hub, keyway, or set screws, making it a good choice for compact assemblies, weldments, custom drive layouts, and applications where the sprocket may need to be mounted or modified separately.#120 roller chain has a 1.500″ pitch, also commonly written as 1-1/2″ pitch. When selecting a 120A plate sprocket, the most important details are chain size, tooth count, outside diameter, bore size, and how the sprocket will be mounted in the application.

Tip: Click any SKU in the chart below to view that specific 120 Chain A Plate Sprocket product page and see more information.

120 Chain A Plate Sprocket Size Chart

SKU	Tooth Count	Outside Diameter
120A10	10	5.52″
120A11	11	6.01″
120A12	12	6.50″
120A13	13	6.99″
120A14	14	7.47″
120A15	15	7.96″
120A16	16	8.44″
120A17	17	8.92″
120A18	18	9.41″
120A19	19	9.89″
120A20	20	10.37″
120A21	21	10.85″
120A22	22	11.33″
120A23	23	11.81″
120A24	24	12.29″
120A25	25	12.77″
120A26	26	13.25″
120A27	27	13.73″
120A30	30	15.17″
120A32	32	16.13″
120A33	33	16.61″
120A35	35	17.57″
120A36	36	18.05″
120A40	40	19.96″
120A42	42	20.92″
120A43	43	21.39″
120A45	45	22.35″
120A48	48	23.79″
120A60	60	29.52″
120A90	90	43.85″

What Is an A Plate Sprocket?

A Type A plate sprocket is a flat sprocket without a hub. Because there is no hub, A plate sprockets are useful where space is limited, where the sprocket needs to be mounted to another component, or where the bore needs to be machined for a custom setup.

For #120 chain, the sprocket pitch matches the chain pitch of 1.500″, or 1-1/2″. The tooth count changes the sprocket diameter, speed ratio, and chain wrap, which is why choosing the correct size matters.

Common Applications for 120A Plate Sprockets

120 Chain A Plate Sprockets are commonly used in heavy-duty conveyors, agricultural equipment, material handling systems, industrial machinery, fabricated drive systems, and OEM equipment. They are a strong choice when a simple plate-style sprocket is needed and the mounting method is handled separately from the sprocket itself.

These sprockets are also helpful for machine shops, maintenance departments, and fabricators that need a plain bore sprocket to modify for a specific shaft, weldment, fixture, or custom drive layout.

Shop Type A Plain Bore Sprockets Online

Need a 120 Chain A Plate Sprocket or another Type A plain bore sprocket? Shop online or contact MDS of Michigan for help matching chain size, tooth count, and outside diameter.

Click Here to Purchase A Plate Sprockets