Morse Taper Dimensions Chart

What it is

The Morse taper is a self-holding taper used to mount drills, drill chucks, centers and reamers in spindles and tailstocks. The taper is shallow, about 5/8 in per foot, so friction alone holds the tool and drives it under normal loads. A flat tang on the end of most shanks keys into a slot and is used to knock the tool out with a drift. Sizes run from MT0 (smallest) to MT7.

How to identify

Measure the large end of the shank at the gauge line, or the bore at the mouth of the socket, and compare to the gauge diameter below. The size is also often stamped on the shank (MT2, 2MT, No. 2 Morse). Tangless (drawbar) shanks have a threaded end instead of a tang.

Chart

Key points

• Taper per foot is close to 5/8 in for every size but not identical, so sizes are not scaled copies of each other.
• Sleeves (reducers) let a smaller shank fit a larger socket, such as MT2 to MT3.
• Clean the shank and socket before seating. A chip or burr prevents full contact and lets the tool spin.
• Seat the tool with a firm push or a light tap with a soft mallet; remove it with a drift through the slot.
• Drill chuck arbors pair a Morse taper on one end with a Jacobs taper or thread on the other.

Common mistakes

• Confusing Morse tapers with Jacobs, Brown and Sharpe or R8 tapers, which are different.
• Letting a tool spin in the socket, which scores both and ruins the fit.
• Using a tang for driving under heavy load. The tang is for removal; the taper does the driving.

Governing standards: ASME B5.10 (machine tapers); ISO 296 (self-holding tapers for tool shanks).

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.