Do you know the difference between Cut Taps and Roll (or Form) Taps?

When forming an internal thread, cut taps and roll taps are two of the most popular options. Both taps have advantages and disadvantages, and the right option for you may depend on the material being threaded.

John Butler, a Martin Supply Regional Account Manager and Certified Fastener Specialist, explained some of those differences on the Fully Threaded Radio Podcast.

Cut Taps

Cut taps are generally a cheaper option than roll taps and can be used in a wide variety of materials. However, the material being threaded will also chip and create debris. Those chips can be pulled out of blind holes by using a spiral flute cut tap.

“A cut tap is actually going to cut away material after you’ve drilled the hole,” Butler says. “As it puts threads inside the material, it will cut away a portion and give you a very defined, more of a diamond-shaped thread.”

Despite being versatile and cost-efficient, cut taps also typically have a shorter tool life and will have to be replaced more often. Because the cut tap is literally cutting the material, it can become dull and worn rather quickly.

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Roll Taps

Roll taps, also called ‘form taps,’ have one continuous spiral thread on the tap and do not have flutes. They reform the material inside the hole rather than cutting it away. This typically makes them more durable than cut taps and provides a stronger thread in the material.

“You can use it more often, we’ll say, before you’ll want to replace it,” Butler says. “That’s why so many machine shops want to use a roll tap.”

Roll taps should not be used when dealing with a material that is especially hard, such as cast iron, or soft, such as nylon or plastics. If the material is too hard, it may fracture and break. If it is too soft, it may eventually become displaced.

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The bottom line

Just like with most other tools, the right tap for your job depends on a number of outside factors including material, application, and desired thread characteristics.

Martin Supply has fastening and cutting experts that can help you find the right tool to get things done efficiently.

To learn more, contact your Martin Sales Rep or call 800.828.8116.