Intro to Power Tapping

Added: 2026-05-31

[00:00:01]Good day, and welcome to my channel.

[00:00:04]I've had my mill for over 2 years now.

[00:00:07]It has a power tapping feature that I've never really played with until recently.

[00:00:12]All my tapping, whether on the lathe or on the mill, has been done by hand, and I don't have any issues with doing that.

[00:00:19]Let's have a look at power thread tapping.

[00:00:24]With careful use, conventional taps can be used under power, but the preferred taps are ones specifically designed for power tapping.

[00:00:32]They are generally stronger and built for the task.

[00:00:36]Depending on the purpose, these taps, which are color coded, are generally made from a high-speed steel and cobalt mix or solid carbide and are often paired with specialized service coatings.

[00:00:50]These taps I have here are yellow ring graded.

[00:00:54]They are designed for high-tensile materials such as tool steels, titanium, and nickel alloy.

[00:01:01]They also seem to work well on other alloys like brass, copper, and aluminum.

[00:01:06]They are also coated with moly glide, which reduces friction and improves chip evacuation.

[00:01:13]These are manufactured from premium high-speed steel and alloyed with 5% cobalt.

[00:01:18]This material offers superior strength and durability.

[00:01:22]It's sort of like making a vindaloo curry. The chili is the cobalt. Add 5% of it to the curry, and it's going to be stronger.

[00:01:31]Generally, there are two types of power taps.

[00:01:33]The first is a spiral point tap, commonly called a gun tap, which is designed exclusively for through holes.

[00:01:41]Its straight flutes push the chips forward and out the bottom.

[00:01:45]You cannot use these for blind holes as the trapped chips will compress at the bottom, creating excessive pressure that can easily break the tap.

[00:01:55]The spiral flute tap shown below is designed specifically for blind holes.

[00:02:00]Just like a drill bit, its spiral flutes pull the metal chips upward to ensure a clean thread and hole.

[00:02:07]While it can also be used on through holes, a gun tap is the preferred choice for those applications.

[00:02:15]This illustrates how the spiral geometry of a right-hand twist drill bit facilitates chip evacuation.

[00:02:23]You can see the rotation that the chips would be pulled upwards and out of the hole.

[00:02:27]This is best demonstrated on a lathe where the drill bit is stationary and the part is rotating.

[00:02:36]This mechanism applies equally to spiral twist taps.

[00:02:46]So, how does power tapping happen? Once the power tapping mode is unlocked and the spindle speed is set, the green buttons on the spindle handles become active.

[00:02:59]Lower the spindle by hand until the tap engages the work piece.

[00:03:03]The tap's cutting edges will then pull it smoothly into the hole. Once the tap passes through, engage with the green switch to reverse it and it will automatically back it out along the same thread path.

[00:03:21]Let's get up close and drill and tap an M10 thread blind hole.

[00:03:26]Useful tip. Skip the chamfer tool by selecting an oversized spotting drill and plunging just a bit deeper to create the perfect chamfer edge. You'll see the chamfer after the drilling.

[00:04:09]>> Observe the tap being lowered into the component.

[00:04:13]The tap and spiral cutters engage, pulling the tap along its own helical path, while continuously evacuating chips upward to leave a clean finished hole.

[00:04:27]When machining blind holes, ensure the drill depth is generous, provided the part geometry allows for it.

[00:04:34]If the tap bottoms out during the threading process, it may fracture and cause irreversible damage to the work piece.

[00:04:42]If you plan on tapping blind holes, then adding a tapping chuck set to your toolbox would be a great addition.

[00:04:49]There are many different types available.

[00:04:52]This one shown here can be used on both a lathe and a milling machine.

[00:04:56]These systems generally feature a built-in adjustable torque limiter, also referred to as an overload or a slip clutch.

[00:05:04]This will prevent tap breakage, and they usually have some sort of a floating holder to correct any misalignment between the spindle and the pre-drilled hole.

[00:05:16]You can use a spiral flute tap for through holes, but it isn't the most efficient choice.

[00:05:23]While spiral flute taps are designed to pull chips up and out of the hole to prevent jamming in blind holes, using them in through holes can cause chips to pack up into the flutes as they exit.

[00:05:44]Now, let's examine the gun tap and the cat hair.

[00:05:47]These are engineered specifically for through holes.

[00:05:51]These taps feature straight flutes that allow chips to gather inside them and fall cleanly through the bottom of the hole.

[00:06:30]I created a blind tapped hole in a piece of stock and machined a cross-section to demonstrate the internal geometry and highlight important considerations.

[00:06:41]Observe the initial hole created by the drill bit.

[00:06:45]Specifically, it's point angle and tip geometry.

[00:06:49]Now look at the engagement of the tap within the cut threads.

[00:06:55]Special care is required for thin materials.

[00:06:59]You must factor in clearance space beyond the seated screw to prevent drilling completely through while carefully calculating the minimum thread engagement necessary for structural integrity.

[00:07:12]When tapping through holes, the tap's tapered section must pass completely through the work piece to ensure full accurate threads are formed across the entire length of the hole.

[00:07:24]In conclusion, power taps are highly effective and they're quick and simple to use.

[00:07:30]However, for small blind holes with delicate profiles, manual tapping is preferable.

[00:07:36]This method allows for better tactile feedback, ensuring the tap does not over engage the bottom of the hole.

[00:07:44]I hope you enjoyed the video and thanks for watching.