Tips for Hand Tapping the Perfect Hole

Threading a drilled hole may seem like a simple procedure, but plenty can go wrong if you don’t take the proper precautions with using hand taps. Follow these tips to ensure tip-top taps every time.

Know the Drill

Store taps with their matching drill bits to ensure you use the right tap for the fastener. Holes that are too large can result in too-shallow threads that can strip or fail to engage the fastener sufficiently. Holes that are too small can bind the tap or chip it by forcing it to remove too much material. Regal’s expert customer service representatives can show you how to use conversions and tap/drill charts to calculate the correct hole size.

Stay Sharp

Only hard, sharp hand taps can be counted on to perform the job correctly. Use only high-speed steel taps from a respected manufacturer you trust. Keep new taps in the sizes your shop commonly uses on hand. Replace dull taps promptly. Dull taps must work extra hard to cut threads into workpieces. This compounded work risks chipping the teeth or breaking off the tap inside the hole – a real nightmare.

Be a Straight Shooter

To produce the most precise threading, take the time to ensure the tap enters the hole perfectly straight. A straight start also helps reduce:

Friction
Wear
Possible Breakage

The hole will try to force a misaligned tap to straighten as it moves along. Guard against misaligned starts by chamfering the hole before tapping it. Regal’s taper taps help assure a good start, and their long chamfers allow more teeth to engage in the threading process, reducing stress on the tap.

Keep it Clean

Reverse course regularly to break the swarf into manageable pieces and keep the hole clear of chips. As soon as you begin to feel resistance, back the tap out. Clearing the chips is especially important in thick material. Steel and brass form chips easily, so deep in these materials may require the tap to be backed completely out a time or two. Softer materials such as aluminum, on the other hand, can create longer swarf that must be sheared off the workpiece, and may require as much as half a “back turn” for every forward turn of the tap in order to cut the pieces off short enough to be evacuated out of the hole through the flutes. During the backward action, it is often possible to hear or feel the cut piece breaking off the workpiece. The smaller the tap, the more frequent reversals will be required. Ignoring this step can clog the flutes and bind the tap. Continuing forward, often will break the tap.

Slick as a Whistle

While the slow action of hand tapping does not produce enough heat to be concerned about, lubrication is still important. Depending on the materials, using commercial tapping oil, machine oil, even water or non-stick cooking spray, makes a huge difference in reducing friction and stress on the taps. Added slickness will prevent binding as the tap goes in and assist evacuation of chips along the flutes.

Tap into Regal’s Expertise

Regal carries a full line of machine screw, fractional and metric hand taps. Our master craftsmen precision grind our hand taps conforming to our stringent in-house quality controls and all ANSI standards. Our taps’ high-speed steel construction makes them perfect for most general hand- or machine-tapping applications. Standard taper, plug, and bottom taps in sizes up to six-inch diameters are always in stock, and our sales team can ensure special orders ship within 24 hours. Contact us today for more expert tips on tapping the perfect hole!