Have you ever had a tap break while you’re on the finishing features of a component that has taken hours on the machines to process? At that moment your frustration rises, your machine stops, and you start to lose profitability with every minute that passes. Picking the right tap is vital. You would be surprised how often this happens throughout the course of a year and how much it eats into your profits.
At Triumph Tool, we believe in the importance of offering superior technical support and customer service to our clients. We wrote this article as an introductory guide to help with tap selection of proper flute geometry.
There are so many different things to look at when selecting the proper tap such as material, volume of holes, coolant supply, rigid or floating holders, as well as the tap material, coating, geometry, etc. We are focusing in on selecting the proper flute geometry and what to do with the chip on different applications.
If you aren’t paying attention to where your chips are flowing, you run the risk of breaking taps and eating your profit away with them.
We hope you find this blog helpful! Please leave a comment below or contact us if you have any questions or feedback.
The straight flute is the standard style of tap, designed for a range of different tapping applications. It can be especially beneficial when cutting short chipping material such as cast iron. A straight flute tap can be used in through or blind holes. It is commonly used in smaller shops that prefer “one tap fits all” approach.
Spiral flute taps feature spiral flute designs rather than conventional straight flutes. The spiral fluting feature aids in evacuating chips out of the tapped hole. Spiral flutes are recommended when bridging a gap inside the hole such as a keyway or cross-hole. Commonly available in slow spiral (18-30° helix angle) or fast spiral (45-52° helix angle). Following are recommendations for degree of spiral for various materials:
- High spiral flutes 45° and higher – Effective for very ductile materials like aluminum and copper. If used in other materials, they will usually cause the chips to nest because the spiral is too fast and the chip area is too small for chips to form correctly.
- Spiral flutes 38° – 42° – Recommended for medium to high carbon steels or free machining stainless steels. They form a chip tight enough to easily evacuate. On larger taps, it allows for pitch relief to ease the cutting.
- Spiral flutes 25° – 35° – Recommended for free machining, low or leaded steels, and free machining bronze or brasses. Spiral flute taps used in brass and tough bronzes normally do not perform well because the small broken chip will not flow up the spiral flute well.
- Spiral flutes 5° – 20° – For tougher materials such as some stainless, titanium or high nickel alloys, a slower spiral is recommended. This allows the chips to be pulled slightly upward but does not weaken the cutting edge as much as higher spirals will.
Spiral point taps have the same general physical dimensions as standard straight flute taps. However, the spiral point tap has the cutting face of the first few threads cut at a predetermined angle relative to the tap’s axis angle to force the evacuation of chips ahead of the cutting action. This feature, and the excellent shearing action of the flute, make spiral point taps ideal for production tapping of through holes.
Typically, this type of tap has a shallower flute passage than conventional taps. This gives the spiral point tap more cross-sectional area, which provides great strength, allows higher tapping speeds, and requires less power to drive.
Thread forming taps are fluteless except as optionally-designed with one or more lubrication grooves. The thread form is lobed so there are a finite number of points contacting the work. This tap does not cut, so it is ‘chipless’ and, consequently, will not cause a chip problem. The tool forms the thread by extrusion, thus thread size can be closely maintained. The fluteless design allows high-quality threads, faster tapping speeds, higher production, and generates no chips, which simplifies tapping of blind bottoming holes (threads can be formed the full depth of the hole).
Have a look at what’s to come in the future of tapping from Emuge Corp:
Looking for more information? Contact the team at Triumph Tool to find the right taps for your metalworking applications.