Category: Roll Form Taps

Detailed Guide to Roll Taps

4/18/2023

Technical article courtesy of Regal Cutting Tools

Most craftspeople will agree that whenever an internal thread can be made with a roll form tap, this is the tool that should be used for the job. Roll taps, also known as form taps, hold distinct advantages over cut taps. Roll tap advantages are inherent in the way they create the threads.

As the names suggest, these taps form the threads by rolling and deforming the material inside the hole. They push the metal out of the way to create the thread roots and base. Cut taps, also true to their name, carve metal away from inside the hole, ejecting chips as they go.

Reasons to Use Roll Form Taps

Roll taps are a great option when considering workmanship and price point. First, roll taps are chipless. Because they do not remove material from the hole, form taps generate no chips that must be removed. This carries several advantages:

Tool Life – Cut taps have flutes cut into them through which chips migrate up and out of the hole during threading. Flutes take away the taps’ bulk and rigidity, weakening them and making them more susceptible to wear and breakage.

Efficiency – Flushing chips from a blind hole and disposing of them takes time. Roll taps eliminate this wasted time so machinists can thread more holes in the same amount of time. Roll taps’ strength also permits their use at higher feeds and speeds, increasing their efficiency even more.

Thread Quality – Forming threads rather than cutting them creates more precise pitch diameters and surface finishes. Just as important, rolled threads are stronger than cut threads because the metal grains are deformed along the thread contours.

Speed – Roll form taps should be run at 1-1/2 to 2 times the speed of a cut thread tap for a given material. The forming action creates heat and can “work harden” the material being formed. It is a good practice to form the thread and reverse out of the hole as quickly as possible.

Regal MetFlo Taps

When Not to Use Roll Taps

While an excellent choice for most applications, there are a few situations that do not lend themselves to roll tapping including:

Threading a through-hole – Form taps may deform the exit hole, which will necessitate a second, time-consuming step to repair. Spiral-point cut taps are the best option for such a job. They push chips ahead of the cutting edges, keeping flutes clean. The chips fall harmlessly out the exit hole as the tap breaks through.

You’re threading a big hole – Thread-cutting taps require less horsepower than thread-forming taps. Cutting large holes with a form tap requires twice or three times as much torque as with cut taps, which can take its toll when threading large internal surfaces.

The workpiece is hard –Form taps are suitable only for soft and malleable metals such as soft steel, some stainless steels, aluminum, copper, brass, and lead. Typically, the material to be formed should be less than 32Rc in hardness.

Types of Roll Taps

Roll taps are engineered and manufactured in two main styles to match the type of hole and fastener to be used. Bottoming roll taps feature little to no taper on their end threads. This allows full thread production to the very bottom of the hole.

The bottom 3 to 5 threads on a plug tap are tapered to allow the tap to gradually begin deforming the hole material, creating less stress on the tool and giving the full threading edges a base from which to work.

Regal Cutting Tools has built a reputation for high quality taps and other metalworking tools and an uncompromising commitment to customer service. Regal manufactures a full line of roll taps to suit any application. Regal can even engineer custom taps quickly and affordably. To learn more about Regal’s taps and learn which products are best suited for your workflow, contact our team today.

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The Different Types of Carbide Taps and When to Use Them

8/18/2021

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This is Part 2 of our series on Carbide taps. Be sure to check out Part 1 if you missed it:
Carbide Taps: A Practical User’s Guide to When, What, How and Why

Carbide taps have a lot of advantages, especially when you’re cutting very abrasive materials. The absolute best choice for tapping glass-filled polycarbonates, space age alloys, nonferrous materials, cast iron, and a range of other exotic materials, their anti-friction qualities lead to a longer tool life.

Because of this, you’ll require fewer replacements, less downtime, and increased productivity.

The durability, flexibility, and longevity of carbide taps is unparalleled, allowing you – and your employees – to focus on what’s important: getting the job done.

Regal Cutting Tools offers an unparalleled selection of taps for many applications, allowing you to source all of your essential taps from one supplier.

In today’s post, we’re going to take a closer look at a few of the options that they offer.

Carbide Taps Allen Benjamin North American GW Schultz GWS TOol Tapping

Standard Screw Thread Insert Taps

S.T.I. (Screw Thread Insert) Taps are special taps for helical coil wire screw thread inserts, which provide positive means for protecting and strengthening tapped threads in any material.

Typically used on softer abrasive materials, these taps create more accurate thread forms than other standard taps. When you need to be precise, these carbide taps are the best choice.

STI taps are correctly sized to produce an internal thread that accommodates a helical coil wire screw thread insert. The insert, in turn, will accept a screw thread of the nominal size and pitch at final assembly. Screw thread inserts provide stronger tapped threads (stronger assemblies) due to a more balanced distribution of loads throughout the length of thread engagement.

Thread Forming Tap

Roll Taps (aka, Thread forming taps, Form taps0 offer improved thread quality and strength due to the fluteless design, and therefore allows for greater fastener strength in the threaded product. This tap does not cut, so it is “chipless,” and therefore will not cause a chip problem. This is why thread forming, over thread cutting, eliminates costly and time-consuming chip clean-up and disposal.

Thread forming taps are fluteless and include lubrication grooves. Not intended for general applications, they work by displacing the metal without removing it. Because of this, they are ideal for chip removal in blind holes.

Roll Thread Forming Taps Features

Improved thread quality and strength due to fluteless design of tap; allows greater fastener strength in threaded product.
Tapping speeds can be increased as much as double that of conventional cutting taps…more tapped holes per hour.
Thread forming (over thread cutting) eliminates costly and time-consuming chip clean-up and disposal.
Improved tap life, even in abrasive materials…no cutting edges to get dull.
Lubrication grooves allow forced passage of air and lubricant when tapping.
Simplifies tapping of problematic blind bottoming holes where adequate chip clearance is impossible with chip-producing cutting taps.

Carbide Insert Taps

A cost-efficient solution, only the cutting portion of insert taps is made from carbide. Their HSS body is able to absorb vibration and account for their lack of rigidity.

If you’re considering testing the waters with carbide taps, insert taps are a great option. It's a very economical way to utilize the benefits of carbide with solid carbide cutting face inserts meticulously brazed to a H.S.S. tap body.

Carbide Insert Tap Features

High speed steel body absorbs excessive shock and offers the rigidity necessary to minimize carbide breakage or chipping.
Ideal for high production runs, offering the capability to achieve higher speeds and feeds, with fewer tool changes.
High performance tapping allows greater efficiencies in part throughput.
Can also be used in conjunction with surface treatments for enhanced performance.
Carb-I-Sert® Taps are available in a wide range of sizes (inch and metric) in both straight and taper pipe threads.

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Once Upon a Time There Was a Magical Form Tap

11/15/2017

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Once Upon a Time There Was a Magical Form Tap

If you follow any industry long enough, history will become a useful tool to apply to your understanding of modern developments and designs. One such piece of history, as related by someone who was there in the 1950’s, will create an illustration of the importance of learning from errors, and creating opportunities.

Once upon a Time, not so far away, a tap manufacturer with a long history in the industry made an error processing a manufacturing order. We all do from time to time. Where it went from there is the story.

A cutting tap left the manufacturer missing a feature. The customer complained that they had received a tap without any flutes. Being desperate, they used it anyway, and reported that it “kind of” worked. The manufacturer quickly got the customer the finished tap as originally intended, but decided to research the performance of the “unfinished” tap.

They saw the obvious benefits of a “chip-less“ tap, but identified multiple downsides. As the material is not being cut, but pushed out of the way, friction would likely be an issue. On top of that, threading a blind hole would create hydraulic pressure in the hole (with 100% thread engagement, there would be no escape route for air or liquid beneath the tap).

Tru-Flow Thread Forming Tap

Both issues would be addressed with “lube-grooves” and a geometry utilizing “lobes” (high points on the circumference of the tap) to reduce the surface contact between the tap and the material being threaded.

These features would facilitate lubrication, by allowing some clearance between the surface of the tap and the material being threaded. They would also allow an escape route for any building pressure at the bottom of the hole.

They realized that the material being formed “flows” in multiple directions, both into and away from the thread-form of the tap. One very important detail was quickly recognized. The material being formed must be malleable. No flow, no go!

Ferrous and glass-filled materials are not a candidate for forming. A different hole size would be recommended to reduce the percentage of thread produced to a more acceptable level, and allow the same clearance for the minor diameter of the mating part allowed by a “cutting” tap.

Further tweaking followed. Method and form of “chamfer” was changed, to more efficiently begin the threading process. Lobe geometry tweaked for better performance in different materials.

Additional lube grooves were employed in applications that benefited. Recommended speeds were increased. Coatings were added to reduce friction and improve wear resistance. Coolant-holes became an option for those with the machine capability. Base materials were developed and improved. Like anything else, improvements continue as application demands evolve.

According to the trusted source, this is the way it happened. The real point of the story remains the same whether or not it is completely true. The “error” and solutions that followed illustrate most of the differences between the two styles of producing thread, and the taps that do the job.

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Detailed Guide to Roll Taps

Reasons to Use Roll Form Taps

When Not to Use Roll Taps

Types of Roll Taps

The Different Types of Carbide Taps and When to Use Them

Standard Screw Thread Insert Taps

Thread Forming Tap

Carbide Insert Taps

Once Upon a Time There Was a Magical Form Tap

Once Upon a Time There Was a Magical Form Tap

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