W&WP April 2004


Insert Cutting Tools Fill Niche

Despite the ever-growing trend toward switching to diamond-tipped bits, industry experts say inserts will not become obsolete.

By Susan Lorimor


The decision to invest in insert router bits can be a tough one, largely driven by economics. You can stick with the less-expensive, basic brazed carbide tips, invest in inserts, or move up and splurge on diamond-tipped bits.

Such movement is a natural progression, industry experts say.

Sure, improvements in diamond-tipped bits have helped attract many users, while brazed carbide can get the job done. John Michel, director of technical services for Leuco Tool Corp., says that of his customers who do profile routing, about 10 percent buy brazed carbide tips, 40 percent use inserts and 50 percent, diamond-tipped. But there is something to be said about inserts. Experts say there will always be a use for them.

Their versatility has landed them in virtually every shop, says Glenn Mihalovic, marketing manager of Gladu Tools. "They have grown tremendously in presence over the last five to 10 years."


Insert Router Bit Sources

Listed below are some of the companies that offer insert router bits. For more information, contact the companies or visit their Web sites. Additional sources can also be found in the Red Book Buyer's Guide, which can be accessed online at www.redbookonline.com.

Amana Tool Corp.


Bull Sharpening Service


Byrd Tool Corp.


DeHart Tooling Components Inc.


FS Tool Corp.




Guhdo-USA Inc.


L.R.H. Enterprises Inc.


Leitz Tooling Systems Inc.


Leuco Tool Corp.


North American Products Corp.


Royce-Ayr Cutting Tools Inc.


Charles GG Schmidt & Co.



Mihalovic says almost every shop has at least one machine that requires straight-edge and profile insert bits.

"The big benefit with insert is that it can allow for a constant cutting (cycle)," says Mike Staudacher, who works in technical sales for Guhdo-USA Inc.

When the bit grows dull, a user only has to switch it out, instead of stopping production until a brazed carbide bit is sharpened - which can spell a loss of time and money.

Costly Tools

While some say inserts will be more cost-effective in the long run, others are hesitant to make the investment. They fear the costs, claiming it will be too expensive. However, it all hinges on how you define expensive.

A brazed shaper bit can cost $15 to $30 a pop, and insert bits can set you back anywhere from about $14 to $500, depending on the quality and intended use. Yet, insert bits can give you 1-1/2 to two times better tool life, according to Gary Metzgar, who works in marketing and training for North American Products.

"If it's a pricing issue (that deters someone from inserts), they're not looking at the entire picture," Metzgar says. He adds the move to inserts will give users a better finish on the wood with which they are working.

To some customers, primarily those with small- to medium-sized shops that Norm Hubert, vice president of sales for L.R.H. Enterprises in Chatsworth, CA, sells to, price does matter. "We make custom router bits, not insert," Hubert says. "It's really not our forte. Guys aren't willing to pay for it."

On the other end of the spectrum, there are the diamond-tipped bits. Some can cost several hundreds of dollars. However, Staudacher says disposable ones can run about $125. He says over the past years, diamond bits that compete with insert bits have shown a three to four time reduction in price.

Improvements in Clamping

One of the concerns that steers woodworkers from insert router bits is safety. High speeds, reckless operating and inadequate clamping can throw an insert off a machine.

"One reason that holds people back (from inserts) is a fear they will come apart," Metzgar says. "Spindle speeds on a CNC machine are very high.''

And they are getting higher. There is a trend toward toward machines with increased RPMs.

Metzgar says he is working with an industry organization to try to come up with minimum and maximum RPMs for machines.

"There is a lot of human error," he says. "All you need is one scare with a company. They will blame it on insert tools."

Improvements in the way inserts are clamped to machines will quell some of the fears. There have been several enhancements over the past couple of years.

"One of the things that has improved greatly are the ways of holding onto them (inserts)," Mihalovic says. "There are a couple of designs that require a gib and hold-down screws, (and) some require no gib."

The latter type of hold-down allows a close cut and is said to be very popular. Mihalovic went on to say Gladu won a 2002 IWF Challengers Award for its ProcentriX insert cutting tools. They have what Gladu calls a unique clamping and positioning system, which is said to provide faster machining speeds, quicker changeovers and the ability to maintain a constant diameter after sharpening.

Michel says his company also has focused on improving clamping systems.

"(What is important) is how (profile) knives mount so they are not only easy for the operator to use, but as accurate as possible. We have a variety of clamping and indexing systems for the tools," Michel says.

He says usually there is some sort of tapered holder that goes into the collet to secure the knives. "We have a system that bypasses that," he says.

Michel says a woodworker could have the clamping system for around $300. "This interface system is about five times more accurate than (the) conventional (method)," Michel adds.

Freud is another company to address insert tool clamping. Its profiled insert tooling features a seat pocket design with a safety locking system, which consists of serrated, backing plates to prevent knives from coming loose when they are screwed to the body of a bit.

According to Freud, the seat pocket design of the router bit also allows knives to be replaced quickly and easily without removing the router bit from the machine.

Sharp Bits

Sharpening a brazed carbide bit can be cause for concern. A tip's pattern is whittled away each time production is stopped for sharpening.

Meanwhile, insert tips are simply switched out when things get dull.

"Insert (tooling) gives you much better return on your money, because you have to spend money to send out for sharpening (of brazed carbide bits)," Mihalovic says.

Sharpness of insert tips and knives is a concern, and Staudacher says Guhdo's recent innovations include roughing and finishing cutters that will slice through solid wood. Staudacher says the tool has a maximum feed rate of 600 inches per minute for solid wood.

"This is exceptional considering most insert tools are only able to cut chipboard and MDF effectively," Staudacher says. The smallest diameter offered is 26mm.


While diamond-tipped bits are gaining in popularity, some woodworkers continue to steer away from them because they fear breaking an expensive tip.

"If there are a lot of tight knots (in a material), diamond may not be the right thing," Leuco's Michel says.

But he says composite materials made today are not as rocky as they once were, so they can be profiled with diamond-tipped router bits.

Michel says inserts are best if a woodworker is running lots of small quantities and "needs lots of flexibility." If someone is running a lot of product, but does not need as much flexibility, then maybe they should stick with diamond, Michel says.

"Diamond-tipped tools are the most valuable and cost-effective tool when dealing with a large quantity and (if a user) wants to maintain a specific dimension for a long time," Mihalovic says.

However, diamond-tipped inserts are not the end-all, be-all. "There will always be somebody who has an application that is not favorable to diamond-tipped," Michel says.

Staudacher says inserts "probably will not become obsolete," because of the fact there are some materials that could chip diamond.

"I think there will always be a home for insert bits," Staudacher says.

He says inserts have a slower feed-through rate, but some materials must go through a machine slower, "so it doesn't matter."

He says chipboard with melamine or some kind of laminate is a good application for inserts.

Shopping Tips

Michel says choosing the right tooling is like buying a car: If you go to a dealership that only offers a specific type of car, that is what you will get. If you go to a superstore, you will have more options.

"When a customer is looking to buy a tool for routing, he should talk with someone who sells a full range (of options)," Michel says.

Mihalovic says he asks a tool buyer the following questions:

* How many spindles are on your machine?

* How many items are you making?

* What are the machines you are using?

* What type of wood are you using?

From there, he gets an idea of what would work best for a customer.

Metzgar says he requires a customer to send "a wood sample or mechanical drawing to make sure (what I recommend) is correct."

Metzgar adds the product to be routed determines specifics about the needed bits.

If customers do choose insert tooling, they are faced with a plethora of questions. Profile or straight-edge? What type of system should you use for your profiled insert?

Michel says a straight-edge insert is generally available from his company's stock, in different sizes and geometries. If a profile, or universal system, is used, Leuco can grind the knives to fit it.

Michel says of the three types of systems for profiled insert router bits, the universal is very flexible and works with a lot of production in small volume. A tool body system consists of a body and knife designed together, for a specific use. A custom system consists of perhaps a multitude of knives, because a variety of angles is needed.

Michel says woodworkers also need to look at the type of machine they have when thinking of tooling.

"A customer may buy a machine and not think of the tooling at the same time," he adds. "The tool supplier and machine supplier should come into the equation at the same time to get the best, optimum use."


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