Frequently Asked Questions on Cutting Tools

Reposting this article, in case you missed it, which was compiled by the Vance Publishing Team (Wood&Wood Products/CWB/

Industry experts answer woodworkers’ frequently asked questions regarding cutting tool usage.

Q: How do I know if my tooling is balanced?

A: The absence of a drill mark does not automatically indicate that a tool is not balanced, and the presence of a drill mark should not be proof of balancing either. The only way for customers to know a tool is balanced is to request and store balancing certificates whenever a tool is manufactured or re-conditioned. Submitted by Ron Migedt, Riverside Tool

Q: What is chipload and why is it important?

A: Chipload is a term for the thickness of the chip produced in the machining process per edge, per revolution. It is determined by the rotational spindle speed, the speed that the tool is moving through the material and the number of cutting edges of the tool. Chipload is an important factor in tool life because as it increases, it carries more heat away from the cutting tool. The formula for determining chipload is: chipload= feed rate/(rpm x #cutting edges). Submitted by Scott Feimster, LMT Onsrud

Q: What is a compression spiral?

A: A compression spiral is a spiral with an upcut on the bottom and a downcut on the top. This effectively pulls the material together and gives a clean edge on the top and bottom of the workpiece. Submitted by Chuck Hicks, Southeast Tool Inc.

Q: How will the cost of the tool affect my bottom line?

A: Unfortunately it’s too common that tooling purchase decisions are made in the spotlight of the tooling budget with little consideration as to how it affects the other budgets that make up the bottom line. You should take into consideration how the tooling decision affects throughput, scrap/rework, edge quality and maintenance costs. Submitted by Garry Davies, Surrey Precision Tools

Q: How can I get more tool life after sharpening?

A: This question requires a two step approach. First, request a re-manufacturing of your tool when it is submitted to service. This requests an OD grind and re-fluting grind process be performed. The OD grind from most service centers provides a sharper, stronger cutting edge while re-fluting removes more of the chips and wear points with minimal affect to the diameter. Next, reduce the runtime of your tooling so as not to produce as much wear. Because wear occurs at an exponential rate, reducing your runtime by a small amount can pay significant dividends. Submitted by Frank Horvath, FS Tool Corp.

Q: How do I determine if I should use carbide-tipped, insert, or diamond tooling?

A: A cost analysis is the best way to determine what is right for each customer individually. Based on work load, run times, material types, and potential bottlenecks in your process, you can determine which tooling is right for you. Each provides advantages as well as detriments. Carbide-tipped provides quick turnaround servicing and less expensive repairs for damage. Inserts provide consistent profiling without the necessity of sharpening. Diamond provides longer run times without diminishing quality. Submitted by Philip Broussard, NAP Gladu

Q: Can we utilize diamond tools for nesting, without giving up feed speed?

A: New diamond router designs offer users significantly improved tool life in small diameters to less than ½”. These true three wing diamond tools perform at or above speeds offered by solid carbide tools. Tool life of 20-30X longer than carbide provides exceptional return on investment. Submitted by Mark Alster, Leitz Tooling Systems LP

Q: Is there a diamond tool that incorporates the mounting interface in a single body construction?

A: These types of monolithic tool designs are in fact more accurate, but tend to not be cost effective. A better solution would be to mount the tool in a heat or mechanical shrink clamping unit and sharpen it while it is in the holder. You now have achieved the same level of accuracy and can re-use the holder when the cutting tools can no longer be sharpened. Submitted by John Michel, Leuco Tool Corp.

Q: When starting a new project, how do I achieve the desired finish or tool life?

A: It is important to understand that every time you change the material being cut, you must also change the machining parameters to obtain the proper chipload for that specific material. Cutting with the incorrect chipload will result in poor tool life, burning and chipping, and even tool breakage. If you change tooling to a different tool diameter or number of wings, you also need to recalculate your chipload as it will change. Submitted by Karin Deutschler, GUHDO USA

Q: How can I reduce my tooling costs?

A: Tooling costs should be measured in cost per cut. Reducing tooling cost per cut is about maximizing production time and decreasing downtime. The way to achieve this is to make sure you have the correct tooling for each application. The correct tooling type, configuration, and chip load are all important factors in achieving maximum tool life and resulting in more production time. Submitted by Philip Broussard, NAP Gladu

Q: How can I quickly determine if I have a tooling problem or a machine problem?

A: The quickest way to determine if you have a tooling or machine problem is quite simply to change the tooling with a spare. If the problem remains your issue could be with your machine. If the problem ceases you may have a tooling issue. Submitted by Philip Broussard, NAP Gladu

Q: Why am I breaking tools?

A: More than likely you are getting vibration or a movement of which you are not aware. This is commonly caused by worn collets. Submitted by Chuck Hicks, Southeast Tool Inc.

Q: Which is better – a V Point or Brad point drill?

A: V points will work better if drilling all the way through the material. The Brad Point seems to do better if drilling shallow (drilling shelf pins, for example). Submitted by Chuck Hicks, Southeast Tool Inc.

Q: How often should I change my collets?

A: The rule of thumb is to change collets 2-3 times a year if running production (meaning 8 hours a day of routing). Submitted by Chuck Hicks, Southeast Tool Inc.

Q: Why aren’t my tools lasting as long?

A: This could be due to a material change that you may or may not have been aware of, improper feeds and speeds, or the collets and/or holder. Submitted by Chuck Hicks, Southeast Tool Inc.

Q: What is the difference in an upcut and a downcut spiral?

A: An upcut spiral pulls the chips upward or toward the shank, depending on how the tool is running. A downcut spiral forces the chips down away from the shank. It is also helpful in getting a clean edge on the workpiece. Submitted by Chuck Hicks, Southeast Tool Inc.

Q: How do I dial in my feed rate on my CNC?

A: The rule of thumb is to keep increasing the feed rate until the quality of cut decreases to a point that it is not acceptable. Back the feed rate off 10% and that is your optimal feed rate. Submitted by Chuck Hicks, Southeast Tool Inc.



Cutting Carbon Composites Example

Workpiece : Carbon composite

Similar materials: Fibreglass-reinforced plastics

guhdo carbon composite cut cutting

carbon composite tooling examples

1 Diamond-Dowel Drill

2 DIATEC-4 Diamond Router Cutter

3 DIATEC Diamond Cutter with alternate shear angle

4 DIATEC-4-QUATTRO Diamond Router Cutter

For more information visit our website or check out this expanded article on cutting composites or feed rates in plastics.

Cutting Particleboard with Rough Cut Veneer or Stainless Steel laminate

Workpiece left: Particleboard with rough cut veneer
Workpiece right: Particleboard with stainless-steel cover

(Similar materials: Particleboard with magnetic foil etc.)

cutting particleboard guhdo illustration router bit stainless steel veneer

1 Cutter with rev. T.C. tips Z2+2 No. 22029-5

2 Solid T.C. cutter with alternate shear angle Z2+2 No. 20252-6

3 ISODUR Dowel Drill T.C.T. Z2 No. 30570-5 4 Dowel Drill T.C.T. Z2 No. 30540-5

5 MEGASPEED Diamond Router Cutter Z4+2+4 No. 15600-9

6 Double Edge Trimming Cutter w. rev. T.C. tips Z2 No. 22293-5

For more information visit our website at

Feed Rates for Plastics

DSC_0615“Feed rate” refers to the speed at which material is being “fed” through the machine. It is generally measured in inches per minute or meters per minute, depending on whether the Imperial or metric system is used. The Feed rate is part of the formula used to calculate chip load (size of the chip created in the cutting process). The other parts of the formula are motor speed on the router (rpm) which dictates how many revolutions per minute the tool is turning, and the number of flutes (wings) on the tool. To calculate chipload the formula is Feedrate / (RPM x number of flutes). The most common problem, in regard to incorrect chipload is premature tool wear, tool breakage, most often due to excessive heat buildup and poor material finish/chipping.


Typical chip load range for Plastic Materials

Hard Plastics .004-.016″
Soft Plastics .006-.014″

The smaller the tool diameter, the lower the chip load that applies, will be.



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