Tech Tip #30 - Cutting Tool Formulas for Speeds and Feeds

Speeds and feeds are the most important considerations to achieve the best results from cutting tools. Improper speeds and feeds often cause low production, poor quality, and damage to the tool. Speeds that are too high or feeds that are too light can lead to rapid wear and dulling of the cutter, reducing tool life.

Speed is measured in peripheral feet per minute. It is often referred to as cutting speed or surface speed. Feed is usually measured and stated in inches per minute (IPM). It takes into consideration the number of cutting teeth (or flutes), the feed per tooth (or cutting edges), and the revolutions per minute. Feed recommendation tables for drills are based on 2-flute drills.

To establish operating conditions, all feeds rates should be calculated from the chipload or feed per tooth. The highest possible feed per tooth will usually provide longer tool life. However, excessive feeds may overload the tool and cause the cutting edges to chip or break.

Following are many of the commonly used formulas for calculating operating parameters for cutting tools:

        NOTE: for all formulas, D = diameter.
        SFM: surface feet per minute/cutting speed: .262 x RPM x D
        RPM: revolutions per minute/rotational speed: (3.82 x SFM)/D or SFM/(.262 x D)
        IPM: inches per minute/machine feed rate: RPM x IPR (or) T x IPT x RPM (T = # of teeth)
        IPT: inches per tooth/feed per tooth: IPM/(RPM x T)
        IPR: inches per revolution-feed per revolution: IPT x T (or) IPM/RPM
        Inches to mm: Inches X 25.4 or Inches/ 0.03937
        MM to inches: mm/25.4 (or) mm x 0.03937    

You are about to add to your My Solutions page. Do you want to proceed?
Please adjust the following properties from

ISO Catalog Number

ANSI Catalog Number

to find similar products.

The following files are available

Please select a file to download


Product data

You should be logged to see your dashboard information
Session expired due to inactivity, please login again
The product/s () you were trying to add to the cart is/are not available, please contact customer service
item(s) successfully added to the cart
View Cart

. Please enter the desired qty for the material(s) you want to include in your promotion or Proceed Without Promotion and only your base materials will be added to the cart.

Minimum quantity should be

SAP Material Number ISO Catalog Number Grade    

Thank you for your registration, pending approval & completion of the registration, your access is currently limited. Full utilization of product search capabilities & collaboration space is available and will remain. Please allow 2 business days for registration completion.

Thank you for your successful registration. You now have immediate access to log in and utilize the site.

You are about to leave the Solution building process.

Are you sure you want to leave?