End mill sharpeners range from the simple, manual diamond wheel machines to a full blown CNC tool and cutter grinding machine. For one-off or special in house needs the manual grinder works well, but for complex cutters or when there are dozens to sharpen, an NC or CNC machine is the best choice.
The Makino Seiki CNJ2-30 is an industry standard tool and cutter grinder that is very versatile and reliable. It handles cutters from 1/8” to 9” diameter and can sharpen almost any shape of cutter. Together with the menu driven software and automatic tool measuring system this is the ideal type of grinder for a tool sharpening house. This is one of the best end mill sharpeners out there.
The Darex E90 End Mill Grinder and Sharpener costs around $3,500 and is great for in-house grinding of light to medium duty applications. It is available for both HHS and carbide. This manual machine has a capacity of 1/16” to 1” diameter. Many tool shops use this type of end mill sharpener for limited quantiites.
Cuttermaster makes a universal grinder that is popular in tool shops everywhere. It is made in the US and built to last. It is easy to use and very handy to keep your machines running without taking valuable time to send cutters out to be sharpened. The basic machine costs around $3,200, not bad for a quality end mill sharpener.
Another common cutter grinder is the Deckel SO, which has been around for many, many years. The ingenious design has been copied many times, but never equaled. They are very versatile and easy to use and very accurate as well. They are not really designed for high production, but are great for small batches or special cutters. They are available for both carbide and high speed steel.
The type of end mill sharpener you choose depends on your needs and your budget. On the one end is the CNC tool and cutter grinder, on the other end is a simple manual machine. In between is the higher end manual machines. A word of caution when buying a used machine: make sure the spindle is not worn out. If it is, you will never be satisfied with the results and your work will be inferior.
Many 5 axis or high speed machining operations use indexable end mills. These throw away inserts are not really designed to be resharpened. Typically, as the name implies, the insert is quickly indexed and the cutter gets back to work.
Some carbide cutter manufacturers offer end mill sharpeners as part of their package. These are worth investigating because you may be able to negotiate prices if you are a valued customer. Carbide router bits are often able to be resharpened.
A good grinding shop will be able to handle your volume, close tolerances and special cutter needs. A fast turn around can mean a great deal when the deadline is rapidly approaching and you need it now!
Most shops do not keep a large inventory of cutters anymore because shipping and availability have become so reliable. It is easy to receive items overnight for less money than you might imagine. Every mold making, precision machining or tool and die shop needs sharp carbide cutting tools, and the decision to buy an end mill sharpener is a question of cost versus quantity and quality.