Vision Engraving & Routing Blog

There are two basic types of spindles that can be used on an engraving or routing machine. This article explains the advantages and disadvantages of each type, to help you choose the ideal spindle for your application.

Rotary Top Load

This is the most commonly used spindle in engraving.  It accepts industry standard cutters of varying shank sizes. Most are 11/64” or ¼” and use 6 ½” long cutters. There are no particular advantages to any particular size, except that the maximum width of a single pass cut is limited to the cutter size. The exception is cutters with oversized tips, which are loaded from the bottom for wide cut applications.

Advantages

• Less expensive spindle
• Industry accepted
• Easy to use
• Changing tools is very quick

Rotary Top & Bottom Load (Collet Style)

This spindle will accept both a top load long cutters and “bottom” loaded shorter cutters depending on the collet size used.  Using a collet spindle turns the engraving machine into a light milling machine.  The collet is pulled tightly around a cutter by a drawbar which tightens easily from the top of the spindle.  The use of collet spindles eliminates most of the vibration during engraving of hard materials and deep cuts in plastics.  The interchangeable collet sizes allow the holding of tools such as end mills, router bits, short shanked engraving bits, drills, and specialty tools. Since collets can easily be changed, different shank diameters can be used in a single spindle design. Collet spindles can be equipped with solid collets so they can be used easily with drop in cutters.

Advantages

• Great flexibility and versatility
• More rugged in design

Disadvantages

• More expensive

This article will discuss the 3 main materials that cutters are made from, as well as the 3 main cutter shapes, in order to help you select the best cutter for your engraving application.

Cutter Materials

Micrograin Carbide – A fine grain of carbide that remains sharp longer and produces cleaner cuts. Susceptible to breakage in smaller tip sizes.

High Speed Steel – Not as durable and wear-resistant as carbide, but has greater tip resiliency for deep, fine cuts in metal.

Carbide Tipped—A carbide tip is brazed to the end of a steel shank. The shank may warp, twist, or rust. Less expensive than solid carbide tools.

Cutter Shapes

Parallel – Produces a square straight-edge cut. Can also be designed to drill holes.

Burnisher – Designed to rotate against material and remove a layer of coating, without actually cutting the material.

Dovetail – For making an angled undercut in plastics, for applications such as directories with slide-in legged strips.

Tool Life

The cutting conditions that determine the rate of material removal are: cutting speed, feed rate, and depth of cut. These conditions and the characteristics of the material to be cut determine the power required to take the cut. The cutting conditions must be adjusted to stay within the power available on the machine used.

The characteristics of the material to be cut must also be considered in relationship to the tool life. Tool life can be defined as the length of time that a cutting tool will cut before it can no longer be re-sharpened and must be replaced. Care when choosing your cutter type and material can substantially increase tool life.

The good news, of course, is that an unbroken tool of normal wear may be sharpened many times – therefore eliminating expensive replacement costs.