Replaceable tip router bits

What are replaceable blade router cutters?

Replaceable tip router cutters (also known as Rota-Tip cutters) are comprised of a solid tungsten carbide blade held by retaining screws to a ground steel body. When the blade becomes dull, it can be replaced or rotated to reveal a new sharp cutting edge. 

Design

Blades

These cutters come in one or two blade models, with the blades having between one and four cutting edges, which can be rotated and locked in identical positions to expose a new sharp cutting edge. The more blades a cutter has, the finer the finish will be. 

Bottom cut

Some replaceable tip routers cutters have central tips, allowing them to be used in a plunge router to cut grooves in the surface of materials.

Some models have a central tip that can be removed and replaced once it becomes dull

Guides

Replaceable tip cutters are available with a shank-mounted guide, bottom guide, or no guide at all.

Applications

Replaceable tip cutters come in a variety of different profiles, including straight, radius and V-groove.

Generally, however, replaceable tip cutters are used over regular cutters for the following tasks:

High production applications

While initially they are more expensive than standard TCT cutters, they prove effective in high production applications where downtime required to change cutters is kept to a minimum. 

Their use is normally aimed at fixed head applications i.e. Computer Numerical Controlled (CNC) routers. 

Working with abrasive materials

The smaller size cutters are limited to hand-held applications where the use of abrasive materials necessitates the frequent renewal of a keen cutting edge. 

Advantages and disadvantages of replaceable tip router cutters

ADVANTAGES

DISADVANTAGES

• Tool body remains in place when changing blades, thus reducing tool downtime

• They are more economical in the long run, compared with conventional brazed tip tooling

• The blades can be rotated 180 degrees to give double the life of a standard cutter

• Initially more expensive to purchase

• The finish given by replaceable tip cutters is not as fine as that of regular cutters, but by reducing feed speed a neat finish can be obtained

• The selection of router bits available with replaceable cutters is still somewhat limited.

What are the different types of replaceable tip router cutter?

There are nine main types of replaceable tip cutter. 

Rota-Tip straight cutters

Rota-Tip straight cutters are designed to produce flat-bottomed grooves for a wide range of applications.

They come in one or two blade models, with the blades having between one and four cutting edges, which can be rotated and locked in identical positions.

Staggered blades

Some models have staggered blades, much like the staggered cutting edges on some regular straight cutters. Replaceable tip cutters with staggered blades are best suited to rough cutting only. 

Plunge cutting

Cutters that are able to plunge cut will usually have one of the following features:

• A blade that extends past the bottom of the cutter and over half way across the cutter base

• A TCT tip brazed into the nose of the cutter

• A replaceable central tip slotted into the bottom of the cutter

Rota-Tip rebate cutters

Rota-Tip rebate cutters are used to produce rebates, types of grooves, on the edge of materials.

They are available with one or two ball-bearing guides beneath their cutting edges. 

Rota-Tip trimmers and profilers

Trimming and profiling Rota-Tip cutters are essentially straight cutters with a guide pin or bearing fitted.

They are commonly used to trim the top layer of material (often veneer or laminate) flush with the edge of a base material, or trim a workpiece flush with the edge of the top layer (usually a pre-cut template).

There are 90-degree trimmers, bevel trimmers, template profilers and double bearing-guided template profilers.

Rota-Tip V-groove cutters 

These cutters are designed to produce V-shaped grooves, chamfers, and bevels for a wide range of applications.

Rota-Tip round over cutters

Rota-Tip round over cutters typically have two blades and a bearing guide fitted beneath their cutting edges. They are used for rounding over the edge of materials.

Rota-Tip radius cutters

These cutters usually have a single blade and are designed to rout radius grooves in the surface or on the edge of materials. They have a ball-bearing guide mounted on the shank, above the cutting edges, which can follow the edge of a template.

Rota-Tip ogee cutters 

Rota-Tip ogee cutters have two blades and a bearing guide fitted beneath their cutting edges. They are designed to produce the ogee profile on the edges of materials.

Rota-Tip stair housing cutters

These cutters usually have two blades, and specifically designed to cut out stair housings/trenches, which are grooves made in the surface of the stair string in order to accommodate the treads and risers. 

They are designed for use in stair housing/trenching machines or with stair housing jigs. 

Rota-Tip espagnolette cutters

These cutters are used to rout the stepped grooves for espagnolette lock recesses.