How to Set Up TAFJ 90 B 1/2 and TAFJ 60 1/2 Finger Joint Router Bits

Updated: 25 September 2026

Finger joint router bits machine a series of matching fingers into the edges of timber, increasing the available glue area and allowing components to be joined accurately. They can be useful for lengthening timber, joining boards and other woodworking applications where a purpose-machined joint is required.

The Carbitool TAFJ 90 B 1/2 and TAFJ 60 1/2 are both finger joint cutters, but they are set up differently. This guide explains the key differences and the setup process for each.

What is the difference between the TAFJ 90 B 1/2 and TAFJ 60 1/2?

If you are still deciding which cutter or joint style suits the job, see our router bit selection guide and guide to joining bits.

Setting up the TAFJ 90 B 1/2

The TAFJ 90 B 1/2 is supplied with removable finger-slot cutters. The number of cutters used determines the range of timber thicknesses the assembly can accommodate.

Step 1: Measure and mark the timber

Measure the timber thickness accurately and mark its centreline along the edge that will be machined. A marking gauge can make this easier to repeat accurately across multiple components.

Step 2: Set the cutter height

Set the cutter so the lower edge of the middle slotting-cutter tooth aligns with the timber centreline. The shoulder remaining above and below the finger profile should be equal.

Step 3: Align the router fence

Place a straightedge across the two halves of the router fence and adjust the fence until the straightedge meets the cutter's bearing guide. Secure the fence and, with the machine isolated, check that no cutter can contact the fence when the assembly is rotated.

Step 4: Make test cuts

Use two scrap pieces that are the same thickness as the finished material. Machine the test edges, invert one piece and bring the two profiles together.

Step 5: Correct any face misalignment

If the two faces do not finish flush, adjust cutter height by approximately half the measured face offset and repeat the test. For example, a 1 mm difference between the two faces calls for a 0.5 mm height correction. Keep testing on scrap until the two faces align correctly.

Setting up the TAFJ 60 1/2

The TAFJ 60 1/2 uses a different method. One edge is machined to form the male component of the joint, then the cutter height is changed before machining the matching female component.

Step 1: Mark the timber centreline

Measure the workpiece accurately and mark the centre of its thickness along the edge to be machined.

Step 2: Establish cutter height

Align the manufacturer's Y reference, located at the centre of the middle cutting finger, with the centreline marked on the timber.

Step 3: Set the fence

Set the router fence to the manufacturer's Z reference shown in the TAFJ 60 setup instructions. If the router table has a two-piece fence, ensure both halves form one straight reference line.

Step 4: Machine the male component

Machine the edge that will form the male side of the joint. If the machine is labouring, reduce the depth removed in the initial pass, then return the fence to the final setting for the finishing pass.

Step 5: Set up the female component

Lower the cutter by 3.8 mm before machining the corresponding female profile. Check the setup on scrap timber of the same thickness before machining the finished components.

Carbitool also describes using the completed male component as a setup reference. In either case, make a test piece first rather than using the finished timber to establish the final setting.

Step 6: Check the finished alignment

Fit the male and female test pieces together and check that both faces finish flush. Make any necessary height correction before machining the production pieces.

Common setup problems

A test cut is part of the setup

Finger-joint accuracy depends on cutter height and fence position working together. A small setup error can become obvious once the two machined components are brought together, which is why a pair of same-thickness test pieces should be part of the normal setup process rather than an afterthought.

Technical reference: Carbitool finger-joint router-bit specifications and manufacturer setup guidance. Always refer to the current instructions supplied with your cutter and routing machine. View the Carbitool setup guide .