Isoloc I1A, I1B and I1C

Revolutionary Design

These truly unique templates offer great features

The revolutionary Isoloc joint represents the first entirely practical alternative to the traditional half-blind dovetail. Read on to find out how easy it is to rout these stunning joints.

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Isoloc Joint Templates video — D4R Pro/D-series Jigs

Template Setup and Use

Remove the guide finger assembly and slide the Isoloc Template onto your jig in seconds.

It takes less than a minute to replace the dovetail finger assembly on your Leigh Dovetail Jig with one of three Isoloc templates, and you’re ready to produce some very creative joinery. In fact, Isoloc joints are as easy to rout as finger/box joints and even easier than dovetails. Each template has two joint patterns. A single 5/16” or 8mm straight bit, preferably an upcut spiral, does all the routing.
Template scales have inch and metric measurement markings.

To set up for pins and sockets, the template is shifted left or right, and the control pin at the right end of the template secures the template in place. The template is in the pin mode in the image above.

The control pin secures the template in place (see inset image). The template shown here is in the “pin” mode.

The control pin secures the template in place (see inset image). The template shown here is in the “socket” mode.

Joint Fit Adjustment

Perfectly fitting joints are easy using, the Variable Template Guidebush System (VGS) patented “fit” technology, included with each template.


VGS Variable Guide Bush System
When attached to your router base, Leigh’s unique VGS guarantees easy and precise joint fit with its three tapered guide bushings*, one for each comb size.


This adjustable 3-piece guide bushing mounts to your router base. Rotating the tapered barrel of the VGS, up or down, increases or decreases its active diameter.


* Patented in USA, Canada and Europe

3-piece Variable Guidebush System (VGS)

Rotating the barrel of an installed VGS 1/8 of a turn adjusts joint fit by a incredible 1/1000 of an inch! Pin wrench included.

Rotating the tapered barrel of the VGS up or down changes its active diameter.

The VGS mounts directly to many router bases. Some routers may require a Leigh guide bushing adaptor.
Click here for Guide Bushing Adaptor Selector


VGS with an adaptor mounted to router

Leigh Brand Router Bits

Regular Isoloc joints can be routed with a single 5/16" (8mm) bit. Leigh offers individual router bits for use with these Isoloc templates in HSS and solid carbide, and a bit set for savings. Learn more


For even more unique joinery, try inlaid Isoloc Joints, routed with with two bits. Learn more


Note: Leigh does not sell metric router bits.

Technical Specifications
Key Joints
Board Width   23.75" [603.25mm]
Pin Centers 1.033" [26.2mm]  
Isoloc Key pattern D-Series jigs
Mirror Key Joints
Board Width   22.75" [577.8mm]
Pin Centers 2.34" [59.4mm]  
Isoloc Mirror Key pattern D-Series Jigs
Clover Joints
Board Width   23.75" [603.25mm]
Pin Centers 1.048" [27.5mm]  
Isoloc Clover pattern D-Series Jigs >
Bears Ears Joints
Board Width   22.25" [565mm]
Pin Centers 1.919" [48.7mm]  
Isoloc Bears Ears pattern D-Series Jigs
Ellipse Joints
Board Width   23.25" [590.5mm]
Pin Centers 1.106" [28.1mm]  
Isoloc Ellipse pattern D-Series Jigs
Wave Joints
Board Width   22.25" [565mm]
Pin Centers 2.312" [58.7mm]  
Isoloc Wave pattern D-Series Jigs
I1A, I1B, I1C
  • Length: 31.5" (800mm)
  • Width: 4.9" (125mm)
  • Height: 0.39" (10mm)
  • Weight: 4.28 lbs. (1.94 kg)
I1A, I1B, I1C
  • Size: 36" x 12" x 2.5" (914mm x 305mm x 64mm)
  • Weight: 6.68 lbs. (3.03 kg)
Each Isoloc Template carton includes:
  • One Template
  • 5-piece Variable Guidebush System (VGS)
  • Fully illustrated user guide
  • Hex key