MasterGage 1-2-3 MicroGage - Canadian Woodworking Magazine

An essential tool for every shop - well designed, precisely manufactured, and makes just about any machine alignment task fast and easy


MasterGage 1-2-3 MicroGage

In order for your saw blades to cut precise 90° angles, router bits to plough grooves with crisp straight walls, drill bits to drill holes that are true and straight, and jointer and planer to flatten stock uniformly, your woodworking machines need to be precisely aligned. The rigors of heavy shop use can put a lot of stress and strain on machinery, so it's important to check your machinery alignment regularly.
Paul Reilly, a practicing mechanical engineer, has designed a number of tools that can help you set up and align your shop machinery quickly and easily. With his new 1-2-3 MicroGage the task of maintaining your machinery is greatly simplified.
The MicroGage is a precision made tool that consists of three parts - a steel machinist's set-up block, commonly called a 1-2-3 set-up block, a dial indicator, and a carriage for mounting the indicator on the set-up block.

1-2-3 set-up block   
The case hardened steel 1-2-3 block is so named because it measures a precise 1" x 2" x 3". It's surfaces are dead flat and square to each other to within 0.0002". Machinists use the holes to attach bolts to the block for use on milling machines - which is why you'll notice that some of the holes are tapped.
The block can be used by itself as a substitute for a try square to check that saw blades, router bits, and rip or miter fences are square, as well as to check for square on small assembled parts, such as drawers and frames. At just under 1 pound the block is heavy enough not to inadvertently shift in use.

Carriage bottom view: (A) base; (B) lock screw; (C) support; (D) hex bolts; (E)plunger; (F) adjustment screw    
A carriage, made of two parts, connects the 1-2-3 block to the dial indicator. The base (A) of the carriage is made from Delrin, a strong, hard, rigid thermoplastic polymer with a low coefficient of friction. It slides smoothly along the edge of the 1-2-3 block, and can be quickly locked into position by means of a lock screw (B).
The base is connected to a support (C) by means of two hex bolts (D). The support is made from 6061-T6 aircraft quality aluminum. The dial indicator plunger (E) passes through a hole in the support. You can rotate the face of the dial indicator a full 90° by loosening an adjustment screw (F) with the supplied hex wrench, making the dial easy to read in any situation.

Magnets (A) hold carriage on 1-2-3 block; lock screw (B) secures carriage in position   
Two rare earth magnets (A) embedded in the top of the carriage base work in tandem with the lock screw (B) to secure the carriage onto the 1-2-3 block. The magnets are very strong — they easily support the weight of the 1-2-3 block — yet, the low-friction Delrin base enables the carriage to slide freely along the block. Once the carriage is in position, you turn the lock screw to lock it firmly in place. And, of course, you can mount the carriage on any of the four edges of the 1-2-3 block.
The dial indicator, which has a 1-1/8" long plunger with an interchangeable tip on the end, has a full 1" stroke. As the plunger moves in and out from the body of the indicator it rotates the indicator arm on the dial face.

Dial face: (A) Indicator arm; (B) .001" line; (C) .010" count; (D) .100" count; (E) markers     
The dial face might look somewhat complicated, but it's rather simple. Each of the 100 black lines on the dial represents .001" of plunger travel, while each of the 10 black numbers represents .010". A full revolution of the indicator arm represents .1" of travel (just over 3/32").
There is a smaller dial, called the turn counter, which also points to a zero position. Each time the large indicator arm rotates 360°, the pointer on the small dial moves to the next black line (1/5 of its circumference), representing .1" of travel.
You'll also note two movable markers on the outside of the dial face. These can be used as reference points. However, I've removed them since I never use them.

Dial lock (A) enables bezel rotation        
The rim, or bezel (A), that surrounds the face of the dial turns 360°. A knob on the side of the dial body holds a clamp that locks the bezel in place. If you loosen the knob you can rotate the bezel freely so that the zero point can be placed at any position that the indicator arm points to.

Interchangeable tips         
The 1-2-3 MicroGage comes with two tips. The rounded tip is the one you'll use most of the time, particularly against flat surfaces. The 3/8” diameter flat tip is better for use with  round and pointed surfaces. I store one of the tips, along with the hex wrench for loosening the carriage support adjustment screw, right on the rare earth magnets.

Check for runout on a drill press
Align jointer blades
I find it best to preload on the plunger by extending it slightly against the contact surface, locking the carriage in place, and then, turning the bezel to the zero indicator on the dial face. The 1-2-3 MicroGage comes with an instruction sheet that outlines clearly a number of ways to use it on you table saw, router, shaper, jointer, planer, drill press and the like.
The 1-2-3 MicroGage is an essential tool that should be in every woodworking shop. It's well designed, precisely manufactured, and makes just about any machine alignment task fast and easy.
With proper case, this is a tool that will last a lifetime, and pay for itself with increased accuracy and satisfaction.


  • 1" x 2" x 3" precision ground (.0002"), case hardened machinist's set-up block
  • Removable magnetic dial indicator base with lock screw
  • Precision dial indicator with 1" of travel and .001" accuracy
  • Two dial indicator tips
  • 30 money back guarantee
  • 1 year warranty

MADE IN:USA (dial indicator: offshore)
SOURCE:Find a Dealer
Carl Duguay, January 2013
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