Bora Portamate Saw Guide

The Bora Portamate Saw Guide: What It Actually Does and How to Use It Right

The Portamate is one of those tools that sounds like a gimmick until you try cutting plywood on a ladder or across sawhorses without it. It is a portable track system designed to attach a circular saw to a rigid aluminum rail so your cuts stay straight. The saw guide is the rail assembly itself. It locks into the Portamate frame and provides a reference edge for the saw base plate. That is the simple version. I have used this setup on residential framing, cabinet installs, and some awkward job sites where there was no flat surface big enough for a table saw. The setup takes about two minutes once you know what you are doing. I usually cut the rail to length first with a hacksaw or a cutoff wheel, then mount it onto the Portamate frame using the included cam levers. You do not need a torque wrench or any special tools. Hand tight is fine.

Bora Portamate Saw Guide Setup and Usage

Here is how the thing actually works in practice. Clamp the Portamate frame onto your workpiece so it is square. Slide the saw guide rail onto the frame and position it at the measurement mark. Tighten the cam lever. Make sure the saw base plate is sitting flush against the rail before you start the cut. Run the saw along the rail with steady, moderate pressure. Do not force it. The rail does the squaring work; your job is just to move the saw along it. One thing people get wrong is measuring the offset between the rail and the blade. The blade does not cut exactly at the edge of the rail. There is a gap, usually around three eighths to a half inch depending on your saw model. If you measure from the rail edge without accounting for this, your cut will be off by that amount on every piece. I used a scrap piece of plywood and ran a test cut to find my offset. Mark the rail with a piece of painter's tape showing where the blade actually contacts the material. That saved me from ruining a bunch of trim pieces. Another practical issue I ran into involves cutting very long sheets of material without the rail itself bowing. If you are cutting an eight foot sheet of plywood and the rail is only four feet, the unsupported section sags. The saw follows the rail, not the material underneath it. This means your cut will curve slightly at the far end. The workaround is simple: support the overhanging portion of the board at the same height as the rail, or use a second rail extended with a Bora extension piece. I keep a couple of 2x4s on site for this exact problem.

The guide also has a problem with dust buildup in the cam lever mechanism over time. Sawdust gets into the threads and the lever starts to slip. I keep a small brush and compressed air in my toolbox and clean the levers after each project. It takes about thirty seconds and prevents the rail from becoming unusable after a few months of use. If you are only making occasional crosscuts on short boards, the Portamate might be overkill. A speed square and a straight edge clamped to the board will get you 80 percent of the way there for less money. But if you are doing repeated rip cuts, breaking down sheet goods on site, or working without a stationary table saw, the Portamate saves significant time and reduces waste from crooked cuts. I would rather spend fifteen minutes setting up the rail than discover halfway through a cut that I am three sixteenths off square and have to start over.