General Tools #820 Marking Gauge: A Review

I want to make one thing clear up-front: if you’re a woodworker, you should make your own marking gauges.  With only a few scraps of wood and some simple tools, you can make a functional tool in a single afternoon.  You can make them to your exact preferences, and the precision work required will build your skills.  The problem for beginning woodworkers, however, is that it’s really hard to make a marking gauge if you don’t already have one.

So most serious woodworkers have at least one mass-produced marking gauge.  There are many types on the market today, from rosewood-and-brass works of art to slick “wheel” gauges, at widely different price points.  What to begin with?  A beginning woodworker (especially one on a strict budget) will be looking for a simple, functional, and affordable gauge.

Here’s one option to consider: The #820 marking gauge made by General Tools, which retails for about $15.  (Disclosure: this model was provided to me by the manufacturer for review.)  It’s available from several online retailers, including Amazon and Wal-Mart.

It’s a small gauge, inexpensively made, but functional once you tune it up.  The fence locks securely.  The fence itself is well designed, offering a generous reference surface (1 1/2″) given the overall size of the gauge (about 6″ long).  My only initial complaint is that, when loosened, the fence is a little too loose on the arm, making precise setting finicky.

General Marking Gauge 4-2016

It fits reasonably well in the hand, or in a tool chest drawer.  For myself, I prefer a gauge with a bigger fence, but the trade-off is that storing several of them in a drawer becomes difficult.

Oh yeah, I almost forgot.  Like some other mass-produced gauges, the General Tools gauge has graduations up to 5″ in 1/16″ increments.  The look nice, but they’re pretty useless.  You don’t use a marking gauge for replicating numerical measurements.  You set them according to the actual dimensions of a physical object–say, the thickness of a board or the width of a chisel.  The beauty of a marking gauge is that it is more precise than any ruler you could easily read with your naked eye.

General Marking Gauge 4-2016

This is a pin-style gauge, which I find useful for marking stopped lines.

General Marking Gauge 4-2016

So let’s see how it performs out of the package.

General Marking Gauge 4-2016

I’m testing it against one of my own pin-style gauges, which is tuned and reliable.  Each of the parallel lines above was scribed with a different gauge.  Scribing with the grain is no problem–you probably can’t tell the difference between the two.  (The General Tools gauge is the one closest to the edge of the board.)

But across the grain, there’s a big difference.  My shop-made gauge sliced across this soft pine nicely, but the General Tools gauge tears the wood instead of slicing it.

But that’s exactly what all manufactured pin-style gauges will do out of the box.  Many woodworkers don’t know this, but you have to sharpen the pins correctly in order to be able to use them across the grain.

The pin is ground to a point, but to slice across the grain, you need a blade.  The way to achieve this is to hone the front and back of the pin, forming a rounded knife-edge.

General Marking Gauge 4-2016

This pin is nice and hard–I couldn’t easily cut it with a file–so it should hold an edge once honed.  I honed the pin on a whetstone using a side-to-side motion. A little on one side, a little on the other side, until a burr is formed.  A little on one side, a little on the other side, until the burr is gone.

Now let’s try it again on that soft pine.

General Marking Gauge 4-2016

A properly sharpened pin and a light touch results in a much cleaner line.  It’s not perfect, but serviceable.

Pine is difficult to cleanly cut across the grain anyway.  So let’s see how it does on a cabinet-grade hardwood.

General Marking Gauge 4-2016

On this scrap of claro walnut, you would be hard-pressed to distinguish the marking gauge lines from a line struck with a marking knife.  (Answer key: the bottom line was made with my own gauge, the middle one with the General Tools gauge, and the top one with a marking knife.)  Any of those lines would be clean enough for workmanlike joinery.

Can you get a better manufactured marking gauge?  Of course you can–much better, but for a good deal more money.

If you are looking for a basic, affordable gauge, or if you need  a worksite marking gauge that you wouldn’t be heartbroken (or bankrupted) to lose, you might consider this tool.

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