Saturday, March 21, 2015

Marking gauges

Updated 23 Jan 17

On the third day of Spring, my true love brought to me...

20 Cm of snow, mix of rain, and a partridge in a tree :-)

I love marking gauges, they make our life so much easier. If you ever use the old "Run your finger along the board edge" to mark a line with a pencil, you know how they work.

They come in many flavours, but can be divided by the way they make their marks.
Some use a pencil, other a scratch pin or a cutting knife, or a cutting disk.  They are also further divided by the specific jobs they are designed for: Marking gauge, cutting gauge, panel gauge, mortise gauge, butt gauge etc.
They all have a place in my tool set, they all have their plus and minus, so depending on usage, I will reach for a specific one.

Here's a small sample of my favorite ones.

Mortise gauges.
So called because they have 2 pins to mark both sides of a mortise at once. They are usually set by using the actual mortise chisel to be used

Typical British gauges (W. Marples shown) uses a recessed screw to lock down the fence. 

To me this is the Summum type of British mortise gauge.
Fully enclosed and screw adjustable mechanism.
Fool & Bob proof if left set for a long time.

A more modern, Ward (UK) Boxwood, fully enclosed gauge

American ones (Stanley No 76 shown) tend to use a thumb screw instead.

Some don't like having to use another tool, screwdriver, to adjust the British types.  In my way of working, leaving the gauge set throughout a project, I really do not mind and it prevent inadvertent changes of setting. Which is a good thing for me :-)

With mortise gauges, I much prefer the ones with an adjustable slide with a thumb screw, or enclosed screw. They also come with a simpler slider arrangement, no threads. I'm not a big fan of dual beam mortise gauges.

Watch out for bend mechanism, the brass slider is kinda soft and damages easily if you are ham fisted and the head is locked on solidly. The head locking screw is bearing against the sliding bar, locking it together with the fence setting.

Be  very careful trying to unbent slightly the mechanism, 
being mostly brass it it easily damaged if abused.
If it work throughout the range you need, leave it alone.

The 2 pins are press fit into the brass bar and can be knocked out or pulled out to replace them when worn out. The fix pin retaining plate is removed by one screw and the movable one would need the whole mechanism to be screwed out. Not a big deal and makes it easy to assess the brass slider condition and to give it some small corrections.

Note that on most mortise gauges, the pin plate is using the same
 sliding cut-out along the whole beam.

Pins types have a bad reputation for scratching more than they mark.  They typically come with a cone shape pin, re-shaping the pin into a half crescent, flat on one side makes all the differences in the world. If you look closely at my mortise gauge pins above, that's the shape they are in. Although they are a bit flat on top and I see I need a touch up.

Wheel types
Another type that is all the rage now a days, is the wheel type. 

Mine is the old original LV one, the disk cutter does not recessed into the head and the screw is proud at the end. Both of these small things have been changed on the current productions one

Nothing new, they existed in the late 19th century, 

E.G. Stanley No 97 1900-1958

but re-popularized by LV and Mark-Tite.  Their big advantage is being a fixed wheel they cut instead of scratching across the grain. They are also super easy to sharpen, remove  the wheel and rub the flat side against your medium to fine sharpening stone. It's that easy! And remember that marking tools do not have to be super sharp to work, we are not paring wood, we are simply marking it. And since the head and the wheel are circular, just rotate the gauge in your hand to get a fresh edge.

Their biggest problem is a tendency to follow the grain, more so than the pin types. You need both a firm pressure against the fence and a light touch on the cutter. The other is to roll off the bench too easily.  Some fix that problem by simply filing a flat spot on the fence.

The fence and beam arrangements
There is a variety of ways to hold the fence secure to the beam, but regardless of types, the two of them should lock solidly, with no wiggles. Easier said than done!  
Traditional gauges uses a simple square or somewhat rectangular hole in the fence head and the beam is shaped accordingly.

Problems are the beam must fit the hole without much play and the heads often blow out on the grain line from the pressure exerted from the locking screw. Solution? Make the head bigger where it count and shape it for a better fit in your hand based on how you use it.

That one above, is one I made about 15 years ago.  It is based on a traditional Japanese design, such as the one's sold at LV, but it used the traditional wedge to lock the head. 

Japanese gauge bought at LV. Notice bent instead of cast shoe

My inspired from, version. Wedge locked fence.

The fences are often brass faced for better wear resistance

And/Or with a dual bumpers to follow curve surface

Locking both together
Next problem is how you secure both firmly. Often a wood, plastic or metal thumb nut is used.  The problem with that arrangement is that the pressure on the beam is only felt on 2 parallel surfaces, but the head is only bearing on one face. 

L- Iron screw, R- Boxwood, broken,  typical failure. 
Same Threads, interchangeable...
Of course the screw threads bearing on the beam is going to cause wear. Simple solution is to add a small shoe piece (often long lost in antique gauges)

Tell tale cavity, should be a brass shoe filling it

Tell tale brass shoe on a variety of wooden marking gauges.
Shown on Stanley No 68. Note also the third permutation of the thumb screw, brass this time, instead of wood or metal, later plastic.

Brass shoe appears cast, but is being drilled through by Thumb screw (probably brass plated steel), it is also being bent out, causing stiffness on beam(s)

Some shoes have a recess cut on one side to bury the marking pin inside or flush with the head. Later model Stanley No 65

Unless you have a very tight fit in the square hole, the beam is going to rotate inside (wiggle). Of course if it this made too tight, the head would not move on the beam.  Turns out out there are all kind of patented ideas to accomplish that better.

Turn the beam 45 degrees and you now have 2 surfaces bearing on the head. Or put 4 diagonal beams together and three surfaces are now in contact.  Add a pin on each beams and you have a multi-arms gauge 

C. Sholl joiner's gauge patented March 8th 1864

Under the same patent, there is a also a 3 beams gauge (pic from web, not mine)

This is getting ridiculous, beam wise, there has to be another way? Yes, there are of course, the round beam in a round hole, and the multi-beams proliferation's, borne from the idea that 2 parallel beams adjusted individually on the same head, make a mortise gauge. Never better expressed than by our very own LV with one of their famous April Fools Day's joke
And, Yes they do make a real Dual beam mortise gauge.  If you get that one, highly recommend the extra shaft clamp. So that you can adjust the fence after locking the beams together

Stanley No 71. Not all dual beam gauges are true Mortise gauge. This one has the pins on opposite sides. But in reality this Stanley No 71 Dual gauge, should have its beam pins facing each other out. One beam is reversed in pic. Has been taken apart prior and that is the best way to lose those little brass shoes...
How does the beams locks? There are 2 screws, one on each side

Patented ? (Unknown maker) metal dual beam mortise gauge.
Notice Octogonal head shape prevent the gauge to roll when put down on bench. 

Yet a different means to lock the head to the beam, and looks pretty darn good to boot are the Hamilton gauges

Pic is from his site. Never tried but from what I read it does a good job of locking square and securely.  I love the look of this fence/beam arrangements, I must get one ...:-)

Another way to lock the head is via a wedge action. Some are set up as to require simply the pressure of your fingers one way to lock, the other to unlock, very quick once used to it. Also very quick to unlock on you when least expected, until you get used to it :-)  See article from Popular Woodworking Art & mystery marking gauge.

Bob, who could go on forever on the gauges, but...time to go clear the @#&$ snow...again!


  1. Thanks Bob, Found one the other day for $15 Aussie. In process of fixing it up. same as the Marples one you have at top. Missing the brass and fixed pin at the end, and the shoe inside. Reckon I can fix all that though :) Thanks heaps for all the valuable info. Hope you don't mind but shared your blog with the guys at

  2. No problems, glad you found it useful.
    Cheers Mate

  3. In the process of updating my posts with better pictures, as available and minor formatting and typos corrections. New or updated information added. Date entry on top read latest Revision date

  4. This was really an interesting topic and I kinda agree with what you have mentioned here! Best Accurate Rain Gauges