I was reading an online review of a marking gauge and there were critiques about them being out of square. Am I missing something? Never worried about the fence on the gauge being square to the beam.
So does it have to be square for some reason?
[OP]
Member
I was reading an online review of a marking gauge and there were critiques about them being out of square. Am I missing something? Never worried about the fence on the gauge being square to the beam.
So does it have to be square for some reason?
Contributor
As long as it is reasonably square it shouldn't be a major problem.
Imagine the cutting point being square to the beam and the fence off square. Then it could cause a problem if the cutting point is a wide blade or a wheel.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Right, if I set the gauge via a rule for a specific measurement and the beam is at a 2* angle, my measurement is off. I would think that if the gauge were off enough to affect my joinery I would notice while using it. Certainly it should be perpendicular.
Last edited by glenn bradley; 06-03-2015 at 5:21 PM.
"A hen is only an egg's way of making another egg".
– Samuel Butler
[OP]
Member
I agree that a cutting gauge with a blade should be square, but a marking gauge just has a pin. Kind of like using a fence on a router table versus table saw fence. Doesn't have to be square to the router bit but does have to be square to the saw blade.
Unless I'm missing something it seems like the fence to the beam could be pretty wonky out of kilter and still work perfectly as long as it locks up tight.
In Memoriam
When stem is out of square to face, the face can be thrown out of contact with a square edge.
Squareness is very important.
David Charlesworth
Yes, this. Think about it for a moment and you'll have an "ah-ha" moment.Originally Posted by david charlesworth
"A hen is only an egg's way of making another egg".
– Samuel Butler
Member
Would it be correct to think that's due to a ploughing action by the blade/knife - wher the blade will want to run parallel to the reference edge, but this results in the stem/beam tiling the face?
Contributor
Just try cutting a clean line with a cutting gauge where the knife is not aligned with the fence.
Regards from Perth
Derek
Contributor
Knife gauge then the blade alignment is important to ensure proper tracking and marking. Pin marking gauge, then this is not an issue. Double pin gauge for morticing, etc, then squareness to the fence becomes important again. Now, if you have that knife gauge set to be slightly off square such that as you use it it has a tendency to pull the body up to your reference edge, and this still leaves a clean mark you are golden. It might take a relatively stiff marking blade for this to work (without blade bending deflection). With the grain marking is going to be somewhat troublesome on many types of wood regardless.
Last edited by Pat Barry; 06-04-2015 at 7:50 AM.
Member
Pin gauges are less fussy, both mortice and marking. I can't imagine even bargain bin pin gauges have a head out of square enough to cause a real problem. Knife edges are a different matter. That's why I like pin gauges.
Member
Sqareness is important, the longer the fence, the more being square counts. Think of 3 points....the cutting knife and two extreme ends of the fence as a triangle. That triangle needs to be a right triangle to get the exact distance from the edge. I hope this helps.
Member
The op asked about a marking gauge. I'm not sure if he mentioned a knife or a pin. If it's a knife in my book it's a cutting gauge and in that case the knife must be parallel to the headstock. If it's pin marking gauge it works on a circular pin, parallel to the headstock then does not matter. Perhaps the op could confirm the type of gauge?
Contributor
The type of gauge doesn't matter, it needs to be square to be accurate. David and Charles are absolutely correct. Think about it. As the fence angle relative to the arm changes away from square, the perpendicular distance of the marking point to the fence gets shorter while the distance from the point to the fence along the arm remains unchanged.
In Memoriam
Just to elaborate a little.
In use the stock face is pressed firmly against the face edge which should be square.
The stem has three possible positions.
1. Pointing up in the air so the pin is above the surface.
2. Pointing down so the face is displaced when the stem is pushed onto the surface. Thus causing error.
3. Laying correctly on the surface so that pin depth of cut can be controlled by pivoting on its leading edge.
I am certain that squareness matters. A decent gauge should be reasonably square but some cheap Sheffield ones are not. We cure them by adjusting the face by planing. If present, those redundant brass strips are simply reversed.
best wishes,
David
Member
Hi Mike,
I might regret this but I'll try and knock up a video later. I do appreciate that there is a degree of accuracy required, I just can't recall ever checking a gauge for square.
Cheers
Last edited by Graham Haydon; 06-06-2015 at 6:25 AM.
Posting Permissions
Reply With Quote