Setting a Mortice Gauge?

[PAC1]

This does not apply to the wheel type mortice gauge.
I am thinking of changing my practice for setting a mortice gauge. So when setting a traditional mortice gauge do you set the points to the size of the chisel or do you allow for the V shaped grooves and set the pins to allow for the depth of the V groove?
I have been noticing an opportunity for error. Even if each V is only half a mm thick then the mortice could be half a mm out of line from where I wanted it.
The difficulty with a change of practice is that the depth of the V groove is determined by the hardness of the wood immediately under the gauge and varies all the time.
Maybe I just need to be more delicate when I gauge the lines.

 

[Blackswanwood]

Another approach may be to file the pins so they only have a bevel on the inside edge of the mortice?

 

[AndyT]

I think this is an interesting question, but just because nobody ever asks it.

There are clearly several possible variables.
- The sharpness and shape of the pins.
- The hardness of the wood.
- Whether to set the pins exactly in line with the width of the chisel or a little wider.
- How deeply you score the lines.

I don't think a single bevel on the inside is the answer, as it could be misleading when cutting the tenons, marked with the same gauge.

On the mortice, the gauged lines show where to put the chisel, but it's the thickness of the chisel that determines the width of the mortice.

On the tenon, you need to decide how close to the line you cut.

Overall, I think it's a question of getting used to the job in hand, maybe after cutting one or two test joints in the same wood. Just as cutting dovetails in compressible pine is so different from using oak, you adapt the positioning of the chisel and saw until it starts to work, when the joints fit without any individual paring after cutting.

If you're lucky!

 

[Blackswanwood]

I don't think a single bevel on the inside is the answer, as it could be misleading when cutting the tenons, marked with the same gauge.

I retract my earlier suggestion as that’s obvious now you’ve pointed it out

 

[Trevanion]

The traditional mortice gauge is a very simple tool, only the single-pin marking gauge is simpler. I would say that the craftsmen in days gone by who used a mortice gauge on a daily basis weren’t overly bothered by slight variances in the joinery as most work would be planed flat and just used the gauge lines as a reasonably accurate guide.

Typically you work the pins to the width of the chisel, chop out your mortice and then cut the tenon and pare it down to fit the mortice, though some might just work straight off the saw without paring. If you needed dead level joints you could always lay the tenon against the morticed section and see how close the edge of the shoulder is to the edge of the mortice, and pare back until they are flush with each other.

 

[Andy Kev.]

I write this as someone who had to develope a method for compensating for not being terribly good with a mortice chisel. It's a bit round the houses but it definitely works, including five minutes ago (am on a tea break).

I mark the edge of the mortice nearest the edge of e.g. the table leg and for that I use a wheel gauge. Then I take the mortice gauge to the tenon and get the pin tips as close as I can to bang on the edges of the tenon. Then with one pin in the already marked line, I scratch in a bit of the other, then pick that up with the wheel gauge and finish it off.

This slightly elaborate approach is because I'm never comfortable with keeping the fence of the mortice gauge flat on the face of the wood, whereas I have total confidence in my ability with the wheel gauge. Then I do a quick visual check by laying the tenon on the mortice mark. Then, using a square, I mark at approx 1/8" intervals across the mortice mark. This is to give me something to lay my chisel tip into as keeping it square to the line of the mortice is my biggest weakness. I also reckon that the mortice is always going to end up a hair wider than marked due to human error with the chisel. Clearer that latter point is probably peculiar to me. Some of the Youtube experts just bash away in a carefree manner and get perfect mortices. Mine never look perfect but the tenons fit snugly and squarely enough. To overcome incompetence is quite satisfying.

 

[PAC1]

The traditional mortice gauge is a very simple tool, only the single-pin marking gauge is simpler. I would say that the craftsmen in days gone by who used a mortice gauge on a daily basis weren’t overly bothered by slight variances in the joinery as most work would be planed flat and just used the gauge lines as a reasonably accurate guide.

Typically you work the pins to the width of the chisel, chop out your mortice and then cut the tenon and pare it down to fit the mortice, though some might just work straight off the saw without paring. If you needed dead level joints you could always lay the tenon against the morticed section and see how close the edge of the shoulder is to the edge of the mortice, and pare back until they are flush with each other.

That has been my approach for 46 years since being taught this as an apprentice. I usually make my tenons to the actual mortices rather than the theoretical mortice.
I have just been a bit slow to wonder if there is another way.

 

[Richard]

I was taught fifty plus years ago, continue to use, and teach learners the following:

Set the pins so that the width of the mortice chisel just barely rests between the two points. In other words, when the chisel is resting between the two points, each point sits above the chisel corners by maybe 0.1 or 0.2 mm. I aim for the same setting when using a hollow chisel mortice. This setting gives just enough wiggle room to excavate the mortice efficiently whether executed with a bench chisel, hollow chisel morticer, or a router. In practice, whichever method is used to excavate the mortice the gauged mortice width lines will get taken out because of the little bit of side to side wriggling of the hand chisel as the job is done, and hollow chisel morticers cut just a shade wider because of the slight flaring of the corner points than the size of the chisel body indicates when used to set the gauge.

As others have said, cut the mortice first, and adjust the tenon to suit, ideally straight off the saw rather than sawing then paring the tenon faces to suit, whether by hand of machine. Paring tenon faces just adds time to a job, and best avoided if possible. Slainte.

 

[derekcohen]

I have a different method. Note that, while the mortise gauge below is a Japanese cutting gauge, it would apply equally to a gauge using pins.

This is taken from my website ....


I laid out the 3 ¼” wide boards to create a tenon cheek 2 ¾” wide - that is, the length of the rail less a ¼” shoulder at each end.

Once the length of the tenon is marked, the width needs to be determined. Since we are using boards slightly under ¾” thick, the “1/3 Rule” indicates a tenon/mortice width of ¼”.

Use a rule to mark off a ¼” at roughly the centre of the board. It is not critical that this is exact, as long as all markings are made from the face side. Make sure that you have clear reference marks to avoid confusion.

Now mark across the width with the mortice chisel, as shown below.

This is going to aid in setting up the mortice gauge. Simply place the ends of the knives (or points) in the ends of the cut. This sets up the cutting width.

Now slide the head of the gauge against the work piece to set its depth. This completes setting up the mortice gauge.

Mark the mortice lines.

And then mark the tenons with the same settings.

Regards from Perth

Derek

 

[CStanford]

This does not apply to the wheel type mortice gauge.
I am thinking of changing my practice for setting a mortice gauge. So when setting a traditional mortice gauge do you set the points to the size of the chisel or do you allow for the V shaped grooves and set the pins to allow for the depth of the V groove?
I have been noticing an opportunity for error. Even if each V is only half a mm thick then the mortice could be half a mm out of line from where I wanted it.
The difficulty with a change of practice is that the depth of the V groove is determined by the hardness of the wood immediately under the gauge and varies all the time.
Maybe I just need to be more delicate when I gauge the lines.

With a traditional, Western conical pin gauge (leave them alone, they're fine as-is), you set the gauge between the pins about as deep as the pins with scratch -- just barely inside the tips. You can scratch a trough that the saw slides into - akin to running it in a ditch, but you should strive to make a light mark and saw beside the mark. Then, the tenon will be a perfect fit in the mortise with all six lines showing from marking the four-shouldered tenon. The scratch you make with a mortise gauge should be basically unmeasurable in width. Examples of how not to mark them abound in this thread - too deep, wide, and ragged. Japanese gauges should only incise a very fine line as well. One stroke. It is not a white-knuckle exercise. A six year old can easily bring enough pressure to make the mark required.

The traditional gauge is for making a mark, not incising the wood. The single-pin marking gauge is used similarly. All you need is a scratch for the operations in which it is used.

 

[CStanford]

With a traditional, Western conical pin gauge (leave them alone, they're fine as-is), you set the gauge between the pins about as deep as the pins with scratch -- just barely inside the tips. You can scratch a trough that the saw slides into - akin to running it in a ditch, but you should strive to make a light mark and saw beside the mark. Then, the tenon will be a perfect fit in the mortise with all six lines showing from marking the four-shouldered tenon. The scratch you make with a mortise gauge should be basically unmeasurable in width. Examples of how not to mark them abound in this thread - too deep, wide, and ragged. Japanese gauges should only incise a very fine line as well. One stroke. It is not a white-knuckle exercise. A six year old can easily bring enough pressure to make the mark required.

The traditional gauge is for making a mark, not incising the wood. The single-pin marking gauge is used similarly. All you need is a scratch for the operations in which it is used.

I should add that the marks, correctly made, photograph incredibly poorly.

 

[derekcohen]

Charlie, knifed marks or, as you term them "incised", do not need to be scratched. Scratching is for a point. Japanese knives are bevel shaped. That means that the indent is on the inside of the boundary wall. This creates a knife wall, which aids in registering a chisel.

Regards from Perth

Derek

 

[CStanford]

I realize the Japanese gauge is a knife. It should make a very fine line, which yours hasn't. You had to have gone across the joint at least three or four times. What's the use in all that fine Japanese steel and uber-sharpening? You could plow those marks with something no sharper than a butter knife. In one photo you can clearly see where the gauge tipped and the line wandered from previous passes. One reasonably firm stroke is all you need.

The only place you need perhaps something deeper is at the ends, but actually not even there. "Register the chisel in the knife line" has produced more gappy joints than just about anything. Register the chisel just in front/just barely kissing a finely incised line is much more preferable.

 

[derekcohen]

Charlie, we will have to disagree here. It is just a storm in a tea cup, which you enjoy stirring up. Perhaps you might demonstrate from actual pieces of furniture you build?

Regards from Perth

Derek

 

[CStanford]

I see a post has been deleted, so I'll leave the thread with this: You don't have to be a Michelin 3 star chef to know when a plate of food has been oversalted.

 

[Dr.Al]

I see a post has been deleted, so I'll leave the thread with this: You don't have to be a Michelin 3 star chef to know when a plate of food has been oversalted.

Your message was deleted on my request. We try to keep this forum polite & civilised and, I believe, accepting of the fact that there are more than one way to do things & that different things work for different people.

Rob loves his shooting board and produces beautiful work with it. I tried that style for a while but really didn't get on with it so have found an alternative that works for me. Does that mean Rob is wrong? Of course not!

Derek Cohen is a well-respected member of the forum who has written some very detailed WIPs showing how he makes some furniture that have received pretty-much universal acclaim on this site (and elsewhere). You came along and made some quite snarky remarks about how he's "doing it wrong".

If you really believe that, how about writing some detailed WIPs of your work, showing us your method and demonstrating why it works so well for you? We can then judge for ourselves whether it produces superior results to the method that Derek (and others) use with great success.

Making snide remarks convinces no-one.

 

[SamQ aka Ah! Q!]

I see a post has been deleted, so I'll leave the thread with this: You don't have to be a Michelin 3 star chef to know when a plate of food has been oversalted.

I reported it too Charlie. Al put it well above, disagreeing on methodolgy is fine; different strokes and all that. Disagreeing, without presenting evidence to clarify WHY the method in question is unacceptable veers perilously close to pure dogmatism. I believe, most readers on this forum appreciate informed discussion. Your serve.

 

[CStanford]

Here's an old favourite in American black cherry. No electric tools other than the lathe use in the turning of the knobs. White oak drawer bottoms; drawers with centre muntins. Through dovetails at the request of the client, in sympathy with other pieces in the room. Again, sawing beside a very faint line, a scratch is really all you need, and leaving the entire fine line, will transform your joinery. The gauge mark on the DT joint was left at the specific request of the client, as such they were slightly emphasized in the layout.

 

[AndyT]

Maybe it's a UK/US thing, but I've never seen through dovetails like those on drawer fronts. Is there a story behind them? Are they widely used?

 

[Mike G]

.....I've never seen through dovetails like those on drawer fronts. ......

Yeah you have.



Unfortunately I can't find a close up.

 

[AJB Temple]

I've seen through dovetails and also through box joints on some Arts & Crafts furniture, but I can't find a photo. I think it may have been in a Dutch museum. It's an odd aesthetic to many, but with contrasting woods as in the photo above it looks quite nice I think.

 

[AJB Temple]

On the mortice marking thing, on furniture, like tables I've always cheated a bit. Although I try my hardest to do neat mortices (and I mainly use the Japanese style tool like Derek, which someone on the other site made for me a few years ago and is one of my most cherished tools) I make sure that the tenon shoulder overlaps the mortice slot on all four sides. It's normal for it to be on two sides, but I do the two short sides as well with a fine gentleman's or dovetail saw. The mortice hole is never seen unless it is a through tenon and I tend to wedge pin those. I must admit it has never occurred to me to consider the technique of marking. I just do it. Sometimes I just use a sharp pencil and a small combination square set to the correct distance from each side.

 

[AndyT]

Ok, but I was thinking about the living room or the dining room, not some utilitarian piece in the staff wing!

 

[akirk]

Maybe it's a UK/US thing, but I've never seen through dovetails like those on drawer fronts. Is there a story behind them? Are they widely used?

ctsanford mentions that it was at the request of the client and to match other furniture...
I could see it being an arts and crafts type thing - seeing the honesty of the construction / showing the inside on the outside etc. I quite like it...

 

[CStanford]

ctsanford mentions that it was at the request of the client and to match other furniture...
I could see it being an arts and crafts type thing - seeing the honesty of the construction / showing the inside on the outside etc. I quite like it...

What you saw in the photos was 99% the

Maybe it's a UK/US thing, but I've never seen through dovetails like those on drawer fronts. Is there a story behind them? Are they widely used?

They matched (to a "T") another Scandinavian piece (actually another desk) in the same home office. I was asked to duplicate the drawer dovetails from the other piece, which I did.

 

[SamQ aka Ah! Q!]

Here's an old favourite in American black cherry. No electric tools other than the lathe use in the turning of the knobs. White oak drawer bottoms; drawers with centre muntins. Through dovetails at the request of the client, in sympathy with other pieces in the room. Again, sawing beside a very faint line, a scratch is really all you need, and leaving the entire fine line, will transform your joinery. The gauge mark on the DT joint was left at the specific request of the client, as such they were slightly emphasized in the layout.

View attachment 29251

That is a NICE table. I especially like the contrasting pins on the 'breadboard' ends of the top.