Tenon shoulders, more advanced...
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Jacob
New Luddism. Wake up and resist.
Sorry yes - the great and notorious heavy-weight Oval Bolster Mortice chisel!
It's equivalent to a building labourer's pick-axe and can do a lot of work very efficiently.
Three half inch chisels. OBM, Sash Mortice, Firmer
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pe2dave
Established Member
If the line (pencil?) is thick enough to be split, surely it cannot be accurate?
Thinner pencil or knife line.
Jacob
New Luddism. Wake up and resist.
Mortice and tenons you'd do with a two pin mortice gauge.
Even a knife line has a width. In theory, "splitting" it would leave the side of the knife cut still visible on the edge of the tenon shoulder.
But it's more a question of getting a routine in place which works for you, whatever kit you are using.
Thick pencil lines can be precise if the middle of the line is in the right place.
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Reffc
Established Member
I think a lot of links back to historical methods and traditional tools have their place but the over-riding consideration for me anyway, is what the timber species is, what the joints intended are and what tools or methods best fit the making from a purely practical standpoint. I am the first to admit that I do not possess a plethora of different traditional chisel types and generally only use two: Mortise or bevel edged. I have never had any problems cutting M&T's or dovetails or rebates with these and whilst specialist wood chisels may be designed for specific applications, most can get away with just the two types although I do intend to buy some others. Heresy I know!
Further, the discussions on riding the lines, splitting the line etc are all ones where common sense plays a big part. I never try and split a line when making joints as it's difficult to be precise and where I use pencil lines, often I'll only use a 0.5mm pencil to infill a line cut with a marking knife which is the only precise way of setting a precise line imho, and then try, if sawing the joint, to cut close to the line in one go, including removing the back, then use a chisel to tidy precisely up to my cut line centre. The other advantage I see of using the marking knife is it removes all error when using the bench saw because I can snick the outward facing tooth of an ATB blade such that it precisely locks into the marking knife line and that is more precise than trying to line the fence up by eye along a pencil mark.
Further, the discussions on riding the lines, splitting the line etc are all ones where common sense plays a big part. I never try and split a line when making joints as it's difficult to be precise and where I use pencil lines, often I'll only use a 0.5mm pencil to infill a line cut with a marking knife which is the only precise way of setting a precise line imho, and then try, if sawing the joint, to cut close to the line in one go, including removing the back, then use a chisel to tidy precisely up to my cut line centre. The other advantage I see of using the marking knife is it removes all error when using the bench saw because I can snick the outward facing tooth of an ATB blade such that it precisely locks into the marking knife line and that is more precise than trying to line the fence up by eye along a pencil mark.
Jacob
New Luddism. Wake up and resist.
I completely avoid marking with a knife as you can't correct it or erase it when the job is done. No advantage in a precise line if it's in the wrong place!
I think they are misnamed and should only be used for cutting a line where you really want a clean edge e.g. on the visible face of a shoulder. Or for making a deliberately indelible line which I've seen on old work, where I guess the foreman has marked up one side from the rod, for the bench hand to complete in pencil.
I'm wondering if I have misunderstood something from this conversation, Surely, the way to achieve accurate shoulders to a tenon , is to knife the lines. If you use a marking knife that has a single bevel, and this is handed to suit whether you are right or left-handed, then the shoulder cut will always be perpendicular, (and if measured accurately) in the correct position.
If one feels a bit 'iffy' about being able to cut faultlessly to this line, then relieving the cut line by forming bevel to the waste side, with a chisel, will produce a ramp, the lowest point of which will allow you to locate the saw in exactly the right position.
If, upon examining the shoulder, there is a slight step between the cut and sawn line, this can be pared away with a wide chisel riding against the knifed edge. If the lines are knifed deep enough, then even if the chisel undercuts the join, the shoulders on the finished joint will appear faultless.
In my own case, I have to admit, all my tenon shoulders -and indeed the tenons themselves- are machined on my Wadkin radial arm saw, using a stop - so neatness and accuracy is something I don't really have to worry about anymore.
If one feels a bit 'iffy' about being able to cut faultlessly to this line, then relieving the cut line by forming bevel to the waste side, with a chisel, will produce a ramp, the lowest point of which will allow you to locate the saw in exactly the right position.
If, upon examining the shoulder, there is a slight step between the cut and sawn line, this can be pared away with a wide chisel riding against the knifed edge. If the lines are knifed deep enough, then even if the chisel undercuts the join, the shoulders on the finished joint will appear faultless.
In my own case, I have to admit, all my tenon shoulders -and indeed the tenons themselves- are machined on my Wadkin radial arm saw, using a stop - so neatness and accuracy is something I don't really have to worry about anymore.
Jacob
New Luddism. Wake up and resist.
Precise yes, but not necessarily accurate i.e. in the right place.
Adam W.
A Major Clanger
It's normal in all historic work to see scribe lines, and they can also be seen on historic carved and inlaid ornamentation too.
Cheap machine made pencils didn't really become widely available until the late 19th century. Prior to that pencils were mostly made by hand and relatively expensive, so the cheap option in a joiners shop was the marking knife or awl.
My uncle trained in London as a joiner in the 1950's and he spent the first three years of a seven year apprenticeship learning to sand and finish, so that the scribe lines couldn't be seen.
Imagine that, three years of sanding...phew!
Then, surely, it is not the knife marks that are at fault, but the measuring. If you knife properly around the shoulders. working off the face-side and face-edge with your square, and using your knife, dug in at each corner, as you go round each corner - then you will have knifed lines that meet. This is all that is required for forming good shoulders. Any inaccuracy, is then down to things not being measured properly
Jacob
New Luddism. Wake up and resist.
Yes. And can't easily be corrected if it's a knife line.
Everybody's done it at some point - where they carefully mark around 4 sides with pencil or knife, only to find that they mysteriously don't meet up in the right place!
If I wanted a cut line I'd mark first with pencil (2H) and only then cut the line.
I can see how they are necessary for some sorts of work and working environments.
Jameshow
Established Member
Also with pine you can get away with a heck of a lot more, as the wood has much greater ability to flex and compress, whilst with hardwood like oak, your fit needs to spot on, its a fit or it dosent!!
Reffc
Established Member
I mark out initially in fine pencil lines, double check all my measurements and always from a reference edge and then scribe them with a marking knife. It is the way I was taught and ensures absolute precision so stick by it. Mistakes do happen but can be avoided by paying heed to the old addage “ measure twice, cut once”
Not saying I can do this but japanese pull saws have a grind that creates a line of alternating points along each side of the blade.
If your line is a knife cut, you can place either the left or right line of points in the cut and start the saw cut either side of your line.
If your line is a knife cut, you can place either the left or right line of points in the cut and start the saw cut either side of your line.
Since the push isn't into them (bearing down), they also will often start wherever you put them. But a little skip at the start of the cut and there's a small but too big mark to remove.
My only issue with them (they're resharpenable, too, and pretty easily) is that if they get off a little bit in a long tenon cut like that, even due to varying wood density or grain direction, it's very difficult to make the small adjustments mid cut that are easy with a back saw.
A thumb or finger beside the blade obviously keeps them from popping up and landing next to the line and cutting on the non-waste side, though.
Jacob
New Luddism. Wake up and resist.
You can do that with a set western saw too. Tilt it into the cut then straighten up as you go. Easier to do it the normal way though!
johnnyb
Established Member
making stuff is not cutting a mortice and tenon. it's making many mortice and tenons. with this in mind the marking out from the rod and transferring onto the components is much more critical than cutting a single joint. all work has tolerance but accuracy on the face and a trim off the back shoulders so they pull up is normal.
Reffc
Established Member
That's all true but there are Japanese saw designs which are backed such as the Dovetail Dozuki made for export markets. I almost exclusively use Japanese saws now because I find them more comfortable to use and they stay razor sharp for a very long time. Their other advantage is the thin blades create less dust, remove very little material and need less energy for each stroke than more traditional western designs.
Jacob
New Luddism. Wake up and resist.
Absolutely. Layout and marking up from a rod is the biggest time saver and most accurate way of making stuff, even simple one-offs. Seems to be another key technique which is more or less forgotten - perhaps the most important of all.
In fact for me it's the reason I gave up looking at woodwork mags for ever. I'd been buying and collecting them for some years but when I started learning how to do stuff properly I realised I hadn't seen any of this stuff in a woodwork mag, neither rods, nor how to use a mortice chisel and a lot of other stuff. Haven't looked at one since about 1982 when I binned a huge pile of them.*
Books are good value though. Old ones that is. Say from before 1960 perhaps.
*PS except I had a sub with Chris Schwarz's mag but it folded. I kept a small stack.
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Reffc
Established Member
That’s a very good point. I rarely see any marking up and producing detailed drawings from a rod. Come to think of it, having visited a fair few workshops over the past few years I don’t remember seeing a trammel or other instruments often used to mark up from a rod. A lot of workshops seem to not bother. Having been bitten part way through one project a few years back, where a job didn’t come together as expected I now keep a large roll of paper which covers my main assembly bench for new designs for this purpose. I find it essential so nothing’s missed and produce my cutting lists from sketches made based on a full scale rod then A3 sized scale drawings. I wonder if the advent of CAD has something to do with this as you can view designs in 3D on packages like Solidworks. I don’t use CAD for my own drawings but guess it could be why we rarely see setting out from a rod these days?
