why are they called dividers?

[Sgian Dubh]

In the book.

Which book Jacob? Not Joyce's The Technique of Furniture Making I presume because figure 268 in my copy of that is an image of slot hinge.

I haven't got the time to respond to the rest of your points I'm afraid as I have other things I really need to attend to. Sorry. Slainte.

 

[Modernist]

What ever happened to the single kerf DT? It's effective, easiest, most common, and is neat and tidy.

It's among the dovetail types we were taught at school and used during my apprentice years and since. I still prefer their appearance, as well as ease of execution.

Nothing wrong with it but it is not the strongest so some limits as to use. Also it can be awkward to clean out when the mating piece is thin leaving a very narrow triangle to remove (assuming a decently shallow slope is used).

Fine therefore for the backs of pine drawers where it was regularly found with a steeper slope.

 

[GazPal]

Strength-wise I tend to err on the side of improving the partnership between increased long grain gluing surface and mechanical interaction between constituent parts. Matching a joint to an end product's purpose tends to influence type and variation, but pins don't need to be massive for the sake of structural strength and single kerf dovetails aren't necessarily a weaker variant if correctly constructed with tails and pins snugly interlocked.

It's quite surprising just how much structural stress a simple pine drawer can be put through during it's lifetime, but it's corner joints are only part of a larger equation including the attachment of front and bottom to a drawer carcase.

 

[Jacob]

....
Fine therefore for the backs of pine drawers where it was regularly found with a steeper slope.

Not as far as I know, from what I've seen.
DT pins at the back usually fatter double kerf; due to thinness of the back has to be beefed up and appearance not an issue. Single kerf DTs seem to be common at the front of hard and soft wood drawers. Seen everywhere in older furniture wherever hand made, apparently first choice of many makers, presumably because easiest and also quite elegant. Mainstream makers that is, not arts n crafts etc. Did A&C make them unfashionable?

 

[bugbear]

....
Fine therefore for the backs of pine drawers where it was regularly found with a steeper slope.

Not as far as I know, from what I've seen.

My observations (from attending many auction viewings, and looking at lots of furniture) agrees with Modernist, at least for pine.

Backs of drawers, say 5" deep, with 3-4 isoceles triangles for pins.

BugBear

 

[bugbear]

It's much more interesting and informative to look at real woodwork and to find out what real woodworkers used to do in the real world. Start now (if you have an oldish piece) - how are the DTs set out, and why?

I think what you're espousing is more generally known as archaeology, and what I've been doing in this thread is more generally known as history.

I think both approaches to knowledge are normally deemed useful.

BugBear

 

[Jacob]

....
Fine therefore for the backs of pine drawers where it was regularly found with a steeper slope.

Not as far as I know, from what I've seen.

My observations (from attending many auction viewings, and looking at lots of furniture) agrees with Modernist, at least for pine.

Backs of drawers, say 5" deep, with 3-4 isoceles triangles for pins.

BugBear

I just had a quick look around the house. (I know, I know. I should be doing some work - it only took minutes!)
Drawers in 9 pieces of furniture with hand made DTs (not made by me):
the back pins on 7 were trapezoid and 1 was triangular ("single kerf")
The front pins on 6 were triangular ("single kerf"), 1 was in between - probably started as single kerf but got widened. 1 was trapezoid.
The odd one out had peculiar shapes all slightly different!
Large majority conform to what I think was the most common pattern; single kerf at the front and double kerf at the back. This was true of the best (nice little davenport with mahogany 2ary timber and ebony, ebony veneer, birds eye maple as 1ary timber) and the worst (wardrobes and 2 pine chests of drawers), so quality and materials seem to have nothing to do with it - it's just best (and easiest) practice.
A triangular back pin is least likely as drawer sides usually overshoot the back in which case a triangular pin couldn't fit - a trapezoid becomes inevitable.

The arts n crafts DTs are all trapezoid, for no good reason other than fashion. Strength doesn't come into it as in ordinary furniture DTs never fail, large or small. Even that wreck of a dresser (which I worked over in another thread) which arrived in bits, had DTs still in good condition, just needing sticking back together again. Incidentally (Rob take note!) what had failed in every drawer (7) was the bottom edge of each side, due to having slots, not slips.

 

[Jacob]

It's much more interesting and informative to look at real woodwork and to find out what real woodworkers used to do in the real world. Start now (if you have an oldish piece) - how are the DTs set out, and why?

I think what you're espousing is more generally known as archaeology, and what I've been doing in this thread is more generally known as history.

I think both approaches to knowledge are normally deemed useful.

BugBear

Hmm. But there isn't much history - that's the nature of trad craft work everywhere - it's largely passed on by word and demonstration. "The Wheelwrights Shop" is very unusual. But there is plenty of archaeology.
History without archaeology might be only hearsay or myth. Troy was thought to be myth until it was excavated. But much archaeological evidence exists without any history at all, other than what can be inferred from the artifacts. Hence archaeology is tops especially when you are discussing artifacts.
So - if you want to know about woodwork, look at woodwork; there's plenty of it about. There's a bit near you, even as we speak! (It's behind you!)

 

[Alf]

..as I had the first volume of The Woodworker out anyway (1901), ...

DRIVE BY!!!

Oh, I wish - 'tis the reprint. They did it very nicely though.

I thought she was younger :wink:

You should see the portrait in the loft... :lol:

 

[Racers]

Doreen Gray?


Pete

 

[Jacob]

:lol:
So it's been Doreen all along? Now we know!

 

[Tony Spear]

Can you use a triangle and straight edge to create parallel lines? If so, then this is how we were taught to divide a line A-B into n equal parts.

Draw a line starting A at an angle to AB, say 45 degrees, but it does not matter really. The mark of n equal units (any size, but approximately the right size is best. the last mark is point C Now draw line BC. Set up your triangle and rule to draw parallels to BC. Draw a parallel through each of the marks on AC so that the line intersects AB. You have just divided AB into n parts with no measuring.

This is almost the same as the method suggested above by CheshireChappie, except that you do not need to choose the length of AC. It can be completely arbitrary.

I find that sort of technique much more pleasing.....

Even easier if you have a parallel rule, as I do, along with my vintage brass compasses from my Yacht Master days.

 

[Modernist]

I just had a quick look around the house. (I know, I know. I should be doing some work - it only took minutes!)
Drawers in 9 pieces of furniture with hand made DTs (not made by me):
the back pins on 7 were trapezoid and 1 was triangular ("single kerf")
The front pins on 6 were triangular ("single kerf"), 1 was in between - probably started as single kerf but got widened. 1 was trapezoid.
The odd one out had peculiar shapes all slightly different!
Large majority conform to what I think was the most common pattern; single kerf at the front and double kerf at the back. This was true of the best (nice little davenport with mahogany 2ary timber and ebony, ebony veneer, birds eye maple as 1ary timber) and the worst (wardrobes and 2 pine chests of drawers), so quality and materials seem to have nothing to do with it - it's just best (and easiest) practice.
A triangular back pin is least likely as drawer sides usually overshoot the back in which case a triangular pin couldn't fit - a trapezoid becomes inevitable.

The arts n crafts DTs are all trapezoid, for no good reason other than fashion. Strength doesn't come into it as in ordinary furniture DTs never fail, large or small. Even that wreck of a dresser (which I worked over in another thread) which arrived in bits, had DTs still in good condition, just needing sticking back together again. Incidentally (Rob take note!) what had failed in every drawer (7) was the bottom edge of each side, due to having slots, not slips.

I don't necessarily accept the idea that because it was done in the past that was the best way. It may have been the quickest or cheapest or more probably both but that doesn't make it best.

If drawer sides overfly the back then they have to be wider but more often if was the bottom which was the back stop.

I stick to my view that single kerf are OK on backs with less load and they need to be wider on fronts which get much hauling about.

 

[GazPal]

I stick to my view that single kerf are OK on backs with less load and they need to be wider on fronts which get much hauling about.

Form follows function and dovetail dimensions are typically matched to suit the purpose of the piece within which they're used. This form can shift anywhere between elegant and robust and there is no hard and fast rule apart from being at the discretion of the designer and manufacturer.

In terms of aesthetics, production speed certainly influences cost, but the time factor can become a lesser consideration once aesthetics gain precedence over whether or not a piece can be used as a battering ram and pricing is gauged to suit whatever the market can bear.

 

[Jacob]

....
I don't necessarily accept the idea that because it was done in the past that was the best way. It may have been the quickest or cheapest or more probably both but that doesn't make it best.

It's not so much how they were done in the past but more about how they were done when the tradition was strongest. More activity and more ingenuity was being applied to the craft than at any other time before or since, in the Georgian/Victorian era. Which is a sweeping statement of course!

 

[MatthewRedStars]

I stick to my view that single kerf are OK on backs with less load and they need to be wider on fronts which get much hauling about.

Wider dovetails may be a lot stronger... but neither wide nor narrow will fail in normal use, or rough use probably, so its a moot point.

 

[matthewwh]

In modern furniture single and double kerf DT's have the advantage that they can't be machine cut and therefore make it easier to single the piece out as handmade.

Given that this is a better guarantee of future value than what could potentially be a set of machined pins with a knife line drawn across them I would suggest that although identical trapezoids may be marginally stronger, the further you can get from something that looks machined the better.

If I were buying handmade furniture I would be looking for elements that single it out as handmade and therefore guarantee future value as opposed to an inefficient replication of machine made stuff.

 

[Jacob]

In modern furniture single and double kerf DT's have the advantage that they can't be machine cut and therefore make it easier to single the piece out as handmade.

Completely wrong. It's the other way round. All machine cut DTs are double kerf (or look like them). Triangular single kerf pins can't be cut by machine as far as I know. The A&C style double kerf DTs can be faked on a machine.

 

[mtr1]

Triangular single kerf pins can't be cut by machine as far as I know. The A&C style double kerf DTs can be faked on a machine.

The pin holes can't be cut with a machine, the sockets can be hogged out with a router. This is how I cut mine, though I don't single kerf mine because I don't like that look.

 

[bugbear]

The A&C style double kerf DTs

I'd have said (with some confidence, although I'm never as "confident" as Jacob) that the use of non-zero-width-apex pins is both wider and earlier than A&C?

BugBear