Dovetailing on a long board

[RogerS]

The problem...

Making six longcase clock cases. The backboard is nearly 2m long and 350mm wide. Lot of work gone into making them, let alone the cost of the exotic hardwoods. At the top, is a small horizontal panel (for want of a better word) that spans the width of the backboard and needs to be dovetailed in place using a few chunky dovetails.

Normally I'd stick both pieces of stock in the vice and do them by hand but at 2m long that wasn't practical. Options were to lay the board horizontal on my table saw, climb up on top and do the dovetails vertically. I wasn't too enthusiastic about doing that. Not that the table saw would not easily take my weight, just that I wasn't convinced about the eye-hand co-ordination with everything re-oriented let alone not being able to use any of the various dovetailing jigs, aids, mirrors that I sometimes use.

Option 2 was to use one of the various jigs available on the market although I had my reservations about this approach as well since the router would have to be held square and true in the vertical direction and on all the jigs I saw there didn't seem to be enough landing area to give the router adequate support. I did buy a secondhand Leigh jig but in my naivety discovered that it wouldn't cater for boards of the thickness I was using so that idea was scratched.

Still humming and hah'ing, it was surprising just how much displacement activity I could find rather than bite the bullet and 'do something'. Further research suggested the latest Leigh D4R with the optional vacuum/router support would fit the bill but at £600 a bit eye-watering.

As serendipity would have it, I was discussing my dilemma with DaveR (Dave Richards of SketchUp fame) and he thought that he had a solution. This is what he came up with



Looked very very promising. Lots of MDF dust later, I came up with these two.





Time to put them to the test. Thank God for a fully retractable table saw blade and riving knife. Board clamped down firmly, jig in place, router set to Go.



Initial cut made with a straight bit to reduce the workload on the dovetail bit and then the dovetail cut. First cuts made.





Carefully clamp the top panel in place to mark up. I use a knife tight on the inside of the tails to mark the line of the pins on the top panel. The trouble I had was that bubinga is very hard and dark and I found that the knife lines were not very visible once I got them in the jig. To get round that I laid masking tape down the edge of the top panel and marked that up. Worked well.



Using bearing guided trimming cutter for the pins I started to make the first cut. Then the Cock-Up fairy decided to lend a 'helping hand' as I forgot I was using a bearing guided cutter, decided I was uncomfortable hogging out the complete cut in one go and so raised the router cutter, lost the bearing reference surface and gouged out the jig. Epoxy and judicious filing and several hours later ready to go again.



This was when the F***-Up fairy though that it would join in the fun as yours truly started to rout out the wrong side of the line....

Remedial work done to the top panel and pins cut.



Offer up the two pieces together to test the initial fit and looking good. Bloody Hell. It works!



Bit of careful filing and jobs a good'un. Just need trimming down the excess.



Huge Mega-Thanks to DaveR for the original idea.

 

[Karl]

Nice work Roger - but those Sketchup drawings could do with a bit of rendering :lol:

 

[Jacob]

Normally I'd stick both pieces of stock in the vice and do them by hand but at 2m long that wasn't practical. Options were to lay the board horizontal on my table saw, climb up on top and do the dovetails vertically. I wasn't too enthusiastic about doing that. Not that the table saw would not easily take my weight, just that I wasn't convinced about the eye-hand co-ordination with everything re-oriented let alone not being able to use any of the various dovetailing jigs, aids, mirrors that I sometimes use.

Much easier by hand at knee height with the long panels resting on saw horses.
Much easier without "various....aids" :lol:
Aren't they supposed to go the other way with the top panel tying across holding the verticals together?

 

[bugbear]

The problem...

Making six longcase clock cases. The backboard is nearly 2m long and 350mm wide. Lot of work gone into making them, let alone the cost of the exotic hardwoods. At the top, is a small horizontal panel (for want of a better word) that spans the width of the backboard and needs to be dovetailed in place using a few chunky dovetails.

Normally I'd stick both pieces of stock in the vice and do them by hand but at 2m long that wasn't practical.

Here's quite a famous thread from OLDTOOLS, "How about dovetailing long boards?"

http://swingleydev.com/archive/get.php? ... t_thread=1

Humour and wisdom in liberal quantities.

BugBear

 

[Jacob]

....
Isn't it interesting that even after the work is done, there are those who have to tell you that you should have done it a different way. :roll:

He only had to ask :roll: .
Or better still - look at a long case clock, a chest of drawers etc and see how the DTs are set.

 

[tomatwark]

....
Isn't it interesting that even after the work is done, there are those who have to tell you that you should have done it a different way. :roll:

He only had to ask :roll: .
Or better still - look at a long case clock, a chest of drawers etc and see how the DTs are set.

Sorry Roger I have to agree with Jacob ( I never thought I would say that :lol: ) but I would have done them the other way as well.

Like the jigs though, at the end of the day it is the how it looks when finished not how you got there.

Tom

 

[Jacob]

Luckily there is a simple trad remedy for failed DTs (or DTs going the wrong way) - put a nail or two through each tail and/or pin if they are wide enough. The secret with nails in good furniture is to pre drill.

 

[RogerS]

Doesn't matter which way round they go. They're stuck at the back and out of sight anyway.

Regarding asking for advice. I ask where the advice is sound...that's why i spoke to DaveR.

The only time I see Jacob's quotes, in any case, are when they are quoted by someone else.

 

[Andrewf]

Helped my father do something similar years ago. We dragged a bench outside and then dug a hole for the wood to fit into. In my grandfathers boat building shed. Digging holes in the floor was a fairly standard task. Though the building shed did have a dirt floor.

 

[Dodge]

Please dont think I am in any way being critical, but with the time spent making the jigs etc wouldn't it have been just as quick to cut by hand, I often find the unusual joints can be cut and assembled long before the appropriate jig is designed, worked out and constructed let alone used, and once said jig has been used is often useless for anything else as made specifically for one joint.

As I said, not having a go, or being critical as what you have done is great. =D> =D>

Rog

 

[RogerP]

Please dont think I am in any way being critical, but with the time spent making the jigs etc wouldn't it have been just as quick to cut by hand, I often find the unusual joints can be cut and assembled long before the appropriate jig is designed, worked out and constructed let alone used, and once said jig has been used is often useless for anything else as made specifically for one joint.

As I said, not having a go, or being critical as what you have done is great. =D> =D>

Rog

Making six longcase clock cases

maybe worth it for 6?

 

[RogerS]

Please dont think I am in any way being critical, but with the time spent making the jigs etc wouldn't it have been just as quick to cut by hand, I often find the unusual joints can be cut and assembled long before the appropriate jig is designed, worked out and constructed let alone used, and once said jig has been used is often useless for anything else as made specifically for one joint.

As I said, not having a go, or being critical as what you have done is great. =D> =D>

Rog

Rog...I tried to explain in the OP why I didn't fancy climbing all over my table saw and cutting them looking at the floor. And mucking about tweaking 6ft long boards isn't my idea of fun....especially when the wood cost an arm and a leg....and I cant afford the time to cock it up.

And as t'other Roger said...I do have six....for the moment...with maybe more to come downline. So a jig was definitely the way to go.

 

[Dodge]

Thats fine, I fully understand and agree - anything to make life easier!

Its a bit like the old sit in the queue of traffic traffic and get very frustrated or turn off the road and take a longer pleasant route to avoid the queue - neither is right nor wrong and both courses of action get you to the same place - whats important is choosing the right route to you!

that was rather philosophical although I say it myself!!

The other Rog

 

[Jacob]

Machines are brilliant of course, but when you have to go to a big effort to get them to work with jigs and gadgets it might well be quicker by hand. Certainly would be here by the sound of it. It becomes the most practical way of doing the job (or part thereof).
Run of six? Perfect! By the time you get to no.6 you are an expert in hand dovetailing.

It's just so easy to go the gadget way. I was at it today, looking at how to support large window frame on edge while I fettled and fitted. I've got one of those Triton superjaws gadgets for work holding and it does the job, but I've only got one. So I supported the other end with a trad wedge and 2"x4" door prop. Much easier to handle so I knocked up another one (5 minutes?) to replace the Triton, and it does a much better job. Triton will be on ebay soon! It's a good bit of kit but is easily outperformed by a few scraps of wood and wedges all hand made.

 

[RogerS]

Tom

If you do them the way you're suggesting then from the back all you see are what look like big finger joints thus defeating the whole object of making dovetails!

 

[jasonB]

Tom

If you do them the way you're suggesting then from the back all you see are what look like big finger joints thus defeating the whole object of making dovetails!

You are missing the point Roger, I'm with Jacob & tom. Dovetails are not there just for the look, the shape resists the joint putting apart, think about a draw box, if the parts were the other way round and the glue failed as you opened the draw the front would come off, the way they should be done would allow the draw to be pulled open even without glue.

The way you have orientated the joint it resists a pulling force from above and there is no need for that, done as the others say it will resist any tendancy for your wide board to cup. Also you say its hidden so your finger joint look is not valid.

J

 

[RogerS]

But it isn't a draw so pulling off the front of draws doesn't apply.

The dovetail is there for aesthetic reasons and will be seen in the showroom..that is when it counts.

I accept that there might be some marginal resistance to the wide board cupping but in this case, it is the visual impact that matters.

 

[jasonB]

Doesn't matter which way round they go. They're stuck at the back and out of sight anyway.


The dovetail is there for aesthetic reasons.............it is the visual impact that matters.

You have lost me there, one minuite they are out of sight next they are there for visual impact?????

I this a more modern design of long case as the 2.0m seems big for the usual large base, thinner middle, large top look?
as this may explain your choice of construction.

J

 

[RogerS]

......

You have lost me there, .....

J

You're spot on in that it is a modern clock. It will be visible from all directions until it is fixed to the wall. So having the dovetails done that way round gives maximum visual impact at the point of sale.

For what it's worth, i timed how long it took me to make and tweak the last one. 29 minutes which ain't bad.

Of course, I expect Jacob to come along and tell us how he would have done it by hand in under half the time but then i couldn't care less and will never know, more to the point.

 

[StarGazer]

Maybe I am missing something here, or customers now expect something different from the non-visible parts of the clockcase, the 1700s longcase clock (and almost everyone I have looked at) at home while uses very fine oak and fruitwoods for the display parts of the case, the backboard, mechanism supports and anything not on display are very ropey softwoods.

Likewise visible joints are very fine indeed, but the internals have parts nailed (albeit with handmade iron nails) together.

StarGazer