Full Chisel Blog

July 21, 2008

Folding Lap Desk

Filed under: Dovetails,Hand Planing,Historical Material,Techniques,Uncategorized — Stephen Shepherd @ 9:55 am

These were very common in the nineteenth century, it is in effect a briefcase or laptop of the period.   Most were constructed of common secondary woods, pine, poplar, chestnut, etc and covered with fancy veneer such as rosewood, mahogany, etc. and even stringing, inlays, marquetry and metal mounts. 

When folded up, it had a lock to keep it together and private, and when opened provided a slanted writing surface plus two storage areas for papers, ink, quill, sander or blotter and other accouterments needed for proper correspondence to conduct business in a neat manner.  They were for use in the household, at the shop for business or while traveling.

The construction of the carcase varies from through dovetails to half blind dovetails, like I selected for this example.  Again another one of those items I can cross off my list of things I have always wanted to built.  If that list wasn’t getting bigger when I see new things, it would be getting smaller because I am actually building many projects that I have planned to do sometime in my life.

I will make a variation on this particular one as I will just paint on the veneer and the stringing.  There are painted examples (a few leather covered also exist) but most are veneered.  So don’t say anything about the dovetails, they will be filled with putty and painted and you will never see them.

I started out with the four sides glued together, held with a rope tourniquet and toggle.  I use ropes and toggles for clamping all kinds of objects, especially chairs and for repair work.  A mostly overlooked technique, it is as about as cheap a clamp as can be had.

Box, glued up

Here is a view from the side showing the half blind dovetails.

side view

Here is a view on the inside, alright, I did saw past the score line, but it is on the inside, so who cares.

saw marks

 

Here is what the box looks like all closed up.  The top and bottom are cut to fit, glued and nailed in place.  Should I worry about cross grain, yes, just as much as the original craftsman did.  And most of the time on old lap desks there are problems caused by this.  Together with the fact that most are only veneered and finished on the outside, but with smaller pieces, this single side treatment isn’t much of a problem.

closed

And this is what it looks like open with the hinges installed.  I made a fundamental mistake when laying out the position of the dovetails, can you spot the glaring mistake?  If not I probably won’t say anything.

open

Now I thought that the second set of hinges I ordered were like the first set, but oh no, the leaf in between is bigger, so it left a big gap at the back.

hinge

This required me to remove the hinges and re-mortise them a bit deeper to remove the gap.  Wow, that nasty mistake rears its ugly head, won’t do that again, and I have another set of hinges so I will build at least one more.  I want to copy the one that is in Baltimore that was used by Edgar Allen Poe.  It is a big one and has a table base for use when not traveling.

I am fashioning the writing surface(s) from some thin soft maple I have, the hinge will be either leather or cloth, depending on what I choose for the writing surface.  If I use cloth, I will paint it to look like leather, with a little glycerin in the paint to keep it flexible.  I will also add a bit to the hide glue for that same purpose.

Stephen

 

5 Comments »

  1. If you’re using cut nails then they will undoubtedly hold the bottom in for centuries. No problem there. It does look ugly, though, when the bottom shrinks a bit and you end up with gaps around it.
    As for the dovetails, I’m not sure what you’re getting at. A couple of half-pins might be a bit thinner than might have been optimal, and I’m not sure why you’d bother making half-blind dovetails instead of through dovetails if it’s going to be puttied and painted, anyway… The only thing I can think of that you might be unhappy about is the middle part where you split a tail with the cut-line instead of a pin. I don’t think that’s necessarily a bad thing, insofar as it gives the hinge something better to grab onto, and the tails won’t be visible anyway.
    I’m looking forward to seeing the finished product.

    M.Mike

    Comment by Metalworker Mike — July 22, 2008 @ 6:44 am

  2. M.Mike,

    I did the half blind dovetails because in this application they are better than through dovetails. And the reason is one more bearing and gluing surface on the end of the tails. I will paper line the inside so the gap will not show. I am not sure it will develop a gap as the wood was very dry.

    You spotted the problem, I did make the tails different and cut through the ones on the front edge correctly but should have split a tail not a pin on the back side through the wide dovetail placed in the center. The problem is the short piece of end-grain on the outside of the hinges. Next time I will plan and cut through pins.

    And your comment about holding better is a good one, I did notice that if I had done it correctly one screw in the hinge would catch each part of the joint, one screw in the side one in the back, that might be better.

    Thanks for your comments.

    Stephen

    Comment by Stephen Shepherd — July 22, 2008 @ 8:28 am

  3. Hi Stephen,

    I was wondering if you could comment on two things:

    1. Using a rope tourniquet for clamping. This seems like a great technique when you run short of clamps or when you have an odd shaped piece. Now that I think of it, this may be worth a blog entry or two.

    2. Any tips you have on sawing the closed box apart to make the lid and bottom. The reason I ask is that it looks like you basically laid out a compound angle for this cut, which would cause all sorts of consternation if you were trying to set up a power tool for this cut. Still, I have at least one source that says that this is the most technically difficult cut to make with hand tools as well.

    Take care,
    Wilbur

    Comment by Wilbur Pan — July 22, 2008 @ 9:50 am

  4. Stephen,
    Nobody is going to see the tails, and the joint will still be way strong enough, so no blushes for that box. It’ll be a nice one, I’m sure.

    Wilbur,
    Just a comment about your question about cutting the closed box apart – it’s actually not that hard with hand tools. Mark out the cut all the way around the box, then start on the sides, which are a vertical cut. After the sides have been cut through a few inches deep then those cuts help to guide the cuts for the front and back. It would be difficult if it was a box that was longer than your longest saw, but as long as you can do the whole cut in one go then it’s not bad at all. If it’s a bigger box then you have to start on the corners, and it’s more miserable, but you just clean the cuts up with a plane after the fact, and if you lose an extra 1/8″ in the process it’s not going to matter. I’m curious which approach Stephen took when cutting his box apart.

    M.Mike

    Comment by Metalworker Mike — July 22, 2008 @ 6:10 pm

  5. Wilbur,

    I use the ropes all of the time even if I have clamps available, it is just such a good clamping method. I taught the technique to Mr. Buss the fellow that works in my shop on Saturdays, and he uses it all of the time and multiples, he has taken it to a new level. I will do a post on them and a couple others I use all the time.

    As for cutting the box apart, I just lay out lines all around and start on one corner. I progress slowly until I am sure my rip is straight. With a box of this size, I try and keep the saw cutting on at least two sides. On larger boxes you can’t do this in the middle but you can on all four corners then continue carefully connecting the lines.

    You also have to worry about buggering up the inside with the tip of the saw if it comes out of the kerf. The technique requires you ripping at some angles to which you are unaccustomed, but it is possible to get it done without too much effort.

    Stephen

    Comment by Stephen Shepherd — July 22, 2008 @ 9:33 pm

RSS feed for comments on this post. TrackBack URL

Leave a comment

Powered by WordPress