Replies

1. 
   Dale_Krech | Jan 03, 2002 01:12am | #1

   *
   Bill,

   I'm on a similar mission. I recently had an opportunity to visit James Krenov's school at the College of the Redwoods. I met Jim Budlong, who instructs at the school in addition to running his own shop. I saw a chair he built with back slats (vertical, right?). I incorrectly assumed they were bent laminations; no, they were bandsawn. Several years ago Woodsmith magazine published plans, which I will use as a guide for my project. The plans are available on their web site http://www.woodsmith.com

   Good luck

   Dale Krech

1. 
   Bill_Lindau | Jan 04, 2002 03:48pm | #2

   *Bill, I have been using laminated back slats for several years. Not only are they much stronger than a bandsawn version (which cut across the grain), they use far less wood. I use four 1/8" strips, kept in the order they came out of the board. Once you get a shape you like, the whole process of cutting the strips and gluing up three sets of back slats takes about 45 min. To make a form, I cut the shape out of 3/4" plywood, clean the cut up on a spindle sander, cut two more slightly oversized pieces of 3/4" plywood from this template, glue and screw the three pieces together with the template on the outside, and then run them through a flush trim bit with the bearing riding on the template. This gives me a form which is 2 1/4" thick. To see if I like the shape, I will use this one part form by clamping the four glued up strips to it with a fifth strip covered in packaging tape to take the brunt of the clamps. The form should be taped as well. If the shape is a winner, I make two more identical forms. All three get a nesting mate. Now they are each two part forms, which sandwich the strips. This provides even pressure and doesn't require as many clamps.If you would like, when I get my digital camera working, I'll take a picture of a form and post it. Here is a picture of some dining chairs I made with laminated back rests. The plans are in my head or I would send them to you. I will be glad to give dimensions and any help you want if you want to try one.Bill

1. 
   Bill_Szydlo | Jan 04, 2002 04:42pm | #3

   *Bill, thanks for the information. The slats you made are just what I am interested in. I would like to ask a few more questions if you have time. What type of glue do you use? Have you ever a vacuum press to mold the legs? When you mount the slats to the top and bottom rails do you use mortice and tenon joinery or some other type? If you use tenons, how do you cut the joint on the curved slats? Do you have a standard curvature you use or is mainly by experimentation? Thanks again for the information, Bill

1. 
   Bill_Lindau | Jan 04, 2002 07:58pm | #4

   *Bill, I started out using Garrett Wade 202gf which was advertised as being especilly good for laminations. However, it was expensive, had to be mail ordered, and the solids tended to settle out. For the last several years I have been using regular Titebond. There's alot of debate about whether or not this is the appropriate glue, but I have never had any touble. It seems to me that the size of the individual strips and the number of them is more crucial. Springback is inversely proportional to the square of the number of strips. So,I would think that by reducing springback (which is a function of the internal stress) that creep wouldn't be a problem.I turn the legs on a lathe. I use a 1/2" sprial bit to cut the mortises. The backslats are 1/2" thick (four 1/8" strips). I round the edges with a 1/4" roundeover bit. I cut the backrest the same width as my mortise and the rounded edges fit the 1/4" radius of the mortise.Most every time I make a new design, I make new backrest forms. Here are a few tricks I've leaned. Use a straighted out clothes hanger and shape it to fit someone's back to get the rough shape. The tendency is to use more curve than is needed. The backrest should enter the mortise at a right angle, (at least the first design should)because your spiral bit will be cutting at right angles (unless you shim it- better keep it simple at first).After the backrest curves for the lumbar support, it must return to the same plane as the crest, which is held by the rear leg post. So backrest shapes are matched with rear leg post shapes for a given chair design. A full sized drawing is helpful to work this out. I usually get a rear leg post out of a 7" board. Here are a few pictures of a rocking chair backrest form. Feel free to ask more questions.Bill

1. 
   Bill_Lindau | Jan 04, 2002 08:06pm | #5

   *Here is a picture of four strips in the form (no glue)

2. 
   Bill_Lindau | Jan 04, 2002 08:07pm | #6

   *A picture with the clamps in place. The bottom of the backrest is on the right.

3. 
   Bill_Lindau | Jan 05, 2002 04:45pm | #7

   *After reading my own post #4, I realized there maybe at least one point that needs some clearing up. When I said the backrest must enter the mortise at a right angle, I meant the backrest must enter the mortise at right angles to the horizontanl surface of the seat because the spiral bit is cutting at right angles to the horizontal surface of the seat. Bill