Page Last Updated 05 June 2005
Advance Design Bed Wood Specifications
Provided by Jeff Nelson

The bedwood in the Advance Design trucks was originally southern yellow pine. The wood came from the factory treated with a combination of linseed oil and lampblack, giving it a dull, black color. The boards were held down with metal strips between the boards which were painted black also. Remember that these were working trucks, meant to haul hay, manure, gravel, etc.

Many of the vendors listed at the Chevytrucks.org homepage (Vendors) sell bed replacement kits. You can buy the entire kits or any of the individual components. These kits can include the boards (usually available in either pine or oak), the metal strips (available in stainless steel or plain steel for painting), and all of the necessary hold down hardware. Most of the vendors also carry a booklet for around $4 or $5 titled "Bed Assembly and Restoration Manual." Although the booklet does not include the dimensions (given below) it has lots of useful information about restoring and reassembling your bed.

When replacing the bedwood, people usually take one of two approaches to finishing the wood. They either try to duplicate the original look, or they go with a clear finish to show the wood grain. If you want to have a bed that resembles the original, here are two methods suggested by our members that you might try.

Method #1

Get a pint of Pine Tar, usually from farm supply outfits, mix it with enough 'turps' Turpentine, to thin it out, and then add it to at least a gallon of Boiled Linseed Oil. Do this when all of it is warm, as in sitting out in the sun for a few hours. Mix and stir well and coat the 'be jabbers' out of the boards. For a different fragrance, toss in a bit of diesel or 'kero' Kerosene. Do not let it dry out. Keep flooding the wood with the mixture and at night cover well. The Boiled Oil will start to skin over if left exposed to air so I made a 'tub of old boards lined with plastic to hold the mess. After about a week, take the boards out drain the excess back into the tub and when all are done save the 'goo' for other like minded jobs. Hint, after saving the 'goo' float a layer of kero or diesel on top to prevent the linseed from drying out.

Method #2

I finished the wood by rubbing on an oil-based paint (black to go with the bed strips painted black w/ clear coat), and wiping it off within 1 minute. For final finish, if possible, I think a clear coat would be sweet, but with budget in mind, I used a UV resistant outdoor, spar varnish, lightly sanded between coats. It sure looks good. The wood grain is dark, yet very visible.

Many oletruckers, when they replace the bedwood, choose to use a variety of clear finishes to bring out the beauty of the wood grain. When purchasing a clear finish for this purpose, be sure to get a finish that is UV resistant to reduce the potential damage from the sun. Most marine type varnishes will meet this criteria.

If you prefer to use your own boards, you need numbers and dimensions. From 1947 to early 1951, there were 9 boards making up the bed. From late 1951 to 1955 1st, there were 8 boards. The boards were nominally 1" thick (making them a measured 3/4" thick). The width of the boards varied depending on position. The tables below show the width of each board and its relative postion.

1947 to Early 1951 - 9 Boards
4 1/4"
5"
5 1/2"
5 1/2"
6 3/8"
5 1/2"
5 1/2"
5"
4 1/4"
Late 1951 to 1955 1st Series - 8 Boards
4 1/4"
7 1/4"
5"
7 1/4"
7 1/4"
5"
7 1/4"
4 1/4"

The individual boards were held down by steel strips (called "wear strips") which sat in grooves in each board. You will note from the drawing below that the outer edges of the wear strip came down lower than the middle of the wear strip. This explains the somewhat unusual groove pattern of the wood (see below for dimensions.)

Wear Strip

The two outside boards had grooves only on their inside edges. All of the other boards had grooves down both sides. The drawing below shows how the boards were grooved. The dimensions given are from members measuring old bedwood. If I was going to create my own board, I would purchase the wear strips first and use those measurements to adjust the dimensions below. The shallower the inside groove is, the higher the wear strips will ride above the bedwood. Orginally, the top protrusions of the wear strips were just slightly higher than the bedwood.

Board Dimensions
Dimensions
A. 3/4" (Board Thickness)
B. 1/4"
C. 1/4"
D. 1/2"
E. 1/8"

Why would GM go through so much trouble designing the bedwood? Eric Phillips sent me the following information that explains this...

"The reason for the unusual design is wood movement due to moisture content change. A six inch wide board can easily change width cross grain by 1/16" - 1/8" due to seasonal humidity changes. The groove design allows the boards to float without buckling while still being firmly held to the steel supports underneath.

"My GMC fleetside box has 12 boards across ranging from 5" to 7" in width, so the bed may change width by over an inch between dry winter storage and humid summer time conditions. For people who are making bedwood as I did, please note: different species of wood move different amounts in response to humidity (moisture content) changes. It is important to allow clearance between the hold down bolts and the wood so that movement can occur. If you're working dry wood in a heated shop (shrunk condition) more expansion room should be allowed than if you're working air dryed wood in the humid part of summer with no heat in the shop (expanded condition). Varnish or polyurethane does not prevent this natural wood movement but may slow it down some, so if you don't varnish or seal both the upper and lower surfaces of the boards, they will change moisture content faster on the unsealed surface causing cupping of the wood. Interestingly, the wood changes little along the grain (lengthwise) so it is not necessary to allow for much change in length.

"Bedwood is a project that anyone with a decent table saw can do, and it allows an infinite number of choices for wood material. I chose quarter sawn white oak because it is hard, naturally rot resistant, cup resistant (due to quarter sawn orientation) and its quite attractive. The draw backs are it's heavy and expensive. My 12-board bed cost $425.00 for S2S planed, kiln dried stock."

Eric A. St. Phillips
1959 GMC 100, long fleetside

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