[ TOC | RetailSource ]
Knives are used on two basic pieces of equipment -- a lathe and a slicer. The lathe is the basic equipment in the commercial veneer field. It functions in the same manner as the cabinet maker's lathe. The long knife is stationary and the log, fastened in the center at each end to spindles, is revolved against it. This method of manufacture most resembles the un-rolling of paper from a large roll. Production is high speed and relatively inexpensive. Thickness of the veneer varies with the end use, with face material being cut relatively thin. Since our stock plywood panel size is four feet by eight feet, lathe equipment is sized accordingly, usually being designed to produce an eight foot long piece of veneer.
The slicer also has a stationary knife, but the log requires processing prior to being brought to the knife. A log is generally split in two or more pieces in the sawmill. Each individual piece or cant is then trimmed and cleaned. The cant is then fastened to a large steel table, which moves up and down in a straight plane, and is passed across the stationary knife at an angle. As each slice of veneer is removed from the cant, the knife moves forward the same distance as the thickness of veneer removed. This is repeated until the entire cant is converted to veneer.
In both the foregoing methods, the log or cant is often put into a steam chest or a hot water vat to bring the wood to a proper consistency for processing. The amount of steaming or cooking varies with the species, and some require none at all. After the manufacturing process, the veneer is run through a dryer which removes all excess moisture under carefully controlled conditions. It is then crated and stored for shipment.
Since the slicer is the basic piece of equipment in the fancy veneer industry, a bit more about its use and results is appropriate. As the veneer is removed from the cant, it is kept in the same sequence, and the cant is literally re-built in veneer form. This is important for its future use. Also, the reverse side of one piece of veneer will be the mirror image of the face side of the next piece. The grain changes from one piece to the next will be gradual as the grain of the log changes. This too is important for future use.
Since much of this veneer is used in furniture manufacture, no attempt is made to produce it in standard sizes. It is all based on the maximum sizes a given log will yield. Standard slicer (knife) lengths in this country are 10', 12', and 17', thus the maximum length veneer which can be produced is about 17 feet. In other parts of the world a four meter (about 13') slicer is most common. Thickness also varies a good bit. Depending upon the wood species involved, the thickness in the U.S. can be 1/28", 1/32", or 1/36". for special uses, a small quantity of 1/85" is produced. In Europe, the thickness is a bit thinner, with 1/40" and 1/48" being more common. In the Far East, 1/85" is quite common. I cite this only to show that the oft specified thickness of 1/20" or 1/28" in a face veneer specification is rarely available any longer.
Some of the terminology used should perhaps be defined at this point also. The sliced up cant is called a flitch, and a single piece of veneer in this parlance, is called a leaf.
At some stage of manufacture, after the slicing, sample leaves are selected from each flitch to represent it for color, grain, texture, quality, and physical size. These sample leaves are the same size and thickness as those left in the flitch. Normally, these are selected at various points as one runs through the flitch, the actual number varying with the size and grain differences in each individual flitch. It is important to remember that all fancy face veneer in this country is bought and sold on the basis of these samples, and that they are available for perusal. When the more expensive exotic woods are in question, some manufacturers will allow the inspection of the entire flitch.
Measurement of a fancy face flitch is based on total surface area in the stock regardless of thickness. In theory, the width of each leaf is multiplied by its length, and these products are totaled for all the leaves in the flitch. This is expressed in terms of square feet.
The numbering on a set of flitch samples contains much of the above information. First, a serial or flitch number has been assigned the cant in the sawmill. This number follows it through the production process and is put on the sample leaves also (as well as the crates in storage). There is also a hyphenated number such as 1-3. This means that there are three samples to represent this flitch and this is the number one. By viewing all three in proper sequence, one has a representation of the variation of grain pattern, etc., within the one flitch. Lastly, on one of the samples is generally included the quantity expressed in square feet.
The basic manufacturing procedures are the same regardless of species or country of origin. Different types of grain patterns are produced by varying techniques, and these shall be covered next.
[ Previous Page | Next Page | TOC ]
This article is brought to you by RetailSource
Comments, Questions, or Feedback? Contact
RetailSource or e-mail: retailinfo@RetailSource.com
Created by Good Northwest Corporation
Last Updated: Friday, April 5, 1996
Copyright © 1996 RetailSource - All Rights Reserved