What We Learned about Wood

by Anthony M. Rud

 

What We Learned about Wood

By Anthony M. Rud

Administration Building of the Forest Products Laboratory. The Organisation Occupies This and Nine other Buildings, All on the Campus of the University of Wisconsin at Madison

THE man from Madison, Wisconsin, felt a surcharge of hostility in the convention atmosphere when he rose to speak. All the eloquence, argumentative power and resource of the Baltimore delegation had been thrown in support of the three-nail policy. All the preceding speakers had declared themselves for a continuation of the same scheme for holding packing boxes together. Among the hundred-odd canners, box manufacturers and wholesale grocers, assembled in joint committee, perhaps a few might listen without prejudice. Most, however, would be thinking of the changes his proposal would necessitate in the nailing machines, and not of the advantages he portrayed.

Straightforwardly he quoted the findings of the Forest Products Laboratory, telling the delegates that boxes made to standard specifications would stand up in service far better if held with six nails to the edge than if nailed with only three.

Back came the quick question: "How many actual tests on these particular packing boxes have been performed by your laboratory?"

"Four hundred and twenty-six in total.”

The Baltimore canner smiled broadly.

“That sort of evidence scarcely should be admitted," he said. “My firm has been using these boxes for years; we have shipped upward of thirty million, and we know exactly the service a box will give.”

That seemed to clinch the matter. The convention adjourned, making no recommendation for a change in existing practice. The Forest Products expert had wasted his time, it seemed.

Several of the box manufacturers had said nothing in convention, however. Immediately afterward these men summoned the delegation from Baltimore and asked that one hundred Number Three can boxes, nailed in regular fashion, be shipped to Madison for comparative test. The Forest Products representative was notified that he should prepare for a buffeting tournament, in which the stamina of the respective containers would be demonstrated. He was delighted, for he knew just what his big compression-on-edge and hazard machines would do to boxes held by three nails to the edge.

Without a qualm as to the outcome of the tests the Baltimore men assented. It was not until some of the boxes were actually dropping and sliding round in the hazard machine that any of them evinced a desire to hedge.

The Results of the Test

Boxes Held by Three Nails to the Edge Proved Too weak. This No. 3 Can Shipping Case Stood Eleven Thumps Before its Contents Spilled. The Photograph Shows the Inside of the Big "Hazard Machine" Used for Box Testing

THE machine—which, with its smaller nephew in the laboratory, is unique—is a mechanism constructed to give a box, in ten minutes, all the hard knocks the container might normally receive on a freight or express trip of one thousand miles. It is a hexagonal wheel, revolving vertically. On the inside faces ridges of wood and metal project, with here and there a sharp point, made to do the same damage to a box that might be accomplished by the corner of another packing box. Each time the wheel revolves the box being tested drops six times, a meter keeping accurate count of the thumps. Each box of the same size put in gets identically the same treatment; so it is fair to all. In the tournament arranged by the Forest Products expert the three-nail boxes came off a decisive second best. A few turns of the wheel at low speed spilled their contents, the edge joints proving to be far too weak. The boxes held by six nails stood more than twice the racket; while the demonstrations of seven and nine nail containers were even more impressive.

At the conclusion of the tests even the Baltimore delegation expressed itself unanimously in favor not only of using six but of adopting seven nails for a box edge as common practice! The Forest Products expert was delegated the task of rewriting the specifications to be used henceforth. The service rendered to industry in this case is a fair example of the manner in which the Forest Products experts solve any container problems presented to them. When such a problem rises they either possess comprehensive data gleaned from the hundred of thousands of timber tests they have made or they are prepared to secure experimental data immediately.

Just after the United States entered the war the Ordnance Department decided to let contracts for $3,000,000 worth of containers for overseas shipping. The published specifications called for white pine boxes of definite sizes to be used for packing shell, powder, guns and other matériel. The notice urged that bids be submitted immediately, as there was pressing need for the boxes. Two weeks after the specifications had been sent out the Ordnance Department — in a condition of excitement closely approaching panic — summoned the aid of the Forest Products Laboratory. Not a single bid had been received!

In studying the situation and specifications it was found at the laboratory that two main factors kept the box manufacturers from submitting bids: First was the scarcity of white pine, and second was the fact that the box sizes mentioned were such as to require the sawing of new lumber for the work. The plan in use up to that time had been radically different; waste ends of lumber had been utilized for boxes by all the manufacturers. The Forest Products Laboratory rewrote the specifications, substituting a group of woods— hard maple, dogwood, holly, wahoo, yellow buckeye, witch-hazel, rhododendron, mountain laurel, haw, orange wood, torchwood, mastic, yellow cedar, Sitka cypress, red cedar and piñion— for white pine, though not outlawing the latter. Then it designed new boxes for the war matériel, making these of sizes that could be cut from waste lumber. When the new specifications were published the Ordnance Department received bids by return mail.

Real Money Savers

THROUGH the case of the white-pine boxes the work of the Forest Product Laboratory won increased respect from the Ordnance Department, and late in 1917 an agreement was reached whereby many of the container problems of this Department were submitted to the laboratory.

Immediately results began to show. The laboratory demonstrated the advantage of using cement-coated nails instead of wooden screws for rope-handle cleats on ammunition boxes. They tested and redesigned most of the boxes used by the department, strengthening and improving—in most cases without raising the cost of the individual container.

Some of the boxes were found to be space wasters. In redesigning one destined to carry 140 pounds of cannon powder, for example, fourteen per cent cargo space was saved. Cargo space just then was costing the Government six dollars a cubic foot.

A school for government packers was established, and more than three hundred men were trained in the construction and packing of overseas containers. One of the men so trained redesigned a box being used for overseas shipment while at the laboratory. His new design was snapped up; it saved $50,000 to the Government on the first contract alone, and more than $100.000 in freight in six months of use.

Other striking examples of how money was saved by redesigning boxes are many. In one case a container intended to hold thirty one-pound cans of saddle soap was refashioned with a saving of forty-three per cent. On the first shipment, 3,000,000 pounds, the Government is said to have saved $414,000.

Another crate to carry two Browning automatic machine rifles with their equipment was made over with a saving of twenty-eight per cent. This amounted to $5.37 in cargo space, which sum, added to forty cents saved on the lumber in each crate, put $5.77 in Uncle Sam’s pocket every time two of the guns went overseas—and for months the shipments exceeded 900 guns a day.

A full third of the total space necessary for packing United States army rifles, 1917 model, was reclaimed by the new box designed by Forest Products experts. This saved $1,500,000 each time a million Enfield-Springfields crossed the Atlantic.

Just as the laboratory solved the puzzles of the can shippers and the Ordnance Department it now stands ready to conquer the shipping-container problems for all private businesses that care to consult its experts. The points of nailing strength and space efficiency only hint at the many phases to the question. How many shippers know that the strength of their package is dependent directly upon the percentage of moisture in the wood at the time it is nailed? How many have taken into consideration the psychology of stevedores in building export boxes?

Saving Space on the Cars

BOTH of these points — the two showing how divergent are the investigations at the laboratory — matter immensely. If a box made of wet wood is nailed and then shipped to a hot arid country the wood shrinks. This leaves large spaces round the nails, and the box loses at least a quarter of its total strength.

On the docks at St.-Nazaire, France, a few months ago stevedores were unloading packages from the United States intended for our boys in France. When one of the workers found a package that looked as if its contents might suit him an accident occurred. He tripped over a pile of rope — or his own Number Twelves, if no better obstacle offered. The box he carried landed on end; and if it proved weak in construction — well, the supposed recipient of the consignment was in hard luck that day. This incident explained fully why many of our boys waited in vain for the presents mailed them by fond relatives over here, and also showed how much unexpected stress boxes have to stand at times.

In ordinary freight handling, employees are not so apt to allow this sort of accident. The precaution has to be observed, however, of making the boxes of the right size and weight to facilitate handling, not dumping. It is human nature to lift a small, relatively heavy package from car to platform. It is just as natural to allow a bulkier box to drop the three or four feet intervening.

For the express purpose of finding just the sort of fiber container that would give the best shock insulation, strength and the least liability to being thrown from the car to platform the Westinghouse and General Electric Companies recently smashed up $4000 worth of lamps in experiments at the Forest Products Laboratory. Containers that eliminated more than half the accidents and breakage were discovered by this means.

For the two months preceding the signing of the armistice— during which period overseas shipping containers designed by the Forest Products Laboratory had been used, in the main— the Government losses caused by breakage and box failures had been reduced to fifteen per cent of the amount suffered previously on shipments to France! A large percentage of this saving must be credited directly to the work of the laboratory.

What the work of these experts may mean to industry in the United States is indicated by estimates made by Dr. A. W. Bitting, secretary of the National Canners’ Association, and Col. D. W. Dunne, chief ordnance inspector of the Bureau of Explosives. According to figures given out by these men an average saving of thirty-five per cent can be made on all package shipping! This means that in times of stress on the railroads when car shortages loom, more than a third more packages can be carried in the space now given over to this branch of freight shipping! It means also an enormous saving for individual businesses that are willing to concede the Forest Products Laboratory the ability to assist them — in most cases without charge.

Colonel Dunne advances the suggestion that if Federal control of railways continues for a few months longer freight packages of efficient design may be introduced universally. The same purpose might be accomplished as easily through the instrumentality of the Interstate Commerce Commission, however. The reason for placing the responsibility upon either Government or the Interstate Commerce Commission lies in the fact that it would be business suicide for one railroad or group of roads to attempt to dictate to shippers — even to the manifest pecuniary advantage of the shippers themselves. The road or group of roads simply would find their business transferred to their less scrupulous competitors.

Though the results achieved in box designing are bound to save money for every United States business man who ships goods in any sort of container, this is only one phase of the Forest Products Laboratory’s usefulness. It was interested in doing things with boxes simply because boxes are made of wood, of paper or of fiber obtained from wood. Likewise the laboratory is interested in every other use for wood, its products or properties; work of research character is carried on constantly with the view of utilizing every last bit of value in the raw material and of eliminating the criminal wastes usual in the manufacture of wood products.

As an example of this may be cited one of the unsolved problems on which experts of the laboratory are now working. Stated tersely in the words of the director: “A ton of dry wood yields only nine hundred pounds of dry sulphite pulp for paper. The rest is lost in the waste sulphite liquor. Can't we do something with that other fifty-five per cent?”

Sooner or later the experts of the laboratory will do something. A means will be found either for increasing the pulp yield immensely or for utilizing the waste with profit in some other direction. In any event, success in this investigation will mean a big drop in the cost of newsprint paper.

Nine years ago the Forest Products Laboratory was established as one of the three branches of research of the United States Department of Agriculture’s Forest Service. It occupied one rather small building, was assigned an annual appropriation of only a few thousands of government money, and could have been overlooked rather easily amid the important and expensive bureaus of the Department.

On November 11, 1918, its organization had grown to consist of 450 persons. It had spread out to ten separate buildings and was receiving $700,000 a year appropriation for its experimental research work. In magnitude it ranked and now ranks with the greatest industrial research laboratories, whether Federal, private, domestic or foreign. Only Canada, of all other countries, possesses an institution similar in organization and purpose; this, though much smaller, is patterned after the Forest Products Laboratory.

At the start the laboratory began quietly to collect a mass of data on wood and its properties, about which little has been written in any publication. Hundreds of varieties of native woods were studied, and all points concerning which it was possible to imagine a future application were tabulated. This work was of immense importance. If the laboratory did not know the elementary properties of all the materials it is to handle each set of experiments conducted would suffer huge handicaps. In order to build an airplane propeller in the great emergency it would have been necessary to go back and begin with mahogany under the microscope, instead of merely looking to files for accurate data.

Practical Problems Solved

THE reason why little was said of these preliminary experiments was because intense practicality was demanded of the laboratory always, and though the experts know just why a complete file of information on Sitka spruce would be of assistance in building a speed scout airplane no definite problems had presented themselves for hundreds of the varieties of wood studied. With all this out of the way, however, the laboratory is ready to be judged by the most pragmatic tests the public wishes to apply. For several years it has been ready to talk turkey on any subject within the fields of lumbering, timber physics, timber mechanics, wood preservation, products derived from wood, wood pathology, and pulp and paper. Thousands of practical problems have been solved for private business and for the Government, and scores of original improvements in processes have been perfected and donated to the public. In this time of reconstruction the laboratory wishes to be remembered by business men as established to give any information relative to wood, its uses and products that it possesses, free of charge. In addition to this service it offers facilities for the solution of special problems that require experimentation. Where this experimentation is made on a problem having wide application no charge is made. If the work done benefits chiefly the particular business that brings up the problem an apportionment of the cost of experimentation is made, the laboratory standing part and the business firm the rest of the expense. Withal, the arrangements are much more generous than could be secured from any organization working for private gain.

When America found it necessary to build war airplanes the War Department called upon the Forest Products Laboratory for information relative to the strength and desirability of various woods for this work. From more than 300,000 tests made previously upon 130 possible varieties of wood the laboratory immediately furnished a table of strength values at fifteen per cent moisture. With this table went a comprehensive summary of the relation between strength and density in the different woods, the influence of defects, and the laboratory’s recommendations in regard to the relative suitability of Sitka spruce, Douglas fir, Michigan birch and many others. Spruce was shown to be the best material for airplanes.

Immediately a howl of protest rose from certain lobbyists in Washington. One individual had gone to the capital to tell everyone the virtues of Western yellow pine. Another expected to convince the powers that were that birch from Michigan was the ideal airplane wood. It developed, however, that the production of both the yellow pine and the birch was to be shut down by the Government as nonessential, and that the agents at the capital simply were attempting to develop the first government market that offered. Since wood for airplanes was needed they tried to sell the Government yellow pine and birch for that purpose. Needless to state, the report of the Forest Products Laboratory was accepted and used by the Spruce Production Division immediately.

Now that the ban of war secrecy has been lifted partially it is permissible to tell what followed. It was found right away that there was practically no seasoned spruce stock in the United States suitable for airplane manufacture! To air-dry green spruce stock three inches thick, such as is necessary for airplanes, requires one to two years. Obviously this process was far too slow. Owners of lumber kilns all over the country therefore wrote in, recommending this or that process for getting the lumber out in a hurry.

Several of these kiln methods were tried out, and many of them proved sad failures. When baked — as the wood was sometimes treated — it checked, collapsed, honeycombed, exploded or casehardened so badly that it could not have been used for building a picket fence, let alone putting it into struts, wings, ribs, engine bearers and other points of stress on an airplane.

The Forest Products Laboratory recommended a method of water-spray kiln-drying developed by one of its experts. This method gave perfect stock in ten to twenty days’ drying, and because it dried the spruce sticks from the inside outward no honeycombing, casehardening, checking or collapse was present. Kilns were designed for the Army and Navy, and men furnished to operate them until other operators were trained. Thus seasoned stock, equal — and in some respects superior — to the air-dried spruce, was assured in whatever quantity became necessary.

A great amount of slightly defective wood is found in every consignment of spruce lumber. Ordinarily this could not be used for airplane manufacture, but in the war exigency the Government was anxious to utilize every resource. The Forest Products Laboratory therefore prepared a catalogue of spruce-timber defects, showing what lumber should be rejected entirely, what could be used if necessary in lightly stressed parts of the airplane, and recommending strongly that none but the finest stock be used in places that were called upon to bear the shocks and strain of flying. This report, however, nearly doubled what had been considered the available supply of spruce.

Aluminum Waterproofing

THE problem of propeller manufacture also went to the laboratory. At the time the United States declared war British, French and Italian plane makers were still struggling to manufacture a satisfactory propeller. In order to obtain one that would give real service it was known to be necessary to use only mahogany or walnut. Blades made of any other wood rapidly lost or absorbed so much moisture —unevenly— that they lost balance and flew to pieces when whirled by a powerful motor. Even with the expensive propellers made from walnut or mahogany sixty per cent were dead loss either from the cause of lost balance or because humidity conditions affected the glue with which the parts were held together.

After hundreds of quick tests with spar varnishes, so-called "waterproof" paints and shellacs and other liquid coverings the Forest Products Laboratory invented the aluminum-leaf spirit varnish method for proofing propellers against moisture and the resultant evil of lost balance, changed pitch of blades and warping.

The method consisted of smoothing the surface of the propeller until it shone like a mirror: this meant a coat of silex varnish filler, followed by an orange gum shellac coating for open-grain woods. Then came a coat of size, which was allowed to dry slightly before the aluminum leaf was applied. The latter process was done by hand, the leaf being slipped rapidly from a book held in the hand of the operator, and smoothed down by a dab of cotton. After the propeller was covered completely a coat of colored varnish finished the job.

When treated in this manner propellers could be immersed in water or subjected to long stays in a hot arid region without gaining or losing enough of their moisture content to make a particle of difference. Less than one-tenth as much variation could be observed after a month’s trial under the worst conditions as was shown by propellers treated with many coats of the finest procurable varnishes.

Immediately upon securing this process the United States started to make arrangements for manufacturing aluminum-leaf propellers. The end of the war came before many machines in France were using them but it was shown definitely that instead of facing a sixty per-cent loss on propellers the loss need not exceed two or three per cent. It also was discovered that possibly several of the cheaper woods would make just as good propellers as walnut or mahogany if covered with the aluminum leaf. This, with the saving made in spoiled propellers, meant a decided decrease in the cost of each completed airplane.

As it is a matter of great importance we shall mention here that the Forest Products experts, knowing manufacturers would wish a chance to use the process, have dedicated it to the public and have prepared a set of instructions whereby any maker of waterproofed-wood articles can learn, free of charge, the whole method.

In one way most wood is stronger than steel, weight for weight considered. The proof of this statement is easy. Take a bar of steel just strong enough to support one hundred pounds without breaking. Then secure a piece of oak, hickory, spruce, pine or another of the fairly dense wood of the same length and weight. Fasten the wood in such manner that the grain runs in the same direction the pull is applied, and instead of one hundred pounds the wood will be found to be capable of sustaining ten to two hundred per cent more of a load. In this quality lies the chief reason why wood always has been the best airplane-building material.

When weight is applied sidewise to the grain — that is, so the tension tends to pull the grain apart — no such strength is found, however. Right there is the joker in the pack. Wood is very strong in one direction and relatively weak in another. In spite of the most careful airplane designing it is next to impossible to keep some of the parts from bearing double stresses, one of which is exerted against the weak side of the wood. This necessitates great additions in weight for certain parts in order to provide a margin of safety in strength.

Another fault of all wood used in airplane manufacture lies in the fact that across the grain it shrinks badly, while along the grain this phenomenon scarcely is apparent. No treatment yet discovered has been able to eradicate this condition on a plain bar or stick of wood.

These were the reasons for plywood. Plywood simply is ordinary wood of any variety cut thin into veneer sheets, and then glued back together again in such fashion that the grains of the two sheets cross each other at right angles. In actual use the plies may be of any number. Seventeen plies to an inch of thickness has become a standard for certain parts of airplane construction. When multiple ply is used often a light softwood is taken for the ‘‘heart,” and the layers of veneer are built up on this, each additional layer being laid crosswise the preceding. The resultant material has satisfactory strength in all directions. It cannot shrink much in either direction because this tendency in the cross-grain pieces is prohibited by the non-shrinking sheets glued on each side. It has a high resistance to splitting, and it is worked with the greatest ease. Taken with the fact that its strength is equal in all directions — unless the maker of the plywood desires otherwise — it is the finest material yet devised for use in certain parts of airplanes.

A Question of Glue

IN preparing standard specifications on plywood for this purpose the laboratory faced another stiff problem. Whatever plywood had been made prior to 1917 had been glued with vegetable or cheap hide glue, neither of which was waterproof. When immersed in water this material simply came apart, the glue dissolving in water and losing all its adhesive properties.

Cloud flying necessitates staying for long periods of time in an atmosphere often approaching one-hundred-per-cent humidity. It is obvious that plywood that tended to disintegrate under moist conditions would be murderous to the aviators who depended upon it. The one answer lay in finding a waterproof glue.

Questioning manufacturers revealed the astonishing fact that only four or five concerns were making glue of any kind that laid claim to waterproof qualities. Samples were secured, however, and tests started. By this time —late in 1917— it had been decided to build the DeHaviland 4 in the United States, and the Signal Corps, alloting a small sum of money to the Forest Products Laboratory, became insistent upon securing a waterproof glue in short order.

Pending the results of further tests the laboratory recommended the use of the best of the submitted samples. This had the immediate effect of skyrocketing the price of this material. The company felt that it had secured a monopoly of the sale of plywood glue, and meant to profit by the situation.

This adhesive was made from the albumen in the blood of animals, and after a short series of experiments the laboratory discovered a means for making a similar glue, fully equal to that being purchased by the Government. As the supply of blood albumen was short, though, prices would be dependent upon a control of the raw material. The laboratory answered this by developing a casein glue which, though not quite equaling the resistant quality of blood albumen, still made a satisfactory substitute. The general situation therefore was relieved, and the price of plywood reduced steadily.

Successful Use of Plywood

THE most severe tests were made on the new glues. Pieces of plywood were boiled for eight hours and then subjected to the “shear test." This consisted in having a powerful machine exert a mounting force until the point of giving was reached somewhere in the plywood. As the force exerted tended to shear one ply from another weak or defective glues invariably gave way. Even when boiled or when soaked in cold water for ten days the new blood or casein glue retained ninety-odd per cent of its original strength; usually the wood itself proved weaker than the glue which held the piece together, and a tearing of the wood fibers would occur while the glue still held. In many cases the plywood panels used on airplanes possessed a shear strength exceeding 600 pounds to the square inch.

Plywood made with glue unaffected by moisture became so interesting to experts of the laboratory that they conceived the notion of trying it out as a substitute for linen on the wings of airplanes. This necessitated the development of a new process of gluing, as before it had not been possible to glue together sheets of plywood of one-hundredth of an inch thickness.

The new process consisted in coating tissue paper sheets with blood glue, allowing this to dry, and then applying the thin veneer sheets to each side of the coated tissue with heat and pressure. Though not offering much advantage, weight for weight, over linen the material made in this fashion would not rip when perforated by bullets, and gave more efficiency in lifting power because it did not flap back and forth on the ribs like linen. Whether or not this material will find widespread use in the manufacture of airplane wings still is problematical.

The practical results achieved in developing the plywood made with the new waterproof glues consisted of more than $6,000,000 directly saved to the Government through reduced costs of plywood, and countless numbers of airplane accidents prevented — which last item cannot be measured in money.

For us to-day the work in this field possesses added interest because of the many peacetime uses for plywood — particularly waterproof plywood. Space forbids description of many of these but mention can be made of the fact that door-panel manufacturers are now experimenting with the new material with a view to producing doors that will not warp or crack under varying conditions of humudity. One expert formerly at the laboratory suggested a field for manufacture in which he thought a fortune might be made by some enterprising individual. He professed to believe that the thin plywood, of the type tried out on airplane wings, would make a wall covering of great beauty and durability. He vouches for the fact that this material, which in appearance equals the finest veneer panels, can be made at a cost less than the old-style wood panels or even than the better cloths now used on walls.

Several years ago a well-known American building contractor was viewing the Great Pyramid of Egypt. The guide, calling attention to one wonder after another, pointed out the vast size of the stone blocks of which the pyramid was built.

"Each stone you see," he said impressively, “represents the labor of six slaves for three months, hewing and finishing the block. And the labor of many men was necessary to raise the block into position. In all more than 4000 slaves worked on the pyramid daily."

“And how long did it take Cheops’ slaves to complete the whole thing?” asked the contractor, squinting up at the broken apex.

“It is not known exactly, sir. Probably thirty years or more.”

The contractor snorted. “Well,” he replied, “give me plain American bricks and 4000 plain American bricklayers and I'd have done it for you in six months!”

Though his view in no wise detracts fron the wonder of Cheops' tomb the contractor made a distinct point. The vast pile could have been built with a great saving of labor and expense had small bricks been used instead of 400-cubic-foot stone blocks.

The same principle holds good to-day in the main; we may cite some of the work of the Forest Products Laboratory as an example.

Bowling pins, from the inception of the ancient game in this country, have been turned from single wooden blocks. This has seemed necessary, because a pin has a life full of hard knocks; balls hurled at approximately the speed of the cannon balls used by Tilly and Wallenstein against Gustavus Adolphus knock them spinning against the wall, frame in and frame out each evening in the season. A weak pin soon becomes a casualty. Because of the fact that they have to be made from solid perfect blocks they are rather costly. Much Waste occurs in securing the original blocks.

The Forest Products Laboratory, mainly because of the new glues it has invented — many of which, as stated previously, are actually stronger than the wood upon which they are used — has perfected laminated bowling pins. These pins, formed of three standardd parts, are glued together so perfectly that they stand every bit of the racket possible to their single-block rivals. They can be made out of much smaller sticks of wood, and waste is cut down forty to fifty per cent. This means a substantial saving for the manufacturer.

Laminated Gunstocks

MUCH of the same situation existed at the beginning of the war in respect to walnut stocks for our army rifles. Because these wooden parts had the function of holding the rifle barrel rigid inspite of the continued stress of firing, specifications called for making them from a single piece of fine walnut. The Forest Products experts working under the presence of an alarming scarcity of walnut and all other woods possible for this use made laminated stocks from several pieces. This daring attempt was rewarded by finding the laminated results fully as good in every way as the single-stick product. On the laboratory's recommendation the Government is now trying out these stocks with a possibility thereby of saving a considerable amount on each gun, and protecting our soldiers from a possible future famine in gunstocks.

It would require considerable space to detail all the activities in this direction of the Forest Products Laboratory. Just in passing it might be well, however, to note that so great have been the steps forward in laminated material made by these experts that the were able to develop new built-up I-beams of spruce for use in airplanes. These beams, made in three pieces instead of one, as previously, stood up perfectly under the stresses of flying, and they cost much less.

When this much can be done satisfactorily the laboratory experts feel that they are in a position to be of great assistance to manufacturers of all varieties of wood-turned articles. Many of these, which tradition says must be made of a single piece, no matter what they wastage incurred may amount to, now can be laminated. The laboratory experts stand ready to help all who wish advice in this direction.

The war activity of the Forest Products Laboratory now is practically at an end. This article has attempted to furnish a few hints of the manner in which the organization can and desires to make itself useful and valuable to business and industry in the United States during the next years of reconstruction. Whatever points may be left in doubt will gladly be cleared up for those interested by the director of the laboratory.