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The Splicing of the Paper and Cloth Belts is an Important Detail Which Should Be Thoroughly Understood by Operator---Suggestions on the Process By W. S. McCONNELL
N A BELT sanding machine a joint in the belt is a factor of no little importance. There are several patent dies available for cutting the belts for jointing, but it cannot be said that any of these are popular with experienced sanding machine operators. The points to be desired on a joint are as follows:
First of all it is essential that the joint will not break or become loose, or tear out. Secondly, the joint must be so made that the belt can be run in either direction and must be as thin and flexible as possible. Having given this subject a great deal of attention, I have found that a butt joint, reinforced with cloth, produces very satisfactory results.
It is optional whether this joint be square or on an angle, but I believe I am safe in saying that a joint cut on an angle is the most popular for belts up to eight inches in width. For reinforcement, a cloth having the same thickness and texture as that used in making flour bags, is preferable, while for wider belts, a cloth similar to that used in making overalls is satisfactory. course, the starch should be washed out of the cloth before it is used.
For a joint on a belt six or eight inches wide, the width of the cloth should be about three inches. First of all cut the paper to the right length and then bring the two ends together, tacking them down on a board, grain side down. Then apply the glue to the paper, having the cloth about three inches longer than the width of the paper. Place this cloth over the glue and then take two pieces of veneer, three inches long and two inches wide, and with these scrape all the surplus glue out of the joint, being careful to remove all wrinkles. This scraping forces the glue into the paper and through the cloth, producing the flexible joint so much desired. The selection of cloth for making the belt joints, and the scraping of the surplus glue out of the joints, are two points far more important than the average sanding machine operator is willing to concede. After the wrinkles and the surplus glue have been removed, place a piece of newspaper over the cloth, and then lay a board on top before putting between clamps to dry. When thoroughly dry the edges of the joints should be trimmed. A good method is to make enough belts on Saturday to last through the following week, and after being made they should be hung up on pegs ready for use. In no case should they be rolled up in small rolls, for it is almost impossible to roll a sanding belt without cracking and weakening it, which shortens its life considerably. Any good hide glue will answer for making joints, providing it is of the necessary consistency.
After a new belt has been run for a few hours, it should be removed, turned around and then run in the opposite direction. This will add to its life as well as
its cutting qualities and is a practice followed by all experienced operators.
On belts that are 15 or 18 inches wide, or even wider,
and which are used on what is called the table type of belt-sander, the joints are often cut as shown in the accompanying drawing, or a modification of same. Where this style of joint is used, it is necessary to make a templet to cut by; outside of this its construction is the same as that of the joints described, and there are numbers of operators who claim wonderful results from this type of joint.
Joints on Cloth Belts
The joints made on cloth belts in the wood-working trade, are commonly known as lapped joints. These are made by removing the grain from one end of the belt and applying the glue, while the other end is brought up and clamped down on the glued edge. The grain is removed by moistening and scraping.
If left to dry by itself, the cloth will wrinkle, and this can be overcome by having a flat piece of iron heated and used to lay on where the grain has been removed, using this iron in the same manner as you would a flatiron. If trouble is experienced by a joint drawing during the drying process, this can be overcome by placing a strip of wire fly-screen on the cloth side of the joint when putting it in the clamps to dry. This wire screen will come off easily when the joint is removed from the clamps. The same joint as used on paper belts may also be used on the cloth belts. Users of the cloth belts in the wood-working trade generally buy their cloth in 14-inch rolls, using this for belts 14 inches wide and then tearing various widths to meet their requirements.
Fifty Million Feet of Walnut
WING to the fact that a good deal of interest has been excited in the minds of furniture manufacturers in connection with the prospective increased use of American or black walnut, the question has been raised as to the extent of the production of this wood. The only reason it has not been used generally of late years is the supposed scarcity of the wood. In this connection a leading producer said recently:
"The estimated annual production of walnut in America is fifty million feet. This is enough to keep a lot of factories going on this wood, especially when it is remembered that a lot of walnut veneers are produced. The figure quoted is board feet. The German and British factories which have been using walnut for many years have never found any scarcity of the wood, and have been able to get all they need. They have found in it an excellent material, and have shown American manufacturers that they made a mistake in dropping it. I am hopeful, however, that it will not be long before this error is corrected, and a substantial part of the production of walnut used here at home, where at present it is least appreciated. It is another case of the prophet not being without honor save in his own country, for foreign lands have always shown great appreciation of the wonderful qualities of this superb wood."
ANY new business idea that offers to help a man get more profit out of his business is hailed with welcome— mixed with suspicion of the motives of the man offering it.
The Importance of Keeping Bearings and Saws in Perfect Repair---Interruption or Slow and Difficult Operation Where Work Starts Affects Results By ALEXANDER T. DEINZER
WRITER recently stated that the break-out department in the furniture factory is the backbone of the business. This is very true, indeed. However, in order to do good work and to hold this department up to 100 per cent. efficiency, attention must be directed to the selection of proper tools, their care, etc. The progressive manufacturer will buy the very best and most efficient planer, swing-saw, double cut-off, band and circular rip machines, jointers, etc., but it requires common sense, combined with years of practical experience, to operate them.
clamp on the cap, slip the end collars up, putty them properly, and build up a funnel of putty around the oilhole, through which the metal is to be poured, so as to get sufficient weight of the metal to drive it into the bearing and pour in the metal, which will carry down through the channels in the liners and fill the bottom of the boxes as well as the top. When the metal has cooled we remove the top box by means of a cold chisel. If your men are babbitting the old way, have them try this and they will be pleasantly surprised. Of course, we do not claim that this method is original, but there are hundreds of factories doing this work in double the time necessary. Experts have proven that the right temperature at which to pour babbitt metal is 460 degrees C, and the best temperature at which to have the shell into which the babbitt is poured, from 100 to 150 C. It is important that good babbitt metal be selected. It may also be well to state that the babbitt which may prove successful in a heavy, slow-running box, would not be advantageous to use in a high-speed bearing.
ALEXANDER T. DEINZER
Hot boxes are by no means uncommon. Why have hot boxes? Bearings won't run hot without some good reason. One common fault is the use of a poor lubricant. There are buyers today in the furniture factories who know very little about lubricants, so to speak. They say oil is oil, and the man with the lowest priced grade, regardless of gravity, gets the business. We may at some time take up the question of lubrication; space will not permit our doing so in this article. The next cause for hot boxes is bearings which are too tight. The babbitt may require scraping, or the caps may be set down too tightly. The oil holes may be clogged, or the mantle may be crooked. If you employ a millwright who cannot correct hot box troubles, by all means discharge him and engage a man who can. If your plant is too small to afford a first-class millwright, have one of your expert machine men do this work. The trouble with most factories is that the foreman is supposed to do all of this work. Do not impose these duties upon your machine room foreman. If your foreman is an idle man, he is certainly neglecting his duties.
A mistaken idea of many millwrights is to pour hot metal on a journal. This very thing may spring your journal and we all know that a journal once sprung can never be the same as new. Some of the progressive machinery manufacturers furnish mandrels with their machines. Too often, however, these mandrels are placed in some corner where they will not easily be found. It is a simple matter, though, to have a mandrel turned. It is imperative, however, that it be absolutely the same size as the journal.
Pouring the Boxes
I have, in times past, read with interest articles contributed by millmen, discussing the advantages and disadvantages of pouring top and bottom boxes at one pouring. We, at one time, employed a superintendent who could not be convinced that it is a saving of time to pour both boxes at the same time. Experiments have proven otherwise and we are not only saving time, but believe our men are doing better work. We cut the box liners so they will fit out snugly to the shaft the full length of the bearing on both sides. We then cut small V's in one edge, all of them next to the shaft, through which the metal can flow to the bottom of the bearing. We next
If the best results are to be obtained in your break-out department, Mr. Furniture Manufacturer, Superintendent, or Foreman, you must insist that the saws be kept in proper shape. This is especially necessary in running thin saws, for while a thick or standard gauge saw will give very fair results where only medium skill in the management of saw and mill is used, a thin saw would fall far short of giving fair results under the same methods and management. A thin saw cannot reasonably be expected to stand as much crowding as a thick one and requires more skill and better appliances to give good results.
The Swing Cut-Off Saw
In the February number of THE FURNITURE MANUFAC TURER AND ARTISAN we discussed modern methods of handling and drying lumber. The first machine to which this lumber is delivered in the break-out department is usually the swing circular saw. There are many men who do not know how to "fit" saws. These men seem to have considerable trouble with saws and many an innocent saw manufacturer is compelled to suffer owing to the ignorance of these would-be saw fitters and filers. We also find operators on swing saws who put off the re-setting and sharpening of their saws just as long as they can force a cut of any kind. When gumming, it is best to gum around the saw several times instead of finishing each tooth at one operation, for by going over the teeth several times, they are less liable to case-harden or blue, and a more uniform gullet is obtained. After gumming, it is advisable to file all around the saw, taking care to remove the fash or burr left on the edges and all glazed or hard spots. Gumming and sharpening with the emery wheel will cause the saw to "let down" or lose its tension much quicker than by the use of file or burrgummer, as it heats and expands the rim of saw, putting
it in the shape generally termed by mill men "buckled," which makes it appear loose and limber and causes it to run "snakey," in the cut. Many saws are condemned just from this cause, and thrown aside as worn out, when by proper work and hammering they can be made as good as new saws of the same size. In sharpening, a saving in time and files is effected by taking a good, deep, full cut, instead of a light, scraping one. A tooth becomes dull on its face in proportion to the depth of cut taken at each revolution of the saw. For instance, when each tooth cuts a thirty-second of an inch, it takes thirty-two teeth to cut one inch, whereas, when each tooth cuts one-sixteenth of an inch, it takes only sixteen teeth to cut the same amount. In other words, the fiber or grain of the lumber has to be broken thirty-two times in one instance, and only sixteen times in the other; when the tooth starts to break the fiber one-sixteenth of an inch in the board it will do so with nearly as much ease and will consume very little more power than if the cut was a thirty-second of an inch per tooth. I simply state this to show the advantages of proper sharpening.
Concerning Saw Filing
"Peg" teeth are used on many double cut-off saws, miter saws, and saws used for ripping veneered stock. When filing these saws, to carefully gum out the gullet do not permit the corner of the file to touch the saw. Experienced operators will tell you that saws filed in this way will cut easier, last longer and do not crack. When selecting your band re-saw blades be certain to have them made so as to have as many teeth cutting as possible, but the teeth must not be placed too close together or the dust produced will be very fine and have a tendency to plaster
on the sides of the board and cause friction on the blade. The coarser the sawdust can be made the better the teeth will drag it out of the cut. We, of course, know that teeth can be much closer together for soft-grained woods than for hard, close-grained woods, because in the soft woods the dust breaks out in large particles, while in closegrained woods it breaks out in the form of a very fine powder. Sufficient room should always be provided in the gullet of the tooth to "chamber" the dust properly. The life of a band saw depends very largely on the way it is handled, particularly when it is new and before it has been perfectly adapted to the wheels on which it is run. Many men expect a new saw to do more work than one that has been perfectly adapted and adjusted to the wheels and alignment of the machine. There is a certain quality about a new band saw which can be best described by calling "surplus" elasticity and until this quality is brought down to its proper bearing by the judicious use of the hammer and saw stretcher, in connection with the first "runs" of the saw, it will not be at its best. The blade should, under all conditions, maintain a practically fixed position on the saw wheels. The teeth should project over the front edge of the wheel and the saw should maintain this position without any support whatever on the back edge of the blade. In other words, the saw blade should stay in place without a back-thrust wheel or any other mechanical device for holding it in position. This result may be attained entirely by means of “tension.” Of course, all experienced filers and operators know, or should know, that too much tension, excessive speed, uneven tension, case hardening, or glazing from the emery wheel, gum adhering to face of wheels, crystallization from too heavy hammering, cuts on the surface of saw from sharp-faced hammers, vibration of either machine or saw, sharp angles in the gullets, imperfectly adjusted guides, backs of saws too long or too short and excessively cross aligned to make them "track," insufficient throat room and hook, crowding the saws against the guard wheel, will cause it to crack. Of course, pages could be
written on the subject of saw fitting; however, we must not also discuss other problems in this article. Saw manufacturers will at all times be glad to solve your problems.
A New and Interesting Process
T WOULD seem that wide possibilities have been opened up through a process for simultaneously bleaching and extracting the coloring matter from woods, which has recently been perfected and placed upon the market. The editors of Hardwood Record have seen samples of wood treated with this preparation, which is a patented article, and in some cases the results have been really astonishing. For instance, a specimen of mahogany was shown which had been bleached out by this process and it is difficult to imagine a more beautiful wood surface than the white, satiny piece which resulted. It would also be difficult to imagine anything more peculiarly adapted to piano work for the gorgeous drawing-room or music-room than this unusual class of wood. In fact, negotiations have actually been completed with several piano concerns which will result in their placing at least a limited number of their pianos on the market finished in this way. The process has also been used in connection with bird's-eye maple, entirely eliminating the objectionable yellowish stain which results from the ageing of this wood. It is used on red maple to make it white, on red birch to make it white and on other woods, such as basswood and similar species, which go into kitchen utensils.
The possibilities are too broad to enumerate. The idea of the process is to render different colored picces of an equal color or to make colored wood absolutely white, as after the wood has attained the desired grade of whiteness any finish can be applied and the wood can be oiled, stained, shellacked or varnished in the usual way without danger of future change in its color. This is a great advantage over the old method of whitening wood with oxalic acid.
One process for which it is particularly recommended by the makers, Francke, Phillipson & Co., of Chicago, is in the whitening of hardwood floors after they have been laid. This will make the selection of flooring material a much easier proposition, as uniformity of color when laid will not be entirely essential.-Hardwood Record.
COMMON practice in the construction of factory and mill buildings is that of installing "skeleton stairs," and, in the interests of the safety movement, this is a practice which should be discouraged.
These skeleton stairs are built with treads only and without risers. The open spaces between the steps make it only too easy for some one going up the stairs accidentally to drop something and kick it through the open space to fall on the head of whoever happens to be coming up below them.
Another bad feature of this type of stairs is that it is impossible to sweep them down without the dust and dirt falling through on those who are using the stairs below.
While this feature may not be considered exactly and directly unsafe, it certainly is unsafe in that it is insanitary besides being a nuisance.
In one factory a start has been made toward remedying this evil by nailing a vertical board or riser below the first step at each floor and at each landing. It is at these places that there is the most danger of things getting started for a drop onto some unsuspecting head below. It is the intention to complete the good work and make tight stairs all the way.-W. F. H. in The Factory.
High Speed Knives Impose Responsibilities Which Should Be Complied With---The Grinding of Knives No Simple Process to Be Carelessly Done
By ALEXANDER T. DEINZER
RUCIBLE steel knives are becoming very popular in wood-working plants. More good knives are ruined by poor grinding in the hands of the consumer than in all other ways. If you heat the knife at all in grinding, the temper is changed and the knife often seriously damaged. When grinding with a water stone wheel, see that the wheel is plentifully supplied with water. When grinding with an oilstone wheel plenty of oil should be used. Do not hurry the work; if you do, you may blue or burn the steel, even though water or oil be used. If you are careful to grind slowly, so as to never heat your knives, you will find that they will hold the edge and last, for the temper will be unchanged, remaining just as left when leaving the knife manufacturer's factory.
The temper of a knife is the principle part of the same. We must assume that anybody who uses knives knows that the bevel must be ground in a certain way as far as the dimension of the bevel is concerned, but in relation to the matter of temper this in a certain way is a hidden subject, and ideas differ thereon. So, instead of going into a long discussion of grinding crucible steel knives, or heavy planer knives, molding knives, I simply state the few facts above, hoping the reader may retain this information, and knowing that if he does, as far as the temper is concerned, he will not alter the temper in the grinding.
A Study of Knives
As regards high speed steel knives, would say that these knives are made from an alloy steel. The steel is very difficult to handle. All the steel manufacturers in this country, and those in Europe, from whom this steel is purchased, acknowledge that they have not been able to maufacture this steel with entire uniformity. It is the writer's understanding that none of them will guarantee the steel. They simply state that it is free from visible defects before using. Then, if you use the steel and trouble occurs, it must be assumed that the steel has been damaged by the user. If you find any flaws in the steel prior to its use, then you can recover from the steel manufacturer. The manager of a knife factory only a few days ago told the writer that this is the position they assume themselves in making high speed steel knives. The question may now be asked by the reader: "How would you grind high speed steel knives?" and I suggest the following:
Exercise great care in the grinding. Never use water on the wheel. Use a soft wheel, which wears away rapidly and grind the knives slowly, so as not to heat them. This is just as essential, and even more so, than the suggestions regarding the grinding of crucible steel knives, since a much larger percentage of high speed steel knives is ruined by the grinders.
The grinding of a knife is a matter which requires unusual skill and long experience, and yet, at first thought, one would not think that this is the case. It is difficult to go into the furniture factory and tell the man who has been grinding knives for years that his methods are wrong, since if you come out with such a blunt statement as this not infrequently, and in fact usually, we have offended this man. It requires as much diplomacy
for the manager or superintendent to handle these men as to be Secretary of State at Washington and keep things running smoothly.
I know of traveling men who often go into factories and grind knives, not only of their manufacture, but knives made by other knife makers, in order to show the grinders and superintendents just how this work should be done. There is no question but that there are a good many manufacturers of knives who make good material. Some make better than others; but I would say there are quite a number of manufacturers whose goods are uniformly first-class. They reach the hands of the grinder in a factory and he ruins the knives.
Some time ago a man applied for a position at our plant. He represented himself as an expert. Of course, he knew all about grinding. The superintendent told him to grind planer knives. I chanced to catch this man at his work and what was my surprise to find that he ground a bevel of approximately 25 degrees. The knives were, through an oversight on part of the millwright, placed on the planer and ruined. Unfortunately, there are but few men who thoroughly understand the various classes of knives and the methods used in grinding them.
There are a number of different machines manufactured for knife grinding. Some are equipped with cup wheels from four to twenty-four inches in diameter which grind with a straight bevel. Other machines carry straight wheels up to thirty-six inches in diameter and from one inch and a half to four-inch face-these grind with a slight concave bevel, the concave increasing as the wheel wears, which is not at all objectionable. On some the position of the wheel is stationary and the knives move on the carriage; on others, the knives are stationary and the wheel moves, but in both cases the result is the same, the knives are ground. How quickly and accurately the work is done depends entirely upon the wheel that is used, considering, of course, in any case, that the operator is careful and competent.
The manufacturer of grinding wheels should exercise great care to see that every wheel is in perfect condition before leaving the factory. Every reader knows that a grinding wheel is placed under a severe centrifugal strain, therefore its bond structure must be tough enough to insure against breakage. Put your grinding wheel troubles up to the manufacturer making them and after you learn the kind of wheel you require see that that particular kind of wheel is always furnished. It is possible that a wheel may be injured in transit; so, before being mounted on the machine, it should be lightly tapped with a hammer; if it is sound in every way it will ring clear. One of the best abrasives we have on the market today for grinding steel is Aloxite, which consists essentially of aluminum oxide. It is strong, hard, compact, and tough; fast, clean, and cool-cutting. It breaks with a rough fracture that makes it easy for the bonding material and glue to take hold. Aloxite itself is colored either a dark reddish brown or a bluish grey.
In many furniture manufacturing plants grinding wheels are operated under most unfavorable conditions
and in practically every instance where an accident occurs it is due to negligence or ignorance on the part of those using the wheels. It may be well to offer suggestions in this article. It may also be to your interest, Mr. Reader, to have your operator read these suggestions and for you to enforce them:
Do not have the rest so far away from the wheel that the work may become cramped. The use of a releasing rest may be the means of saving crushed fingers.
Keep the boxes well oiled so that the arbor will not become heated and by causing expansion rupture the wheel.
Never crowd an emery wheel upon an arbor. Have the wheels slip easily on the mandrel, and screw them only tight enough to prevent slipping. Wheels should be mounted so as to run true and steady.
Do not allow the wheel to vibrate when running at normal speed. If there be vibration, either true up the wheel or re-babbitt the boxes after truing up the journals,
Never mount wheels without flanges. The Carborundum Company has informed the writer that it will furnish a special type of safety flange, when required.
Do not use too small or too light flanges, and have them properly concaved. They should be at least onethird the diameter of the wheel.
Never screw a nut directly against the emery wheel. It will "creep" and rupture the wheel from excessive side pressure at the bushing.
Never run a wheel above its indicated speed.
Other Timely Advice
A workman on an emery wheel should keep his eyes and body out of the plane of rotation of the wheel; chips from the wheel will be less likely to strike him if this suggestion is heeded. The grinder will find that large glasses made of plain glass, or indeed, his own spectacles, should he wear them, will afford some protection from flying particles. Goggles should, in my opinion, be worn by every operator while grinding. The "Saniglas" is a popular sanitary goggle, made of non-corrosive white metal, having ground plano lenses of special glass which will withstand a heavy blow.
Great care should be exercised in storing your wheels to keep them free from dampness. They should not be stored with the stone standing upon the ground, as it will absorb moisture.
The use of safety hoods or guards is recommended under all conditions possible. It is, without doubt, the very best safety device that can be placed on a grinding machine. These hoods can be made of sheet steel and held by braces attached to the grinder, or they can be made of heavy wrought steel forged into shape, and also braced to the grinder. Malleable iron guards, if sufficiently heavy, are also a very good protection.
Use Substantial Machines
Machines should be heavy and stiff, and bearings long and kept properly adjusted, so that there is no vibration. The minute there is vibration there is something wrong, and it should be remedied at once. If the wheel is out of true, it should be tuned up. If the machine and wheel are both running true and the vibration remains, the wheel is out of balance and it should be taken off and balanced before used again.
After grinding your knives be sure that they balance. The importance of this is no doubt appreciated by every reader. Balances are sold for this purpose and every furniture factory should have one. I should, however, not forget to mention that if you were, for instance, running a molder, and were to make a heavy cut in a molding, you find that your knives balance on the scale, but
when put on the machine one may stand over more than the other, and when the machine is running this will throw out of balance and disturb the center, and that disturbance is vibration.
One thing is certain: there is no economy in running knives too long without grinding. No dull knife can do good work, even though there is a tremendous power back of it. Be careful to grind the knives straight. One of the reasons for getting a hollow edge is due to the fact that more or less heat is communicated to the steel, and the process of radiation being slow leaves the greatest heat at the edges, and, consequently, the greatest elongation.
Setting knives on the buzz planer is a comparatively simple matter, yet, as already stated, it is important that they be well balanced and the cylinder run well. The buzz planer is a dangerous machine at best. A short straightedge about one foot long is very convenient for setting the knives and should be used on the forward or stationary bed; and, if the cylinder has provision for it, four knives should be used. It is a good plan to put the knives on the machine as they come from the grinder and Joint them after they are set, then use the oilslip to bring them to an edge.
I might suggest that it will pay the average furniture manufacturer to save his old planer knives. Of course, for standard shapes special cutters would be provided, but special knives can often be made from old knives. A power hacksaw will do the trick. The power hacksaw can also be used to good advantage for cutting slots in cutters. Don't, however, cut down one pattern knife to make a cutter for some other mold if the knife is for regular stock. This practice is more general in furniture factories than is most generally supposed and should be severely condemned by the foreman or superintendent. An Oil Stone Grinder
There is on the market an oilstone grinder which deserves mention in these pages. These machines are already used in many factories and are, I believe, giving excellent results. The machine is provided with an automatic knife grinding attachment that will grind knives up to forty inches in length. The superintendent of the company making these grinders told the writer that in the seven years that these machines have been marketed he is proud to say that not one has ever been returned to them for not doing satisfactory work and that they are endorsed by heads of departments everywhere.
Vibration and noise can be, to a certain extent, eliminated. Increase in the size and the speed of machines has added largely to vibration and, consequently, measurably increased the volume of noise. A certain amount of noise in our break-out departments is to be expected; especially so, the planers and rip-saws, but when that noise becomes a rattle or a screech or a pounding, it has no excuse from the point of view of efficient mechanism. In reducing vibration-preventing it is mechanically impossible the first consideration naturally is the construction of the machine; the second, its installation; the third, its operation.
Special attention in designing and building should be given by wood-working machine manufacturers to those parts that will be most subject to strain and vibration in operation. This point is sometimes overlooked by designers of machines. Given a properly constructed machine, it ought to be so set that not only will its own tendency to vibrate be restrained, but its vibrations will be kept as far as practicable from traveling beyond itself.
With a machine rightly made and set up to the best