WOOD-WORKING MACHINES.

Press, Volume LX, Issue 18151, 14 August 1924, Page 5

WOOD-WORKING MACHINES.

A MATTER OF CHOICE. "When a man goes to buy wood-worlc-ing machinery to help him in his joinery work, it often happens that ho lias lew definite ideas to guide him in making a decision. In a "good many ins.tswioos the main factor is the price, and this is about the worst one ho could lm.ve for the purpose. Whilo it is only right that ho should be influenced by how much money he has to spend on wood-working machinery, yet so many factors have to bo considered that tho monetary pomt cf view is of but minor importance. Wood-v.orkiag machines vary from tho first-class specimens of our leading British makers to those which are designed and mado in small engineering shops. Some of these are excellent, others have many essential parts deliberately cut out, so they can be puton the market, at a very low price. Not only this, but wood-working rm'duiies vary in design, even those made by first-class makers. For instance, machines aro still being sold which are over fifty years old. These aro mostly mado by some of the very best makers of British wood-working machinery. In many cases thes© machines have been fairly well used, and arc in a condition to do work. They were made to last ccr-turies, providing a renewal of working parts w'as made to spindles and gearings. They can be bought fairly cheaply, and to a certain extent they are worth more than the money asked for them. If they .aro all that, it may be said, why go ori, and point out their faults? For this reason, an old machine has serious defe ts in its design. For instance, an old typo planing machine. Fifty years' continuous work in designing and making saw-mill machinery has taught tho leading makers a great many things. 'One is that tho bottom cutter block is a very awkward one to set, as arranged on .tho typo machine. It lias a. fixed bottom spindle, if I may be allowed to express it in this maimer. With most of these machines,' the spindle runs in bearings or cones—this depends on the machine—which are fastened to the body of the machine The way to nut the cutters on the cutter block of such a machine is to crawl under it, and then with spanner end rule or level, to put on the cutters. It is a tedious and very awkward job. Not only that, the amount of cut which these cutters will take off is very limited, and tho greatest of care has to, be taken to set the cutters so they take off just that amount which will allow the finished board to come on to the bed of the machine. The amount, too, is limited by the bottom rollers. These are put into definite fixed position, so they cannot be either lowered or lifted. This makes n. great difference to tho amount you may want to take off tho board by the bottom

cutter. It limits the amount, and reduces the usefulness of tho machine. Another ooint to watch, or. rather, to examine," is tho bed of tho machine. Wnring tho «nirse of years, tho possibility is thct- a greater amount of narrow stuff will be planed on the machine than stuff the whole width of the bed. It does not seem possible, yet it will oc found in a great, many instances Uat the continual running of narrow stuff will cut a slight depression in the bed. This should be examined, and if it is badly worn in this manner it will require planing before it can be said that the machine, is in working order. Tho old type of planer, such as has been described, has over-hung centres to hold the upright spindles, mostly fitted with cone bearings. If they are in ex_ cellent condition they are capable of beinf* adjusted so the spindles run without anv side play. While this is all to the good, tho overhang method of fastening the spindles has the effect of limiting the machine to the cutter block on the spindle. Tho Modern Machine. Just a review of what a modern machine should be with regard to these two items, the overhang bearing and tho bottom cutter. The modern spindle would have ball bearings or large phosphorous bronze ones, which, while taking the downward thrust of the spindle, is arranged so that any upward lift can be avoided or adjusted. The cutter block, which would be lipped to enablo the cutters to be set so that they can cut hardwoods without tearing out the cross-grain, is made so that it can be easily taken off the spindle and yet come to an exact lit upon it. Several ingenious cutter blocks have been arranged to take up any differences there may bo between the spindle and the hole ia the cutter block. This accessibility of the vertical cutter blocks is of enormous advantage. Two or more spare cutter blocks can be used with each machine. The machine may have a large number of spare cutter blocks; all or one can bo set while tho machine is running, so the time used for setting cutters can be cut down to a slight amount. Tho bottom cutter block of a modern machine differs from the old one, in that it is adjustable, so it will take either a fine or a heavy cut. Another important alteration is that the whole of the bottom cutter block with bearings can be drawn out, so that the cutters can be put in with the same ease as a top cutter block, or sharpened without the operator having to crawl under the machine. These are the principal alterations between what might be termed the modern and the old type machine. There aro others, mostly dealing with tho feed, holding the timber while it is being machined, etc The differences arc such that it is only someone who wants a machine very badly and has very little money who would buy an old type machine when he can obtain a modern one *°r,_of course, considerably more money. The difference in cost between tho two

I machines would be saved ia a few months.

Of planing machines tby planins machines we mean four cutters) two types are made, the inside and the outside. The inside litis the cutter blocks and the spindles within the box-like framing of the machine; the outside has the top cutter fixed on the framework of the machine; aud at the side is the bed, attached to which are two vertical spindles and one bottom cutter block. The feed rollers are fixed on to the framework of the machine similar to the top cutter. It may bo asked: Why two types of machines? The reason is the inside planer is best suited for boards and square stuff, while the outside is best for mouldings. The outside planing machine is very accessible. Everything being outside the frame of the machine, it does not require any great effort to put on the cutters. The shoes to hold the wood down are easily put on the machine, and, what is more, important taper feed rollers can bo put on to feed the various shaped pieces of wood which may be used for making mouldings.

Points to Consider. The advantage of the inside moulder or planing machine is that it is much heavier built. A great degree -of solidarity can be obtained by the bos shape of framing, and this helps to ensure the steady running of the cutter blocks.

Saw-benches should be examined for cracked finger plates, shaky or wornout bearings. A good saw-bench should be cast in one piece. While it is possible to use framed-up saw benches—indeed, some of these will last a very long time—yet the massive solid framing of some of the old type sawbenches ensures a machine which will stand an enormous amount of hard wear.

See that the bod of the machine is true. Take out the finger plate and examine the saw spindle for wear. _ It should have no side play, no uplift. If there is side play, see whether the sa,w spindle has adjustable nuts for taking this up. If it has not, then it is a point against the machine. If you intend to do a good deal of crosscutting and ripping with the saw, have one which has the fence fastened to a long spindle at the end of the machine. If it has this, the fence can bo easily turned back for cross-cutting purposes. If the saw-beneh. ia to be used solely for ripping, and, say, especially for cutting thin stuff, then have one with the spindle which goe3 to the centre of the fence. The ono which turns over has a certain amount of spring in it, owing to it_ being fastened at its end. This is not so with the other fence, as it is fastened to the spindle in the centre of the fence. As far as possible, see that the fence is adjustable two ways—first, the way it can be moved to take various sized saws; secondly, by four set screws to tilt the fence according to how tho saw is cutting in the wood.