Thread (fastener)

“ It has been found from experiments that have been made that our present threads are stronger than their bolts, which is desirable, inasmuch as it gives a margin for wear on the sides of the threads. But for threads whose nuts are to remain permanently fastened and are not subject to wear, it is questionable whether it were not better for the bolts to be stronger than the threads. Suppose, for instance, that a thread strips, and the bolt will remain in place because the nut will not come off the bolt readily. ”

“ It is obvious, then, when it is advantageous to increase the strength of a thread, that it may be done by increasing the depth of the nut, or in other words, by increasing the number of threads used in computing its strength. This is undesirable by reason of increasing the cost and labor of producing the nuts, especially as the threading tools used for nuts are the weakest, and are especially liable to breakage, even with the present depth of nuts. ”

“ The thread in dies which take successive cuts to form a thread may be left full clear through the die, and will thus cut a full thread close up to the head collar or shoulder of the work. It is usual, however, to chamfer off the half threads at the ends of the dies, because if left of their full height they are apt to break off when in use. ”

“ That in the course of their investigations they have become more deeply impressed with the necessity of some acknowledged standard, the varieties of threads in use being much greater than they had supposed possible; in fact, the difficulty of obtaining the exact pitch of a thread not a multiple or sub-multiple of the inch measure is sometimes a matter of extreme embarrassment. ”

“ If the nut then be withdrawn from thread g, and the work allowed to make another revolution, the nut will stand in a precisely similar position with relation to the lead screw thread as it did in position 2, and by forcing it down into thread h the carriage would be again forced to the right, causing a third thread, c, to be cut. ”

“ The curves for a United States standard form of thread are obtained in the same manner as from the V thread in Figure 208, but the thread itself is more difficult to draw. The construction of this thread is shown in Figure 208, it having a flat place at the top and at the bottom of the thread. A common V thread has its sides at an angle of 60 degrees, one to the other, the top and bottom meeting in a point. ”

“ Smith blinked. "Sure. Yeah! Hey!" His face brightened. Then it looked sad again. "But what good would that do us?"
"You said that all we have between us and success is a fraction of an inch of metal. If we can remove that fraction of an inch, we're successful."
"But how can you put a thread into that socket?" Smith asked.
Jayjay beamed as though it were his birthday. "We don't have to put a thread in there. All we have to do is give the thread on the male plug room to move in. All we have to do is clear away that metal. So we'll use the drill motor to turn the sleeve as if it were on a lathe." ”

“ In the case, however, of work of large diameter requiring to be threaded, the threading tool may be held and operated differently and more rigidly as follows. i is a lever carrying under its bend and over the projecting end of the live spindle, a segment of a nut whose thread must equal in pitch the pitch of thread to be given to the work. A collar or ring, oftentimes called the leader, having a thread of the same pitch, is then secured upon the live spindle, so as to rotate with it, and have no end motion ”

“ It cannot be doubted that the sharp thread offers us the simplest form, and that its general adoption would require no special tools for its construction, but its liability to accident, always great, becomes a serious matter upon large bolts, whilst the small amount of strength at the sharp top is a strong inducement to sacrifice some of it for the sake of better protection to the remainder ”

“ The fewer the cords that are tied to each hook, the greater is the variety of shedding that can be made on the same number of warp threads, till, when there is but one cord to the hook, any thread or any number of threads can be raised independently of any of the others. ”

“ The whole depth of the thread equals the linear pitch multiplied by 0.6866, and the width of the thread tool at the end equals the linear pitch multiplied by 0.31. Gages notched for threads of different pitch are ordinarily used when grinding worm thread tools.
When it is necessary to cut multiple-threaded worms of large lead in an ordinary lathe, difficulty is sometimes experienced because the lead-screw must be geared to run much faster than the spindle, thus imposing excessive strains on the gearing. ”

“ In the machine under consideration, the feed and delivery rollers of the card stop simultaneously with the stoppage of the draw-head mechanism.
One of the chief aims in spinning is that of producing a uniform thread; uniform not only in section, but in all other respects. A so-called level thread refers, in general, to a uniform diameter, but there are other equally, if not more, important phases connected with the full sense of the word uniform. ”

“ The neatest way of doing this is to pass the [Pg 301] needle through the centre of the thread and draw it tight; this is a useful trick for any unskilled worker with needles and thread, for re-threading also may be a difficulty. When work has to be unpicked it is better to cut the threads rather than do any drawing out, for they are in any case unfit for further use, and this method wears the material less; a beginner must not shirk unpicking if first-rate results are to be obtained. ”

“ As a result of the wear upon the tools for cutting internal threads, the thread grooves, when cut to their full widths, will be too shallow in depth, or, more correctly speaking, the full diameter of the thread will be too small to an amount corresponding to twice the amount of wear that the tool point has suffered. ”

“ In considering their revolutions it is to be borne in mind that when d has more teeth than s the speed of the lead screw is increased, and the lathe will cut a thread coarser than that of its lead screw, or when d has less teeth than s the speed of the lead screw is diminished, and the pitch of thread cut will be finer than that of the lead screw. ”

“ If, however, we should make one side of the thread perpendicular to the axis of the bolt, and the other at an angle to the first, we should obtain the greatest amount of strength, together with the least frictional resistance; but we should have a thread only suitable for supporting strains in one direction, and constant care would be requisite to cut the thread in the nut in the proper direction to correspond with the bolt ”

“ If a tiny hole is to be filled in, tack it smooth over stiff paper, then with ravelings of the stuff or thread exactly matching go over the warp way, setting thread for thread, barely catching at the ends, then weave in cross threads, same as the original fabric, and press. ”

“ A hook must be fixed in some convenient place to make the waxends on, or, as they are called in the trade, "threads," which term it will be as well to call them by here; thus a four-cord thread means a thread or waxend containing four strands of hemp, a six-cord contains six strands, and so on. One of the greatest difficulties for the amateur is to produce a well-formed thread. He generally finds it thicker a few inches from the point than at any other part. ”

“ Of the rapidity with which some portions of the machinery operate, we may form an idea from the fact that the very finest thread which is used in making lace is passed through the strong flame of a lamp, which burns off the fibres without burning the thread itself. The velocity with which the thread moves is so great, that we cannot perceive any motion at all. ”

“ It is upon the sides of threads that the contact should exist to make a fit, and the best method of testing the fit of a male and female thread is to try them together, winding them back and forth until the bright marks of contact show. Giving the male thread a faint tint of paint made of Venetian red mixed with lubricating oil, will cause the bearing of the threads to show very plainly. ”

“ Another frequent cause of defects occurs by what is termed the ballooning of the thread as it comes from the bobbin, that is, the swing which the thread makes in unwinding itself when it encounters the resistance of the air, a matter which depends on the bulk of the thread and the amount and nature of its surface fibre. ”

“ The zero line on the hub a stands, if the thread is true to pitch, parallel to the axis of the screw c, but if the pitch of the thread has become coarser from hardening, this zero line is marked at an angle, as shown in Fig. ”

“ With White ch 14, insert hook in any d c, pull loop through, ch 1, 1 s c in next st of ch, 1 s d c in each of the next 3 sts (s d c: thread over hook, insert in st, pull loop through, thread over and work off all loops at one time) , 1 d c in each of the next 9 sts, 6 s d c in end st, working on opposite side of ch, 1 d c in each of the next 9 sts, 1 s d c in each of the next 3 sts, 1 s c in next st, sl st in same d c, break thread. Skip 1 d c, work another petal in next d c. Continue working in same manner all around. Work a 2nd daisy same as 1st daisy, joining it to 1st daisy as illustrated. ”

“ Suppose the threaded hole in the dies to be cut by a hob or master tap of the same diameter as the thread to be cut by the dies; when the dies are opened out and placed upon the work as in Fig. 304, the edges a, b will meet the work, and there will be nothing to steady the dies, which will, therefore, wobble and start a drunken thread, that is to say, a thread such as was shown in Fig. ”

“ Very often the size of a threaded hole can be tested by using as a gage the threaded part that is to fit into it. When making such a test, the tool is, of course, moved back out of the way. It is rather difficult to cut an accurate thread in a small hole, especially when the hole is quite deep, owing to the flexibility of the tool; for this reason threads are sometimes cut slightly under size with the tool, after which a tap with its shank end held straight by the tailstock center is run through the hole. ”

“ Of Thread Controllers.—One of the earliest difficulties encountered by the maker of a sewing machine was that of effectually controlling the loose thread after it had been cast off the shuttle. In some machines this slack thread amounts to six, in others to one or two inches. Howe got over the difficulty by passing his thread, on its way to the needle, over the upper extremity of the needle bar—the ascent of the bar, then, sufficed to pull up the slack. Singer improved upon this by furnishing his machine with a spring take-up lever, partially controlled by the needle bar. ”

“ When thread is used as an outline, a second, and much finer thread is used to tack it down. The coarse thread is laid on the outlines, and the needle is brought up on one side of it, and down, in the same hole, on the other. The stitches are taken at the rate of five or six to an inch, one being always placed at the point of each angle, so as to keep the outlines as accurate as possible. To fasten on a thread, run the needle along the braid a little way, taking a button-hole stitch to secure it. ”

“ Lead screws are usually provided with square threads of the usual form, or with threads whose sides have about fifteen degrees of angle, so that the two halves of the feed nut may be let together to take up the wear. It is obvious that in a V-thread or in a thread whose sides are at an angle, the feeding strain tends to force the two halves of the feed nut apart, and therefore places a strain on the feed-nut operating mechanism that does not exist in the case of a square thread. ”

“ When the Thread Breaks,
as it will again and again at first, thread your spindle as before, tie the new thread to the broken end and begin once more. A better way to mend the thread when you are really doing good work is to unwind a little from the bobbin, thread it backward through the spindle, bring [13] the end up to meet the end from the distaff, and let the two lap three or four inches; then moisten your fingers and twist the threads together, making one thread again.
Moistening the Fingers
occasionally is a good thing while twisting, as it makes a smoother thread. ”

“ Supposing the thread is uniform in quality but varying in size, the force required to stretch it varies directly with the size or sectional area of the thread itself. In the automatic reeling machine this stretch is obtained by causing the thread to take a turn round a pulley of a given winding speed, and then, after leaving this pulley, to take a turn around a second pulley having a somewhat greater winding speed. ”

“ But if the lathe tailstock sets over as in Fig. 1247, then the pitch of the thread will be cut correct, because the length of b will equal the length of tool traverse; hence at each work revolution the tool would advance one-twentieth of the length of the surface on which the thread is cut, which is correct for the conditions. ”

“ By the aid of this, every [90] little warp thread or cluster of threads can be lifted by its own hooked wire without interfering with any other thread. Cards of paper or thin metal are made for each pattern, leaving a hole wherever the hook is to slip through and lift up a thread. After the cards are once made, the work is as easy as plain weaving ”