1/2-inch tool steel with the point spread out about 2 inches wide and
well tempered, after which it is ground to a good sharp edge, and then
an oil stone run over the edge until it has been dulled so that it will
not cut. The right kind of an edge can only be secured by trying; it is
one of the tools that is very hard to get just right. You will notice
that the manner in which this splitter is built may seem to be rather
too much work to bestow on such a simple tool, but the reasons for so
doing are as follows: in opening a 36-inch belt an old splice opener
that was driven into the handle like an ordinary file was used and the
handle split; that sharp point came back through the handle, and when
it finally stopped it had gone about 2 inches into the palm of the
operator's hand. Some 1/2-inch hexagon steel was turned down 6 inches,
just enough to round it up; then a solid brass washer was turned out
1-1/4 inches in diameter and 1 inch thick, a hole bored through it that
was a driving fit on the piece of steel and was driven down to the
shoulder. Washers were cut out of old pieces of belt and put on with a
liberal coat of glue on both sides; when the handle was filled, a steel
washer which was 1/2 inch thick was screwed down hard on the leather
washers, and when it had dried well the whole was turned down to size
shown in the sketch. Two of these tools were made, one for belts up
to 18 inches, and another that will reach through a 40-inch belt. The
tool shown in Fig. 67 is an ordinary heavy screwdriver with the point
rounded nicely, and it is used to raise the thin points that the larger
tool will sometimes tear.
[Illustration: FIG. 67.]
[Illustration: FIG. 68.]
Fig. 68 shows a handle made almost like the one in Fig. 65, with the
exception that the brass washer referred to in Fig. 65 is here turned
down to 3/4 inch, commencing 1/2 inch from the large end, which is 1
inch in diameter. The leather washers are slipped on over the small part
until it is filled, and then a washer is screwed on the small end and
the whole turned as shown in the sketch. A hole that will tap out 3/8
inch is bored in the large end of the brass center, and then tools made
with threaded ends on them that will fit into it. These tools are made
of 3/8-inch tool steel with scraping ends, as shown. These scrapers
are used only for removing glue that is too hard and too thick to be
removed by the scraper shown in Fig. 69.
[Illustration: FIG. 69.]
[Illustration: FIG. 69a.]
[Illustration: FIG. 69b.]
Figs. 69, 69a and 69b show views of the only tool that is hardly worth
being referred to as a leather-cutting tool. It is made of a thin piece
of steel, about 18 gage, or any old hand-saw will make the very best
scrapers that can be secured. They should be about 4 inches square,
perhaps a little smaller, and fixed in a hardwood handle (usually of
hard maple), simply by sawing about 2-1/2 inches into the handle and
then driving the blade in. The saw cut should be just a trifle thinner
than the piece of steel. Should they get loose from use, a piece of
paper folded over the back of the blade and forced back into the handle
with the blade will usually tighten it all right.
This is the tool that will ordinarily worry the novice more than all
the rest to keep in proper condition. Fig. 70 shows an exaggerated view
of how the blade should look when properly finished. It should be
hooked considerably.
[Illustration: FIG. 70.]
Fig. 71 shows a small steel for sharpening the scraper after it is
turned, and it should be absolutely smooth.
[Illustration: FIG. 71.]
[Illustration: FIG. 72.]
Fig. 72 shows the equipment for turning the edge of the scrapers. A
large three-cornered file, about 12 inches long, which has all the
teeth ground carefully off of it and then nicely polished, is fastened
to a piece of good clean belt leather by means of the staples shown.
[Illustration: FIG. 73.]
Fig. 73 shows the method employed in turning the edge of the scraper,
which is as follows: After the blade has been set firmly in the handle,
grind the edge rounding, as is shown in Fig. 69; then grind sharp with
a good long taper of about 3/8, and grind from both sides just as you
would an ordinary axe. After you have a good smooth edge on it, put
it on an oil or water stone and put as fine an edge as possible on
it, then put on a smooth piece of leather and hone it down until it
would shave you. You will then have a tool that will do a world of
work for you, "if you will turn it right." The method shown in Fig.
73, if properly carried out, will do the trick for you; the thing to
be remembered is that at no time in the turning of the scraper must
the cutting edge bear on the smooth file. The first position is not
shown right; the handle should be allowed to touch the file the first
few times it is passed over, and then gradually raise the handle and
keep on passing the blade from side to side, as is shown in Fig. 74;
allowing it to slip off on the leather every time you cross the file;
this is to keep the corners in proper shape. Another thing to remember
is to bear down on the blade as it is passed over the file; you can't
bear too hard; the only thing to look out for is not to raise the
handle too fast. An ordinary blade can be turned in about fifty strokes
across the file. The edge turned over should be at least 1/16 inch long
and should be well hooked, as is shown in Fig. 73.
[Illustration: FIG. 74.]
It is well to keep on hand about six of these scrapers, and as they
get too dull to cut leather use them on glue. With one good scraper
that is not too sharp all the glue can be cleaned off of both points
of a 36-inch belt in from five to ten minutes. When the edge gets a
trifle dull, use the small steel on both sides of the edge; first wet
the steel with the lips, it makes a much better edge. For the benefit
of beginners who may attempt to splice a belt for the first time, do
not use a glue that will not allow you to remove the clamps and put on
the full load in forty-five minutes after the glue has been applied and
well rubbed down. The time given here applies only to clean belts that
are absolutely free from all oils, and does not include old oil-soaked
leather that no glue will ever dry on.
Fig. 75 shows the equipment necessary to do a good, quick job on a
belt, and most of them are required to be done quickly and well. With
such an outfit and half-dozen sharp scrapers a joint in a 36-inch belt
can be made and run again in four hours after the engine is stopped.
This includes all the time consumed in putting on and taking off the
clamps, etc.
[Illustration: FIG. 75.]
The top of the platform, 76d, is level with the bottom of the belt
and is held in position by the hooks, 76b, which are shown in Figs.
75 and 76. These hooks slip over the 2×4-inch pieces that project
outside the platform to which they are attached, and should be made
of three-quarter iron and not too long, or some difficulty may be
experienced in getting them on the two-by-fours.
[Illustration: FIG. 76.]
The rods should be long enough to take care of the longest possible
splice and still give plenty of room to work. There should be about
2-1/2 feet between the inside ends of the threads and the threaded end
should be 3 feet long. This will make the rod 8 feet 6 inches long,
and it will be none too long at that. For instance, in removing the
glue from the splice, if the last end point is very close to the clamp,
there will be great difficulty in cleaning it and also in fitting the
leather after the belt has been shortened. What is meant by the head
end splice is the one that is on the pulley first--the arrows in Figs.
77 and 78 will make this clear: they indicate the direction in which
the belt should run; therefore that end of the piece of leather that
is on the pulley first is the head end (or first end) and the end that
leaves the pulley last is the last end. If the two belts shown in the
sketch were reversed, the points would be turned up by everything
that touched them; whereas, running in the direction that they do,
everything that touches them has a tendency to rub them down.
[Illustration: FIG. 77.]
[Illustration: FIG. 78.]
We will suppose that the belt shown in Fig. 75 had a "first end" point
that opened on the top of the belt instead of the bottom as this one
does (see left-hand end of belt between the clamps, on the lower side);
one can easily see how hard it would be to work if the clamp were near
the point. There should always be enough room between the clamps to
allow the splicer to take the last end (which is always the forked
end), carry it entirely over the clamp toward the left in Fig. 75, lay
it down on that part of the belt that is outside the clamp and slip an
extra splicing board under it. Fasten the two belts and splicing board
all together by means of a couple of 8-inch hand-screws (of which every
belt splicer should have at least six or eight); then clean and shape
it to suit the other end. It can be passed back over the clamp from
time to time and tried for a fit.
[Illustration: FIG. 79.]
The proper mode of procedure in splicing a belt on the pulleys is as
follows: Decide on where the belt is to be opened, and always open it
in the worst place in the belt for that is the place you certainly want
to fix. Pay no attention whatever to any former splicing place that
may be in the belt, but take it apart at any place where you are sure
repairs are actually necessary. First put in the most convenient place
possible the point that you have decided to open and then put the
clamps in position. If you are sure that it is going to require very
hard pulling to get it as tight as you wish, take a damp cloth, moisten
the inside of the clamps and then sprinkle powdered resin on both upper
and lower clamp. Put the "first end" clamp on first, as this is always
the easiest point to clean and fit; decide how much you will have to
take out, or as near as possible, measure off this amount on the belt
and place the clamp this distance plus about 10 inches from the "first
end" point. This extra 10 inches will give you plenty of room to clean
the glue off and also to shorten up the belt the right amount, for all
the shortening must be done on the "first end" point on account of the
ease with which the new scarf can be made.
Should you try to shorten up from the "last end" point, by referring
to Fig. 78, you can easily see the amount of work you would be in
for. There would be two thin ends to scarf, and outside ends at that;
whereas if you shorten up from the "first end" you make only one thin
end and that one in the inside of the belt.
The first clamp, with the center mark of the clamp coinciding with
the center of the belt, should be very tight; for should it slip when
the load is put on, it will very probably slip in the middle of the
belt and may not slip on the edges at all. Should you glue it in this
condition, the chances are very much in favor of the outside edges
giving away on a heavy load, due to the middle being too long. After
the first clamp is in position and tightened, put on the second one and
leave the bolts loose, so that it can be slipped easily. Then put the
belt rods in position with just a "full nut" on each end and tighten
the clamp. Tighten the rods enough to take most of the load, then get
the large splitter shown in Figs. 65 and 66 and open the joint. The
place to commence is between _X X_ in Fig. 75; this inclined point
is about 4 inches long and must be opened at both ends of the splice
before the middle is touched.
The tool should be entered at _O_, in Fig. 78, and worked gradually
toward _A_; when the point is raised to _A_ clear across the belt, open
on down to _C_. After both ends of the splice have been opened up in
this way, proceed to open the middle, which is now an easy task, there
being no thin stock that a separating tool will pass through easily.
After the belt is entirely apart tighten up on the rods until the belt
is the proper tension and hang the hooks (76b, Fig. 75) on the belt
rods. Throw the two ends of the belt back over the clamp and put the
splicing board in position. After this is in place, throw the two ends
of the belt back on the board and proceed to lay off the scarfs. To
do this, first take a square and get the two thin points perfectly
square, then put the "first end" point in between them. This is shown
very clearly in Fig. 77, the shaded end being the last end. Of course
the "first end" point at _C_, Fig. 77, will have to be cut off before
the belt will lie down properly; the amount to cut off of this end will
be just as much as you have shortened the distance between the clamps.
After the point has been cut to the right length, take the square and
make a mark across the belt, using the end of the thin point as your
measure for length; then without moving the belt make a mark on the
edge of the belt, showing just where the lower thin point came on the
bottom. Throw the "last end" over the left-hand clamp out of the way
and scarf down the top of the "first end" point, letting the scarf be
about 4 inches long. Be careful not to gouge a hole in the belt where
the scarf is started, but try to make the inclined plane from _X_ to
_X_ perfect; try to keep the whole surface of this incline true and
straight. After the short 4-inch scarf is finished, clean the glue off
of the inside of the "first end"; lap up to where it enters the "last
end"; then turn it over by bringing it over the right-hand clamp, place
a scarfing board under it and make the scarf shown at _T_, Fig. 75.
Now clean all glue off the "last end" lap and take a sharp scraper
like the one shown in Fig. 69 or 69b, place a piece of glass under the
points that have been previously squared up, and scarf them down to a
knife-edge.
After the thin points are properly scarfed, lay the whole splice back
on the splicing board just as it will be when it is glued, and do any
fitting that may be necessary. Be very careful to get it thin enough,
or it will make a hammering noise when going over the pulleys. When
scarfing down the thin points with the scrapers, be sure that they
are very sharp; if not, they will tear the point off when it gets
down to an edge; also give the blade a drawing motion in order to
facilitate cutting. It may seem to the novice that to use a piece of
glass to scarf on, when one is using a tool with a razor edge, is a
trifle inconsistent, but it is not so in the least; if the blade is
held well back at the top and a considerable pressure applied to it,
there will be no danger in the edge actually touching the glass; the
edge is turned past a right-angular position, or hooked, and the heel
is all that touches the glass. A good piece of plate glass about 12 ×
18 inches is large enough for any width of belt, although a piece much
smaller will do all right. Do not attempt to do any scarfing on the
board 76d, for if you do it will be so full of holes that have been
gouged by the scraper that it will be ruined for any purpose.
This board must be kept smooth in order to be able to do a good job of
rubbing down when gluing. Never hammer a glue joint in order to set
it; it is just that much unnecessary work and does absolutely no good;
simply get a smooth block of wood 2 × 6 × 8 inches and rub hard and
fast as soon as the glue is applied. Do not try to glue more than 6
inches in length at one time. Use a heavy brush--a high-priced paint
brush is the best; the regular glue brush is about the only thing in
existence that will not put on any glue at all--about a 3-inch brush
is the thing; have the glue just as hot as it is possible to get it.
Keep the brush in the pot all the time the glue is heating; also have a
strong stick made somewhat like a three-cornered file, only larger, in
the glue--this last is used to scrape off the brush all the glue that
it is possible to get off without allowing the glue to get too cold.
When you take the brush out of the pot, work fast; get all the glue
possible off the brush and get the rest on the belt at once. Make two
or three fast strokes across the belt and close down the splice and rub
for dear life. After the first brushful has been applied (and rubbed
for about two minutes), have an assistant raise the point up until
you can see the glue breaking all across the whole width of the belt.
Then have a second brush ready and repeat the former process, with the
exception that you need not apply the glue to both sides of the leather
as in the first case; for if you will keep the brush down in the fork
between the two laps you will give both sides a coat, and in addition
to the time saved by using this method you will get the joint closed
while the glue is hot. As fast as you go across the belt with the
brush, have the assistant roll the belt together after you; when you
have used all the glue out of the brush, the joint is closed and ready
to rub. You will keep the glue much hotter by immediately closing the
splice after the brush, and there is nothing else so important as using
hot glue; as soon as it commences to get shiny on the surface the thing
is all off and it will not hold anything.
You cannot do any quick work with water in your glue--that is, unless
it is old and has been heated up several times. If this is the case,
it will have to be thinned with water. The proper consistency is about
that of a very heavy grade of cylinder oil; if it is too thin, it will
not dry in any reasonable time and it will also cause pockets in the
splice by opening up after the joint has been rubbed, and the air in
the pockets will open the whole splice. In important work never use
a glue that will not stick so tightly between every application belt
that after rubbing down you can give it a good, hard pull without its
opening up. In all statements regarding the time necessary for the
joint to dry, the belts are considered absolutely clean, dry and free
from all oils.
The most disagreeable portion of the belt repairer's work is the
splicing and repairing of oil-soaked belts. It is a well-known fact
that the action of oil and that of glue are in direct opposition to
each other: the oil prevents sticking and the glue sticks, if it has
a chance. Such being the case, the first thing to do is to eliminate
the oil completely, and the efficiency of your joint will be in direct
proportion to your success in getting rid of the oil. To this end
secure a large gasoline blow torch, such as painters use to burn off
old paint. If you are not used to it, be very careful; at all events,
have a bucket of dry sand to use in case of trouble. Just throw the
sand on the fire and the fire will go out--that is, if you can get the
sand in the right place.
The torch is to be used after the splice has been all completed except
the thin points. The flame will burn them if finished, so leave them
tolerably thick until after the oil has been removed; then finish them
as directed before. When the scarfs have been made and the old glue
has been removed, turn the flame (which should be an almost invisible
blue if the torch is working properly) directly on the leather and
move it over all the surface of the splice until the leather has
become thoroughly heated; never allow the flame to remain directed
at any point long enough to make the oil in the leather boil. If you
do, the belt is burned. Continue to move the flame over the surface
of the belt until the leather is so hot that the hand can scarcely
be held on it. With one of the scrapers shown in Figs. 69 and 69b
(69b preferred) scrape the oil off as the heat raises it up. Turn the
cutting edge of the scraper up and wipe the oil off after every stroke;
keep the scraping process going right on after the torch; never allow
the leather to cool off until you can get practically no oil and the
leather begins to turn brown. By heating the leather and bringing the
oil to the surface you do just what the glue does when you put it on
an oil-soaked belt without removing the oil. By means of the heat
contained in it, it brings up all the oil near the surface to which it
is applied and in consequence does not take any hold on the leather.
It will take two men with all the necessary tools and appliances at
least six hours of good hard work to remove the oil from a well-soaked
36-inch belt--that is, to remove it to an extent sufficient to warrant
the gluing of it.
In case of overflows in which the wheel pits are liable to be filled
with water, pour cylinder oil on all belts that are liable to get wet
and then remove them from pulleys if they will be covered for more than
twenty-four hours, clean them with gasoline and they will be found to
be all right and dry.
Hold a clean piece of waste against all belts at least twice every
twenty hours, and wipe them clean.
IX
THE CARE AND MANAGEMENT OF LEATHER BELTS[6]
OUTSIDE of the direct care and management of high-pressure boilers and
the steam lines pertaining thereto, there is no other part of a power
or lighting plant, mill or factory in which a large number of indirect
connected machines are used that is of such vital importance as leather
belting and rope drives. The subject under discussion in this chapter
will be the former, and the selection, care and management thereof.
[6] Contributed to Power by Walter E. Dixon. M. E.
The first thing in order will be the selection of a leather belt, and
when we consider that all makers make good belts, that there are no
particular secrets in the belt-making business, and that in order to
get the very best we must take every advantage of all small details in
construction, it stands every engineer and belt user in hand to get all
the information available; for we must remember that the percentage of
good hides does not run very high, that all that are bought go into
belt stock of some kind or other, and that some one must buy the goods
that are not quite up to the standard of belt excellence. It is very
evident that no man wants anything but the best when he is paying for
the best, and it is also evident that no maker is going to say that he
makes inferior goods; so therefore we must read the quality by what is
in sight, and in the judging of leather that is already made up, the
proposition resolves itself into a very hard one.
The two principal things left for an opinion to be based upon as to
quality are the relation the pieces that constitute the laps bear to
the hide from which they were cut. They should, in belts running from
18 to 36 inches, be cut from the center of the hides, or should be
what is known as "center stock." Of course all belts should be "center
stock," but where they are very narrow or so wide that one hide will
not be wide enough to make a lap, then there is always a lot of narrow
stock worked in that cannot always be strictly center. The next thing
to look out for is brands that are so deep that they destroy the life
of the leather and will cause it to break after being used. Then look
out for the length of lap. If this is too long, you will know that it
runs into the neck, for about all that it is possible to get out of
average hides and still leave nothing in that is not first class is
54 or 56 inches. Ordinarily, you can tell if a lap is "center stock"
by the marks that run down either side of the back bone; they will
be usually a little darker than the rest of the belt. These marks or
streaks should be in the center of the belt. The principal objection to
neck leather is that it is liable to stretch excessively, and on this
account it will put too much load on the piece immediately opposite it
in a double-ply belt; for the point of one side is in the middle of the
lap on the other side. Next look out for holes, which will usually be
found so nicely plugged as to escape detection unless subjected to the
most careful examination.