6. Making the Rope Thimble
The thimble fits into the eye known as becket that the strop streches around, and allows it to attach to another rope, shackle or spare. While a metal thimble is not a neccesity, it does add strength to the becket, and also prevents chafing of the rope against shackles and other attachments that might otherwise cut through the rope.
The common thimble is an oval eye shape, and can be readily purchased at most hardware stores. While functional, the modern thimble does not have quite the salty look as the traditional round brass thimble of yesteryear.
Manilla round brass Thimbles for a more traditional look
The manilla brass thimbles provide a much more traditional look, they can be ordered from a specialty marine supply store for example, Duckworks BBS
, and R&W Rope
However, the cost of thimbles can be rather high if you need to make alot of blocks, with a 3/4" thimble which handles a 3/8" runnign a nearly $5 a thimble, it can be cost prohibitive.
Alternatively, while not brass, you can make your own thimble out of some old copper tubing, which gives a similar aesthetic appeal, but is considerably less expensive.
Start by obtaining a length of coper tubing in the diameter that you need; generally speaking a 3/4" I.D. tube is about right for most small boating thimbles.
The first thing is to cut the tubing into the width you need, a standard size chart for commercial thimbles is a good rule to work from, and a slightly larger I.D. would not hurt since we need to work within the standard sizes of copper tubing.
That being said, copper tubing of an I.D. of 3/4" should work for rope from 1/4"-1/2". It is a good idea to use a commerical size chart to get a good idea of the size of thimble you require for the thickness of rope strop you plan to use. A standard 1/4" strop would need a rope thimble about 1" wide and an I.D. of 3/4."
To make the thimble we first cut a ring about 1" from the length of tube using a metal cutting bandsaw blade. You could also use a simple plumbing pipe cutter and save the wear on your bandsaw.
we marked off a 1" section of pipe to make our rope thimble.
Cutting the the timble piece on the bandsaw -
make special care to make sure that your cut is square
A successfully cut section of pipe to use as the basis for our thimble. If you are wondering how wide to cut it, basically allow for 1/4" more than the actual outer diameter of the finished thimble. O this means a 3/4" wide thimble should have a width of about 1".
A piece of copper tubing cut to size for our thimble.
The next step requires the use of two medium sized ballpeen hammers. The first one needs to be securily mounted so it doesnt move. We clamped it up against our cast iron lathe.
A ballbeen hammer clamped down to a secure surface
Next, take the length of copper tube that was cut to the size of the thimble and place it square on the ballpeen hammer.
Tap the copper section with another ballpeen hammer of the same size.
Begin tapping the top of the copper tube with a ballpeen hammer of the same size. Making small quick taps, the bottom of the copper tube should begin to "flange" outwards.
The bottom of the copper tube should begin to flange outwards.
Another view of the thimble
Once you have a reasonable flange started, then flip the thimble over, and begin the process on the other end. once you have decent flanges started, then you can place it ona flat surface and using the flat end of the hammer you can even out the flange shape with a few taps.
Place the thimble on a flat surface to even out the flange.
The finished thimble
Tons of rope thimbles made easily and cheaply
7. Making the Rope Strop
The "strops" or strap is made up of a rope grommet or "grummit" as a sailor would say. To the landlubber they are sometimes referred to as quoits. The grommet is pulled together at the top to form a single becket - an eyelet which is used to attach the block, you could also opt for a "double becket" with an eye at the top and bottom, just size your grommet accordingly.
In any case, a rope strop is simply a rope ring of a single strand about itself 3, 4, or 6 times over. There are many different kinds of rope, but for this kind of a strop the easier to work with is three strand braid. To complicate matters, rope can come in different materials, traditionally tarred hemp was used because of its superior qualityies. Today, hemp rope can be difficult to find but there are some suppliers, alternatively one could work ith manila, but usually the manila found in most retail outlets is not of yachting quality and is of low strength, and unless tarred deteriorates rapidly.
In contrast to organic rope, there are three types of synthetic fibres used currently: nylon, polyester and dacron. In terms of durability, and stretch, dacron is the best choice, followed by polyesther, and lastly nylon. Nylon is not a good choice for rope strops because of it's tendency stretch and be very eleastic. The biggest concern with polyesther is that it breaks down with the UV rays. In our rope stropes, we chose high grade synthetic manilla.
If you would like to use traditional hemp, we suggest: Hemp Traders
who sell hemp by the yard at a reasonable price.
In order to make the strop, unwind a single strand from a three strand rope. Be careful to unwind the three strands gently. The goal is to preserve the twist of each strand. To maintain the tight twist of each strand's individual fibers, allow the strand to twirl while unwinding it from the original rope. Do not grab a strand and pull it like shucking corn, the fibers will seperate. Each strand needs to be unwound from the main rope rather than pulled apart.
It will require a length that is three times the circumference of the desired grommet, plus six times the circumference of the rope. In determining the size of the grommet, put the thimble and block one on top of the other, allowing a space about the width of the rope between the two. then wrap a string or rope around the whole outside circumference, and you'll have a general idea for the size of the strop. In general, you want it very snug, but not too tight, as you will need to cinch it closed with a tight lashing.
So tor example, a 3/8" thick rope grommet six inches in diameter requires a single strand of rope that is approximately 64 inches long.
When unwound, each strand maintains the "memory" of its winding from the original rope. It is these corkscrew undulations, or wind Intervals that will provide the guide for re-winding the strand onto itself.
Make the grommet by bringing one end around to form a ring, then simply cross the strand work
it around the ring as in fig. 2. Then form a third circuit, leaving the ends of the strand A & B.
Bring one end around to form a ring the desired diamter and cross the strand as shown in figure 1. Now pass aloing the long or working end about itself one complete circuit of the grommet as in figure 2.
Each wrap should fall in place with the original wind shape and the strand should intertwine naturally with the original Wind Interval as a twisted pair.
Keep working the strand it all the way around the ring until one complete circuit.
In the grooves remaining make a third circuit around the ring, as in figure 3. At this time you should be left with the ends A & B. You are now faced with the problem of disposing the two strand ends, in such a manner tas o tuck them in so as to increase the diameter of the rope as little as possible.
There are many ways to do this, but by using this method of splicing it is very simple and practical.
Split the rope ends A and B into two pairs; so you should have end A split into strands 1 and 2; and end B split into strands 3 and 4.
Split the two ends into four strands: 1,2,3 and 4.
Next, create a left-hand knot by passing the end of of strand 4 under strands 1 and 2, and the end of strand 2 under strands 3 and 4 as shown below. Tighten them together, rolling the grommet as you make the tucks to help keep its form.
Make a left hand knot with the strand ends,
tucking strand 2 under 3 and 4; strand 4 tucked under 1 and 2.
Now, temporarily leave strands 1 & 3, but begin tucking strands 2 and 4 such that you tuck over one and under two, over one and under two in that pattern, basically
strand 2 over stands 3 and 4, and the under two strands, over one, and so on until you reach the end of the strand. Then do the same for strand 4, over strands 1 and 2,under two, ober one, and so on. It should then look like the figure below:
Leave strands 1 and 3, and tuck strands 2 and 4 in a pattern of over one, under two etc...
Complete the same pattern with strands 1 and 3, whereby where strand 2 is over one, strand 1 is under two, continue rolling the grommet and following the over one and under two pattern until about three repitions are completed.Finally, pull all the strands snug, rolling in your fingers or whacking lightly with a mallet to maintain a consistant shape and uniformity, then cut the ends and tuck the ends in, and your grommet is now completed.
Now, as a final step you may want to whip over the splice whith tarred marline, to help hold in the frays, as well as, keep the rope from fraying on the thimble.
How to whip a line: 1. Make a loop, wrap the line around the loop,
2. Pass the end through the loop, 3. Pull the ends tight.
A completed rope grummet with a tarred marline whipping
8. Assemble & seize the grommet
Now it is time to assemble everything together, and finally seize the grommet around the block and create a beckett (eye) with tarred hemp marline which is commerical available (although expensive)via mail order from most marine supply stores.
Alternatively, you could use hemp twine and tar it yourself, we used this route and made a tar mixture using imported genuine Stockholm Tar which you can get from a variety of sources including:
Ancient Pine Tar Recipie
Combine equal parts of Genuine Pine Tar and Boiled or double boiled linseed oil.
Heat to 80 degrees F and mix thoroughly.
Apply warm if possible.
We used 20 lbs (20#) hemp twine from Global Hemp
. You can also obtain reasonably priced hemp twine from Hemp Traders , from them you can also order "waxed" hemp which is similar to soaking it in beeswax.
With untreated hemp, take the roll of twin and simply soak it in the pine tar mixture. When it dries it will become tacky to the touch.
Lastly, you could use a synthetic twine such as a no.15 mason line from a place like Home Depot, and soak it in beeswax, which can be found for candle making in craft stores at about $10 a pound or a traditional pine tar mixture. The beeswax will be hard at room temparature and it needs to be made into a creamy "tar" like mixture.
To make a beeswax tar, crumple about 1/2 ounce of beeswax into a small amount of turpentine, and stir the mixture until it has the consistancy of a hand-cream in a small jar or tupperware container.
Then submerge and swirl a loosely coiled length of twine in the beeswax cream until the twine is saturated. Then, remove the twine and set it aside to allow the turpentine to evaporate leaving the twine stiff and tacky with no loose fibers.
The hemp marline or beeswax nylon line will add a surprising amount of strength, and stiffness to the strop. Closing the grommet around the shell of the block is done by with a seizing. Place the rope around the shell and start the seizing about two rope diameters above the top of the block - the seizing is worked towards the block, drawing the rope together and pinching the shell in place.
There are a few different methods that can be used to close and seize the grommet. The first thing is that most seizings are generally started with an eye. Of course, this can be a little troublesome, as marline and twine are very fine things. The easiest way to makean eye is by using a method known as the tucked eye. Basically, just twist the twine in the opposite direction of the lay to "unwind" it a little, form a loop and then tuck in the loose ends between the strands in the lay. Leave the end rather long, and if the tucks and the end are buried under the first few turns of the seizing it will become very secure.
Another method is to create a spliced eye, which is a bit more involved, but neater and more secure. It is basically formed in the same method as the tucked eyed, but then the end strands are opened up and then woven through the remaining strands in an over and under fashion, like a typical eye splice.
A figure showing how to make a proper eye in marline for seizing
Howeverm the most basic way to seize (close) the eye is to simply seize the grommet using a knot and frapping procedure known as throat seizing, this method does not require the use of an eye, and is shown below:
Note:If you are having trouble getting the grommet to close, in order to get it really tight you may need to use a spanish windlass to draw the ropes together, and make it easier to work the seizing.
The round seizing is probably the most used and practical of all the seizings. In this version you draw the two parts together by using the looped marline. This type of seizing works very well with the spanish windlass, shown above. Once you have drawn it together put on ten to twelve turns working upwards towards the thimble, until you are slightly longer than the rope is wide, then at the top, finish off with a single hitch. Then working downward apply a second layer of turns over the frist, but two less in number. These are called riding turns.
Finally, pass the end of the marline through the tucked or spliced eye, between the two parts of the rope to the back, and around the riding turns three or four times. These turns are called crossing or frapping turns, and are hauled as tight as possible and then secured with a single hitch. Then simply trim, and tuck end of the line under the wrappings.
The round seizing is one of the most common, easy and practical methods.
Another style of seizing is called racking seizing and was originally designed for wire rigging. In a racking sezing you begin with a tucked or spliced eye the end of the marline, the loose end is passed through the eye like a round seizing, and the two parts of the rope are drawn tight, then the twine is wrapped in a figure eight pattern, over and under, around each of the two parts of the rope and with each turn of the twine the seizing is drawn tight before the next turn is put in.
Once the top is reached, then the twine is run down the seizing, by simply wrapping a second layer of twine over the first, with each turn sitting in the groove between turns on the first layer. Unlike the racking turns, these 'riding turns' do not weave in and out between the two ropes. Instead, they are simply wrapped round the whole bundle. They do not need to be hauled as tight as the racking turns - hand tight is fine. Ideally the finished seizing should be about at least as long or slightly longer than it is wide.
With the racking and riding turns in place, a several frapping turns are taken around the seizing, between the ropes. To finish off, the start and end of the twine can be square knotted together. and the ends trimmed and buried or if you prefer simply leading the end of the twine around the frapping in a half-hitch, and then drawing all tight before cutting off the tail.
Once you have finsihed yor seizings VOILA! A finished rope stropped block!