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The Comprehensive DIY Compound Bow String/Cable Making Guide

1206776 Views 9193 Replies 699 Participants Last post by  Gene1
Automan26 and I collaborated to bring you all this information. Hopefully it will inspire and help people to star making their own custom strings.

There are a lot of guys who want to start building their own strings, but two things are holding them back: 1) They are reluctant to invest hundreds of dollars for a jig with the possibility that they might not like string building and don’t want to end up with a $350 dust collector. 2) Many guys don’t have a clue about how to build a string and are afraid the process is more complicated than they want to get involved in.

This thread is designed to take care of both of these problems so anyone can start building strings fast, cheap and easy.

This thread is going to get quite long, but I want to make sure that you have everything you need to get starts as well as some instructions on string building to make you successful.

Auto part Suspension Engine Machine

BEFORE YOU BEGIN— All the parts on this jig have an important purpose. I had to work through a number of difficult problems that are not readily apparent just from looking at the finished product. If you leave anything off, you will run into a problem I worked hard to avoid.

Unistrut and Superstrut parts are nearly identical. I have used parts from both manufacturers simply because I had to use what my supplier had on hand. Mix and match parts as you wish, they will go together just fine.

Parts List

2, 10’ sections of 1 5/8” Superstrut channel (Flip one over and bolt it to the bottom of the other to help stop it from flexing when stretching long strings).

4 Superstrut/Unistrut corner brackets—3 ½” X 4”

2 pieces of 7” long, ¾” wide by ½” thick steel bar (If in the Kansas City area, Metal by the Foot will cut it to length)

4 Superstrut/Unistrut spring nuts

5/8” All-thread rod—Cut to make 2, 7” sections

1 Compression spring— McMaster Carr part Number: 9573K81 Medium Load Chrome-Silicon Steel Die Spring 1.5" Hole, .75" Rod, 2" L, .135" X .345"

6, 5/8” nuts—(3 for each section of All-Thread)

4 coarse thread, 1” X ½” bolts

4 coarse thread, 2” x ½” bolts

8 coarse thread ½” nuts

8” x 3/8” eye bolts with internal diameter large enough to fit the 5/8” threaded rod

4, 3/8” bolts with 8, 3/8” washers and 4, 3/8” nuts (To bolt the strut together. 3/8” because that allows you to fit a socket into the channel to tighten them down)

2, 1/4X20 X 3” Grade 8 hex bolts (handles)

2, 1/4X20 X 2” Grade 8 hex bolts (jig posts)

If you look at the pics above you can figure out most of the assembly, but there are a few things you will need to know:

1. Adjust the height of the eye bolts so that they keep the All-thread level when tension is applied to the jig posts. Due to the fact that the tension is not centered along the axis of the All-thread, the posts want to tilt down when under tension. This causes a severe binding problem that you will want to avoid.

2. Drill a hole through the nuts and All-thread, and then tap them to fit the bolts. This is more difficult than first appears, so if you do not have confidence in your abilities, a machine shop can do the task very cheaply. These holes need to be dead center and squared-up. I found it was easier to thread the nut on the all thread and drill through them at one time rather than drilling separately.

3. Screw the Grade 8 hex bolts down ALL the way down. You don’t want any threads from the bolt still showing as it would not be a smooth post to build on.

4. Grind a flat spot (prevents drill bit from “walking” on you) on top of the other end of the all thread 1” from the end. Drill and tap another hole in the flat spot for the “handle” screw.

5. Clamp the 7” pieces of ½” x ¾” steel bar between 2 of the corner brackets. Make sure the steel is centered, and drill them all at once if you can. If you cannot drill them at the same time, clamp them together, mark the circle of each hole in the corner brackets on the flat bar with a pencil. You may need to go around several times with the pencil. Then use a straight edge and make an “X” in the circles so that the “X” crosses dead center in the circle. Use a steel punch to make an indention where the lines of your “X” cross so there is a place for your drill bit to settle to prevent it from walking. If it walks, you may have a hard time lining all the holes up.

6. Between the two existing holes in one of the corner brackets, drill a hole big enough for one of the 3/8” eye bolts. On another corner bracket, between the existing holes, drill a hole big enough for one of the coarse thread 1” x ½” bolts. You can see on the picture which bracket has the eye bolt between the existing holes and which has the 1” x ½” bolt between the existing holes.

7. Adjust the eyebolts until they cause the 5/8” all thread rod to sit at an angle like in these pictures.
Screw Nut Dumbbell Gear Clamp
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This will prevent excessive binding when you tension the string.

Tensioning the String

There are two methods which can be used to put tension on the string. First, you can pretention the tension spring and use the adjustments on the opposite head and tighten until the compression spring begins to move slightly. As soon as the stop bolt on the spring head moves slightly, the pre-tensioned spring is pulling on the string. Automan26 likes this one but I use the second method because my jig is built slightly differently.

The second method simply involves adjusting the non-spring jig head to do all the pulling and compressing of the compression spring. This allows you to use the spring as your scale. I like this one because long strings will take a different amount of adjustment to reach the same poundage as a short string. It also seemed easier since I will go up and down in weight often during the build process. To calibrate your spring, hook up a heavy scale that is capable of weighing something to at least 300lbs. Use the spring-less jig post to start tensioning the spring and watch the scale climb. When you reach 100lbs, measure the spring and record that measurement. You can also build a “jig” to that fits between the ½” thick steel bar and the washer on the outside of the spring when you reach your poundage. (That’s what I did and it works great.) Keep tightening the jig until the scale reaches 300lbs and measure or mark your jig. With these measurements or “jig” you will not need to use your scale again except to check periodically to make sure you don’t need to recalibrate. (I have not need to recalibrate for the several months I have been doing this.)

Also, keep things well lubed up. This is an inexpensive starter jig and is thus not the same quality as something you will pay $300+ to purchase. At times things may bind a bit and need a small tap here and there. It’s no big deal, but it is a small price to pay for a jig that costs as little as this one and can build the quality of string that this jig can build.

String Building Formula

Here is a good formula for determining the proper number of twists and the finished string length:
Finished Length X .75 = Number of Twists
Number of twists X .012 + finished length= Initial Jig Post Setting.
Example: 100” String
100 X .75=75 (Twists)
75 X .012=0.9”
100” + 0.9”=100.9” (Initial Post Setting)
Add 75 twists to your 100.9” string and you should be very close to your finished length.

Building the String

Note: I build all my strings and cables with the top loops on the post without the spring. This helped to keep me from getting confused about serving direction when I started and I have kept it the same for consistency. We’ll call that post A. Post B will be the stationary post that has the spring on it.

1: Set and measure you jig to the appropriate length. Measure from outside of one post to the outside of the other jig post.

2: Tie off a tag end and lay out your material so that none of the strands overlap on the jig post.
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I am only on page 12 (only 400 pages to go) but I figured there was some issue with understanding which way to serve and this seems to work for me and seems to be always right.

I use my hands!! All joking aside, I really do.

1. I choose which way I will twist my string, clockwise or counterclockwise.

2. If I choose to twist my string clockwise, I will use my right hand to tell me which way to serve. If I turn counterclockwise, I will use my left hand.

3. Now, I lay my thumb along the string and point my thumb in the direction I will be building the serving, away from me or towards me (left or right depending on how the string is in front of you).

4. I will then curl my fingers around the string and that is the direction the serving tool will wrap - from palm to finger tips. The finger tips point the way to turn the tool around the string!

To tell the truth, this comes from figuring out handedness in chemistry and the way current, magnetism and induction or something works as well. I will admit I have forgotten my physics but it works with string building too. I will bet that it also works in biology.

OK, I bet someone in the next 400 pages also figured this out but just in case, I will post it.

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This may help with twisting and serving

Yes, the clock face works as long as you serve towards the clock. It is opposite the clock if you serve away from the clock. That is how I came up with the thumb and finger or my right hand method for clockwise string twisting. My thumb points along the string from the starting point towards the direction I want to build. The other 4 fingers always point the way to turn regardless how you stand or direction you want to serve. The best thing is, I can never lose or misplace my hands :). Also works if you need to replace the center serving in the field and the clock face is at home. Also, if I want to twist counterclockwise, I just use my left hand and it works too.

As long as the person can figure it out, all is good. nice video and thank you for all you have contributed here.
Is it possible to use a piece of 1 x 1 square tube stock instead of the 1/2" piece of plate steel in the jig?

I am new to string building and was thinking of how I could use those test pieces.

1. Make a piece long enough to use to tension a 4 post from the 2 post puller. I think this was shown in the post #5009.

2. Create loops on both ends of a short test piece and I wonder if you can use it to serve loop ends together. I was thinking of passing the short section so that the test piece would pass through the tagged or served end and be use to attach to the 1/4" post. Both ends of the test piece would be on the same post and the loop formed would hold the new string end. Sort of like a middleman between the post and the string being made. Since the string is far narrower than the 1/4" post, it might be easier to bring the two sides of the loop together. Just a thought. might be good use for a 6-10" piece.

3. Us those really short pieces as a connector to a carabineer to attach your keys.

4. Use test pieces to attach things to your case or quiver to have them handy or put different colors on thing you use frequently so as to find them fast in a pocket or drawer.
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automan26, Huntinsker and several of the others who have really made this thread so valuable and full of great information.

I would like to send out a big thank you!!! It took me 2 weeks of reading every spare minute but I have finally finished every post.

What a wealth of information and a wonderful comradery you have developed. I hope to join your ranks both as a newbie learning and maybe one day as a provider of help and information. I have recorded several links just from this thread and from all the videos you all have made. It really boosts one's confidence that the time and investment will be successful.

I have decided that I would like to build my El Cheapo out of pipe similar to this one Post #5486 - 5487.

From what I gather, the 'T' is a 3/4" T and uses 3/4" thread by 1/2" sweat adapters. The ID of the 1/2" sweat is actually 5/8" since copper pipe is measure ID and is 1/2" so they need some material for the walls which are 1/16" thick. This is why the sweat fitting, I found out, is really 5/8" since the sweat fitting goes outside the pipe.

My local Home Depot has galvanized and black pipe. Can I use either for the T or the vertical pipe?

Both Lowes and Home Depot sell 3/4" pipe nipples (threaded at both ends) in lengths of 5", 6" 7" and 8". What would be a good length
? I know I can buy a longer pipe and cut it in half but I do not have a chop box to get a square end. Easier to spend a few dollars for the right length.

Any idea as to what length 5/8" bolt to run through the entire assembly? What grade?
Do you think a Dremel cutoff wheel and grinder bits will allow me to cut the threads out? I like the idea of the locking screw on the top.

Huntinsker, as I was reading, I had the same thought as you to use the threaded coupler. I was thinking how can I weld it to the screw to make it permanent and I love your idea of the JB weld. I look forward to doing that on mine as well so as to allow for a central twisting point ( The Comprehensive DIY Compound Bow String/Cable Making Guide ). I just love your solution!! As I came upon your post, it screamed Eureka!!! awesome idea. Not sure if it can be used with pipe parts or not. Will need to see. I think this uses a long bolt that has no threads cut except for the end which might limit which way it can be inserted. Not sure if the thread hampers the pipe fitting build or not.

Any suggestions how to prevent the T from rotating? I have a fear that when I drill the vertical pipe, I will somehow be off center or twisted and will not be able to get the top to line up. I fear having the vertical pipe attach to the L brackets so that the top T is not pointing down the rail. Any ideas? OK, a big pipe wrench and some muscle but besides that!!I might be able to run a small bolt or pin through the T and the pipe to lock everything in place but that too might require some skills..

Anything go inside the T fitting? I see the washers, springs and bearing are all on the outside so I believe nothing but air.

Do the 3/4" x 1/2" threaded adapters need to be cut down at all? I am thinking the sweat side. If yes, how much? Not sure if the cut most of the sweat fitting side off or not.

Again, thank you all who have offered help and posted ideas.

With deep appreciation,
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Also, I would love to get a string material that can be used for both recurve and compound. Suggestions?
I was thinking Mercury but I was several on here buy some and then saw they put it up for sale and wonder why?

I know that 8125 either creeps too much or heat issues makes it a poor string for compounds otherwise I might buy that. I am not sure if Mercury is better for both. I have a feeling I may need some older material for the Hoyt and some 8125 for the recurve (will show it below)

Anyone have the measurements for a 1997 Hoyt Enticer Carbonite with MasterCams? 56" and 32.25" come to mind.
Any idea on the serving mapping? I should probably post this in the other thread.

I also have a Gillo G1 (27" riser, long limbs (69" string) that I just got so I am not sure the final string length. I purchased strings that I am not super happy with and would like to buy material for both of them - possibly the same material. Being an older bow, it might not be able to take the stiffer and newer material. I do not know.

Finally, in Brownell or BCY, I was wondering what colors would match the Gillo G1 in Blue and the gold found on the bow It also has white with some black limbs.

Even the wood grip is rather orange:

I think the picture doesn't look as orange as it really is. This grip picture is very close to spot on.

I got a 8125 string in blue and flo yellow and it doesn't go with the orange-gold pieces. The string looks great but not for this bow. The second string I got is the blue with white spec. which looks really good. When I waxed it, the white now looks dirty. Making my own would afford me a clean set always but I am open to alternative suggestions. Also, the white speckled is not available in Mercury. Only solid colors.

Any idea if the Gold string material would be a closer match or would something else be?

I have no idea about Brownell colors so I would welcome those suggestions as well.

I have a feeling I will buy some black and replace the compound string and then buy some colors for the recurve. Not sure. At the same time, I would like to get experience in one material if possible.

Thanks for the suggestions
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I know, I have a lot of questions but I have just finished 413 pages!!

I was wondering if anyone made their Unistrut - takedown?

I was planning on using 2 struts, one above the other. I was thinking of cutting them 6' and 4' each. One would have the 6ft on top and the other on the bottom so that I can use something to bolt the two together at the 2ft overlap to make a one piece?

If 2ft of overlap just seems logical but I have no engineering experience to support these dimensions. Being 6ft tall will fit almost anywhere. Also, I might be able to make some string on just one piece. Sure, I would have a 2ft section unsupported but I would be able to make at least a 4ft string without needing to join them. If I buy a two foot piece, I might be able to go 6 ft and make a mini setup.

I fear I will have no place to store 10ft worth of steel.


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Just a final suggestion.

Maybe make a Part 2 of this thread and let the first one end. This way, you can reorganize the info now that so many have made various improvements and suggestions. You could always make a set of links to good posts in the first.

Again, just an idea.
thanks for the material suggestion for the Enticer and the colors for the Gillo. I will have to check Blue and silver out! sounds cool. thank you.

As for the jig rail, I have a feeling what I am looking to do is being lost in my explanation and I have a little bit of an improvment to it as well that might hold water better.

I have read where some are taking two Superstruts and bolting them together for more rigidity. Here is a super quick (and lousy) diagram showing that I would like my rail to be comprised of 4 pieces of Superstrut, 2 x 6ft and 2 x4ft cut from 2 x 10 ft pieces. This would be more so for takedown and storage but I feel that I can also make any short string or cable with just one section. I understand your comment that I need extra width to support the entire post and that will narrow down what the usable length will be. I would not have any space between the two section and have them butt against each other. The red lines are the bolts (much longer than in reality) bolting the backsides together. The two ft overlap would have at least 3 or 4 bolts joining the overlap. I have shown three here just for diagrammatic purposes.


This would allow me to dismantle the 10 ft rail for easy closet or corner storage.

I was also thinking of using a separate 2ft Superstrut to make 1/2 of my rail setup be useful at a full 6ft in length. I have seen that they make a short flat piece, similar to the L brackets, that has holes in it to join two Superstruts together. I could put a 2ft piece and that strap across the bottom for further reinforce the joint and make a 6 ft doubled rail. The top would be in compression during string stretching so there is no need to add it there. Just need to make sure the two are tight against each other. At least that is the thought.


What do you think?

For me, the only time I would need a full length 10 ft rail is when I am making my 68.5" recurve string. The Enticer only needs a 56" string and 34.5" cable and if the rail is 72" of usable space, I think your design for the posts would still fit.

The benefit would be easier storage and would only cost me the price of the flat strap and 2ft section to get a 6ft rail instead of having to buy 2 more 10ft sections to cut down should i desire a shorter rail.


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Does 8125 elongate with heat? That seems to be the Olympic recurve string of choice. I wonder if it matters with a recurve. I am new to recurve but I have heard that it is advisable to check the brace height and tiller each time. I wonder if you need to add twists if the nocking point moves too?

Doesn't X99 have Vectran? I think for most recurves that is a no no. Might still be curious for the Hoyt.
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I believe what he is referring to is the tension on the serving jig is set to have a 10lb load when the string is pulled out.
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