# Building A Lever Bow



## WillAdams (Jun 6, 2009)

very cool!

What are you planning on using for the outboard limbs?

I've got a couple of drawings for what I hope will be a simpler lever limb bow --- still tweaking stuff, and I'd like to find an opensource finite element modeling program I can wrap my brain around.

In the meanwhile I'm working on a first pass at a two-piece bow cut out of Ipê using my CNC machine (need to get homing switches set up).


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## tctwaites (Jul 2, 2014)

I am thinking of using a thick fiberglass mix as I tried with the first set of power limbs as it was unbending, and my research shows that the outboard limbs should be very very stiff. 

And im definitely interested in seeing your finished work. Always nice to see other creative designs.


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## tctwaites (Jul 2, 2014)

Cleared the riser









The green one on the left is mine, the blue on the right is one my girlfriend is making.

I will be making my cam brackets out of some sheet metal, but I am looking into carbon fiber to get a lighter, cleaner look.


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## Fury90flier (Jun 27, 2012)

On the limbs...try vacubaging...will remove much of the voids in the layers.


are you going to make cams or just threads only like the old Discover and Monster bows?


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## tctwaites (Jul 2, 2014)

At first it will just be a simple pully, but I would like to fab up some legit cams. 

And I will look into vacubaging.


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## tctwaites (Jul 2, 2014)

When it comes to vacubaging, is there any good writeups on it?


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## Fury90flier (Jun 27, 2012)

yes there is, just do a yahoo search- google sucks.


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## tctwaites (Jul 2, 2014)

That looks really effective. After my first couple prototypes are done I will definitely look into that.


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## tctwaites (Jul 2, 2014)

Just picked up some carbon fiber wrap for the brackets and limbs when all is said and done to add some look appeal.


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## tctwaites (Jul 2, 2014)

Got a bunch of items to finish the bow, hinges, screw inserts, metal for the brackets, wood for limbs, and materials for the string. 

I got a couple different types of wood for cores to see how they compare to each other. 

Tomorrow I will be making the first set of power limbs.


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## tctwaites (Jul 2, 2014)

Traced out the brackets for the cams/pullys. 









Measured out the power limbs. I decided to go with 7 1/2" rather than 6" as it just seemed to short.


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## Silverstar723 (Apr 30, 2012)

tagged


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## tctwaites (Jul 2, 2014)

Was able to do a few things before work. 








Cut the power limbs









Got ready to cut the metal brackets. 

When I get off in a few hours ill be going at it again.


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## tctwaites (Jul 2, 2014)

Drilled and inserted the thread inserts. A little off, but not to bad, will just have to make sure limb holes are in the same spot. 









Layed the fiberglass backing on the first power limb, I did 5 layers of fiber cloth and I will do 2 layers on the belly of the limb. Clamped and drying. 










This is my small work space, isnt much, but its a start.


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## tctwaites (Jul 2, 2014)

Little dark, but I think I rolled to much resin off this one, so I now have a second one which I didnt roll and clamped lighter then the first. We shall see how it turns out.


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## tctwaites (Jul 2, 2014)

Looks like the second one did it as well.  but this is my first attempt at something like this, so there will be some trial and error. 

What wpuld you guys suggest as a way to lay fiberglass as a backing? My next attempt will be to just let it air dry with no clamps or anything.


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## b0w_bender (Apr 30, 2006)

maybe you should find some old limbs from a youth bow or something and use those. This is a great thread I'm looking forward to seeing how this bow turns out. I expect some will accuse you of being sloppy but this is the best way to learn how things work and to get proof of concept. You can be all detailed and and finicky on the mach 2 or 3 when you have a more refined direction. Great thread and fun topic lets see some more.


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## tctwaites (Jul 2, 2014)

b0w_bender said:


> maybe you should find some old limbs from a youth bow or something and use those. This is a great thread I'm looking forward to seeing how this bow turns out. I expect some will accuse you of being sloppy but this is the best way to learn how things work and to get proof of concept. You can be all detailed and and finicky on the mach 2 or 3 when you have a more refined direction. Great thread and fun topic lets see some more.


I was looking into it, unfortunately in new mexico there isnt alot of cgeap second hand bows. Haha. 

I did get some fiberglass tape and a wood epoxy that I am going to try. Because as you said, this is just the first one, it doesnt have to look pretty yet, just function.


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## tctwaites (Jul 2, 2014)

Picked up some Gorilla wood glue and some fiberglass tape. 









First of 4 layers with about 10min set time in between layers. 

Lets see how these ones turn out.


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## BluMeanie (May 5, 2014)

That is an interesting laminate idea.


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## tctwaites (Jul 2, 2014)

BluMeanie said:


> That is an interesting laminate idea.


Thanks.  We shall see how it turns out.


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## tctwaites (Jul 2, 2014)

Got bored while waiting for glue to try so I decided to take an attempt at a home made sight. 

































Wrapped it in some carbon wrap. 

Doesnt look the best, but it functions.


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## STAUGUSTIDE (May 6, 2014)

I am a first time poster on this forum but I do alot of work with different fibers and resin systems. When you are looking to for strength in you laintation you need to think about the cloth not so much the resin. the resin is basically for wetting out the cloth and binding the cloth layers together to increase strength. More cloth=more strength given a properly executed lamination. vacuum bagging was mentioned earlier and as you progress through this process I would seriously encourage you to research some of those techniques. It definitely involves more money and knowledge bt the end product will be vastly superior. When you are talking about something like a bow that is going to have massive loads placed on it I would definitely want the laminations to be of the highest quality. BTW the fiberglass tape used in the last picture isnt going to offer you any significant strength gains due to the open nature of the weave. Just my .02 worth.


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## STAUGUSTIDE (May 6, 2014)

Sorry the spelling is so horrible in the above post. I didnt proofread. My bad.


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## tctwaites (Jul 2, 2014)

STAUGUSTIDE said:


> I am a first time poster on this forum but I do alot of work with different fibers and resin systems. When you are looking to for strength in you laintation you need to think about the cloth not so much the resin. the resin is basically for wetting out the cloth and binding the cloth layers together to increase strength. More cloth=more strength given a properly executed lamination. vacuum bagging was mentioned earlier and as you progress through this process I would seriously encourage you to research some of those techniques. It definitely involves more money and knowledge bt the end product will be vastly superior. When you are talking about something like a bow that is going to have massive loads placed on it I would definitely want the laminations to be of the highest quality. BTW the fiberglass tape used in the last picture isnt going to offer you any significant strength gains due to the open nature of the weave. Just my .02 worth.


I am currently looking into a few different vacuum bagging techniques. The tape as a backing is just for a base build, I.e., to make sure everything will function. Once I get a functional first, I will improve it from there piece by piece. 
Thank you for your input.  this is a learning process for me.


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## tctwaites (Jul 2, 2014)

Got it all trimmed up. Looks like this one will work. Letting it cure over night, then sanding the edges smooth and moving on.


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## tctwaites (Jul 2, 2014)

Going to not be able to get alot done today, got stuck pulling a 14 hour shift at work. Going to try and get the limbs mounted when I get home and get a template for the outer limbs done.


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## tctwaites (Jul 2, 2014)

got the power limbs finished and attached. I am definitely looking into making it out of a different material as this wood is very soft. But it will function for the first bow. 








Made a remplate for the outer limbs. They will be made of fiberglass matt cloth and resin.


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## tctwaites (Jul 2, 2014)

Used some soft velcro for the arrow rest.


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## tctwaites (Jul 2, 2014)

Just layed the first outer limb. We shall see how it turns out in the morning. 

I am looking at mold making for vacuum bagging to make the limbs more perfect. The next, mach 2, bow will be better then this one, as will mach 3. By the 4th I am planning on having it almost perfect. 

When this build is done, I will be editing my first post and placing a guide to each post of the build to make navigating easier.


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## tctwaites (Jul 2, 2014)

Not shapped yet, but first outer limb is layed.


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## Fury90flier (Jun 27, 2012)

if you want pointers on making the limbs, call up Joe at American Eagle Bows. He probably won't tell you step by step since he makes power limbs and outboards but he'll probalby give you some ideas on what to watch out for.


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## tctwaites (Jul 2, 2014)

Fury90flier said:


> if you want pointers on making the limbs, call up Joe at American Eagle Bows. He probably won't tell you step by step since he makes power limbs and outboards but he'll probalby give you some ideas on what to watch out for.


I will definitely give him a call. Thank you. Ive made many recurve bows, just nothing like this before. Haha.


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## tctwaites (Jul 2, 2014)

Got the brackets cut. A little rough and a little short, but for the first bow im just making notes of changes. The second one I will be implement ing the changes.


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## tctwaites (Jul 2, 2014)

Been making some phone calls, and after getting some advice from Joe at American Eagle Bows, I have redesigned the bow. I am still going to continue with the mach one bow and finish it, but alot of changes are being done to the second one

For the power limbs I will be using an E-Glass composite. 

For the outer limbs I will be using a carbon composite. 

I am talking to a friend about machining me some cams and timing gears along with some high grade hinges. 

I am also looking into different materials for the riser as wood wont be able to handle the final product.


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## tctwaites (Jul 2, 2014)

I am in the market for a decent CNC machine to craft aluminum risers. Dont need anything fancy, just some recommendations on some good quality machines.


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## WillAdams (Jun 6, 2009)

Biggest bang for the buck at the low-end is the Shapeoko (ob. discl. I did the assembly instructions in exchange for a machine): http://docs.shapeoko.com/

Hopefully anything you might wish to know about CNC machining (or the machine) would be on the wiki: http://www.shapeoko.com/forum/index.php

Lots of people cutting aluminum --- I got mine to do brass hardware for my woodworking, but still learning about the machine and filling in the wiki --- please let me know if there's something you want to know but can't find.

There is a list of CNC projects here: http://www.shapeoko.com/wiki/index.php/Other_CNC_projects


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## tctwaites (Jul 2, 2014)

WillAdams said:


> Biggest bang for the buck at the low-end is the Shapeoko (ob. discl. I did the assembly instructions in exchange for a machine): http://docs.shapeoko.com/
> 
> Hopefully anything you might wish to know about CNC machining (or the machine) would be on the wiki: http://www.shapeoko.com/forum/index.php
> 
> ...


Thank you for the response. This is a few months away, but it will give me time to pick out the one I need.


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## tctwaites (Jul 2, 2014)

Got the brackets and pullys attached. 









Got some basic hinges. 









And got the outer limbs attached. 


















Tomorrow I will be making the strings and seeing how she does. First one almost done.


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## WillAdams (Jun 6, 2009)

tctwaites said:


> Thank you for the response. This is a few months away, but it will give me time to pick out the one I need.


My pleasure --- please let me know what sort of information you're looking for in making your decision and anything else which you think would be helpful to first-time buyers.

Next project is tweaking the Parts and other images to make them more efficient file-size-wise and more dynamic.


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## tctwaites (Jul 2, 2014)

WillAdams said:


> My pleasure --- please let me know what sort of information you're looking for in making your decision and anything else which you think would be helpful to first-time buyers.
> 
> Next project is tweaking the Parts and other images to make them more efficient file-size-wise and more dynamic.


I just need to be able to mill out risers approximately 18-24" long 1.5" deep and about 2-5" wide.


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## tctwaites (Jul 2, 2014)

Working on some new power limbs today for the prototype. The wood limbs help for a couple pulls then gave out. 


















Im trying a thinner fiberglass limb and seeing how it does.


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## tctwaites (Jul 2, 2014)

Got the new power limbs setting and starting to cure.


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## b0w_bender (Apr 30, 2006)

Looking good, you may end up having to buy an el-cheapo bow off eBay after all, just to get some working limbs. Lets hope the fiberglass ones hold up a little better. Take some pictures of how you are stringing it up, I would love to see the cabling pattern.


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## tctwaites (Jul 2, 2014)

b0w_bender said:


> Looking good, you may end up having to buy an el-cheapo bow off eBay after all, just to get some working limbs. Lets hope the fiberglass ones hold up a little better. Take some pictures of how you are stringing it up, I would love to see the cabling pattern.


Thanks.  And for the limbs I am gping to be eventually using an E fiberglass on the power limbs. And a carbon, e fiberglass layered outer limb. 

But I am hoping the fiberglass I have curing will work for this first one. 

Ill get some pictures up tomorrow of the cabling.


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## tctwaites (Jul 2, 2014)

Got the new limbs attached. 

















Got the lines ran. 









Got it all together.  

Now for the changes.  
I am redesigning the outer limb length and shape to reduce the brace height. 

I am going to shorten the power limbs an inch to also help reduce the brace height. 

I am reshaping the cam brackets after the limbs are redesigned. 

It shoots and functions currently. Now lets just improve it.


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## tctwaites (Jul 2, 2014)

I have a new shape and design for the outer limb. First one curing.


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## Fury90flier (Jun 27, 2012)

go look into the Oneida Stealth...it has a unique cable saddle that sits on top of the outboard.

Look at the stuff that 5150 bows/gulf coast archery has. They have a saddle that allows you to adjust let-off by moving pins forward or back. I tried to find a pic quickly but was unable to...I'd suggest becoming a member and searching their site.


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## tctwaites (Jul 2, 2014)

Fury90flier said:


> go look into the Oneida Stealth...it has a unique cable saddle that sits on top of the outboard.
> 
> Look at the stuff that 5150 bows/gulf coast archery has. They have a saddle that allows you to adjust let-off by moving pins forward or back. I tried to find a pic quickly but was unable to...I'd suggest becoming a member and searching their site.


Will do. I just ordered a cnc machine with a 1mx1m work surface. So I just need some basic concepts and I can fab my own. Thank you for the info.


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## Green River (May 13, 2006)

What are you using for a string?


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## tctwaites (Jul 2, 2014)

Green River said:


> What are you using for a string?


Right now im using a braided dextron fishing line in a continuous liip and bees wax.


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## dolgima (Jun 15, 2014)

how about making monster bow that has no cam It's more simple

http://youtu.be/2se3Z9XaLwk

control cable synchronize each limb moves same time.


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## tctwaites (Jul 2, 2014)

dolgima said:


> how about making monster bow that has no cam It's more simple
> 
> http://youtu.be/2se3Z9XaLwk
> 
> control cable synchronize each limb moves same time.


Its a good design, I just like a challenge. Haha. Im sure ill make one like that eventually.


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## tctwaites (Jul 2, 2014)

Waiting for the first outer limb to finish curing and just layed the second one.


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## b0w_bender (Apr 30, 2006)

Are you seeing an inconsistent flexing from the top limb in comparison to the bottom limb? My experience with cabling that does not tie the upper limb flex to the bottom limb flex is that the limbs have to be really well matched or you get one limb that bends more than the other and can cause goofy tillering and string travel. What doesn't you draw curve look like/ What kind of let off are you getting if any?


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## tctwaites (Jul 2, 2014)

b0w_bender said:


> Are you seeing an inconsistent flexing from the top limb in comparison to the bottom limb? My experience with cabling that does not tie the upper limb flex to the bottom limb flex is that the limbs have to be really well matched or you get one limb that bends more than the other and can cause goofy tillering and string travel. What doesn't you draw curve look like/ What kind of let off are you getting if any?


It is a little off bend wise, however with these limbs I have an inconsistent resin amount. The final limbs will be made under pressure with exact amounts measured. As well as I am designing a timing setup and some cams to keep everything moving together. The pully on it now are just a prototype concept.  I am getting a little bit of let off, however not as much as I want yet.


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## tctwaites (Jul 2, 2014)

Out late lating a new outer limb. Almost have it perfect.


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## thefirstbirddog (Apr 29, 2010)

Following..


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## tctwaites (Jul 2, 2014)

Got the new outer limbs done. And they are damn near perfect. Brace height is now at 5.5". 

I am going ti switch to a metal cable for the cams however as the ones I made snapped on second draw at about 50#


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## WillAdams (Jun 6, 2009)

tctwaites said:


> I am going ti switch to a metal cable for the cams however as the ones I made snapped on second draw at about 50#


Have you done any sort of FEA or estimate to determine what sort of stress is placed on them? 

I'm wanting to do a camless lever bow and the cables are a point of concern.


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## tctwaites (Jul 2, 2014)

WillAdams said:


> Have you done any sort of FEA or estimate to determine what sort of stress is placed on them?
> 
> I'm wanting to do a camless lever bow and the cables are a point of concern.


Not yet, I will be doing testing this weekend however. I will post my results.


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## Fury90flier (Jun 27, 2012)

on let off...I think you need to bring the back cable up and back...

check out some of the stuff done with monster bows, 5150, oneida stealth and discovery....look at the fast flight conversions. It will give you an idea of location vs let off %


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## tctwaites (Jul 2, 2014)

Fury90flier said:


> on let off...I think you need to bring the back cable up and back...
> 
> check out some of the stuff done with monster bows, 5150, oneida stealth and discovery....look at the fast flight conversions. It will give you an idea of location vs let off %


Thanks for the tip. I will definitely incorporate that.


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## dolgima (Jun 15, 2014)

It looks great. I tried to make lever compound bow but I failed. This is what i made.I used fiberglass rod as power limb but it was too weak. draw weight was 15#...







When you finish this project can you make simple template of outboard limb? And I want to know size of power limb, outboard limb, ATA, let off percentage.. details.

How about adding hinge stop like this







And changing saddle positions you can adjust draw length.









can you upload shooting video?


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## tctwaites (Jul 2, 2014)

I got the new cable set up done. However the fiberglass power limbs are cracking under the pressure. 

Ant recommendations on why it does this?


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## snowshovler (Oct 15, 2011)

Best guess is you are using chopped glass and vinylester resin and the limbs are thick. The chopped glass doesn't do much more then support/fill the resin which isn't too strong. If the limbs were oriented strands (unidirectional) layed up with epoxy you'd have more strength, less weight and more flexibility. Thick resin layups tend to crack. You might want to try building the power limb in a similar fashion to a recurve limb using a core and glass outer laminates to carry the bending loads. There are a ton of variables but I'd start with a change in materials.


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## tctwaites (Jul 2, 2014)

snowshovler said:


> Best guess is you are using chopped glass and vinylester resin and the limbs are thick. The chopped glass doesn't do much more then support/fill the resin which isn't too strong. If the limbs were oriented strands (unidirectional) layed up with epoxy you'd have more strength, less weight and more flexibility. Thick resin layups tend to crack. You might want to try building the power limb in a similar fashion to a recurve limb using a core and glass outer laminates to carry the bending loads. There are a ton of variables but I'd start with a change in materials.


Ill look into an epoxy resin, and I am going to start vacuum bagging as well. Thank you for the advice.


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## BluMeanie (May 5, 2014)

Micro-voids in the resin? Perhaps the omni-directional scumble of the glass fibre you are using is not quite up to the task you ask of it?

I just pulled both of those out of my arse; I do not really "know" anything about practical composite layup.




Teh Editz:

Ignores me, I see someone that actually KNOWS a bit has responded.


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## snowshovler (Oct 15, 2011)

Vac bagging is a great way to saturate the layup and remove excessive resin. Look into what the RC guys are doing and grub around the builders forums. This site is filled with them. http://www.rcgroups.com/forums/index.php .

With the limbs, I'd start with a basic wood core laminate to get the process down. An all composite layup will have a large number of variable to chase down. The expense will be quite high compared to a wood core layup. Part of what makes the limbs strong is thickness and getting the load carrying plys at some distance. The core is akin to the vertical web of an I-beam. Taller web = more stiffness. In general, if you have the proper strength you can change the stiffness (DW) by altering the core. Much easier to tune the bow to the DW you need. Using glass as the core will add weight and altering the stiffness will use a ton of materials which could be used to laminate many cored limbs. Also Vac bagging a mix of resin and glass will be very difficult as the vac will draw out a huge amount of resin which will make your limb thinner and less stiff and will also be much more difficult to repeat. 

PM me if you'd like some more info on suppliers. I've built quite a few RC planes/boats/cars; gun parts; full scale boats and spent plenty of time screwing around with composite materials. There are a few "must haves" to be workably successful with vac bagging. You can have very good and respectable no bag layups but bagging is super cool, fun, and you will have a superior finished product.

The project is awesome and keep after it. I admire your ambition.


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## tctwaites (Jul 2, 2014)

This is what happened to these power limbs. Alot of stress and these babies. 









Wrapped tge outer limbs in a carbon fiber vinyl just for some visual appeal.


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## handirifle (Jun 9, 2005)

If your top limbs do not hold up, I would buy some bow tuff glass from any one of a number of suppliers, along with the epoxy used for it. You will make stronger limbs and longer lasting. Fred Bear developed limb glass in the 50's and it has specific fiber direction layout. The glass fibers hold the pressure but can only do it if laid up properly. Unidirectional fibers are going to be the ONLY thing that will withstand the pressures you are putting the limbs under.

I doubt you'll have $50 in the pair if you do.


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## tctwaites (Jul 2, 2014)

handirifle said:


> If your top limbs do not hold up, I would buy some bow tuff glass from any one of a number of suppliers, along with the epoxy used for it. You will make stronger limbs and longer lasting. Fred Bear developed limb glass in the 50's and it has specific fiber direction layout. The glass fibers hold the pressure but can only do it if laid up properly. Unidirectional fibers are going to be the ONLY thing that will withstand the pressures you are putting the limbs under.
> 
> I doubt you'll have $50 in the pair if you do.


I was actually looking at that site for the outer limbs.  

The riser gave out on me yesterday. I got the power limbs and everything on and the riser just cracked under the pressure.  

Looking into having an aluminum one made now.


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## b0w_bender (Apr 30, 2006)

A wood riser will be fine as long as you laminate it up with vertical grains slightly offset. Use 1/8" laminations and epoxy.


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## Fury90flier (Jun 27, 2012)

yep....wood is fine- go look at some of the old wood compound bows...we were shooting 70/80#. So long as 1, use the proper wood, 2, get the grain going right and proper thickness of laminates, proper glue...seems like the wood is thrown together but there is some science involved....kind of like making wood arrows.


Where did it break
how did it break- not as in, you were pulling. Examine the fracture, examine the glue joint....did it break along the grain, did a joint fail....could there have been a void in the wood prior to gluing the laminates?



That pic that dolgima posted of the cable saddles is exactly what I was talking about earlier....believe it's 5150 bows that makes that piece.


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## tctwaites (Jul 2, 2014)

Fury90flier said:


> yep....wood is fine- go look at some of the old wood compound bows...we were shooting 70/80#. So long as 1, use the proper wood, 2, get the grain going right and proper thickness of laminates, proper glue...seems like the wood is thrown together but there is some science involved....kind of like making wood arrows.
> 
> 
> Where did it break
> ...


The riser failed where the limbs attached. I had threaded inerts into the wood that the bolts screwed into. The one side it cracked down the center and the other it just pulled the inert out of the wood. 

Sorry for the late reply, been very busy on setting up my new cnc machine.


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## tctwaites (Jul 2, 2014)

Designed some timing gears for the bow. My first set should be done in a week or so.


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## Fury90flier (Jun 27, 2012)

just call Joe...he probably has that in stock out of machined aluminum.....wait- I think you said you have a mill.- never mind


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## tctwaites (Jul 2, 2014)

Fury90flier said:


> just call Joe...he probably has that in stock out of machined aluminum.


Im trying to design my own. Thank you though.


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## tctwaites (Jul 2, 2014)

Getting ready to test out my new shapeoko 2. Then I will be making the timing gears.


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## BluMeanie (May 5, 2014)

Those things ROCK! Wish I had the patience (and space!) for one right now.......


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## tctwaites (Jul 2, 2014)

BluMeanie said:


> Those things ROCK! Wish I had the patience (and space!) for one right now.......


Ya I love it so far.  I am just working on generating g code for it. Haha.


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## Wolfpackhowl (Apr 22, 2012)

Have you considered laminating your fiberglass power limbs with ABS? I've seen lots of lower end bows with compressed ABS limbs that shoot fantastically, I'm actually considering trying it to make my bow when I get the time. Excellent work


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## bowcycle (Aug 26, 2011)

so any updates on this?


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