# Awwwww CRAP!!!



## jskeen (Feb 7, 2011)

I don't like to post mistakes, but this one, A) has me concerned, and B.) might save somebody else some problems, so here goes. I took both of these up to Visit my old people last weekend, and do a little plinking with the family. Both of them ate the big one in almost the exact same spot, and for the same reason. Frame hit from a large (54 cal) lead ball. I was shooting the little one, and my baby brother was shooting the big one at the time. He has an excuse, He had not shot in years, but I don't know for sure what happened to me. Frame hits suck.

My question is this. Is a break in a board cut like this a normal effect from a hard frame hit, or is it pointing out a weak spot in my current designs? The frames did break along the grain, diagonal to the frame but in both cases the break intersected the mortise that the crossgrain tennon is glued into down the center of the frame. Not a large section, but there in both cases. Again, the solid wood around the mortise seemed to be weaker than the actual joint itself, but I wonder if the cut, even though it is solidly filled, might be weakening the frame at a critical point.

In any case, I am going to reglue these along the split, then drill for a couple of 3/8 steel pins from the top of the fork down all the way into the handle and epoxy them into place. I anticipate the repaired frame to be stronger than the original, and am considering this as a regular construction feature in my future frames, unless I decide to go with a metal or composite lamination all the way up the forks.

But let me know your honest opinion on the failure, and if you think it's design related, how you would try to eliminate it.


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## builderofstuff (Feb 14, 2011)

Wish I had something helpful to add here but I don't have any experience with board cuts. However I am sorry to see that happen to them.

Chris


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## gaara4sand (Dec 8, 2010)

Now that is why I use multiplex. :-(


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## Dayhiker (Mar 13, 2010)

That's why I use mostly naturals and plywood. But with a spike inserted, it should be okay.


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## gaara4sand (Dec 8, 2010)

Metal spike you mean?


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## smitty (Dec 17, 2009)

This same kind of failure is why many of us have gone to Baltic birch plywood with our slingshots. It's not that a good hardwood is a bad wood, but they all have grain lines that can fracture if hit, especially by a large lead ball. Some call the Baltic birch plywood multiplex. I like to make my slingshots around one inch thick, so I use 1/2" plywood glued together or I use a plywood core with a nice hardwood on either side to give it that nice look on the face. The pins will help to stop a total failure, but the wood can still crack when it takes a powerful hit. I have had many solid hardwood slingshots for years, but I only shoot them once in a great while now that I have some out of plywood.
Another good idea is to glue different hardwood pieces together to get the thickness you want. This way, you have the solid hardwood you want, but the grain lines won't run all the way through the slingshot. In essence, you are building a form of plywood out of three or four thicknesses of your choice of hardwoods and you don't have the lines of the multiplex showing on the sides of your slingshot.








Here is a picture of two I did. On the left is one out of two slabs of 1/2" multiplex and the one on the right has a multiplex core with bamboo on the outside.


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## CHANEKE_JOSH (Feb 10, 2010)

mahogany? it is a beautiful wood, hard ... and fragile, that is why I stopped using super hard woods on my board cuts. thats too bad!!


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## jskeen (Feb 7, 2011)

CHANEKE_JOSH said:


> mahogany? it is a beautiful wood, hard ... and fragile, that is why I stopped using super hard woods on my board cuts. thats too bad!!


*
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*Actually, *_*Prunus serotina or black cherry. very mature tree, from my parents yard. Much denser and harder than Mahogany (but obviously still brittle) *_
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*_
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*


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## jskeen (Feb 7, 2011)

smitty said:


> Another good idea is to glue different hardwood pieces together to get the thickness you want. This way, you have the solid hardwood you want, but the grain lines won't run all the way through the slingshot. In essence, you are building a form of plywood out of three or four thicknesses of your choice of hardwoods and you don't have the lines of the multiplex showing on the sides of your slingshot.


If I was planing to do production work, I would probably go with birch ply too, but I'm doing this because I like it and want it to look cool, so I don't mind the time making my own.

I had originally thought about just laminating the full frame, but I was once again, thinking within the rigid confines of traditional woodworking. The tennon in the center line of the handle is 90 degrees crossgrain to the joint. I had decided that the addition of a layer in the middle of the forks with the grain running directly across them would add little strength to the outer layers where the grain ran (as much as possible) full length from the tip of the fork down into the handle. I still think that's the case, but giving it a second thought, just because the section of the inner laminate runs across the handle, don't necessarily mean that the part that runs up the forks has to. I'm thinking about a 5 piece lamination, a front and back side angled just like these, but instead of a single tennon blind mortised into just the handle, a section of the same thickness, but oriented so that the grain crosses the outer layers at a fairly acute angle. The inner layer won't run from tip to handle like the outer one, but the crossed grains should still provide much more support along the grain lines. Hmmmm, err... no, not that, mumble mumble, rustle rustle. "No Thanks Honey, don't wait dinner for me tonight".......

I'll be back in touch in a couple of days. (just kidding)


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## philly (Jun 13, 2010)

Hate when that happens. I had the same happen to me, repaired it with 3/8" srteel rods and made a second one with rods. They may still break from a fork hit with the .45 cal lead but they won't come back and hit me in the face.
Philly


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## slingshooterman (Mar 21, 2011)

im sorry for your loss


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## jskeen (Feb 7, 2011)

it's no biggie, Both are repaired, reinforced with 3/8 steel pins, and stronger than new. Slingshots are like knives and soldiers, battle scars just give them character. (guns are like women, they look better when new, or extremely well cared for )


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## EdB (Mar 17, 2011)

Smitty,

I'm curious about this glue up technique. Can you get by with just gluing up two boards crossing grain or would sandwiching a cross-grain between two top to bottom grains work better? Is the glue epoxy, titebond 3, or gorrila? How do you get an even lamination pressure during the cure? The reason I ask is that all plywood I've been seeing has voids that can pop up in very bad places. Thanks.


smitty said:


> This same kind of failure is why many of us have gone to Baltic birch plywood with our slingshots. It's not that a good hardwood is a bad wood, but they all have grain lines that can fracture if hit, especially by a large lead ball. Some call the Baltic birch plywood multiplex. I like to make my slingshots around one inch thick, so I use 1/2" plywood glued together or I use a plywood core with a nice hardwood on either side to give it that nice look on the face. The pins will help to stop a total failure, but the wood can still crack when it takes a powerful hit. I have had many solid hardwood slingshots for years, but I only shoot them once in a great while now that I have some out of plywood.
> Another good idea is to glue different hardwood pieces together to get the thickness you want. This way, you have the solid hardwood you want, but the grain lines won't run all the way through the slingshot. In essence, you are building a form of plywood out of three or four thicknesses of your choice of hardwoods and you don't have the lines of the multiplex showing on the sides of your slingshot.
> 
> 
> ...


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## colt (Jun 8, 2010)

my interpretation is that if you created a strong spot around your joints, then you inherently made weak spots. in the case of an impact, those spots simply become exploited and it breaks along the path of least resistance. in this case, i think the mahogany was the weak spot. what a sad story.... i hope you can figure it out.


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## AJW (Apr 24, 2011)

It seems that anytime an idea gets pushed along with no opposition, it gets carried to an extreme, and that's what I think is happening here. How many people do you know who have been hurt by a broken fork? Out of the millions of kids who have used slingshots (now some of us much older now) who do you know who lost an eye?

Here are four reasons not to switch to multiplex: rosewood, black walnut, cocobolo, bird eye maple, there are more. Please lets not get righteous and carried away about mute points of safety. Your safety is your responsibility, wear good safety glasses when shooting and in the shop.


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## flippinout (Jul 16, 2010)

AJW said:


> It seems that anytime an idea gets pushed along with no opposition, it gets carried to an extreme, and that's what I think is happening here. How many people do you know who have been hurt by a broken fork? Out of the millions of kids who have used slingshots (now some of us much older now) who do you know who lost an eye?
> 
> Here are four reasons not to switch to multiplex: rosewood, black walnut, cocobolo, bird eye maple, there are more. Please lets not get righteous and carried away about mute points of safety. Your safety is your responsibility, wear good safety glasses when shooting and in the shop.


I could not agree more. That is why my slingshots are always a minimum of three laminations of hardwoods with grain orientation being paid careful attention. A laminated hardwood slingshot is not only beautiful, but incredibly strong. I have been attempting to break one of my slingshots with a fork hit and have yet to succeed. Cosmetic damage yes, destroyed NO!!

Birch multiplex is strong but not necessarily stronger than well crafted hardwood laminates given the forces at work.

Pay attention having clean mating surfaces, quality glue, and even/sufficient clamping pressures for the given wood species.


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## kobe23 (Jun 28, 2010)

Just like how the big old tree could split into 2. To retain the original solid hardwood look, I would say cut the wood into 3 sheet and laminate the grains perpendicular to each other. Would look awesome and safe to shoot =D


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## Gib (Sep 21, 2010)

Nathan speaks the truth, These exotic laminates are EXTREMELY strong and gorgeous to boot. It is always a good idea to do multi-layer laminates however in this case putting a rod in for repair should be sufficient!

Cheers


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## AJW (Apr 24, 2011)

Hi Flippinout

The pictures on your banner show and say it all. You can have beauty and safety in one package. It may take many more hours of work and days of waiting (glue to set, finishes to dry etc) and cost a few more dollars, but look at the product, every one a center piece for any collection that can be admired for generations. Not just another frame. Plus ... they are Safe.


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## crazymike (May 8, 2011)

burn em.. they are cursed


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## Tex-Shooter (Dec 17, 2009)

If using a hard wood board, Hard maple is the best wood that I have found for not breaking. There are harder and stronger woods out there, but very few have the fine non-splitting grain of Hard Maple. I have board cut slingshots with 2 1/2 inch distance between forks that I have shot for 10 years with out hitting the fork or breaking. Here is a Curly Red Oak for one example. -- Tex
http://talk.slingshots.com/forums/album.php?albumid=5&pictureid=65


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## PebbleShooter (Jul 6, 2011)

Dayhiker said:


> That's why I use mostly naturals and plywood. But with a spike inserted, it should be okay.


Is this spike your describing? Like a metal rod inserted into the fork as reinforcement?


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## slingshot_sniper (Feb 20, 2011)

PebbleShooter said:


> That's why I use mostly naturals and plywood. But with a spike inserted, it should be okay.


Is this spike your describing? Like a metal rod inserted into the fork as reinforcement?
[/quote]

Yes


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## mckee (Oct 28, 2010)

suxh a beut down the drain


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## jskeen (Feb 7, 2011)

I decided to use one of the frames originally pictured in this post to test my new static loading test jig and see how well the repaired item holds up. The box contains 75 pounds of lead ingots. I managed to destroy a couple of cull frames, but most survived this test. I guess the repair is pretty sturdy on this little one.


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## newconvert (Dec 12, 2011)

gaara4sand said:


> Now that is why I use multiplex. :-(


i have seen your avatar ss many times, its beautiful!


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