# Boardcut fork dimensions?



## gbeauvin (Mar 7, 2014)

Although I'm currently playing with a Daisy slingshot, I'd like to make my own. I'm planning to start with a boardcut (unless I stumble upon a good natural fork), as soon as I can kick free some time to go to the store and get some wood. I'm playing around on graph paper trying to work up a template, and discovered that I have no idea how wide the forks need to be, how wide the gap needs to be, etc. I realize this is going to be trial-and-error, but I'd at least like to be able to shoot my first creation without worrying that it's going to snap and fly back to hit me in the face!

I'm planning to cut this out of ~3/4" solid hardwood (unless i find some scrap ply between now and this weekend). What I have drawn up now has fork arms that are 1" wide, with a 1.6" gap in the middle (making the whole thing 3.6" wide... so it fits on a 3.75" board). The hole between the fork arms is 1.8" deep, with rounded edges.

If that makes no sense let me know and I'll draw a terrible paint drawing of what i'm talking about.

Does this sound sufficiently beefy? Is the gap too "deep"? I see lots of shallow forked slingshots on the site, but I figure it's easier to cut wood off than grow more on.

thanks,

GB


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## Henry the Hermit (Jun 2, 2010)

Those dimensions are in the ballpark.

Please do not use hardwood boards, unless you thoroughly understand about grain structure and orientation and the forces involved in slingshot frames.

Michaels and other hobby stores sell 1/2 inch plywood that is great for slingshots, if you can't find a suitable piece of 3/4 inch.

Check out our Templates Forum. There are a lot of tested designs there, which might be better for a first build.

http://slingshotforum.com/forum/27-templates-support-topics/

Good luck.


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## gbeauvin (Mar 7, 2014)

Thanks, Henry. Good to know! If I had better tools I'd sandwich plywood between hardwood scales, but alas I'm not set up for re-sawing. Actually I'll be using entirely hand-tools (I have the coping saw but need to get some rasps) unless I break out the dremel. Unfortunately I'm not a big fan of the plywood look, but safety first!

I checked the templates forum before i started drawing, but I'd like to start with something simpler than what I saw in there, I didn't think to compare measurements though (duh, hindsight).

-GB


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## gbeauvin (Mar 7, 2014)

I drew up a template in visio, and was quite pleased with it until I printed it out and realized just how small it really was LOL. It looked bigger in visio!! Just ignore the smaller one, but the larger one is what I'm thinking about trying :



Also -- would plywood be necesary for a BB shooter using light bands (theratube tan or single strand 2040)?

thanks,

GB


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## Lacumo (Aug 18, 2013)

Lowes and Home Depot sell smaller pieces of plywood --- you don't have to buy a 4'x8' sheet. You'll pay more per square foot, but you can buy 2'x4' pieces. Just be sure whatever you end up buying is around 3/4" thick and is the ~12 layer stuff --- not the ~5 layer stuff.


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## S.S. sLinGeR (Oct 17, 2013)

Lacumo said:


> Lowes and Home Depot sell smaller pieces of plywood --- you don't have to buy a 4'x8' sheet. You'll pay more per square foot, but you can buy 2'x4' pieces. Just be sure whatever you end up buying is around 3/4" thick and is the ~12 layer stuff --- not the ~5 layer stuff.


Also michaels and ac Moore have nice sheets that are inexspencive. I think for 6 $ I could make 6 shooters. Tell them at the register to give you a cupon. The usually give me anywhere from 30-50% off. There is a micheals iPhone app that will give you cupons that you can scan at the register. I know they have a 50 % off one going now. I was just there


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## Rathunter (Feb 14, 2014)

Henry in Panama said:


> Those dimensions are in the ballpark.
> 
> Please do not use hardwood boards, unless you thoroughly understand about grain structure and orientation and the forces involved in slingshot frames.
> 
> ...


Don't try hardwoods. UNLESS you split the board yourself out of elm, or make the forks insanely thick... Red Ceder(not hard to split) forks with every dimension over 1" is sufficiant.

Grain is very complicated. Long story short- splitting wood is much easier than sawing it.

Birch plywood is wonderful. If you want a really pretty slingshot, use 1/2 inch plywood and put Micarta or hardwood lams over it. It will be strong enough to take the force without much work. BTW never make your forks from hardwood plywood thinner than 1/4 th inch and narrower than 1 inch.

Also never make the actual tines narrower than 3/8ths inch if you are using heavy pull bands- some plywood is surprisingly weak.


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## gbeauvin (Mar 7, 2014)

I've got a 40% off coupon so I'll be headed to Michaels this afternoon. Thanks for warning me off hardwoods, guys. I really want to make a hardwood slingshot, but I'll wait until I can either source some thinner sheets to laminate or find a buddy set up for resawing. I've got the car today (normally my wife has it) so I'm going to be on a slingshot materials collection mission this afternoon -- Staples for some Alliance Sterling 107s, Dollar Tree for some marbles (I probably still have 75+ steel bearings but if my next shooting session goes anything like my last then my supply will slowly dwindle), and Michaels for some plywood. I might even swing by harbor freight and pick up some chinese rasps. My Red bands are in the mail for Daisy, and should be here by friday -- this should be a good weekend for slingshot fun, both shooting and making!

I may have to print up a second coupon and go through line twice... once for the plywood and once for a roller cutter thing :halo:. Of course I'll also need a self healing cutting mat, so maybe instead I'll print up several coupons and bring my kids with me on saturday... we used to do that for rocket motors at Hobby Lobby. Here's your coupon, here's your motor pack, and here's a $10 bill. Here's YOUR coupon, here's your motor pack, and here's a $10 bill. Here's MY coupon, here's my motor pack, and I'll just swipe the plastic because I gave the kids all my cash.

Somehow I'm itching to buy lots of stuff for this inexpensive hobby lol.

-GB


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## Henry the Hermit (Jun 2, 2010)

Lacumo said:


> Lowes and Home Depot sell smaller pieces of plywood --- you don't have to buy a 4'x8' sheet. You'll pay more per square foot, but you can buy 2'x4' pieces. Just be sure whatever you end up buying is around 3/4" thick and is the ~12 layer stuff --- not the ~5 layer stuff.


I'm going to mildly disagree with this. I've made and shot a bunch of frames from 5~7 layer 1/2" plywood. The thicker layer Is not as pretty as 12 layer, but unless you're planning on shooting very strong bands, even 5 layer is sufficient. For a lot of us, the nice thin layer baltic birch isn't an option.


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## Lacumo (Aug 18, 2013)

Henry in Panama said:


> I'm going to mildly disagree with this. I've made and shot a bunch of frames from 5~7 layer 1/2" plywood. The thicker layer Is not as pretty as 12 layer, but unless you're planning on shooting very strong bands, even 5 layer is sufficient. For a lot of us, the nice thin layer baltic birch isn't an option.


Good to hear of positive experiences with it and I yield to the voice of experience. I saw a post elsewhere with pix of a 6-layer 3/4" frame cracked and folded while under full draw. Fortunately, it didn't separate into different pieces and result in pieces flying back into the poster's face. My reference to the ~6 layer plywood was made just to pass on a safety suggestion based on that other post I had seen.

The individual 6-layer plywood frame that failed may have been compromised by unfilled voids in it (?)--- I don't know. I was just playing the role of "Mister Sensible Shoes The Safety Guy" with my post.


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## TSM (Oct 8, 2013)

Speaking of, I just got some of that 5 layer 3/4" construction plywood for a new catchbox (weekend project) I should have enough left over to make a frame and stress test it. We'll see just how much weight I can put on it before failure. Nothing wrong with safe, sensible shoes, but I do like a good experiment.


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## gbeauvin (Mar 7, 2014)

As happens the birch 1/2" ply at michaels was 9 layers, so I guess that's what I'll go with


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## Henry the Hermit (Jun 2, 2010)

Lacumo said:


> Henry in Panama said:
> 
> 
> > I'm going to mildly disagree with this. I've made and shot a bunch of frames from 5~7 layer 1/2" plywood. The thicker layer Is not as pretty as 12 layer, but unless you're planning on shooting very strong bands, even 5 layer is sufficient. For a lot of us, the nice thin layer baltic birch isn't an option.
> ...


I probably should have added that all wooden frames should be pull tested before using. I use a length of paracord and my fish scale, and depending on intended use, pull the forks to either 50 pounds combined or 50 pounds on each fork. I really wish I had the option of using premium grade plywood. I didn't mean to imply that you are wrong.


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## Henry the Hermit (Jun 2, 2010)

gbeauvin said:


> As happens the birch 1/2" ply at michaels was 9 layers, so I guess that's what I'll go with


That should work just fine.


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## Whitewolf (Mar 13, 2014)

would it be better to glue 2 parts of 9 ply together???

Dennis


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## gbeauvin (Mar 7, 2014)

I may end up laminating some hardwood to it, Dennis, but I have no plans to glue the plywood together (to form an 18 layer 1" thick board). I did start cutting my first frame out, but my wife is convinced that this is an outdoor activity (and it's been wet... and I have no garage) so I haven't finished yet .

-GB


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## TimR (May 22, 2011)

I just bought a 2 foot by 2 foot 3/4 inch birch plywood square at Lowes for $9.28 plus tax.

I use very light bands due to a shoulder injury, and I'm sure I don't need that much strength, but it's peace of mind.


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## gbeauvin (Mar 7, 2014)

Doh! I just discovered that my POS coping saw (likely from HF) can't rotate the blade!! The part the handle screws into rotates just fine, but the opposite end has a keyed hole and can't rotate!!! And here I thought I'd have a fork cut out tonight


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## gbeauvin (Mar 7, 2014)




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## Whitewolf (Mar 13, 2014)

ummmmm.....thanks for sharing

Dennis


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## SteelBallViking (Apr 6, 2014)

Some rasp and file work it will look fine! Keep it up!


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## gbeauvin (Mar 7, 2014)

After some more sanding I went ahead and banded it up so i could play around with it, but i haven't put any finish on it yet. I think I'm done shaping this one though. The next one will surely be better!

-GB


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