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Catapult

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Project by Paul posted 01-04-2014 02:49 PM 1673 views 24 times favorited 18 comments Add to Favorites Watch

My parents were visiting over the Christmas break, and dad and I needed some shop time. So, we went to the shop and built a mini catapult from another one we had seen before. We actually made two of them for my boys, and they had a lot of fun launching back and forth at each other. Actually, they had more fun launching dog treats and watching them chase them all over.

The design is pretty simple, and only measures 10” long and 5 1/2” wide. All material was scrap pine.

It launches a clay ball (or a dog treat) about 25-30’.

Update:

I’ve added more pictures and measurements for the design. I didn’t have plans for one of these, but built it off of one I had seen before, so using the basic overall dimensions we were able to make a couple of them.

All material is 3/4” pine. The base is 10” long. The width is 5 1/2”. On the ends, you can see that I drilled slots in for the tension bars. the tension bars are just 3/4” by 1/8”. The dowel rod is 10” (1/4” diameter). The bucket at the end is 2 1/2” long and 1 1/4” wide. I just used a 3/4” forstner bit for the hole.

Everything was glued together with a brad nail at all joints. The diagonal supports were just cut at 45 degrees.

The middle rod is just a 1” dowel, with holes drilled in each end for 1/4” dowels (I did not drill all the way through, no need to). You’ll notice 2 – 1/8” dowels in the middle rod. That was done to hold the string.

The end piece (where the dowel swing arm hits) is 2 1/2 inches high with just a padded bumper on it (like you would use for a drawer).

The brace/release arm is 5” long and is 1/2” square, and is held on loosely with a bolt, as it needs to swing freely. It catches the teeth on the middle rod. Notice the teeth are cut at right angles, so it fits the release arm squarely. The tooth/catch wheel is 2 1/2” in diameter. There are 18 teeth. The teeth measure 1/2” x 1/4” each. This was just cut out on the band saw.

I hope that helps with the measurements.

-- Paul, Iowa





18 comments so far

View sras's profile

sras

3836 posts in 1782 days


#1 posted 01-04-2014 03:25 PM

Looks like a fun project – I can imagine the fun with dog treats!

-- Steve - Impatience is Expensive

View skyboy_psu's profile

skyboy_psu

20 posts in 724 days


#2 posted 01-04-2014 05:04 PM

Can you post more pictures from the backside, or maybe a video? My kids want me to build one, but I can’t see how you attached the bucket and I’d like more details on the release mechanism.

View tomakazi's profile

tomakazi

646 posts in 1936 days


#3 posted 01-04-2014 08:11 PM

I would love to make one of these. did you have plans? more pics? could you post a video? thanks

-- I didn't go to college, I was too busy learning stuff - Ted Nugent

View Woodendeavor's profile

Woodendeavor

216 posts in 1260 days


#4 posted 01-04-2014 09:56 PM

Cool project. I am sure you made the kids and dogs very happy

View NormG's profile

NormG

4175 posts in 1657 days


#5 posted 01-04-2014 09:57 PM

Awesome piece

-- Norman

View Francois Vigneron's profile

Francois Vigneron

263 posts in 973 days


#6 posted 01-04-2014 10:41 PM

Now that’s playing fetch at an all new level ! Happy kids and happy dog. Cool !

Skyboy, I think the release is visible : as he pulls the white string through the metal loop at the front, it makes the oblique wedge tip forward, which releases the gear. You can see that the wedge will spin around the bolt that goes through the frame. The eye-bolt ensures proper alignment of the string. The tension in the ropes make the axle spin and the bucket swing. It looks like the bucket is just stuck to a dowel through the axle and will hit a cushioned stop at the front. He will also use the bucket to crank the catapult because there doesn’t seem to be any other lever/handle to do the job. As the ropes are spun 3 times around the axle but the bucket can only travel 1/2 turn, this suggests that the bucket+dowel can be removed from the axle and will fit through a serie of holes around the axle, just behind the gear. The wedge blocks the gear and the axle while you put the bucket+dowel in another hole. This design allows for more than 1/2 turn of cranking before release and the impressive reach of 30’. I am surprised that the force of the impact on the stop doesn’t break the dowel+bucket or flings the dowel out of place.

But anyway, I agree with the others, we need more pictures ! Thanks for sharing this nice toy Paul.

-- Francois Vigneron, Gif-sur-Yvette, France & Altadena, CA

View OttoH's profile

OttoH

881 posts in 1663 days


#7 posted 01-04-2014 10:59 PM

That is a great design, looks like it would be fun to make and play with!

-- I am responsible for how I respond to everything in my life - - Deadwood SD

View hoss12992's profile

hoss12992

2746 posts in 546 days


#8 posted 01-05-2014 12:17 AM

This is really cool. Glad you and your dad got some shop time together. Priceless. Great job

-- The Old Rednek Workshop https://www.facebook.com/theoldrednekworkshoptn

View wseand's profile

wseand

2245 posts in 1695 days


#9 posted 01-05-2014 01:53 AM

Very cool. Good times with Dad and the Kids, excellent.

-- Bill - "Freedom flies in your heart like an Eagle" Audie Murphy

View RonGoldberg's profile

RonGoldberg

33 posts in 1011 days


#10 posted 01-05-2014 03:45 AM

Oh my, what guy doesn’t want one of those? Can’t think of one. Please post plans ASAP. Even my two daughters ( 11 & 13) would love them. Make it happen. Thanks.

View Pieter's profile

Pieter

32 posts in 547 days


#11 posted 01-05-2014 04:06 AM

I have to agree with wanting plans; have build two cheap toy ones (neither worked) so this would be great for the grandson.
Pieter

View Gianni's profile

Gianni

125 posts in 627 days


#12 posted 01-05-2014 11:47 AM

I like this. Did you drill the axle all the way through, or just into the center of each side? If through, congratulations, as I have recently realized how difficult it is to keep that straight.

Neat idea to use separate limbs for the tensioners. I always try to use the swing arm itself and it always gets broken due to handling.

View Paul's profile

Paul

27 posts in 938 days


#13 posted 01-05-2014 04:47 PM

All, I’ve added pictures and instructions/measurements for the catapult. I did not drill the axle all the way through the center rod, I only drilled holes for the 1/4” dowels.

Thanks for all the comments! I’ve also taken a video, but haven’t figured out how to upload the video yet.

Paul

-- Paul, Iowa

View bch's profile

bch

217 posts in 1342 days


#14 posted 01-06-2014 05:45 AM

Completely awesome! Much cooler than the replica I built for my kids. I believe that is a Leonardo Divinci design if I recall correctly. Very nice! Thanks for sharing.

-- --bch

View Paul's profile

Paul

27 posts in 938 days


#15 posted 01-06-2014 01:58 PM

It is a Divinci design, yes.

-- Paul, Iowa

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