SpudFiles

Hubb wrote:

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First shots.

I fixed it for ya.

BTW, I think the entire design is wonderful. Very nice. But I do have one question: Why would you want to shoot it at a target that sits that close to the vehicles? It looks like it is just begging to tear some paint.....

Thanks, and your safety avice will be heeded.

I found it impossible to draw Thera Band Silver elastic rubber tubing in a conventional hand held slingshot.

Even using a pivot lever was not sufficient to draw a pair of tubes.

I added a 1:3 friction hoist to make the draw easy and to hold the 90* angle after tying it off.

The pliers trigger ijn conjunction with the wood trigger lever seems O.K.

I believe that the marble was going about 250 fps.

The leather pouch become embedded in the wooden string guide hole indicating that there was force at the end of its travel. More length is needed.

At this point I am chicken to use 2 sets of tubes.

BTW The wood is free from Home Depot.

It is used for the skids, etc. and I always bring home a few for projects.

The BigShot needs a lot of refinement but it does prove a few points.

1> It is possible to draw a very powerful slingshot. There are several factors; the lever gives about 1:2, the hoist gives an additional 1:3, and the friction in the hoist helps by holding it in place.

2> You can use powerful rubber and be out of the way of any snap back accident.

3> By placing it on its own leg, it becomes a very stable shooting platform.

I would like another safety mounted in front to prevent the lever arm from popping up should the hoist break.

Can you suggest a one way holder to hold up the front at 90* to the leg?

(like an automobile hood rod that holds the hood up.)

I am considering a swinging right angle that will slip in front of the hinge.

This is fun!

BoyntonStu

Stu,

I have built a slinghsot today that does allow me to use Thera Band silver.

The key is a very flat profile over my wrist (braces are illegal where I live).

So I had to eliminate everything between my hand and the tube.







Still very stiff, but I can control it.

Thera Tube Silver is a bitch, very unforgiving. One knot not 100% tight - another welt from a slipping rubber.

Joerg,


That does not look like fun.


Drawing silver looks very dangerous.

Is there enough safety clearance from your fist to the rubber?

Above a certain power point, the rubber should not be able to hit you for any reason.

After I draw the silver with the BigShot (more than 300%), I can relax, aim it holding very steady, and pull the trigger.

My prototype is just a rough proof of principle, needing much improvement.

The neat thing was having it almost drawn and being able to hold the friction rope with one finger.

I wonder if removing the front pulleys and substituting a metal eye bolt would be better.

I could also use a string over design like your new silver slingshot ,and just let it all fly out.


Suggestions?

BoyntonStu

It didn't seem to shoot very fast. Was that just me?

Stu,

it may not look like fun, but then again I am a weightlifter guy and managing to master weights that you could not do before IS fun for me.

The fly-over principle has the advantage that it is most accurate and the parts (string, rubber) last longer. Disadvantage: Reloading time is longer.

As for the trigger, may I suggest to use these clamp-on plyers? I do not know the exact name, but they are used by car mechanics. You can adjust them and they lock tightly, have an own kind of trigger to release.

http://cgi.ebay.at/Promat-Gripzange-Fes ... otohosting

It didn't seem to shoot very fast. Was that just me?

Still, would you like to be standing in front of that

For joerg it looks like its not that hard but for the rest of us i bet its nearly impposible to pull back the strong bands
@ joerg BTW what can lift in weights? bench press ect...

qwerty wrote:

It didn't seem to shoot very fast. Was that just me?

Still, would you like to be standing in front of that

Well, that would probably suck.

qwerty wrote: @ joerg BTW what can lift in weights? bench press ect...

I bench press 175 kg (385 lbs), dead lift is 220 kg. Not bad for a 44 year old fart who never took any steroids!

I run on meat and beer.

Okay then...
I haven't worked out much since I turned 30 three years ago.
I could benchpress 200, or do 8 reps at 170 kg
dead lift I didn;t do that too much but the last time I did that ( bad back) I could lift 280 kg.
The best fun I had doing triceps on the pulleys with the entire pack of weight ( 120 kg) and two 20 kg discs added..Might I add I did the movement correctly.Every eye in the gym was on me..
Legg press with the full 450 kg in added weight, plus my mate sittig on top of the stack.
I did shoulder press with 55 kg dumbells per hand.
side raises with 30 kg ( ridiculous!) again correctly performed.
Over head single handed tricep-lifts with 32 kg dumbells.

My mate went on to become Mr universe in 2008 in his class.
His name is Jerry Koolhoven.Google him if you doubt any of my claims.

At my best I weighed 118 kg at 11% bodyfat.
Then again...I did take some candy to get there...
Three years later, not much of that once impressive body is left...

All, yes ALL of my joints are worn out, most severely my knees, elbows, shoulders, wrists, neck and spinal chord.Starting to feel the hips too.
At 33 yrs old...sigh.
The good old times...

Back on topic..
Anyway..where can I get hold of these silver bands?

Does it surprise anyone he's a bouncer that builds guns that can shoot red bull cans through fridges?

@hubb lol thats what i was thinking ,

and what about the possible ricochet if it was carrying any reasonale force
you could of taken an eye out!!!! try not to fire marbles at hard objects when standing right in front of them,they tend to bounce
apart from the 1 minute 5 second loading time,i like ur enginuity

tell me about these "Thera Band Silver" could i use them on my sling shot
or are they too hard too draw??
my compound bow has a 50-55 lbs draw is it comparable to that??
if so could u recomend a type of tubing ?

JoergS wrote:Stu,

it may not look like fun, but then again I am a weightlifter guy and managing to master weights that you could not do before IS fun for me.

The fly-over principle has the advantage that it is most accurate and the parts (string, rubber) last longer. Disadvantage: Reloading time is longer.

As for the trigger, may I suggest to use these clamp-on plyers? I do not know the exact name, but they are used by car mechanics. You can adjust them and they lock tightly, have an own kind of trigger to release.

http://cgi.ebay.at/Promat-Gripzange-Fes ... otohosting

I went to grammar school with “Ike”. He was amazing!

About 5 feet tall and very slim, his strength was beyond belief.

He would walk up behind you and lift you up by grabbing your ankles!

Once, I saw him do a hand stand on top of the monkey bars, his fly was open, and….

From Wiki:

Isaac "Ike" Berger (born November 16, 1936 in Jerusalem) was an Olympic weightlifter for the United States. He is owner of 23 world weightlifting records, and 12-time United States national titleholder.

Berger came to the United States and become a naturalized citizen as a teenager. The son of a rabbi, and himself an ordained cantor, Berger was the first featherweight in history to lift more than 800 pounds and the first to press double his body weight.

He won the U. S. featherweight championship seven times, from 1955 through 1961 and in 1964.

He was world champion in 1958 and 1961, finishing second in 1957, 1959, and 1963.

Olympics
He competed in three consecutive Summer Olympics. In the Featherweight class at the 1956 Olympic Games in Melbourne, Berger won the gold medal with a lift of 352.5 kilograms (777 lb), setting a world record of for three lifts . Four years later, he took a silver at the Rome Olympiad (362.5 kg, 799 lb). And in 1964 at the Tokyo Games, he again won the Featherweight class silver at 382.5 kg (843 lb). His 1964 Olympic record of 152.5 kg (336 lb) in the jerk, at a bodyweight of 130 pounds (59 kg), made him pound-for-pound the strongest man in the world, a record that stood for nine years


Perhaps he could draw Silver in his prime?

BoyntonStu

and….

Massive steroid usage had caused extreme shrinkage?

Jokes..

JoergS wrote:Stu,

it may not look like fun, but then again I am a weightlifter guy and managing to master weights that you could not do before IS fun for me.

The fly-over principle has the advantage that it is most accurate and the parts (string, rubber) last longer. Disadvantage: Reloading time is longer.

As for the trigger, may I suggest to use these clamp-on plyers? I do not know the exact name, but they are used by car mechanics. You can adjust them and they lock tightly, have an own kind of trigger to release.

http://cgi.ebay.at/Promat-Gripzange-Fes ... otohosting

Like this?

I believe that the leather pouch may be an issue as the power is increased. A single layer of leather may tear through.
However, with the vertical rubber orientation, there is little danger.

How would you beef up the pouch to take 200 pounds of pull?

Another possibility, is to take the tension off the string in front of the pouch. A double trigger mechanism?

With respect to the trigger, I am thinking of using a homemade wooden pliers like device. It would have hemispheres carved into each side to capture the marble. The clamping force of a vice grip is not needed. The serrated edges would be tough on the leather. A pair of ordinary pliers with wood on both sides will hold back more than is required.

BoyntonStu

Massive steroid usage had caused extreme shrinkage?

No...quiting both steroids and training /dieting has turned me back to normal size.

It did cause a lot of wear and tear ( literally) on my joints.
As well as a lot of aggression while I used it..