Thursday, May 30, 2013

Mesquite fork

John from Texas gave me this natural fork. It was very rustic, and obviously the grubs had been at it for some time. Seems like it was dead for at least a year, bone dry for sure.




First, I removed the bark. The grub canals came to dailight quickly.



I then decided upon the shape. I wanted to retain the forward canted angle of the fork, and at the same time I needed enough solid wood to make this a functional, strong slingshot. Took me while.



Then I cut the front and back. The typical hammer handle shape emerged for the first time. You can also see that the grub holes aren't that bad.



I closed the grub canals with a mix of the wood's own sawdust and tow component epoxy glue.



Then, I filed everything flush and started the sandpaper work. Here you can see it at the 80 grit stage.



This is the final slingshot, all polished and oiled (raw linseed oil)!



Some more pics of the beautiful frame:







Wednesday, May 29, 2013

One more caricature

Fellow forum member Raul from Brazil drew this for me...

Love it!

Be a TV star!

Next week Friday (June 7th), a German film team will visit me in my home at Burgkunstadt/Oberfranken.

They'd love to see and film some other slingshot fanatics, and therefore I cordially invite people to come over then. Filming will be in the afternoon, we'll do some slingshot shooting during and after that. BBQ in the evening!

Let me know if you want to join us.

jsprave@macrosystem.de

Lawrence Ross and Waterhead Show

I had a great (recorded) chat with the three guys from the LRWS. Enjoyed it a lot!

The podcast is here:


Monday, May 27, 2013

Rubber science: Slingshot fridge

As shown earlier, rubber stores energy thermally. If you stretch a rubber band, it gets warm. If you relax it again, it gets cold.

This video uses a specifically designed contraption that uses this effect to cool a can of beer with nothing more than muscle power and rubber. In fact this may be the first rubber based artificial cooling device ever. Wikipedia is by now in need of an update!

The video clearly shows how an (empty) beer can is cooled down by 2 degrees centigrade in an instant. This is the proof of concept - the rest is design optimzation.

Of course the contraption doubles as a mini trebuchet - after all, this IS The Slingshot Channel :)


Sunday, May 19, 2013

Greetings from sunny Gran Canaria!

No new video today, The Slingshot Channel is on vacation for  a week!

Sunday, May 12, 2013

RUB-15: First "Upper Slingshot Receiver" finished

Even though I am not happy with the looks, the thing works too good to be thrown away... so I painted it black and attached a scope mount. I used a cheapo red dot.

I think I will make several other uppers, now that I know how this works.




Saturday, May 11, 2013

Toilet brush machine gun: Getting closer

Worked some more on the weapon today. Added a nice front handle, Moorhammer style. Banded all four forks up.



I quickly encountered a huge problem: Return to senders and misfirings!

Those returners are dangerous. I mean seriously dangerous. One hit the door right next to my head... two inches to the right and I'd be in trouble now.

I don't really know what is going on - what I found out is that it works as long as you turn really slow. The fast spinning action of the battery drill is probably too much, destabilizes the "bolts" in flight.

I attached thin rubber bands to at least avoid the return to senders - this works fine. But there is still the issue of the tumbling bolts. About half of them do that. It must have something to do with the rotation - no problems at all if I turn by hand and push the bands up one at a time.

If all else fails, I will convert this baby to manual repeating action.

But it does look cool!





Friday, May 10, 2013

Toilet Brush Full Auto: First pics

I am working on the full auto version of the toilet brush shooter.

I want the same performance (excellent!), but I want four of these deadly cleaning items sent downrange in under one second.

This is basically a supersized version of my pistol dart shooter, just with only four rounds instead of eight (due to size restraints). I also had to employ a battery drill instead of a power screwdriver, the heavy parts need more momentum.

I first tried a more compact "fork wheel", but a misfiring occured and the toilet brush blew the 18mm plywood away. So I made a much larger wheel and had to adapt the frame accordingly.

I only attached one band set so far, more tests tomorrow. 






Thursday, May 9, 2013

Google I/O showcase

Google will have their annual big event, called Google I/O, in a few days (15th to 17th of May), in San Francisco.

Read about it on wikipedia

YouTube will have a booth there and they want to play selected content from their partners.

Believe it or not, they want to play one of my videos too!


I am much honored and gave them full permission, of course.


Saturday, May 4, 2013

Weaponizing toilet brushes

My wife gave me this as a surpise:

Funny! I really have to admit I spend too much time on the John, usually reading in the undisturbed solitude a man can often only enjoy while sitting on the bowl.

The gift made me thinking. Can I turn a toilet brush into a deadly projectile?

Well... yes, I can.



Video:



Ram-bone from Texas persimmon natural

Seems that whenever I come up with a new design, I always have to make a natural before my mind can refocus. The Ram-bone is at a stage where a natural was inevitable. 

I still had one fork left from the four Texas parsimmon shipment John sent me a few months ago. It was cracked and also one of the branches was dead, rotten dark. So I was a bit afraid if it was possible to salvage it.


I had to carefully choose the cuts in order to not run into the deep crack that ran all the way through the dead branch and trunk.

I wanted to integrate a part of the dead wood simply because of the color. This forced me to make the handle a little fatter, but less deep. You have to do that when working on naturals - making the best out of the shape nature provided.

It came out real nice!





Wednesday, May 1, 2013

New design for a plastic mould

A friend of mine wants to start selling slingshots and asked me if I could provide a design. Sure!

This one is a mix between the Moorhammer (handle) and the Hand Mortar (for Cold Steel), The fork is wider than the Hand Mortar's, and also the fork arms a thicker. The handle is pure Moorhammer, but sports a lanyard hole. The idea is that the user can saw the hole part off if desired. Also the slot for the looped bands should not be sawed through as it is a bit of a problem for flat bands - you have to attach those fairly low so they don't slip into the slot.

This is a great slingshot! The fork is 15mm higher than the Moorhammer's, more safe for beginners but still fairly low, The handle is very very comfortable.








RUB-15 - first shooting setup

Have been working on it some more. Made an encapsulated front part, for silencing and rubber protection purposes.

I still have to attach brushes to the front and back holes, but it already is very quiet. I also might include a band heating system.

Equipped with 3,1cm x 3,1cm bands (four strips per side), it shoots the 40 gramm aluminum arrow with mighty force. The field tips penetrate about 3cm into massive oak panels. The field tip is pushed down the shaft in the process.

As happy as I am with the functionality, as unhappy am I about the looks. Boxy, clumsy, foolish. Back to the drawig board.