January 14, 2017

DIY sand scoop for metal detecting on beaches

I'm planning to metal detect the german beaches in the next summer. In preparation of the future treasure hunt, I made me a sand scoop. So let me show you the result of my do-it-yourself project.
It is made from a plastic pipe (12cm diameter /toilet drain) from home depot. I cut everything with a dremel tool. It is easy to bend the plastic material with a  heat gun. I flattened a piece of the pipe with the heat gun to built the bottom of the scoop. I drilled a lot of 14mm holes into the material. That is a bit smaller than a one cent coin and big enough to quickly sieve the sand. The handle is made from an old aluminium door handle. 

October 3, 2013

Why do intuitive archers tilt the bow?

Most intuitive archers do not hold the bow perfectly perpendicular. They tilt it a little bit to the side. What is the reason therefor?

The most represented explanation is: "The arrow does not fall off that easily from the shelf". This seems to be obvious (and may be true) but it is not the intrinsic reason for the tilting. Another presumtion is, that the tilting moves the upper limb out of the line of sight, so that the target can be seen. Olympic archers do not tilt the bow at all - and believe me - they see there target too.

Most intuitive archers experiment with their shooting position and end up with a little tilt, because it feels comfortable and makes them shoot better results. The reason for it lies in the way that our eyes and our brain work, to make stereopsis and the perception of distances possible. For stereopsis you need both of your eyes open and focused on an object. When you point with your finger at something, it works best, when the finger is positioned in the line in the middle between bot eyes.

Make a test:
  1. Point with your finger at some object
  2. You will find, that your finger is just naturally positioned exactly in the middle between your both eyes.
  3. Now move your finger to the left (or right) and keep it pointed to the object
  4. With a rising distance of your finger to the middle line, your uncertainty rises too. At some point you can't be sure, that you are still pointing exactly to the object.
In intuitive archery you are not pointing with your finger, but with the tip of your arrow. Don't get me wrong- you do NOT use your arrow point as a marker- the way that system shooters aim. No, you just stare at your target. And with the trust in the abilities of your brain, your whole body-bow-system gets oriented to your target. The first point of that system IS the tip of your arrow. So - simplified we can say, the arrow points to the target instead of your finger.

When you hold your bow perpendicular - the way that olympic archers shoot - one of your eyes (hopefully your dominant one) is right behind your string. You look at the tip of the arrow, to bring it in a defined position to the target. You have to know the distance to the target before you shoot! Your second eye is absolutely useless. The distance calculation can not be made by the brain, because the informations that are delivered from your eyes are almost useless. The situation gets even worse if you have a cross dominance. That means, that your dominant hand is on the other side then your dominant eye.

The right eye is in the same line with the arrow and can not give any information to the brain that is useful to calculate distances. The left eye has a big distance (A) to the arrow (blue dot). But its information is not being used to make the shot. Some olympic archers even wear a eyepatch to eliminate any information from that eye.

As you may comprehend, such kind of shooting has a lot of disadvantages and it is one reason why archers decide to shoot intuitive/instinctively. So let's tilt the bow.

As you can see, you get the "obvious" advantages. The arrow cannot fall off the shelf anymore and the upper bow limb is out of the sight line. But the optitical geometry didn't changed at all. So now let us tilt the bow and the head too.

Now the arrow is centered between the middle of both eyes. The brain can calculate the threedimensional informations, estimate distances and is prepared for a good shot.

Shoting intuitively/instinctively is the perfect way for archers that had problems with cross dominance in the past. Because both eyes have a equitable role in the shooting. No eyepatches, closing one of the eyes or changing the bow arm is needed.

That's it. Stay curious.

October 2, 2013

DIY Extended Archery Tab

Today I simply want to introduce my 'DIY Extended Archery Tab'. The design is inspired by a tab that a guy named greyarcher1 showed in one of his YouTube videos. It is made of four layers of thin nubuck leather, glued together with contact cement. Furthermore you need some rubber band and two string stoppers to make one by yourself.

The following picture shows, how to wear that tab. One rubber band goes around your middle finger, the other one goes around your wrist. Change the length of the rubber bands with the string stoppers to adjust it to your prefered measurements.

The last picture can be used as a stencil. Just print it out and transfer the form to a piece of leather. The given sizes are perfect for a (my) medium sized hand. Just scale it up or down to adapt it to your hand size.

That's it for today. I hope you liked it - stay curious!

September 30, 2013

My DIY Beta-Release

Today I introduce my just finished selfmade "Beta-Release". The reason why I built this is: I wanted to shoot my 70 pound compound bow in a more 'instinctive' way.

Instinctive shooting of a compound??
YES, for me that means: No fancy stuff on the bow, no sights, no scope, no peep and no bulky expensive release. The Beta-Release is made from one piece of aluminum and it has no moving parts. Its design is dead simple and it performs as acurate as much more expensive releases. At first I wanted to shoot the bow completely without any release. But that did not worked, because the bow is very short. The angle of the string is squeezing the fingers too hard

The release design was inspired by a picture from Istvan Girizd that he posted on facebook. With these pictures in mind I built the first prototype from ply-wood - my "Delta-Release". But it turned out, that the design of that release only works for bows with a relatively low draw weight. (I nearly lost a finger when I tried to shoot my 70 pound compound bow with it)

I took a further look into the internet and found pictures of the 6-Gold release. This was produced in the 60s and cannot be bought today anymore.

They have a nearly equal design - the only difference is: the string of the bow is not placed behind the release but behind a small hook in front of the release. And this fact saves your index finger when you shoot heavy draw weights. As said before, these releases are not sold anymore. I found a nearly similar product from A+ Slingshots that was a little bit too expensive (I'm a man on a tight budget ;) ).

So I made a release by myself, starting with a simple aluminum bar. And after hours of file work and sanding it is finally ready. I'm very happy with it - it's accurate, small, durable and it feels comfortable. It gives me the proud feeling to made something by myself, that really worked in the end. 

This picture shows, how the "Beta-Release" is held and how the hook grabs into the string.

To release the arrow, I simply have to straighten my index finger. (I know: There is no arrow in this picture ;) )

I hope you liked it. Have a nice day - and keep curious!

September 25, 2013

The creation of my DIY custom bow

I always wanted to build a takedown recurve bow by myself. In the past I already made a selfbow and a pvc bow - both with a very low draw-weight. With this project I really did not knew where to start - so I watched a lot of youtube videos and gathered as much as possible knowledge. 

Then, everything started with a drawing that I made on the backside of an old calendar.I took the main measurements from an existing bow, but made the look much more biological. I do not wanted any hard edges on that bow. The sight-window will be a wide curve to let the archer see as much as possible of the target.

I scanned the sketches into the computer and made an Adobe Illustrator file out of it. The first drafts involved the idea to make the riser from two different coloured woods. But I did not know how to saw the elliptical form. So I decided to make a simple prototype from ply-wood. Nothing fancy for the first prototype.

Then I glued (Uhu Endfest 300) three layers of two centimeter thick ply-wood together to a big block and glued printings of my Illustrator-file on top of that. The next step was to saw everything out with a jigsaw and a lot (!!!) of work on the belt sander.

A lot of sanding with sand paper followed and a varnish with linseed oil.

Now I prepared the parts of the riser where the limbs gets attached.

Then I built the riser plates from stainless steel. I brazed three pieces to an "H" shape and drilled the holes for the limb skrews.

I installed the thread inserts in the riser and glued the riser plates into place.

Finally here are some impressions of the completed riser.

September 16, 2013

DIY Serving String Tool

Today I needed a serving string tool and decided to make one by myself. It took me 15 minutes to make it. It works like a charm ...