I made a mki archer automaton out of wood a few years back, it was pretty good and it shot an arrow with a convincing action. The problem was, you had to load the arrow onto the string manually.

I decided to make a mkii, out of steel this time and to make him nock the arrow onto the string himself. I got a nice little gasless MIG welder which can do surprisingly fine work, and it got a lot of use.
Here's a video of him working , and one of the arrow as it is loosed in slo-mo
https://www.youtube.com/watch?v=LiIEFcMz7cM
https://www.youtube.com/watch?v=hQaTh_A4liE
hope you like it
Del

Since this CORVID-19 pandemic, I had mentioned in a earlier post that I developed a Oxygen (O2) Splitter where hospitals that have poor infrastructure the can create the instruments as they need it. What an O2 Splitter does, is acts like a manifold to deliver regulated O2 to multiple patients.

At the time, a call was put out that they were looking for volunteers to develop a very simple O2 Splitter design. It sounded interesting, so I gave it a shot, but in developing it, I had came up with basically (2) designs, One being a very simple and easy O2 Splitter, and one being more robust with repeatable controls. The more robust one I shelved, and basically forgot about it. Until this pandemic occurred.

Now for a little more details, there was a need for medical equipment for country’s that didn’t have the resources or the infrastructure to stock or acquire various instruments and the goal was to be able to 3D print the needed instruments.

In that way, the remote hospital, would only require a 3D printer, a stable electricity, and raw materials (filaments) where they could print what they need as needed.

Here is a link that’s has more details of the O2 Splitter.

I felt like a break from making Bows and Arrows and I'd seen a wooden Hare on a TV program and thought I'd like to make one.

There's not a great engineering content, mind I had to cut down one trunk of a cherry tree a few years back, from which he's made. I had to turn the Walnut eyes and ball joints on my little lathe too.
It was quite tricky getting the arm articulation right, first I tried a small wooden bead between arm and body, but being a small contact area the arms just flopped down. I turned a larger hemisphere which is glued to the arm and I ground a wood bit to bore a hemispherical hole for it to bear in. The limbs are held with stout elastic bands pulled through and held in place with small wooden pegs.

The local art gallery just happens asking for entries to an exhibition of pics juxtaposing things of any sort to places/landmarks/sculptures in Harlow where I live. So I took Mr Hare on a tour of the town

Hope you like him
Del

I've been having fun with my little mini mill, but I noticed the 10mm end mill was getting a bit worn where I'd been using it to improve the quality of my cheapo drill press vice by machining the faces.
I've bought a book about milling and it shows a really fancy sharpening jig with about 10 parts and springs and stops etc.
I thought it would take an age to make and I didn't have the right size material.
Most of you know my love of wood and simplicity, so I made a simple wooden jig, using a long lever to give a controlled feed rather than a screw.
I don't have a bench grinder as the fine wheel in the drill press, or the belt sander serves as well.
It didn't take long to make and it works a treat. It can be adjusted to give a honing angle too but I didn't bother as the edge it produced was already a vast improvement.

I gave it a quick try out facing a bit of steel and the finish was greatly improved. (The pic of the face was taken after the test)

I may produce an improved version, but why bother when it does the job?
Del

I've been messing around with flight bows and their arrows for some time and it's virtually impossible to get consistent test results.
There are so many variables and worst of all is the loose (the act of releasing the bow string).
It's been on my to do list for some time to make a shooting machine so I had a go.
The mk1 was based on Clarence N Hickman's machine, this proved some of the geometry and exposed some of the problems.
His machine was designed for light weight bows as he was developing the modern recurve target bow.
After the mk1 was the mk1.5 modified for heavier bows shooting at 45 degrees (see pic below)

I want my machine for flight bows and warbows of much heavier weight (up to 150 pound draw weight!). One problem is pulling that weight in a stable controlled fashion and getting the machine to loose the arrow at the preset draw length.
Note, it's no good cocking the bow like you would in a crossbow, as wooden bows (especially highly stressed flight bows) shouldn't be held at full draw whilst you mess about loading in an arrow.
Here's the mk2:-
It has a sliding latch, so the bow can be cocked and loaded at about 12" draw. The latch is then pulled back by a rope running through a pulley. The latch runs on a steel track and while the rope is being pulled, the whole contraption is held firmly down by placing your foot in the stirrup.

The bow is lightly clamped (wrapped with rubber strapping) at an angle (about 30 degrees to horizontal) this allows the limbs of a big warbow to clear the ground whilst keeping the machine compact, it also ensures the arrow rests in the correct position.

The whole thing dismantles into two parts:-

I got a new camera for Christmas that takes reasonable slo-mo and I filmed the arrow leaving the mk1.5 machine:-
Note the arrow isn't really going sideways at the top of its flight, the camera is slightly left of the machine and the arrow is starting to arc over at the top. You can clearly see the flexing of the arrow as it has to get around the grip of the bow.
This machine will hopefully allow me to match arrow to bow better and select the arrow configuration that flies best.
Self evidently, once the arrow has left the bow, it's all about the arrow, here are some of the variables that need to be considered when making a flight arrow.
Length (shorter is more aerodynamic)
Diameter
Stiffness
Wood (bamboo is sometimes used, or in modern categories carbon fibre)
Shape (usually barrelled, e.g thicker in the middle)
Weight
Point of balance (usually about 10% forward of geometric centre)
Point shape and material
Fletching size and shape
Shape, strength and size of the nock
Of course some of these variables are interrelated, it's very much an empirical science, which is right up my street
Del