Pencil Shooter  with Paul Reeves
Thu 16^th January 2025 at MWCC Club Night 

The forceful characteristic needed to propel a pencil is stretchiness, which can be obtained from elastic bands or springs.
The majority of online examples rely upon sawn shapes to provide strength for supporting the stress & forces involved with taut rubber bands but as Woodturners, we want predominantly turned components.

For this demonstration, Paul had chosen to use the energy provided from releasing a compressed spring to fire a hexagonal pencil (doesn't have to be a Reeves pencil of course!) that is no larger than 8mm diameter.
The 'weapon' shown below comprises of a Barrel with 2 bore sizes to accommodate the 8mm pencil through the Muzzle end and 18mm bore through the Breech end. The firing mechanism is a combination of Piston (with a notch for a trigger), the Spring and a Rod through the Breech Cap to the Knob, which holds everything together.

  Barrel
Taking account of the length of his Spring and about another 100mm of Bore to keep the pencil's flight true, Paul had selected a minimum 200mm length of 35mm square blank of Beech for his Barrel.
Mounted between centres, a Spindle Roughing Gouge turned it to a cylinder suitable to be mounted in his 38mm o'Donnell Jaws. With the piece firmly gripped in the jaws and a tailstock in support, a Skew Chisel squared off the end in readiness for the Breech component to be a screw tight fit.
The tailstock was refitted with a Jacob's Chuck and an 18mm saw-toothed Forstner bit, chosen because it was just bigger than the diameter of the Spring. The lathe speed was reduced and while starting off carefully with the bit exactly centred, a hole was drilled deep enough to accommodate the sum of the Piston & Spring lengths plus about 8mm for the Breech's thread to screw into the Barrel.  Once the first hole is done, further turning & drilling will be easier to keep true.
 Remember that handling a Jacob's Chuck does need care as highlighted in our Top Tip <here>.
To reduce friction inside, the Bore was sanded smooth with abrasives wound around a pencil.

Paul decided to enlarge the first 10mm or so of the Barrel so that the Spring/Piston mechanism would clear all threads whenever inserted or removed; this only needed the Bore to be increased about 2 or 3mm with a Box Cutter.  Next, a Relief Tool was used to create a slot into the wall of the Barrel next to the step of the 18mm Bore width. The thread is created with the Thread Chaser when it 'lands' and is 'taken off' in a smooth circular motion. That slot will allow freedom for the Chaser to lift clear of the inside threads before it gets stopped suddenly against the step down of width and would damage the threads already made.
Beech doesn't often take a thread as well as some closer grain woods but in this demonstration, a perfectly good thread was obtained with just half a dozen passes without having to resort to wily ploys like stabilizing the wood grain with thin superglue.  The thread and bore were checked and any roughness was dealt with by brush or abrasives.

The piece was reversed in the chuck to expose the Muzzle end and aided by the tailstock, lined up for the Jacob's Chuck (now fitted with a sharp 8.5mm drill bit) to drill its hole down the centre. As previously, start drilling slowly before speeding up, watch for clogging up and clear out frequently until certain that you have drilled through to the 18mm bored hole.
Paul then used a countersink in the Jacobs to create a chamfer in the Muzzle Bore. This will help later when the Breech Cap is completed and screwed on such that the Barrel can be held between centres. Again, to reduce friction, this end of the Bore was 'polished' using a drill bit in a powered drill.

  Breech Cap
Taking another piece of Beech already prepared to a cylinder and clamped true in the o'Donnell jaws, Paul used a Parting Tool to form a parallel spigot with a diameter slightly bigger than the enlarged Breech Bore. This spigot will take the male thread that will engage with the Barrel thread already cut. The oversize start permits a thread to be established and then by trimming the thread tips away, there is enough for the Chaser to easily engage and re-cut the threads which will eventually reduce the diameter to fit the female thread in the Breech Bore.
Similar to the previous Thread Chaser preparations, you will need to use the Parting Tool to slightly lower the level at the front of the spigot and at where the spigot meets the bulk of the cylinder, in order that the Chaser has room to come away from the threads before it barged into the edge of the cylinder. This time, the Chaser is lifted out of the threads by lowering its handle while moving in the smooth circular motion. 
With the lathe speed reduced, new threads were produced and checked against those in the Breech Bore before being trimmed back parallel again and again until eventually they fitted into each other.  Bear in mind that the top of the threads you are creating at this step, need to end up in the bottom of the threads you left in the Barrel.
This time, Paul did need to reinforce the threads by pouring very thin superglue onto them while keeping the piece moving round in order to avoid pooling and allowing enough time for the glue to be drawn into the pores and harden before attempting to re-thread. Only 2 or 3 threads are needed for the Breech Cap to grip the Barrel so once the threads were matched, the length of the spigot was trimmed back accordingly with a Parting Tool and the thread depths carefully cleaned up with 400 grit abrasives.
A centre mark was made on the end where a hole for the Rod to slide freely through the entire Cap was drilled using the Jacob's Chuck. Paul planned to use a 4mm dowel of Bamboo so this hole needed a 4.5mm drill bit. Finally, after allowing enough for space for the curve of the Breech, the piece was parted off square and the drilled through hole was sanded/polished to aid free movement.