This is a fantastic home-made pen that can do lettering from a 5mm stroke width to 5cm stroke width.
Buy some balsa that is 5mm in thickness. It is usually in a plank approx. 45cm long and 7.5cm wide with a thickness of about 5mm. In my photos the balsa has already been cut narrower, but ideally, do the mat (diagonal) cut while it is still 75mm wide.
You can probably use a craft knife but a matt cutter does a lovely clean cut. Do two cuts 12cm apart, so that you have wide ‘pen’ 12cm long with two writing ends. A runcible pen! Then you cut this piece into the widths that you fancy. I cut a very narow 5mm one for children to write with in conjunction with my book ABC Uncials, or anything up to 2-3cm wide. Sometimes I just leave it really wide for enormous letters.
When you write with it using walnut ink (or any ink for that matter) it runs out of ink as you write leaving a lovely effect.
My 5mm ones are sweet, and I wrap them in masking tape as the ink travels upwards. Dip them into the ink and have the obliquue part uppermost when you write.
The balsa pens are approximately 5mm in width – like the Speedball C-0 nib. They are just to go on with and to use to play around with ink. I have wrapped each in masking tape so that when the ink creeps up the wood, fingers won’t get too inky!
The pen is a runcible pen (like the spoon in The Owl and the Pussy Cat) and when you write with it, the sloped edge must be uppermost, so it is labelled TOP!
Balsa pens get blunt or lose their edge quite quickly as they are fairly delicate. The real pleasure in using them is when you can make a HUGE Balsa pen and do massive letters! I always use a balsa pen on large sheets of paper to demonstrate when teaching. You can re-cut the edge when they are dry or make a new one.