Friday, 23 May 2014

Hot Wire Feather Cutter

For some time I've been toying with the idea of making a feather cutter so I can trim low profile fletchings on flight arrows. Back in December 2013 I bought some Nichrome wire from Spiratronics (part number WD3-014) and it's been languishing in the draw ever since. It is ludicrously cheap, 5m was just under £1, the postage cost more!
I'd got some gluing done this morning, and while that's curing I thought I'd have a play with the Nichrome.

I did some very basic arithmetic to make sure I wasn't going to do anything too daft and and then connected up a loop of about 18" of it to the output of an old power supply which I'd rescued from a skip and restored many years ago. The great thing about the supply is it has an output that can be switched up from about 1volt up to 24v in nice small steps, it can give out AC or DC too which can be handy.

The wire is about 19 ohms per metre, so I though a length of about a foot would give about 6 ohms. If I connected that to 6volts I'd be drawing an amp and dissipating 6watts which seemed like a good safe start point. I thought probably 10watts would be needed to get things hot.
To be extra safe I started at 3v and rubbed the feather on the wire... nothing.
Slowly I increased it up
12v and sure enough it started melting through the feather!
The next step was to have the wire stretched between two nails hammered into an off-cut of wood, the excess wire is connected to the power supply by some leads with croc' clips on the ends. I have this sort of stuff lying around as my day job is designing electronics. The advantage of the croc' clips is they can be moved along the wire to adjust the resistance and hence current flow and power, useful for those using say a 12v battery, or a supply that isn't adjustable.

NOTE:- The wire can glow red hot and expand rapidly, so be prepared to switch off or adjust the croc' clip position. A variable power supply is a great help.

Next I did a quick try out mounting the wooden block on the tool post of my little lathe, so that an arrow could be rotated cutting the feathers perfectly evenly.
Before anyone mentions it... yes I know I've used blue and brown wires and these are used for Live and Neutral main wiring. It was the only suitable gauge wire I had to hand, and I have found over the years that electrons can't actually read the colour of insulation.

Just made a mkII wire holder. One end sits in a V filed onto the end of the nail, the other end is tensioned using a bit of band saw blade as a spring. I've tried it out and it works a treat, I even gave it a burst of higher voltage to get it glowing and help stretch out any minor kinks in the wire. I'll be able to make up some nice flight arrows with low profile feathers now, using some thin Greylag Goose feathers that someone gave me ages ago. Regular fletchings are surprisingly thick.


  1. Ooh, ooh, I might be bringing over my over-spec'd flight arrows to shave another 1/8" off the fletches on your hot spinning, shall I rephrase that?! LoL

    Johnny Bodkins :o)

  2. Ah, Mr Bodkins, I'm sure we can accommodate you