Articles

Cutting Neat Holes in Balsa

- by Peter Moseley

If you've ever tried making holes in sheet balsa with a conventional drill bit, you'll no doubt have found that balsa just doesn't like normal drill bits !!
It goes all 'furry' and 'splitty' and generally behaves in a belligerent manner.

So, how exactly do you make those lightening holes, or holes to thread those wing ribs onto a carbon fiber round spar?

I'll let the photos show you how....

Make a thin ply alignment tool to fit a range of tubes. Holes need to be snug fit with the tubes... at a pinch, if you use thinish liteply you can cut the holes with the tube cutters themselves.


Position the hole in the alignment tool on the balsa and hold firmly down with one hand. Inserting the tube cutter with the other hand - then rotate the cutter between fingers while at the same time applying slight downwards pressure until it cuts right through the balsa.

So where do you get these tube cutters from?


For holes of around 4mm to 8mm diameter - can you find an old telescopic antenna from somewhere? .... do you remember those they used to have on 35meg transmitters?
I bet you do !
These tended to be made from chromed brass and cutting about 2 inch long pieces, of the different diameters used, is just the job.


Then file a few small teeth at one end of your 2 inch pieces of tube and there you are.

Easy-peasy.