*Please be careful, don't break your instrument*
This is a quick & dirty method - not pretty to look at, but most assuredly functional - to get a "C-Natural" hole on the back side of a bagpipe chanter.
Not saying you SHOULD do this. But I am saying every bagpipe chanter should have a back-thumb hole for this accidental note, and if you want one on your chanter, this is one idea of how you can get one real cheap and real quick.
But do be careful. No one wants a broken chanter. At least, I haven't thought of a use for a broken chanter yet... I guess there probably is one, I just haven't come across it yet...