Deep narrow irregular holes in plastic: what bit?

[martinw]

Originally Posted by jonboycnc I need to cut irregularly shaped holes in plastic (probably polyethylene or flexible PVC). The nasty thing is that these irregularly shaped holes need to be 1 cm (1/3 inch) (ideally even 2cm) deep but sometimes as narrow in places as 0.5mm (a little more than 1/64 inch). What kind of cutting bit could do this, and how? Tiny, deep, cutting bits anyone??? Thanks! Jonathan

Dear Jonathan,

IMVVHO, it cannot be done with a series of drill holes, and certainly not in the soft plastics you mention.

The people who posted made this clear..

1) You cannot expect a 0.5 mm dia. bit to work well in soft plastics at a depth of 1 cm. You cannot cool the bit, and it will start melting the material. And that is just the drilling problem...

2) Overlapping holes will wander and the bit will break.

3) Please forget any ideas of using a drill bit as a milling tool when you want a profile cut by a drill bit of 0.5 mm dia. 1 cm long. Common sense really.

I know I sound like a right party pooper, but soft plastics are the very worst materials to try and machine at that kind of depth. Or any kind of depth for that matter.

My apologises, and good luck with the project.

Best wishes,

Martin