PVC Plunge Cuts

1

First time poster… Long time reader.

I have the need to plunge cut 3/16" straight holes through 1/4" pvc board. When done by hand I use a regular high speed drill and a 3/16" plastex bit with a rounded head so you don’t get the melt / burr / oversize in the hole. The downside is that in order to get a perfect hole my bit needs to go through the PVC and into a scrap board of some type about another 1/8" to get the nice straight hole. And yes I go through alot of “spoil board” materials.

What would you guys recommend?
I’m using the standard Makita router on the x-50.
I need to avoid the melting of the PVC and completely drill a full 3/16" hole with no real margin of error on the size.
Also what speed would you use on the bit as I don’t wanna melt it.

2

I’d experiment with a 1/8 bit, pocket into 3/16th hole.

Speed at between 1-2 on router

1/32 depth of cut with a short retract after each to enable cut material to get out.

No lead in or lead out (tool path will probably fail to compute), try a tiny helix if feeling nervous.

Speed up from there, first few cuts will be painfully slowwwww, but there again no bust bit or debris to remove.

3

1/8" straight bit? Or is there a bit specifically for plastics like my plastix bits?

4

O flute bits. I’ve had good results using this bit in acrylic, though you’ll need a 1/8" collet (they sell that too).

Edit: I did have a bit of a problem when I was drilling holes though, see here. It didn’t affect the end result though so I haven’t tried any fixes. Maybe do a test without the bit before doing the actual cut just to be safe.

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5

Use an O flute 1/8" end mill. Using VCarve (not sure if alternate software), create a Profile toolpath operation and click on Add Ramps to toolpath and then Spiral.

Do not use a pocket or peck drilling operation. The first will take longer & be prone to more slop in the resulting hole and the latter will beat up your end mill & likely cause micro cracks in your acrylic.

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