Tapping plexiglass

[bradleyheathhays]

Say you had a 1/2" thick sheet of plexiglass and needed to tap a hole that was drilled beginning on the edge and continuing in 3 in. What type of thread density would you choose, coarse or fine? The strain on the anchor will be fairly minimal.

 

[dickm]

Depends how big is the hole! And you will have a job finding a tap of <1/2" diameter that will create a thread 3 inches long.

 

[Lons]

You can tap with either but generally coarse threads are better in acrylic. It's a long time since I sold Perspex and at the time ICI had a lot of information available so I would think a good search on the internet will help. The drilled hole size is more critical than metal especially in edge drilling so choose your sizes carefully.

 

[Lons]

deleted

 

[Cabinetman]

Doubt it will help, but Perspex is wonderful stuff, when it’s heated up it will take an imprint which will stay when it cools, ( it will also spring back to shape when heated up again, ) how about drilling the hole, then heating it up in an oven and screw the bolt into the hole, letting it cool and then unscrew the bolt, doubt it will work but you never know. Ian

 

[Rorschach]

Why 3" deep?

 

[Distinterior]

Why not just drill your hole 3inch deep and use a metal threaded insert in the hole to suit the thread size you require?
As there will be minimal strain on the thread/ plexiglass, the insert would only need to be 1/2inch deep....

 

[Fergie 307]

Simple enough. I would use a standard metric thread, should be coarse enogh. The most important thing is to make sure you use two taps. You want to start the thread with a first cut tap and then run a finishing tap to get the final size. If you try and do it in one go the thread will tear. Your biggest problem will be clearing the debris from the hole as you go. If you can hold it so you are tapping vertically upwards, then gravity will help clear the hole as you go, an airline will also help. And use good quality hss taps.