Perspex drill bit

[Mactriple]

Thanks to all for the info. Perhaps this advice should have gone into "Hints and Tips"
Ian

 

[dja981]

20 posts on how to drill a hole unbelievable.

                                                  Dave
ps can't wait for the follow up "How to tighten a nut"

 

[Lav the impala]

i just ease off on the pressure as the drill is about to break through, to gauge the depth i use a texta-marker and 200rpm.

 

[dja981]

Arghhhhhh 22 now.

                                  Dave

 

[Cosi]

Id get Darty to do it

 

[chrisk]

Must be a big dart, and a bloody good shot!

 

[Haggis]

Dull this corner. (Picked this up from a 'build a plane at home' website). It works.

Use low pressure, high speed. Sort of 'wear' your way through, rather than cut.

 

[chrisk]

OK, so why not start the hole, and just run the drill in revferse at high speed?

 

[Haggis]

I tried that, you just build heat and get nowhere.

 

[chrisk]

Bugger

 

[Shajota]

Ignorance is obviously bliss................
I put a new screen on about ten years ago and just (very) carefully drilled the holes with whatever correct size bit lying around.
Wouldn't be game to now

 

[motoddrob]

A 3mm drill isn't going to crack the plex if you drill carefully. As I said in my previous post anything bigger than about 6mm and you start to have problems. The illustration that Haggis posted is correct. Been dressing my perspex bits like this for 35 years and now that I no longer work with perspex have a drawer full of bits that now need resharpening to be useful again.
I also mentioned earlier that you need to avoid heat. What happens when you apply some solvents/cleaners the perspex will craze on the areas that have been heated. So drilling in reverse is not the way to go.
Just drill the fucker with an 1/8" bit or slightly larger than 3mm so to have some clearance. Piece of piss!!

 

[jotacorsa]

i use small wood bits as lothar illustrated
the screens crack when the bit goes through the back side before the hole is cleanly cut

 

[chrisk]

i use small wood bits

They must be made from aged Oak 

 

[Laverdalothar]

i use small wood bits as lothar illustrated
the screens crack when the bit goes through the back side before the hole is cleanly cut

yeah - I think the main point really is: don't apply pressure/force to the get the drill bit through the plastic, let it cut its way alone. Oh - and not to fast turns, as else the plastic melts and when you stop, it gets hard again and might cause a crack, too. So - make sure you slowly drill with just gentle forces, don't stop after you "broke through" and remove the drill while still turning. The plastic edges at the "rear" side of the drilling can easily be removed with a finger nail and then you have a clean and crackless hole.

another advantage of these "wood-bits" is that the center really holds the drill in place, as it is like a needle poking into the material. makes it quite safe to drill without the drill bit moving around.

 

[ianpm77]

Yes choose a "blunt" well used drill bit or blunt it "on an old brick wall with slow drill ". Then drill screen with Fast speed and gentle pressure.

I got to the "last" hole needed to be drilled of about eight on my first new P&M screen and crack!!!! Is it always the last one????

Phoned richard Peckett and he said use a "well blunt, well used normal drill bit and hold a piece of spare screen tight on the back of the new one"...
"you have got a spare piece of old screen NOW !!!!!"....Ha HA HA i did laugh "NOT".
another ?35 in his wallet .
all the best
Ian
PS. P&M Laverda still on sale best offer over ?9500.

 

[chrisk]

Pestle & Mortar?

 

[ianpm77]

Sorry
Peckett and Mcnab frame 1976.
No 6.