Drilling holes in number plates

What's best? To drill from the front, or the back? High revs or low on the drill?

Everytime I've done it, I've managed to crack the numberplate.

[the_lone_wolf]

drilling holes in number plates is much like making love to a beautiful woman

approach from the front, get your drill up to speed before entering and remember to be gentle, slowly moving the tip in and out getting a little deeper each time

High speed, sharp drill. Go from the back and put a piece of wood underneath for the drill to go into to stop cracking. Put some sellotape on where you want to drill to stop it skidding about, FFS don't centre punch it lol.

Stick the plate on with pads!

it helps if the plate is warm too, a cold plastic plate on a cold day will crack easy, also drill through into a piece of wood so there no snatching and u can go straight through smoothly.

Originally Posted by the_lone_wolf

drilling holes in number plates is much like making love to a beautiful woman

approach from the front, get your drill up to speed before entering and remember to be gentle, slowly moving the tip in and out getting a little deeper each time

[G]

Originally Posted by StreetHawk

Stick the plate on with pads!

Or even better velcro so it can be removed easy

Serioucly though, I sadly used to have to drill plates all the time many moons ago when I worked in Hellfrauds. Alway put masking tape on the acrylic front side, start with a small pilot hole using a small drill bit, then use the final size.

Works everytime, never cracked a plate.

[embee]

Ideally you want a drill bit which has been ground with zero top rake angle at the leading edge. This makes the leading edge like a scraper rather than a cutter. Think of holding a knife at 90deg scraping a surface rather than a shallow angle like when sharpening a pencil.

You can do it easily with a hand stone to put a small flat at the leading edge parallel with the axis of the drill bit. You don't need a very big flat, basically just taking the sharp edge off will do it. Try it and you'll be surprised how much difference it can make. You still want a sharp corner to scrape effectively, just not a shallow angle.

What tends to crack plastic is that the drill bit grabs as it breaks through and very quickly wedges itself through the last fraction of material. Taking the shallow angle cutting edge off will prevent the grab.

I keep a 6.5mm drill bit which I have stoned just for drilling plastics and brittle materials. As others say, I usually put masking tape on the front and drill from there holding the plate firmly onto a flat surface, a newspaper on a piece of wood can be useful to avoid damaging the rear side film.

Originally Posted by embee

Ideally you want a drill bit which has been ground with zero top rake angle at the leading edge. This makes the leading edge like a scraper rather than a cutter. Think of holding a knife at 90deg scraping a surface rather than a shallow angle like when sharpening a pencil.

You can do it easily with a hand stone to put a small flat at the leading edge parallel with the axis of the drill bit. You don't need a very big flat, basically just taking the sharp edge off will do it. Try it and you'll be surprised how much difference it can make. You still want a sharp corner to scrape effectively, just not a shallow angle.

What tends to crack plastic is that the drill bit grabs as it breaks through and very quickly wedges itself through the last fraction of material. Taking the shallow angle cutting edge off will prevent the grab.

I keep a 6.5mm drill bit which I have stoned just for drilling plastics and brittle materials. As others say, I usually put masking tape on the front and drill from there holding the plate firmly onto a flat surface, a newspaper on a piece of wood can be useful to avoid damaging the rear side film.

+1

Or just go and practice on some others in the street first.

Originally Posted by embee

Ideally you want a drill bit which has been ground with zero top rake angle at the leading edge. This makes the leading edge like a scraper rather than a cutter. Think of holding a knife at 90deg scraping a surface rather than a shallow angle like when sharpening a pencil.

Embee, I've read this, re-read it, gone away, come back and read it again and I still haven't got a clue what you mean! I think you've just robbed me of all my maleness!