Enlarging a hole in a plastic bead

(Elizabeth Joseph) #1


Hello there! I have some plastic beads, 15mm wide. There’s a 1mm hole, and I’d like to know how or if I can drill the hole to make it much larger, around 8mm? (I’m not sure what type of plastic it is.)
If you have any ideas which drill, etc. thank you very much!
Have a great day!

(Howard Batchen) #2

How many have you got to do ? If it’s just 1 or 2 you could just hold one in a vice or soft grips and drill 1/2 way through each side. If loads then clamp a thickish piece of wood in the drill press, drill a hole slightly less than the bead diameter then swap the drill to the hole size you want. You might want to use a pin to set the bead about vertical in the hole. If you can’t hold the bead still with your fingers, drill some thin plywood to press / clamp over the top to hold it.
Another way would be to drill a row of holes in 2 pieces of plywood, put the beads between them and screw together Then drill through each one by hand or drill press

(Elizabeth Joseph) #3

hi, thanks for your reply. I have maybe 50 beads. Hmm your first suggestion makes a lot of sense. I can drill a smaller ‘guide hole’ first then change the drill bit to the large one. And use some wood to clamp it in place. Great! cheers!

(Chris Osborne) #4

Be aware that some plastics tend to ‘grab’ when drilling, suddenly pulling the drill into the work and perhaps jamming and pulling the work out of the holding device. A solution can be to take the sharp edge off of your drill bit with an oil stone or similar but that wrecks the bit for other use. Take care!

(Elizabeth Joseph) #5

Thank you…I won’t do anything to the drill bits at SLM. But I might try that with my own ones.

(Helen Quadling) #6

Your other option would be to use a bead reamer which would be manual and maybe too time consuming for 50 beads. However it would be more precise and less likely to damage the bead than using an electric drill. You can get them from Amazon or if you can’t wait then Bellore or Cooksons in HG. If you decide to drill them then a reamer would still be good for removing any sharp edges (especially if you are stringing).

(Elizabeth Joseph) #7

Thank you! I like the look of a Reamer.

(Calum Nicoll) #8

Also to help with the grabbing/better finish - using the correct speed will help alot - try around 1200rpm for an 8mm bit, 2000 ish for a 4mm) will help.

(Elizabeth Joseph) #9

Thanks that’s useful info.