Snapped drill shank!

[Hello from Austria]

How can one drill a 1mm diameter hole in a 5mm thick piece of silver without the drill bit snapping again...? :">

[medusa]

I don't go through 5mm but I do go through 2mm and I've learned that you need to go ..... s l o w

First I punch a dent using a nail and then I apply lube over a 1mm drill and the dent. I drill really slowly and about halfway through I pull out and re-lube before starting again. If you pull out 4 or 5 times and go slow you should get through.

If anyone else has better ways, I'm all ears as well.

[Dennis]

How can one drill a 1mm diameter hole in a 5mm thick piece of silver without the drill bit snapping again...? :">

When drilling metal, make a starting pit with a centre punch or a small ball burr. Always use a little oil when drilling.

If you still have problems, make a pilot hole with a smaller ball burr, say 0.5mm and then follow with a 1.0mm twist drill. If your machine does not have low enough speed, the put your twist drill in a pin vice and turn it by hand. Dennis

[silken]

Slow and steady wins the race :)

I start with marking the position for the pilot hole with a centre punch or whatever I have to hand, just a little indent will do fine. I usually start off with a 0.8mm drill bit and use the lowest speed possible. I also make sure that the twist drill is lubricated with something, I usually just use plain old bees wax. Once I have drilled the 0.8mm hole I expand it a little with a larger drill bit if I need to.

Are you using a pendant motor, dremel type tool or a drill press?

Also, if you snap off the drill bit when you're drilling and can't remove it, leave the whole piece in pickle and it should dissolve the bit and just leave you with the silver.

[Hello from Austria]

I did go by hand, but with no lube and maybe too keen! Many thanks.
Julia

[Dennis]

I took this to mean 0.5mm and wondered what the trouble could be. What are you doing with 5.0 mm thickness of silver??

[Hello from Austria]

I'm drilling into some spheres that are about 5mm in diameter. When the shank broke off luckily I could just melt them, pull out the shank when the metal slumped a bit, and let them cool into roughly a similar shape. A lot of time wasted, but at least it wasn't anything technical that took hours of work. Can't think of any other way of making holes in balls: melt them around some tube or something? That's even more time consuming!

[Dennis]

Ah right, rusty brain. Well I've never done it, but many members say broken drills dissolve in hot alum, which they also use as safety pickle. Bet it turns your silver pink, though.

Anyhow, we all think go slowly bit by bit, introducing lubricant. Find the right speed and don't push hard. I am convinced that small drills sold as HSS (high speed steel) are the most fragile.

If the drill gets blunt change it or sharpen it. All you need is a diamond coated disk and with your handpiece rested horizontally, two touches of the drill will sharpen it. It is quite easy to learn the right angle and my drills are all different lengths from doing that. Dennis.