drilling lead

[jonnyp1]

i dont know if anyone can help but i need to drill a deep upto 400 mm, and wide upto 25mm hole into solid lead. i cant move the lead so need to do it in situ. can i do it with standard electric drill and what sort of drill bit if they make such a thing, any advice appreciated.

 

[breezer]

got to ask, what are you doing?
lead is soft as ..........

 

[Jasonb]

Not an easy one. Half round, aircraft extension and long series bits all tend to stop around the 300mm length and may not go upto 25mm, and slow spirals are too short.

The usual way would be to work up through various sizes to the 25mm dia but with lead being so soft the drill will just snatch.

The easiest option would be to use a 25mm "blacksmiths" drill which will only go to about 150mm deep then make up an extension for this to get you full depth. Take it all in one go at a very slow speed and retract the drill often to clear the swarf.

As the lead is so soft it would be tempting to try and regrind the end of a long 25mm masonary bit and see if it would cut the lead.

Jason

 

[oilman]

You could make a D bit out of a length of steel rod. For drilling lead, you wouldnt need to harden it. It would be a longish exercise, but quicker than spark eroding

 

[^woody^]

Why wont a long sds masonry bit work if the speed is low?

 

[Jasonb]

You would need to regrind the end of an SDS bit as they have approx 45 degrees negative rake, about 5 degrees of positive rake is whats needed.

Jason

 

[jonnyp1]

cheers everyone, jason how would i get the bit reground as beyond my skills or tools

 

[gcol]

Can I recommend that you start with a smaller diameter drill than 25mm. I have a picture in my mind of you spinning round if the drill quickly bites into the lead. I'd say no more than 10mm at first. The trouble is that the drill could wander very easily.
You could get a local toolmaker to regrind the drill for you - call him first and tell him exactly what you are doing cause he's bound to have a better idea. He might even come and do it for you.
Why do you need this hole anyway?

 

[Symo]

My guess is the base for some Architectural stone work, statue maybe?

Symo

 

[joe-90]

Railway platelayers use big long augers for drilling through sleepers to make retaining walls (around 3 ft long) so they are available somewhere.

 

[Nige F]

In Railway museums ....... .I told my M8 who`s been on the P. way for 20 years ........LHAO.....he said the rails don`t go clicket-clack anymore now

 

[joe-90]

They still fasten them to sleepers.