hole in lead

[doodooo_1]

i want to know how to cut a hole of diameter
250 mm in block of lead thickness 100 mm

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[SGW]

What tools do you have available?

[gvasale]

you want to make a hole about 25" dia. in a piece of lead 4" thick? whats the purpose of this excercise? if you could lift it, maybe a vertical turret lathe would be easiest, but you still need to lift the slug out of the center which is still damn heavy.

[gvasale]

correction: about 10 in dia.

[Uncle Dunc]

What are the other two dimensions of the block of lead?

How round does the hole have to be? How smooth?

How about roughing it out with a hole saw (a bunch of ~50mm holes, not a 225mm hole saw) and finishing it with a big fly cutter on a vertical mill?

[Dave the Nave]

Wash your hands after handling that stuff.
Lead is poisonous.

[snorman]

Just wondering, would a reciprocating saw do that? You'd need a starter hole of course. That's a big chunk of lead you got there.

[spope14]

CNC the bugger. Circular interpolate, leave stock, retract the tool, pull out the center plug, do a finish pass.

Oh, no CNC?

OK, I had to cut out a 12 inch hole in aluminum plate 20 x 16 once. Hung the head out a bit, got my biggest boring head out. Created a HSS tool on the end of a HSS bit type boring bar and hung it right out there from the side hole - the head a 3" dia. head, bar out about 4 inches like a big old fly cutter - but ground to cut downwards. Reliefs and such on the tool interesting, but it worked. Cut out the hole at 11.625 first, almost through. Had the plate mounted on a piece of plywood ahimed and such - plywood so I would not cut the table, and to fully support the part on the bottom instead of blocks and such.

Cut nearly through until the part started to break away in the hole "plug" area. Retracted the tool, took a scribe and finished out the bottom scoring through, pulled the plug.

Finished the hole like a bore hole. Did three of these for a full size model rocket flying off in New mexico (one of those 12 ft. things that goes 6000 feet up).

[Thrud]

Lead is real soft - this could be routed with wood working equipment or the slug could be sawn out like the die makers used to with big blocks.

A trepaning tool would also work.

[siminov]

watch your heat when working with lead if sh gets hot it starts to stick to the tool bit and its softness makes things a mess fast. (yes I learned this the hard way)

[EGG]

I think I would use a water jet machine and then bore the inside of the hole to get rid or the kerf/taper.

good luck

egg