OT: need an assist --> cutting a ~30mm disc from a metal plate

[wallymann]

have a small sheet of...basically iron, roughly 3-4mm thick...and i'd like a 30mm disc cut from it *without* a centering hold left after the cut.

does anyone know of a service where i can send in my stuff and they'd do this for me? or even better, any paceliners have the equip to do this? id pay for your time of course!

also, the "iron" is actually meteorite...so its a 4 billion year old artifact, so i'm super keen to have this done right! living in detroit, all the machine shops around here seem to be focused on industrial-scale activities...some random guy with something like this isnt something they're keen to take on!

[ChainNoise]

How perfect does it have to be? Dykem, outline circle, use band saw to get rough cut, bench grinder to make almost perfect.

[AngryScientist]

I have no idea how hard that material might be, but that aside, I don't see why you couldnt just clamp that down good in a standard drill press and run a hole saw through it (without a centering bit)....

Now I'm curious though; tell us more, where'd it come from and what's the vision for the final project???

[wallymann]

Originally Posted by AngryScientist

I have no idea how hard that material might be, but that aside, I don't see why you couldnt just clamp that down good in a standard drill press and run a hole saw through it (without a centering bit)....

Now I'm curious though; tell us more, where'd it come from and what's the vision for the final project???

i bought it online from some random guy. my wedding band has a strip of this stuff as well, and its pretty cool.

very dense, very susceptible to magnetic fields, and the interesting geometric crystalline pattern is called "widmanstätten" which is a characteristic of many meteorites in our solar system.

"widmanstätten is a three-dimensional octahedral structure in the metal that is formed of bands of kamacite with narrower borders of taenite, the meshes being filled with a mixture of these two alloys"

"The formation of the widmanstätten texture is a long and complex process that takes millions of years. If you polish the surface of a tested sample of the meteorite and soak it in an acid solution composed of 10% concentrated nitric acid and 90% alcohol for about a minute, the pattern will appear in all its glory. This hard-won texture is a precious reminder of the origins of our solar system, a masterpiece of cosmic forces acting upon asteroids as old as, or even older than, our planet."

goal is to end up with basically a very simple challenge-coin...probably use it as a super-interesting golf-ball marker.

[Tandem Rider]

It sounds like exact diamater isn't terriibly important. I think Angry has it right, a brand new, quality, hole saw, clamp it onto a drillpress, take out the 1/4 inch centering bit. Just use plenty of fluid and go slow. An 1 1/4 should yield a blank disk a little over 1 1/8 in diamater, so about 29mm, an 1 3/8 should yield a disk a little over 1 1/4 or about 32mm. You could easily hand file/sand any burrs off and mission accomplished. Looks like a neat little project!

[wallymann]

yeah...since there's enough extra material to clamp, this seems do-able!

even if there wasnt any extra stuff, i could just super-glue it down to a piece of wood for clamping.

Originally Posted by Tandem Rider

It sounds like exact diamater isn't terriibly important. I think Angry has it right, a brand new, quality, hole saw, clamp it onto a drillpress, take out the 1/4 inch centering bit. Just use plenty of fluid and go slow. An 1 1/4 should yield a blank disk a little over 1 1/8 in diamater, so about 29mm, an 1 3/8 should yield a disk a little over 1 1/4 or about 32mm. You could easily hand file/sand any burrs off and mission accomplished. Looks like a neat little project!

[martl]

if not tied to a specific precise diameter, i'd propably use a hole drill in a drillpress. or blue it, mark the diameter with a compass, then rough cut to a polygon shape and do the rest moving it on a flat surface against a Bench grinder, a belt grinder or similar; or hot-glue something you can grab with a battery drill to the center and use on a sandpaper glued to the bench.... There is even the old-fashioned way of using a vice and a flat file

[pdonk]

Since you're in Michigan, I'd try cobra framebuilding,

https://cobraframebuilding.com/machining-services/

I think he is over by Grand Rapids, so a bit of a hike from Detroit, but he may be willing to do a small job.

[HenryA]

Try to cut it with a file, maybe on one of the corners. If the file cuts, it can be drilled.

[OtayBW]

Rocks and such - especially a high-density, Fe-rich meterorite, I would think - are typically cut with a diamond or a cubic boron nitride sawblade. If nothing satisfactory turns up, you might want to try a lapidary service, or a petrographic service....