Drilling & Tapping Nickel 200

[Haggismaximus]

I have a potential job where I need to drill & tap 4 3/8" Nickel 200 busbars. Each bar needs 4 M8-1.25 threaded through holes, 16 total for all the pieces. Will a stub cobalt split point drill be sufficient for the hole? As far as tapping goes, any special tooling or should I treadmill them? Any advise on speeds and fees?

Bar will be waterjet cut but are rather spending at about a grand each so I'd like not scrap them.

 

[guythatbrews]

I'd sure splurge for a carbide drill. Call the tap guys to get the best tap for the job. It's amazing how much difference the correct tap can make.

 

[plastikdreams]

Just be careful that stuff work hardens if you look at it sideways...

 

[Finegrain]

I would threadmill them. Less chance of scrapping a part and lots more process control.

Regards.

Mike

 

[boosted]

2nd the recommendation for a carbide drill. We have used quality plug taps to tap through on nickel 200 at some absurdly low SFM. I'm not brave enough to try a spiral flute tap.

Threadmilling is pretty safe and easy; especially with a thread that big, since you can fish a broken tool out easily.

 

[guythatbrews]

I have a potential job where I need to drill & tap 4 3/8" Nickel 200 busbars.

You say the holes are through. How far through? I agree threadmilling is indicated for such high value material.

 

[Zeuserdoo]

I've dealt with this stuff a bit over the years. Buy the highest quality HSS, Cobalt, or powder metal drill you can find, and sharpness is very important. This stuff does not like to be cut, it wants to push out of the way. You could also try a solid carbide drill designed for non-ferrous material, but you will need an extremely rigid setup, if the part moves at all while you are drilling it the carbide drill will grab and you will break it.

A sharp multi-form thread mill is your best bet, but Emuge, and OSG both make taps that are designed for Nickel alloys. I'd go with Emuge, if it were me. As far as speed and feed goes, follow the manufacturers recommendations, or you could start with this:

HSS/Cobalt drilling - 15-25 sfm .0015-.0025 ipr
Tapping - 5-10 sfm
Carbide thread mill - 70-90 sfm .0005 ipt, 2 passes to radial depth.

I hope this helps.

 

[boslab]

Throw them in the freezer overnight was what I was told, not had much experience but it was supposed to make the chips break? Bit of research I’d guess,
Mond nickel has a lab near me, they broke their charpy so borrowed ours, the samples were cooled in alcohol before busting them.
Tough old stuff that nickel!
Mark