Better luck machining aluminum

Aha. I must have missed the model. Still, climb milling in steel will test the rigidity of everything.

Wes fired this volley in news:1zL4o.436081$ snipped-for-privacy@en-nntp-14.dc.easynews.com:

I don't know why this hasn't been mentioned before, but I have much better luck on surface finish with HSS cutters on 6061 than with carbide.

I love carbide for steel, but I always lean toward HSS for Al.

LLoyd

Ignoramus18915 fired this volley in news:MNWdnXYd_57lFc7RnZ2dnUVZ snipped-for-privacy@giganews.com:

NOT! SMOKIN' blue chips are "the right feed rate" for steel.

Red chips are not...

LLoyd

Unless you're doing high-speed machining in hardened steel. I looks like a grinding operation from hell, with red-hot chips hitting the machine covers like machine gun fire.

It's performed dry, BTW, usually with cubic boron nitride inserts.

I witnessed a test at the NIST shops they were doing for Picatinny arsenal, making 105mm artillery rounds out of 1075 (I think) steel. They had all sorts of instruments on the toolpost of a Freyer turning center. It made this HUGE WHAAAAAA when they started the spindle, I'm sure you could have easily heard it out in the parking lot. The light coming off the chips was bright yellow, and lit up the area like a 500 W floodlight. They machined the round from a chunk of bar stock it under a minute.

Gee, I wished I'd paid more attention to the insert they were using, but I SEEM to recall it was just a coated carbide.

The testing was because gun barrels were being damaged prematurely, and the arsenal figured out they needed to specify the actual machining processes (insert, surface speed, feedrates, etc.) and not just the material and final dimensions, to obtain the right surface qualities on the round from the several contract manufacturers.

Jon

Very well said!

Gunner

"A conservative who doesn't believe? in God simply doesn't pray; a godless liberal wants no one to pray. A conservative who doesn't like guns doesn't buy one; a liberal gun-hater wants to disarm us all. A gay conservative has sex his own way; a gay liberal requires us all to watch and accept his perversion and have it taught to children. A conservative who is offended by a radio show changes the station; an offended liberal wants it banned, prosecuted and persecuted." Bobby XD9

I thought that most arty of that size was driven by copper driving bands rather than rifling graving the case of the round?

Gunner

"A conservative who doesn't believe? in God simply doesn't pray; a godless liberal wants no one to pray. A conservative who doesn't like guns doesn't buy one; a liberal gun-hater wants to disarm us all. A gay conservative has sex his own way; a gay liberal requires us all to watch and accept his perversion and have it taught to children. A conservative who is offended by a radio show changes the station; an offended liberal wants it banned, prosecuted and persecuted." Bobby XD9

That would make sense to me, and the NIST folks were not revealing everything about the project. So, I really don't know what the real story was. It is possible it had nothing to do with the barrels, and everything to do with armor piercing qualities of the round.

Jon