Nightmare Materials

[WobblyHand]

I made a 1.5" OD threaded canister out of 304. Knurling it wasn't too bad, neither was drilling and boring it. I did have troubles internal threading it on my mini-lathe though, had a bit of chatter. Thin hollow tubes are not easy to thread and 304 made it tougher to do. I used too small of an internal threading tool in conjunction with an OXA toolholder on a mini-lathe. The lack of rigidity of the platform gave me issues. Wouldn't be surprised if the gibs had loosened...

I need to finish the male cap. (Also in 304.) Didn't think the last cap through very well and basically didn't have enough material to hold it! I wanted to knurl the edge of the cap for grip and I simply couldn't get the knurler where it needed to be and have any material to hold it. Oops. Next time, I'll have to plan things out better. Since I have only a 1" spindle, I have to decide how long of a piece I'm going to waste - ie put in the small stub bin. It doesn't necessarily go to waste, but it's not a big piece either.

I had made a similar canister in steel earlier. It also suffers from chatter in the threads, but I had managed to finish it. Wanted one in stainless, but so far the stainless is winning, and I'm loosing. Putting in the groove for the thread gutter in the 304 burned out my parting tool. That took some of the wind out of my sails. Nonetheless, I need to finish the 304 canister this year.

 

[verbotenwhisky]

It's weird in that I had no issues with 316 or 304 on the Sherline, big problems on the Vevor (at least initially), and I tried 304 on the SB9A I just got working and it cut it with ease. Of course, these are small diameter jobs and I've yet to see how the SB will work with a larger chunk. It's just that I rarely use large diameter SS for anything. No idea if that makes a difference or not...

I can and have worked 304 on my PM1236 I just do not like the way it cuts and the chips...

This is cutting a piece of 304 pipe, ASTM A312-304

 

[RaisedByWolves]

I can and have worked 304 on my PM1236 I just do not like the way it cuts and the chips...

This is cutting a piece of 304 pipe, ASTM A312-304

Yo dog, I heard you like toolholders……

 

[jwmay]

Anything with weld evidence. Lots of what I get is out of dumpsters. I’ve had some good chunks of steel turn into a nightmare as I discover some hidden HAZ. And if you find a pristine piece of round stock with a partly drilled hole in the end, be aware that it might have become work hardened, and that’s how it ended up where you found it. Haha

 

[Mini Cooper S]

So I got this free chunk of Ampco 22 I think. I know it was Ampco but it would take me awhile to find out which one. For some unknown reason I decided it would be a good idea to fix my Vevor lathe by making a tapered gib holder on the underside of the saddle with the stuff.
Let me just say, it was not a good idea.
Hard to cut, blunts good sharp US made endmills like they were made of Chinese mild steel.
I refused to give up so completed the job. Figured I'd learn something. I did. I learned I should select better materials, and most importantly, to recognize a bad mistake early on and not keep going.
I also did learn that milling this stuff requires zero or even a back rake. Anything else is likely to chip it or destroy the endmill.
It also hates being drilled. I hate it, so I figure we're even.

I'm sure others have had similar horrible materials to machine. Let us know so we can avoid them too!

Put a slight negative rake on the cutting edge and it will cut Ampco much more easily. Sounds counter productive, but it works.

Richard

 

[RaisedByWolves]

Anything with weld evidence. Lots of what I get is out of dumpsters. I’ve had some good chunks of steel turn into a nightmare as I discover some hidden HAZ. And if you find a pristine piece of round stock with a partly drilled hole in the end, be aware that it might have become work hardened, and that’s how it ended up where you found it. Haha

Way back in my youth we got this brand new whiz bang machine in called a plasma cutter, was supposed to revolutionize the industrial maintenance industry.

Its use was kind outside of my perview being a toolmaker but a job came up, and the machine was out on the floor for another job so I figured I’d give it a try.

I had to cut a 18”x12” hole in a die bottom plate for slug clearance and not wanting to drag a torch set and set up tanks for the flame wrench I figured I’d give this thing a shot.


Worked phenomenally well. Cuts were thin and straight in this 1.25” plate and it went really quick.


Then I tried to clean up the cut edge in the supermax with a HSS endmill.


Oof. Large very big size Oof! That edge was harder than woodpecker lips.

 

[verbotenwhisky]

Yo dog, I heard you like toolholders……

Assuming you are referring to my extension, sometimes you do what you must.

 

[strantor]

I learned ... to recognize a bad mistake early on and not keep going.

OOH! I know that one! That's one of my favorite lessons, so I teach it to myself on regular basis. Practice makes perfect!

 

[verbotenwhisky]

Yo dog, I heard you like toolholders……

Started off with 8" nom, 8 5/8" dia. S/80 ASTM A312-304 EWS pipe which is a bit bigger than the 7" swing over the cross slide that my PM1236 has.



So I had to turn the outside dia to true 8.060" which meant i was working in front of the carriage.



I tried my boring bar to get the required reach but it chattered and cause issues, rigidity issues and I did not have the time to chase down a better option but I did have a chunk of steel to make a better option.



The boring bar did work okay for the ID which I bored out to 7.45" with lighter cuts


and after parting them off to 2.75 long, this was the final results and I got paid for it....

Sometimes you do what you must.

 

[RaisedByWolves]

Started off with 8" nom, 8 5/8" dia. S/80 ASTM A312-304 EWS pipe which is a bit bigger than the 7" swing over the cross slide that my PM1236 has.

View attachment 500661

So I had to turn the outside dia to true 8.060" which meant i was working in front of the carriage.

View attachment 500663

I tried my boring bar to get the required reach but it chattered and cause issues, rigidity issues and I did not have the time to chase down a better option but I did have a chunk of steel to make a better option.

View attachment 500665

The boring bar did work okay for the ID which I bored out to 7.45" with lighter cuts

View attachment 500668
and after parting them off to 2.75 long, this was the final results and I got paid for it....

Sometimes you do what you must.

Good job!

I was going to take a guess this was the case earlier, but some guy at work says he's my boss and was pestering me.