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Rehash: Turning 1018 CRS

macona

Diamond
Joined
Jun 20, 2006
Location
Beaverton, OR
Well, I know its been brought up before but I bought some 1018 CRS for a project I am working on. I dont know what I was thinking, this stuff is like turning bubble gum.

Tried carbide but cant get the SFM needed. I tried HSS and it is better but still tears. Anyone have a tool geometery they like for turning this stuff? I am limited to about 600 RPM and my work is about an inch or under.

Or should I save this stuff for something else and get some 1144 stressproof?

The finish needs to be aesthetically pleasing as the parts are exposed.
 
As sharp as possible, aggressively high rake angles, nose radius as setup allows, lead if set up allows,go ahead and hit 100+ SFPM on final cut(sacrafice the tool for finish), polish/hone the tool cutting edge,and lube, lube lube.
 
Lots of rake being? 20 to 30 degrees? More?

I cant get past about 80 sfpm on this lathe on 1".

Guess its time for stressproof.
 
I am limited to about 600 RPM and my work is about an inch or under.
I cant get past about 80 sfpm on this lathe on 1".
Lessee once around a 1" part is pi = 3.14 or .26feet. So 600 times around is 600 X .26 = 156 feet every minute. Hmmm ...c'mon now Macona you've got the speed if you have 600rpm. 100sfpm is an eyelash under 400rpm at 1" dia.
Sure try 15-20deg of rake and slope it toward the tailstock for a skiving action.
 
Youre right. I left my thinking cap at home today.


Will give it a try and see what happens.
 
I have a lot of luck with a Komet WNMG style positive rake insert with very little nose radius. I can't remember the specific number right now. I also use Kennametal WNMG negative rake inserts for quite a bit of roughing.

I would probably run that 1.00 bar at around 400-500 RPM and about .008-.012 feed rate, depending on depth of cut. Do not try to take light finish cuts.......I always remove the stock in equal passes, no finish cut. I have much better luck holding size and getting a decent finish this way.
 
Never had nary a problem with 1018 CR,even the Chinese stuff,which is about all you can get around here in small quantity.1045,now there's a night mare especially the Chinese stuff.
 
Well, playing around I finally got a halfways decent finish. Ended up with a pretty high back rake. but thats just it, halfways. On non-visable parts it will be OK, but for the visable ones I am going to pick up either stressproof or maybe some 12L14 if I dont have to weld it.
 
Can you cheat and buff it up with a piece of sandpaper? Belt sandpaper with a shot of oil does wonders. We've turned a number of CRS shafts (the job specifies the lowest priced material) and the finish is never something to write home about. Most of the time, a few seconds of 120 grit will do you right. I know, I know, it's cheating, but as long as the finished product is what you want, just suck up the pride and buff away.
 
Keep in mind that 1117 or 1144 are not recommended for welding either. Leaded stock isn't the way to go if appearance is important and the surface will be left bare. For some reason, leaded screw stock will rust really bad unless its kept oiled or otherwise protected via plating or paint.
 
I suppose I could do that, its just one step I was hoping to avoid.

4130 Then? I know thats weldable! Little overkill... ;)

I had started making a ER collet chuck for a chinese lathe a few years ago and someone gave me a 4" chunk of 4140 to make it out of. That turned nice with carbide. Took it to one of the local model engineer meetings and they thought I had ground or somehow finished the surfaces when they were as turned. Hmmm... Wonder where I put that... Never did finish it. Chickened out when it came time to cut the taper for the collet.
 








 
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