Buckshot
10-05-2005, 02:24 AM
.............I had a memeber here who wanted a Krag action nut to bust'em loose from the barrel. I actually figured regular ole HR or CR steel would be okay. But heck, on E-Bay I ran across a guy with a piece of 3.5" x 4.5" hardened 4140. Didn't say HOW hard, and being the idjit I am, I thought this would be great material for it. After all, I DO have carbide :D
http://www.fototime.com/27DBAFBE166C54E/standard.jpg
It was HR, and here I'm trying to cut under the scale. I figured carbide (any ole carbide) would make short work of it. WRONG! I had a cemented carbide, gr C8 at first (here). It lasted baout as long as you see in the photo.
It cratered and chipped and squeeled and just flat quit. Then I tried a gr C6. That didn't do much better. Then I tried a TNMG coated insert and it went enough to get the 2" lo9ng cut done, but I could see it wasn't the answer either!
http://www.fototime.com/D2525DEA889AD3A/standard.jpg
Kenjuudo to the rescue! He'd sent me some cemented carbides along with some other stuff (for which I'm gratefull) and there were some gr C2 carbides which are supposed to be for cast iron and such. As you can see, it worked here! Oddly enough, the HSS centerdrill had no issues.
http://www.fototime.com/5D8266D7DD3697C/standard.jpg
It took a bit of figureing to find what depth of cut (DOC) and feed to use. My lathe is an 11" Logan, and while it's a nice lathe and I like it alot, it isn't a 16" Le Blond, or Monarch. With just regular ole low carbon stuff I can peel off 1/8" with a pretty good feed. However this 4140H would only allow 1/10" and a .020 IPR feed. If I tried pushing it harder it began to chatter. At this DOC and feed the bit just hissed like frying bacon and gave a good finish.
The one C2 cemented carbide did ALL the turning on this piece!
http://www.fototime.com/4B01FD8DE2746C6/standard.jpghttp://www.fototime.com/78968FB9ECB0079/standard.jpg
I LOVE parabolic drill bits! None of the drills had any issues in doing their job.
http://www.fototime.com/7755569DC1090D2/standard.jpghttp://www.fototime.com/AF0B9C80F77D8E0/standard.jpg
Boring to 1.307". Here it is on the right after being parted off and the 2 wrench flats milled.
Part 2 will see it finished up. More milling!
.............Buckshot
http://www.fototime.com/27DBAFBE166C54E/standard.jpg
It was HR, and here I'm trying to cut under the scale. I figured carbide (any ole carbide) would make short work of it. WRONG! I had a cemented carbide, gr C8 at first (here). It lasted baout as long as you see in the photo.
It cratered and chipped and squeeled and just flat quit. Then I tried a gr C6. That didn't do much better. Then I tried a TNMG coated insert and it went enough to get the 2" lo9ng cut done, but I could see it wasn't the answer either!
http://www.fototime.com/D2525DEA889AD3A/standard.jpg
Kenjuudo to the rescue! He'd sent me some cemented carbides along with some other stuff (for which I'm gratefull) and there were some gr C2 carbides which are supposed to be for cast iron and such. As you can see, it worked here! Oddly enough, the HSS centerdrill had no issues.
http://www.fototime.com/5D8266D7DD3697C/standard.jpg
It took a bit of figureing to find what depth of cut (DOC) and feed to use. My lathe is an 11" Logan, and while it's a nice lathe and I like it alot, it isn't a 16" Le Blond, or Monarch. With just regular ole low carbon stuff I can peel off 1/8" with a pretty good feed. However this 4140H would only allow 1/10" and a .020 IPR feed. If I tried pushing it harder it began to chatter. At this DOC and feed the bit just hissed like frying bacon and gave a good finish.
The one C2 cemented carbide did ALL the turning on this piece!
http://www.fototime.com/4B01FD8DE2746C6/standard.jpghttp://www.fototime.com/78968FB9ECB0079/standard.jpg
I LOVE parabolic drill bits! None of the drills had any issues in doing their job.
http://www.fototime.com/7755569DC1090D2/standard.jpghttp://www.fototime.com/AF0B9C80F77D8E0/standard.jpg
Boring to 1.307". Here it is on the right after being parted off and the 2 wrench flats milled.
Part 2 will see it finished up. More milling!
.............Buckshot