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View Full Version : Proper use of carbide in 4140



becksmachine
07-10-2011, 02:19 AM
This job came along and it reminded me of a recent thread about using carbide on 4340. This material is 4140 which is fairly close as far as machinability is concerned.

Also to demonstrate that a nearly 100 year old machine still has a place in a for profit, modern(??:D) machine shop.

Material is 17" diameter 4140 annealed that needs shafts for 3-15/16" bearings on both ends. Not my style of engineering, but I wasn't paying the bill so.... Started with 4 pieces with a combined weight exceeding 6000 lbs. finished with 4 pieces that weighed 647 lbs. each, that calculates to 8 barrels of chips weighing approx. 3500 lbs.

Depth of cut varied from 1/4"-3/8", feed rate approx .025"-.030". Spindle speeds varied between 66 rpm and 88 rpm, with fpm varying between 200 and 350. Motor rated horsepower is 20 hp, Kennametal calculator says this cut takes 25-27 hp. which is roughly confirmed with amperage readings. Photos to follow.

The last photo shows the four parts ready for heat treating and final machining which I don't get to do this time.

http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0457_2.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0457_2.jpg)http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0458_2.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0458_2.jpg)

becksmachine
07-10-2011, 02:42 AM
http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0464_2.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0464_2.jpg)http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0465.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0465.jpg)

becksmachine
07-10-2011, 02:44 AM
http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0471.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0471.jpg)http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0486.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0486.jpg)

becksmachine
07-10-2011, 02:46 AM
http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0460.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0460.jpg)http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0554.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0554.jpg)

becksmachine
07-10-2011, 02:48 AM
http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0545.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0545.jpg)http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0565.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0565.jpg)

becksmachine
07-10-2011, 02:49 AM
http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0567.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0567.jpg)http://i1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/th_IMG_0577.jpg (http://s1042.photobucket.com/albums/b422/becksmachine/Trunion%20rollers/?action=view&current=IMG_0577.jpg)

JRouche
07-10-2011, 03:16 AM
Soft (annealed) 4140?? They heat treat the rollers after you are done shaping them? Some heavy turning you are doing there. Not for the HSM but still great to see. Bet it ate up some bits.

Saw some of the other pics of the bits, they were eaten up. Looked more like chipping damage then being dulled? Was there an issue with feed rate? Im thinking they shouldn't have chipped like that? JR

http://img.photobucket.com/albums/v366/Jrouche/HSM/IMG_0577.jpg

psomero
07-10-2011, 03:19 AM
now that's some heavy 4140. very impressive...

any more info about the machine to share?

the4thseal
07-10-2011, 03:40 AM
what were you making ..not candle sticks.

PixMan
07-10-2011, 06:38 AM
I don't often see grades of carbide meant for steel in a flat-topped (no chipbreaker) insert. Your failure mode for inserts in that material should be flank wear and perhaps a bit of cratering. It shouldn't be catastrophic breakage.

What maker and grade were those CNMA inserts?

SGW
07-10-2011, 06:47 AM
Reminds me of the time I got a tour of Morgan Industries in Worcester, MA. I saw a guy using a vertical-spindle boring machine to turn a bearing about the size of a 55-gallon oil drum, if not larger. It was for a steel mill.

PixMan
07-10-2011, 08:16 AM
Reminds me of the time I got a tour of Morgan Industries in Worcester, MA. I saw a guy using a vertical-spindle boring machine to turn a bearing about the size of a 55-gallon oil drum, if not larger. It was for a steel mill.

Morgan Construction in Worcester, a builder of steel rolling mills for small-diameter rod and heavy wire and also "Morgoil" large plain babbitt bearings for mills, paper and power plants was bought out by Siemens a number of years ago. My father-in-law retired from there just after the change. Just about a year ago the last of the Morgan family (Phillip) left management, and the Morgan name came down from the buildings. It's all just "Siemens VAI" on there now, though they haven't yet renamed the large bearing product.

Cool stuff. I've been in there a number of times.

loose nut
07-10-2011, 08:29 AM
Sell the swarf and retire.

becksmachine
07-10-2011, 12:19 PM
I don't often see grades of carbide meant for steel in a flat-topped (no chipbreaker) insert. Your failure mode for inserts in that material should be flank wear and perhaps a bit of cratering. It shouldn't be catastrophic breakage.

What maker and grade were those CNMA inserts?
Maybe I should have titled the thread "Proper and IMPROPER use of carbide". :D

Most of the catastrophic insert failures were due to inadvertently stopping the spindle while in the cut, or running into the shoulder from the previous cut. This was usually due to dodging hot, flying chips while trying to get a set of firm joint calipers on the turned diameter while the part is moving. One of the off buttons is located right where I have to lean over the carriage to do this, so a misplaced hip usually breaks the insert. Also, tripping a breaker/thermal overload while in the cut is a very reliable way to cause catastrophic insert failure. ;)

As for the insert grade, I would have to look for sure, most of them were an Interstate Carbide grade that I have had for years, if I had to guess, IP65?? There were a couple Kennametal 850 in there also. Insert life was acceptable as far as I was concerned, if I managed to avoid any of the above mentioned sins, one corner would do an entire end.
Upon further inspection Interstate didn't have a fancy name for the grade, they just called it C5 with TiN (?) coating.

Dave

becksmachine
07-10-2011, 12:33 PM
Soft (annealed) 4140?? They heat treat the rollers after you are done shaping them? Some heavy turning you are doing there. JR

As I said, not my style of engineering, but it isn't unreasonable to harden to RC 40-50 and then finish the bearing fits. The large diameters are probably close enough as they are.

Dave

becksmachine
07-10-2011, 12:37 PM
what were you making ..not candle sticks.

Not exactly sure, but I would guess a support roller for some large drum, like a ball mill or kiln.

Dave

becksmachine
07-10-2011, 01:24 PM
now that's some heavy 4140. very impressive...

any more info about the machine to share?


My father and I have owned the lathe for 30 years, bought it from a private fellow here locally. Moving a machine tool is one thing, keeping all the accessories with it is another matter entirely. Happily, a complete set of change gears did survive and traveled with the machine, along with a steady rest and chuck.

Had to build the drive and supporting framework as I am sure that the top cone pulley is still on the lineshaft wherever the lathe was removed from. One of the disadvantages associated with a flat belt machine is the flat belt, which usually is the limiting factor in how much horsepower can be transmitted to the spindle. However, even flat belt technology has improved enough to allow other aspects of the machine to become the limiting factor(s). Of course a (more?) modern geared head lathe of this size could have as much as 50, 75 or 100 hp, but there was no belt slippage transmitting 20-30 hp, even at it's worst point of sailing, that being the slowest open belt speed where the belt feet per minute is lowest. The belt idler set up, on the slack side of the belt, applies constant pressure on the belt to compensate for any stretch under load, and the drive surface is some of the long term stickiest stuff I have ever seen. Sticky enough that I normally run the belt inside out with the sticky surface away from the pulleys to eliminate the screech when it starts up.

Also had to machine a new quill for the tailstock. It did also come with an assortment of dead centers for use there, but they had something other than a Morse taper, so was unable to use any other tooling in the tailstock. Never did determine exactly what taper it was, Jarno, Sellers?? In any event they are still saved for use in the headstock as the taper there remains original, whatever it is. Interesting feature there, they went to the trouble of making a hole through the spindle for knocking out a tool that may be in the taper in the headstock. But to do so requires that you remove the thrust bearing strap from the outboard end of the spindle to gain access to the hole. Was this considered superior to using a dead center that was threaded for removal? Rolling element bearings sure make life easier in a lot of ways!!

I was guessing it's age at approximately 100 years as any information I can find suggests the Pond name went out of use around 1930 at the latest when the company was sold. It doesn't impress me as being WW1 or prior, but maybe someone here can enlighten me further on this?

Dave