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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Hard spots in 11L14?
I just had something weird happen.
I was boring a .475 deep .624 dia hole in some 11L14 on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. Didn't help any. I also looked for tool rub as in insufficent relief. Anyway, as I worked away, it became apparent my finishing cuts where not tracking the amount of infeed. I was using a telescoping gage and mic to measure. Getting near where I thought I should be at the right diameter, I tried the hex bushing that I planned to press into the hole and it went in about 1/8". Now that is weird. Why only that far? On each pass, I had stopped the lathe, and retracted the carriage w/o backing off the cross feed. That little scratch that can result isn't an issue since I'm pressing something in. I decided to dismount the work and use the bushing to check the back side and that was at least 0.006" oversize. The ways do not have detectable wear. This isn't a whooped lathe. So what the heck happened? 11L14 generally cuts like butter and I've used a lot of the stuff. I've turned a shorter piece from the same round w/o issues using the same setup and I made the same piece I was making tonight earlier. For those that remember my recent post about screwing up a barrel plate by tapping the wrong sized holes, this was the replacement. Wes |
#2
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Hard spots in 11L14?
In article ,
Wes wrote: I just had something weird happen. I was boring a .475 deep .624 dia hole in some 11L14 on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. Didn't help any. I also looked for tool rub as in insufficent relief. Anyway, as I worked away, it became apparent my finishing cuts where not tracking the amount of infeed. I was using a telescoping gage and mic to measure. Getting near where I thought I should be at the right diameter, I tried the hex bushing that I planned to press into the hole and it went in about 1/8". Now that is weird. Why only that far? On each pass, I had stopped the lathe, and retracted the carriage w/o backing off the cross feed. That little scratch that can result isn't an issue since I'm pressing something in. I decided to dismount the work and use the bushing to check the back side and that was at least 0.006" oversize. The ways do not have detectable wear. This isn't a whooped lathe. So what the heck happened? 11L14 generally cuts like butter and I've used a lot of the stuff. I've turned a shorter piece from the same round w/o issues using the same setup and I made the same piece I was making tonight earlier. For those that remember my recent post about screwing up a barrel plate by tapping the wrong sized holes, this was the replacement. Was the heel of the boring tool skating on the side of the hole? It doesn't take much. This has snuck up on me. Joe Gwinn |
#3
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Hard spots in 11L14?
"Wes" wrote in message ... I just had something weird happen. I was boring a .475 deep .624 dia hole in some 11L14 on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. Didn't help any. I also looked for tool rub as in insufficent relief. Anyway, as I worked away, it became apparent my finishing cuts where not tracking the amount of infeed. I was using a telescoping gage and mic to measure. Getting near where I thought I should be at the right diameter, I tried the hex bushing that I planned to press into the hole and it went in about 1/8". Now that is weird. Why only that far? On each pass, I had stopped the lathe, and retracted the carriage w/o backing off the cross feed. That little scratch that can result isn't an issue since I'm pressing something in. I decided to dismount the work and use the bushing to check the back side and that was at least 0.006" oversize. The ways do not have detectable wear. This isn't a whooped lathe. So what the heck happened? 11L14 generally cuts like butter and I've used a lot of the stuff. I've turned a shorter piece from the same round w/o issues using the same setup and I made the same piece I was making tonight earlier. For those that remember my recent post about screwing up a barrel plate by tapping the wrong sized holes, this was the replacement. Wes Very possibly a hard inclusion, like a piece of HSS or carbide that got into the melt. I've related here before our experiences hitting a HSS tap, intact, in the middle of a piece of steel bar. Unless the steel is arc-remelted, it can happen. -- Ed Huntress |
#4
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Hard spots in 11L14?
"Wes" wrote in message ... I just had something weird happen. I was boring a .475 deep .624 dia hole in some 11L14 on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. Didn't help any. I also looked for tool rub as in insufficent relief. snip Wes I've run into more inclusions than I deserve, your turn! |
#5
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Hard spots in 11L14?
I'd suspect the heel, too. Try an hss bit (which would have more
relief) and see it anything is different. I don't know what size insert you are using, but with a relief of only 7° or so, the heel could easily be rubbing. I have pretty much quit using carbides for boring for that reason. Especially for small holes. Pete Stanaitis ----------------- Wes wrote: I just had something weird happen. I was boring a .475 deep .624 dia hole in some 11L14 on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. Didn't help any. I also looked for tool rub as in insufficent relief. Anyway, as I worked away, it became apparent my finishing cuts where not tracking the amount of infeed. I was using a telescoping gage and mic to measure. Getting near where I thought I should be at the right diameter, I tried the hex bushing that I planned to press into the hole and it went in about 1/8". Now that is weird. Why only that far? On each pass, I had stopped the lathe, and retracted the carriage w/o backing off the cross feed. That little scratch that can result isn't an issue since I'm pressing something in. I decided to dismount the work and use the bushing to check the back side and that was at least 0.006" oversize. The ways do not have detectable wear. This isn't a whooped lathe. So what the heck happened? 11L14 generally cuts like butter and I've used a lot of the stuff. I've turned a shorter piece from the same round w/o issues using the same setup and I made the same piece I was making tonight earlier. For those that remember my recent post about screwing up a barrel plate by tapping the wrong sized holes, this was the replacement. Wes |
#6
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Hard spots in 11L14?
Just a dig in the dark - but was the cutter tip below center ?
Or above - and not on the center line ? Martin Wes wrote: I just had something weird happen. I was boring a .475 deep .624 dia hole in some 11L14 on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. Didn't help any. I also looked for tool rub as in insufficent relief. Anyway, as I worked away, it became apparent my finishing cuts where not tracking the amount of infeed. I was using a telescoping gage and mic to measure. Getting near where I thought I should be at the right diameter, I tried the hex bushing that I planned to press into the hole and it went in about 1/8". Now that is weird. Why only that far? On each pass, I had stopped the lathe, and retracted the carriage w/o backing off the cross feed. That little scratch that can result isn't an issue since I'm pressing something in. I decided to dismount the work and use the bushing to check the back side and that was at least 0.006" oversize. The ways do not have detectable wear. This isn't a whooped lathe. So what the heck happened? 11L14 generally cuts like butter and I've used a lot of the stuff. I've turned a shorter piece from the same round w/o issues using the same setup and I made the same piece I was making tonight earlier. For those that remember my recent post about screwing up a barrel plate by tapping the wrong sized holes, this was the replacement. Wes |
#7
Posted to rec.crafts.metalworking
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Hard spots in 11L14?
On Apr 18, 6:50*pm, "Buerste" wrote:
"Wes" wrote in message ... I just had something weird happen. I was boring a .475 deep .624 dia hole in some 11L14 *on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. *I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. *Didn't help any. *I also looked for tool rub as in insufficent relief. snip Wes I've run into more inclusions than I deserve, your turn!- Hide quoted text - - Show quoted text - You can avoid them if you use Colgate and brush regularly. |
#8
Posted to rec.crafts.metalworking
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Hard spots in 11L14?
"Tim Wescott" wrote in message ... Ed Huntress wrote: "Wes" wrote in message ... I just had something weird happen. I was boring a .475 deep .624 dia hole in some 11L14 on my lathe. Work was held in a 4 jaw chuck, boring tool was a boring bar for my Bridgeport's offset boring head, one of those brazed carbide bars. I noticed I'd start taking a cut and after a certain distance in, I'd start hearing chatter. I removed the tool, double checked it was set it on centerline, and even gave the cutting edge a light honing to touch it up. Didn't help any. I also looked for tool rub as in insufficent relief. Anyway, as I worked away, it became apparent my finishing cuts where not tracking the amount of infeed. I was using a telescoping gage and mic to measure. Getting near where I thought I should be at the right diameter, I tried the hex bushing that I planned to press into the hole and it went in about 1/8". Now that is weird. Why only that far? On each pass, I had stopped the lathe, and retracted the carriage w/o backing off the cross feed. That little scratch that can result isn't an issue since I'm pressing something in. I decided to dismount the work and use the bushing to check the back side and that was at least 0.006" oversize. The ways do not have detectable wear. This isn't a whooped lathe. So what the heck happened? 11L14 generally cuts like butter and I've used a lot of the stuff. I've turned a shorter piece from the same round w/o issues using the same setup and I made the same piece I was making tonight earlier. For those that remember my recent post about screwing up a barrel plate by tapping the wrong sized holes, this was the replacement. Wes Very possibly a hard inclusion, like a piece of HSS or carbide that got into the melt. I've related here before our experiences hitting a HSS tap, intact, in the middle of a piece of steel bar. Unless the steel is arc-remelted, it can happen. No pictures? There really was nothing much to see. We were milling a disk cut from the bar, in a Bridgeport, and all hell broke loose when we hit it. If you looked closely you could see the threads of the tap. Cutting across it with an abrasive blade in a power hacksaw, we could see it in cross-section. But you would have needed to etch it to get a good photo. My dad ruined a bandsaw blade on a ball bearing in the middle of some angle iron, although I haven't personally run into such inclusions. I think they used to be more common than they are today. This all happened...hmmm. 39 years ago, I think. Maybe they have better means of sorting scrap? -- Ed Huntress |
#9
Posted to rec.crafts.metalworking
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Hard spots in 11L14?
On Sun, 18 Apr 2010 18:08:24 -0400, Wes wrote:
I just had something weird happen. Another (unlikely) possibility is, are you getting swarf/chips building up beside the boring bar? I once had a problem caused by this. It sprung the boring bar enough to reduce the depth of cut near the bottom of the hole. Mark Rand RTFM |
#10
Posted to rec.crafts.metalworking
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Hard spots in 11L14?
Joseph Gwinn wrote:
Was the heel of the boring tool skating on the side of the hole? It doesn't take much. This has snuck up on me. It looks like at some point, likely before I started, since I did a touch up, I gave the leading edge some negative rake by accident. In my mind, it all works out to fit the condition. I *really* need to invest in some Circle Trigon small diameter boring bars that use inserts. Today at work was strange. One of the engineers bought a new 1 ton Dake arbor press. I think it was made in USA but it might not be. He wanted a .501D by 1.00 dp hole in the center of the ram. First time I used the 4 jaw for the LeBlond at work, usually there I use a Buck 3 jaw true set or collets. After cutting 4 strips of bar stock to protect the ram from the curved jaws, I got my first crack at centering square stock in a 4 jaw independent. It went okay, you rock the indicator near where you think center is and remember the low reading. This was made a bit more difficult since the only indicator I have at work is a 0.0001" .016" travel test indicator. If I knew I was doing this today, I'd have bought one of my long travel plunger indicators in with me from my home shop. Anyway, got it all nice and squared up, center drilled it, drilled it, run a reamer into it. All went fine and dandy using HSS tooling. I was a bit worried it might be fairly hard but it sure seemed in HSS territory. So next I take it over to the bridgeport. Use my center finder to find the edges of the Kurt vise. I *wish* people would just leave the dro on. There is a button on the Sony DRO to mute the display. Now to drill a 1/4" hole so I can tap a 5/16 NC hole. The speed I use for the edgefinder should be fine for a 1/4" drill. I am working my way down to center making nice looking chips and all is well. Suddenly, I hear screeching and all progress stops. Pull the drill and it is cooked. Okay, try another new one. DOA. Try one more from my drilldex in case I have some crappy stuff. DOA. I'm about .050" from breaking through into the .501" hole. This is p*ss*ng me off at this point. Head over to my tool box and find a 7/32 carbide drill I use to modify normal sockets to accept 1/2" pin lock square drives. That punches right through. I also found a 1/4" endmill that I am guilty of using in a drill chuck today since I just wanted to get this ordeal over. No harm came to either. So now I'm tapping this thing. Visions of a broken tap dance in my head and I really don't want to break one. I go a bit and really don't like the forces I'm putting into it and get another one from supply. That one cuts a bit easier but I can tell it doesn't like what I'm asking it to do. Finally, I break through. Now at this point I try to screw a 5/16-18 screw I pulled out of another arbor press when I grabbed the tooling to use it to check fit. It will not screw in. It is the right pitch. The tap I used was H3 or .0015" on the loose side. I head over to the bolt bin and get another bolt, it fits fine, I champher the original fastener and it still doesn't want to go on. I compare it to my tap, perfect match. Go find a metric bolt near the size and it isn't close so it isn't one of those deals. Then there was the MCC I replaced in a CNC lathe, I didn't notice one contact was NC when I expected NO, that took a while to figure out. Some days you fight your way though. Wes |
#11
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Hard spots in 11L14?
On Tue, 20 Apr 2010 20:17:03 -0400
Wes wrote: snip One of the engineers bought a new 1 ton Dake arbor press. I think it was made in USA but it might not be. Should be be just a bit to your SW, Grand Haven, Michigan. See: http://www.dakecorp.com/company.asp The older presses were made there, take a look at the model plate to see if that one was or not. -- Leon Fisk Grand Rapids MI/Zone 5b Remove no.spam for email |
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