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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
Posted to rec.crafts.metalworking
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A slo-mo crash, with little drama and no damage
I was making an arbor for a Norton aluminum-oxide 4" cup grinding wheel from
mild steel using the Clausing 5914 Lathe, and had a minor misadventure. The stock is a 2.5" diameter 12L14 alloy bar held in the 3-jaw chuck. The part I was working on is 1.000" diameter by 2" long, sticking out to the right where the 2.5" diameter bar has been turned down. There must have been two pounds of chips in the pan by then. Anyway, I'm making a near final pass under relatively slow power feed using a BXA-16N toolholder, and the flat full face of the carbide insert comes up against the machined end face of the bar. Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. There were no groans or loud noises, but still this is not a good idea. Anyway, I realized what was going on, and managed to stop the show before anything bad happened, leaving only an undercut as evidence. Another lesson on the way to becoming a machinist. Joe Gwinn |
#2
Posted to rec.crafts.metalworking
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A slo-mo crash, with little drama and no damage
On 4/6/2010 7:47 PM, Joseph Gwinn wrote:
I was making an arbor for a Norton aluminum-oxide 4" cup grinding wheel from mild steel using the Clausing 5914 Lathe, and had a minor misadventure. The stock is a 2.5" diameter 12L14 alloy bar held in the 3-jaw chuck. The part I was working on is 1.000" diameter by 2" long, sticking out to the right where the 2.5" diameter bar has been turned down. There must have been two pounds of chips in the pan by then. Anyway, I'm making a near final pass under relatively slow power feed using a BXA-16N toolholder, and the flat full face of the carbide insert comes up against the machined end face of the bar. Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. There were no groans or loud noises, but still this is not a good idea. Anyway, I realized what was going on, and managed to stop the show before anything bad happened, leaving only an undercut as evidence. Another lesson on the way to becoming a machinist. Joe Gwinn I put a piece of ordinary notebook paper under my tool post to provide a bit of friction. Seems to work. cheers T.Alan |
#3
Posted to rec.crafts.metalworking
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A slo-mo crash, with little drama and no damage
In article ,
"T.Alan Kraus" wrote: On 4/6/2010 7:47 PM, Joseph Gwinn wrote: I was making an arbor for a Norton aluminum-oxide 4" cup grinding wheel from mild steel using the Clausing 5914 Lathe, and had a minor misadventure. The stock is a 2.5" diameter 12L14 alloy bar held in the 3-jaw chuck. The part I was working on is 1.000" diameter by 2" long, sticking out to the right where the 2.5" diameter bar has been turned down. There must have been two pounds of chips in the pan by then. Anyway, I'm making a near final pass under relatively slow power feed using a BXA-16N toolholder, and the flat full face of the carbide insert comes up against the machined end face of the bar. Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. There were no groans or loud noises, but still this is not a good idea. Anyway, I realized what was going on, and managed to stop the show before anything bad happened, leaving only an undercut as evidence. Another lesson on the way to becoming a machinist. Joe Gwinn I put a piece of ordinary notebook paper under my tool post to provide a bit of friction. Seems to work. It's a thought. I've heard it suggested before, but don't know how well the paper will stand up when soaked with soluble-oil coolant. Joe Gwinn |
#4
Posted to rec.crafts.metalworking
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A slo-mo crash, with little drama and no damage
Joseph Gwinn wrote:
In article , "T.Alan Kraus" wrote: On 4/6/2010 7:47 PM, Joseph Gwinn wrote: I was making an arbor for a Norton aluminum-oxide 4" cup grinding wheel from mild steel using the Clausing 5914 Lathe, and had a minor misadventure. The stock is a 2.5" diameter 12L14 alloy bar held in the 3-jaw chuck. The part I was working on is 1.000" diameter by 2" long, sticking out to the right where the 2.5" diameter bar has been turned down. There must have been two pounds of chips in the pan by then. Anyway, I'm making a near final pass under relatively slow power feed using a BXA-16N toolholder, and the flat full face of the carbide insert comes up against the machined end face of the bar. Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. There were no groans or loud noises, but still this is not a good idea. Anyway, I realized what was going on, and managed to stop the show before anything bad happened, leaving only an undercut as evidence. Another lesson on the way to becoming a machinist. Joe Gwinn I put a piece of ordinary notebook paper under my tool post to provide a bit of friction. Seems to work. It's a thought. I've heard it suggested before, but don't know how well the paper will stand up when soaked with soluble-oil coolant. Joe Gwinn How about a piece of fine grit carborundum paper? Something used for wet sanding.. -bill |
#5
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A slo-mo crash, with little drama and no damage
On Tue, 06 Apr 2010 22:47:05 -0400, Joseph Gwinn
wrote: snip Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. snip ======= Old time machinists books advises (when possible) setting up a tool for a lathe cut, that it should be arranged such that if anything shifts the tool swings out of/away from the cut rather than into the cut. Lindsay has many reprints of the older texts that are quite helpful for the home/hobby machinist. A good place to start for an overview is http://www.lindsaybks.com/bks/milne/index.html and any of these will be helpful http://www.lindsaybks.com/bks/milne/index.html and see my web page http://mcduffee-associates.us/machin...ning_books.htm Better luck on the next project, and its a mistake only if you didn't learn anything... Unka George (George McDuffee) ............................... The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953). |
#6
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A slo-mo crash, with little drama and no damage
On Wed, 07 Apr 2010 12:15:02 -0700, Bill Martin
wrote: Joe Gwinn I put a piece of ordinary notebook paper under my tool post to provide a bit of friction. Seems to work. It's a thought. I've heard it suggested before, but don't know how well the paper will stand up when soaked with soluble-oil coolant. Joe Gwinn How about a piece of fine grit carborundum paper? Something used for wet sanding.. -bill I use a bit of yellow legal pad paper on ALL of my lathes. Works very well with no damage to anything. Gunner "First Law of Leftist Debate The more you present a leftist with factual evidence that is counter to his preconceived world view and the more difficult it becomes for him to refute it without losing face the chance of him calling you a racist, bigot, homophobe approaches infinity. This is despite the thread you are in having not mentioned race or sexual preference in any way that is relevant to the subject." Grey Ghost |
#7
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A slo-mo crash, with little drama and no damage
Joseph Gwinn on Wed, 07 Apr 2010 09:06:18 -0400
typed in rec.crafts.metalworking the following: In article , "T.Alan Kraus" wrote: On 4/6/2010 7:47 PM, Joseph Gwinn wrote: I was making an arbor for a Norton aluminum-oxide 4" cup grinding wheel from mild steel using the Clausing 5914 Lathe, and had a minor misadventure. The stock is a 2.5" diameter 12L14 alloy bar held in the 3-jaw chuck. The part I was working on is 1.000" diameter by 2" long, sticking out to the right where the 2.5" diameter bar has been turned down. There must have been two pounds of chips in the pan by then. Anyway, I'm making a near final pass under relatively slow power feed using a BXA-16N toolholder, and the flat full face of the carbide insert comes up against the machined end face of the bar. Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. There were no groans or loud noises, but still this is not a good idea. Anyway, I realized what was going on, and managed to stop the show before anything bad happened, leaving only an undercut as evidence. Another lesson on the way to becoming a machinist. Joe Gwinn I put a piece of ordinary notebook paper under my tool post to provide a bit of friction. Seems to work. It's a thought. I've heard it suggested before, but don't know how well the paper will stand up when soaked with soluble-oil coolant. Paper will stand up well enough. And it is cheap to replace, while not causing a lot of other problems. - pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough! |
#8
Posted to rec.crafts.metalworking
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A slo-mo crash, with little drama and no damage
In article ,
F. George McDuffee wrote: On Tue, 06 Apr 2010 22:47:05 -0400, Joseph Gwinn wrote: snip Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. snip ======= Old time machinists books advises (when possible) setting up a tool for a lathe cut, that it should be arranged such that if anything shifts the tool swings out of/away from the cut rather than into the cut. To the extent practical, for sure. But the setup is an Aloris BXA toolpost with a BXA-16N toolholder held in the left dovetail (and thus perpendicular to the bedway), cutting up close to the chuck, and the carriage can get only so close without a collision. There is an irreducible torque arm here. Another thing to note is that I didn't appear to have the problem when feeding by hand. The power feed was slow, and so the carbide insert didn't cut when presented the full face - the rise in force was too slow, so it just shoved the toolpost gradually aside. If it had dug in and started cutting, the forces and thus torque on the toolpost would have been lower. It appears that the problem is common, as is the solution - a piece of paper under the toolpost, which I will try. Joe Gwinn |
#9
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A slo-mo crash, with little drama and no damage
"Joseph Gwinn" wrote in message
... In article , "T.Alan Kraus" wrote: On 4/6/2010 7:47 PM, Joseph Gwinn wrote: I was making an arbor for a Norton aluminum-oxide 4" cup grinding wheel from mild steel using the Clausing 5914 Lathe, and had a minor misadventure. The stock is a 2.5" diameter 12L14 alloy bar held in the 3-jaw chuck. The part I was working on is 1.000" diameter by 2" long, sticking out to the right where the 2.5" diameter bar has been turned down. There must have been two pounds of chips in the pan by then. Anyway, I'm making a near final pass under relatively slow power feed using a BXA-16N toolholder, and the flat full face of the carbide insert comes up against the machined end face of the bar. Instead of machining the face a little flatter, the whole BXA tool post rotates on the compound, causing the bit on the BXA-16N to dig a bit deeper. There were no groans or loud noises, but still this is not a good idea. Anyway, I realized what was going on, and managed to stop the show before anything bad happened, leaving only an undercut as evidence. Another lesson on the way to becoming a machinist. Joe Gwinn I put a piece of ordinary notebook paper under my tool post to provide a bit of friction. Seems to work. It's a thought. I've heard it suggested before, but don't know how well the paper will stand up when soaked with soluble-oil coolant. Joe Gwinn I use notebook paper for various clamps and fixtures on my mill. It works great. While I do not soak it down continuously at this time it does get quite soaked with oil based lubricant. I have not had it fail during a job or run of jobs where I do not remove the clamp or fixture. Some of the things I use routinely I have precut several pieces and have them stacked up in the cabinet next to my mill. |
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