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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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Grinding lathe bed.
On Mar 28, 9:48*am, Uffe Bærentsen wrote:
Hi I'm sure that the ways will look good when you grind like this guy does. But how about saddle wear? * * * *(don't know how to spell it :-( ) As far as I can see there is no way that you or me can remove saddle wear grinding a bed like this only add more sway to the bed. Am I right or wrong on this? -- Uffe Sometimes most anything will make things better. Many years ago a friend and i purchased a worn out small Sears lathe. I used a file and got it a lot better than it was originally. Not the a good way , but it still was a lot better after I was done. If I were doing a large lathe like the one in the video and the lathe was not very valuable, I would do my best to get rid of the saddle wear and then grind the ways as he did. Dan |
#2
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Thu, 28 Mar 2013 08:24:41 -0700 (PDT), "
wrote: On Mar 28, 9:48*am, Uffe Bærentsen wrote: Hi I'm sure that the ways will look good when you grind like this guy does. But how about saddle wear? * * * *(don't know how to spell it :-( ) As far as I can see there is no way that you or me can remove saddle wear grinding a bed like this only add more sway to the bed. Am I right or wrong on this? -- Uffe Sometimes most anything will make things better. Many years ago a friend and i purchased a worn out small Sears lathe. I used a file and got it a lot better than it was originally. Not the a good way , but it still was a lot better after I was done. If I were doing a large lathe like the one in the video and the lathe was not very valuable, I would do my best to get rid of the saddle wear and then grind the ways as he did. Dan He's probably running the grinder on the tailstock ways, which are likely to be in better shape than the carriage ways, especially up near the headstock. Coincidentally, the guy calls himself "4GSR," which I assume is a reference to the LeBlond 4GSR boring lathe. I was involved in the bed refurb of a 4GSR recently. 70 feet long, 16" hole thru the spindle. -- Ned Simmons |
#3
Posted to rec.crafts.metalworking
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Grinding lathe bed.
Ned Simmons fired this volley in
: He's probably running the grinder on the tailstock ways, which are likely to be in better shape than the carriage ways, especially up near the headstock. --- Ned, you make a good point I didn't look for. If that's the case, the ways just might get ground O.K. (assuming any way to make sure that stone's face is perfectly parallel to the desired angle, and dressed to match!) It might not be 'right', but probably not too bad. Lloyd |
#4
Posted to rec.crafts.metalworking
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Grinding lathe bed.
Ned Simmons fired this volley in
: He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. L |
#5
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. |
#6
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ned Simmons" wrote in message ... On Thu, 28 Mar 2013 08:24:41 -0700 (PDT), " wrote: On Mar 28, 9:48 am, Uffe Bærentsen wrote: Hi I'm sure that the ways will look good when you grind like this guy does. But how about saddle wear? (don't know how to spell it :-( ) As far as I can see there is no way that you or me can remove saddle wear grinding a bed like this only add more sway to the bed. Am I right or wrong on this? -- Uffe Sometimes most anything will make things better. Many years ago a friend and i purchased a worn out small Sears lathe. I used a file and got it a lot better than it was originally. Not the a good way , but it still was a lot better after I was done. If I were doing a large lathe like the one in the video and the lathe was not very valuable, I would do my best to get rid of the saddle wear and then grind the ways as he did. Dan He's probably running the grinder on the tailstock ways, which are likely to be in better shape than the carriage ways, especially up near the headstock. Coincidentally, the guy calls himself "4GSR," which I assume is a reference to the LeBlond 4GSR boring lathe. I was involved in the bed refurb of a 4GSR recently. 70 feet long, 16" hole thru the spindle. That's a monster.... We had a couple of travelling collumn horizontal boring mills with beds about that lengh when I was with Certified Aerospace in the early 80's--pretty sure they ran on a one-piece bed but I can't say for sure. Later, when I was at Boeing Portland, they put in some spanking-new G&L cnc boring mills but these were 20, 40 and 60 foot sections, bolted together with the 60ft bed being the max available if I recall correctly. |
#7
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Thu, 28 Mar 2013 13:07:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote: Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. L He's not running on the functional surfaces of the ways at all: http://www.practicalmachinist.com/vb...rinder-225515/ http://i70.photobucket.com/albums/i1...r/DSCN0611.jpg Even though he claims those surfaces are ground in the same setup as the working surfaces, I'd be concerned how much care was taken grinding the non-functional surfaces. And the rollers have the disadvantage of transferring small irregularities to the grinding wheel. I guess the cost-benefit calculation has to include how bad the worn really ways are, and what you're hoping for after the regrind. -- Ned Simmons |
#8
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Thu, 28 Mar 2013 11:49:48 -0700, "PrecisionmachinisT"
wrote: "Ned Simmons" wrote in message ... On Thu, 28 Mar 2013 08:24:41 -0700 (PDT), " wrote: On Mar 28, 9:48 am, Uffe Bærentsen wrote: Hi I'm sure that the ways will look good when you grind like this guy does. But how about saddle wear? (don't know how to spell it :-( ) As far as I can see there is no way that you or me can remove saddle wear grinding a bed like this only add more sway to the bed. Am I right or wrong on this? -- Uffe Sometimes most anything will make things better. Many years ago a friend and i purchased a worn out small Sears lathe. I used a file and got it a lot better than it was originally. Not the a good way , but it still was a lot better after I was done. If I were doing a large lathe like the one in the video and the lathe was not very valuable, I would do my best to get rid of the saddle wear and then grind the ways as he did. Dan He's probably running the grinder on the tailstock ways, which are likely to be in better shape than the carriage ways, especially up near the headstock. Coincidentally, the guy calls himself "4GSR," which I assume is a reference to the LeBlond 4GSR boring lathe. I was involved in the bed refurb of a 4GSR recently. 70 feet long, 16" hole thru the spindle. That's a monster.... We had a couple of travelling collumn horizontal boring mills with beds about that lengh when I was with Certified Aerospace in the early 80's--pretty sure they ran on a one-piece bed but I can't say for sure. Later, when I was at Boeing Portland, they put in some spanking-new G&L cnc boring mills but these were 20, 40 and 60 foot sections, bolted together with the 60ft bed being the max available if I recall correctly. That machine also has a sectional bed, the longest section being about 30 feet. I spent a fair amount of time documenting exactly what was expected for tolerances on the ways after grinding, and after the bed was subsequently disassembled, moved and reassembled. -- Ned Simmons |
#9
Posted to rec.crafts.metalworking
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Grinding lathe bed.
Ned Simmons fired this volley in
: He's not running on the functional surfaces of the ways at all: Heh! It's pretty clear he "first guessed" all our second-guesses. If one can count on the apron surface and top surfaces to be true, then that should do it. (I still wonder how he establishes the correct angle and dress on that stone, though. Didn't see anythin' in the pictures showing that part.) Lloyd |
#10
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT"
wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. If this L&S lathe bed is representative: http://www.lathes.co.uk/lodgeshipley/ ....then it's the same as my SB, only reversed back-to-front. The tailstock rides on an inner flat and an inner V, while the carriage rides on the pair of outer Vs. Thus, if he's riding on the tailstock ways, he could get some improvement. If not, not. -- Ed Huntress |
#11
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Thu, 28 Mar 2013 15:35:06 -0400, Ned Simmons
wrote: On Thu, 28 Mar 2013 13:07:08 -0500, "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote: Ned Simmons fired this volley in m: He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. L He's not running on the functional surfaces of the ways at all: http://www.practicalmachinist.com/vb...rinder-225515/ http://i70.photobucket.com/albums/i1...r/DSCN0611.jpg Even though he claims those surfaces are ground in the same setup as the working surfaces, I'd be concerned how much care was taken grinding the non-functional surfaces. And the rollers have the disadvantage of transferring small irregularities to the grinding wheel. I guess the cost-benefit calculation has to include how bad the worn really ways are, and what you're hoping for after the regrind. Omigod. Is he rolling that contraption on the TOPS of the Vs? If so, good luck Charlie... -- Ed Huntress |
#12
Posted to rec.crafts.metalworking
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Grinding lathe bed.
wrote in message
... Sometimes most anything will make things better. Many years ago a friend and i purchased a worn out small Sears lathe. I used a file and got it a lot better than it was originally. Not the a good way , but it still was a lot better after I was done. Dan I remachined a well-worn Sears 109 on a big horizontal mill in the high school shop night class. It did a nice smooth job with four passes of a new angle cutter, without having to unclamp it and lose parallelism. Lowering the ways lowered the saddle, and drops the half nuts out of line with the leadscrew. I thought I could shim the saddle back up with 0.025" sheet brass strips but they weren't flat enough after bending the ends up to keep them in place. Now I use it as a speed lathe for polishing and drilling small deep oil holes. jsw |
#13
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ned Simmons" wrote in message
... Coincidentally, the guy calls himself "4GSR," which I assume is a reference to the LeBlond 4GSR boring lathe. I was involved in the bed refurb of a 4GSR recently. 70 feet long, 16" hole thru the spindle. -- Ned Simmons Portsmouth Naval Shipyard? They held an open house on their 200th anniversary. The big lathes were holding ballistic missile sub propellor shafts. jsw |
#14
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ed Huntress" wrote in message news On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT" wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. If this L&S lathe bed is representative: http://www.lathes.co.uk/lodgeshipley/ ...then it's the same as my SB, only reversed back-to-front. The tailstock rides on an inner flat and an inner V, while the carriage rides on the pair of outer Vs. Actually, the carriage on the lathe in your photo seems to be using both of the outside ways for alignment, in addition to it's also being being supported by the flat way section that's located out front. According Oscar Perrigo; "lathe design, construction, and operation ", this appears to have been yet another iteration in a long series of carriage bearing "improvements" that evolved over the years... Eventually, the inside vees were dispensed with altogether, settling on a design that used a pair of vees and a pair of flats in a configuration that came to be called the "Ideal Form" FWIW, the problem with using 4 vees was because the underside of the carriage needed to be cut away in order for it to clear the inside pair, which weakened the carriage. --prior to the advent of the "ideal form", the outside pair of vees was invariably used to carry the carriage; this allowed the carriage to be shaped like a capital letter "H" thus providing substantial addional stability while also allowing it to get in real close to (or even underneath) the chuck and tailstock ram. Thus, if he's riding on the tailstock ways, he could get some improvement. If not, not. It'd still undeniably be a hack-job, Ed. |
#15
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's not running on the functional surfaces of the ways at all: Heh! It's pretty clear he "first guessed" all our second-guesses. If one can count on the apron surface and top surfaces to be true, then that should do it. (I still wonder how he establishes the correct angle and dress on that Accuracy of the angle itself isn't terribly critical, you'll be scraping the bearing surface underneath the carriage to match up to it anyways. stone, though. Didn't see anythin' in the pictures showing that part.) Lloyd |
#16
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Thu, 28 Mar 2013 14:19:00 -0700, "PrecisionmachinisT"
wrote: "Ed Huntress" wrote in message news On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT" wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. If this L&S lathe bed is representative: http://www.lathes.co.uk/lodgeshipley/ ...then it's the same as my SB, only reversed back-to-front. The tailstock rides on an inner flat and an inner V, while the carriage rides on the pair of outer Vs. Actually, the carriage on the lathe in your photo seems to be using both of the outside ways for alignment, in addition to it's also being being supported by the flat way section that's located out front. I don't think so. It looks to me like the classic Lodge & Shipley design (Fig. 37 in your book), which is the same as my SB only reversed front-to-back. The four-way support described as the "ideal form" in the book has, to my knowledge, long since been abandoned. That would be a scraping/aligning nightmare. Likewise, I don't think the L&S supported the carriage on two Vs and an assymetrical flat, because wear would be uneven between the flat and the Vs and, again, a nightmare to keep aligned. You'd be obviating one of the two big advantages of V ways. With two flats you'd at least have more balanced wear but that isn't what a L&S has. My SB just has clearance where that screw-on plate shows in the photo I linked to. I suspect that it's probably just a cow-catcher. g It may be holding a felt wiper. According Oscar Perrigo; "lathe design, construction, and operation ", this appears to have been yet another iteration in a long series of carriage bearing "improvements" that evolved over the years... Eventually, the inside vees were dispensed with altogether, settling on a design that used a pair of vees and a pair of flats in a configuration that came to be called the "Ideal Form" I don't think it's around anymore. FWIW, the problem with using 4 vees was because the underside of the carriage needed to be cut away in order for it to clear the inside pair, which weakened the carriage. --prior to the advent of the "ideal form", the outside pair of vees was invariably used to carry the carriage; this allowed the carriage to be shaped like a capital letter "H" thus providing substantial addional stability while also allowing it to get in real close to (or even underneath) the chuck and tailstock ram. Thus, if he's riding on the tailstock ways, he could get some improvement. If not, not. It'd still undeniably be a hack-job, Ed. Yes it would. -- Ed Huntress |
#17
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Jim Wilkins" wrote in message ... wrote in message ... Sometimes most anything will make things better. Many years ago a friend and i purchased a worn out small Sears lathe. I used a file and got it a lot better than it was originally. Not the a good way , but it still was a lot better after I was done. Dan I remachined a well-worn Sears 109 on a big horizontal mill in the high school shop night class. It did a nice smooth job with four passes of a new angle cutter, without having to unclamp it and lose parallelism. Lowering the ways lowered the saddle, and drops the half nuts out of line with the leadscrew. I thought I could shim the saddle back up with 0.025" sheet brass strips but they weren't flat enough after bending the ends up to keep them in place. Now I use it as a speed lathe for polishing and drilling small deep oil holes. jsw Lower the leadscrew instead. |
#18
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Thu, 28 Mar 2013 16:28:50 -0400, "Jim Wilkins"
wrote: "Ned Simmons" wrote in message .. . Coincidentally, the guy calls himself "4GSR," which I assume is a reference to the LeBlond 4GSR boring lathe. I was involved in the bed refurb of a 4GSR recently. 70 feet long, 16" hole thru the spindle. -- Ned Simmons Portsmouth Naval Shipyard? They held an open house on their 200th anniversary. The big lathes were holding ballistic missile sub propellor shafts. jsw Other side of the state. http://www.dearbornprecision.com/ind...vices-provided -- Ned Simmons |
#19
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"PrecisionmachinisT" wrote in message
... "Jim Wilkins" wrote in message ... I remachined a well-worn Sears 109 on a big horizontal mill in the high school shop night class. It did a nice smooth job with four passes of a new angle cutter, without having to unclamp it and lose parallelism. Lowering the ways lowered the saddle, and drops the half nuts out of line with the leadscrew. I thought I could shim the saddle back up with 0.025" sheet brass strips but they weren't flat enough after bending the ends up to keep them in place. Now I use it as a speed lathe for polishing and drilling small deep oil holes. jsw -Lower the leadscrew instead. The holes for it are part of the bed casting and 21" apart, and I don't have a horizontal boring machine. jsw |
#20
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ed Huntress" wrote in message ... On Thu, 28 Mar 2013 14:19:00 -0700, "PrecisionmachinisT" wrote: "Ed Huntress" wrote in message news On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT" wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. If this L&S lathe bed is representative: http://www.lathes.co.uk/lodgeshipley/ ...then it's the same as my SB, only reversed back-to-front. The tailstock rides on an inner flat and an inner V, while the carriage rides on the pair of outer Vs. Actually, the carriage on the lathe in your photo seems to be using both of the outside ways for alignment, in addition to it's also being being supported by the flat way section that's located out front. I don't think so. Read the text at the site you linked me to. It looks to me like the classic Lodge & Shipley design (Fig. 37 in your book), which is the same as my SB only I have the Lindsay Publications version, and there's no mention of Lodge and Shipley in it anywhere so far as I can tell, and page 37 deals with tapping wooden lead screw nuts in my copy. reversed front-to-back. The four-way support described as the "ideal form" in the book has, to my knowledge, long since been abandoned. I never claimed that it's in wide usage.... That would be a scraping/aligning nightmare. Likewise, I don't think Or that it wasn't a nightmare to recondition...I'm just saying that the author considered it to be superior...however, I'll have to add that indeed, it probably was superior, at least by his fairly logical explanation of the merits inherent in said design. the L&S supported the carriage on two Vs and an assymetrical flat, because wear would be uneven between the flat and the Vs and, again, a nightmare to keep aligned. You'd be obviating one of the two big advantages of V ways. With two flats you'd at least have more balanced wear but that isn't what a L&S has. My SB just has clearance where that screw-on plate shows in the photo I only have three engine lathes, (the rest are second op or cnc chuckers machines) but the ones I do have are as you describe...a vee and flat for the carriage, another vee and flat for the tailstock. I linked to. I suspect that it's probably just a cow-catcher. g It may be holding a felt wiper. According Oscar Perrigo; "lathe design, construction, and operation ", this appears to have been yet another iteration in a long series of carriage bearing "improvements" that evolved over the years... Eventually, the inside vees were dispensed with altogether, settling on a design that used a pair of vees and a pair of flats in a configuration that came to be called the "Ideal Form" I don't think it's around anymore. Like I said earlier, I no longer work in a facility that has dozens of engine lathes, and so I can't really verify one way or the other.. FWIW, the problem with using 4 vees was because the underside of the carriage needed to be cut away in order for it to clear the inside pair, which weakened the carriage. --prior to the advent of the "ideal form", the outside pair of vees was invariably used to carry the carriage; this allowed the carriage to be shaped like a capital letter "H" thus providing substantial addional stability while also allowing it to get in real close to (or even underneath) the chuck and tailstock ram. Thus, if he's riding on the tailstock ways, he could get some improvement. If not, not. It'd still undeniably be a hack-job, Ed. Yes it would. === Reading the text at the lathes.uk site again, it becomes apparent that not only did the classic Lodge and Shipley design have the carriage riding on a pair of vees, it also bore against the horizontal surface clostest to the operator (which was shared with the tailstock) as well as against the inside vertical surface (also closest to the operator)... --jeez.... anyone mentioned "nightmarish to grind" lately ? -- Ed Huntress |
#21
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Jim Wilkins" wrote in message ... "PrecisionmachinisT" wrote in message ... "Jim Wilkins" wrote in message ... I remachined a well-worn Sears 109 on a big horizontal mill in the high school shop night class. It did a nice smooth job with four passes of a new angle cutter, without having to unclamp it and lose parallelism. Lowering the ways lowered the saddle, and drops the half nuts out of line with the leadscrew. I thought I could shim the saddle back up with 0.025" sheet brass strips but they weren't flat enough after bending the ends up to keep them in place. Now I use it as a speed lathe for polishing and drilling small deep oil holes. jsw -Lower the leadscrew instead. The holes for it are part of the bed casting and 21" apart, and I don't have a horizontal boring machine. jsw The reason I mention is because I did the same thing back when I was about 22 years old... Finally ended up drilling the mounting holes in the screw support brackets a tad oversize so as to provide the needed clearance. |
#22
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Grinding lathe bed.
"PrecisionmachinisT" wrote in message
news:QoGdnSLRdekSUcnMnZ2dnUVZ_vydnZ2d@scnresearch. com... "Jim Wilkins" wrote in message ... "PrecisionmachinisT" wrote in message ... "Jim Wilkins" wrote in message ... I remachined a well-worn Sears 109 on a big horizontal mill in the high school shop night class. It did a nice smooth job with four passes of a new angle cutter, without having to unclamp it and lose parallelism. Lowering the ways lowered the saddle, and drops the half nuts out of line with the leadscrew. I thought I could shim the saddle back up with 0.025" sheet brass strips but they weren't flat enough after bending the ends up to keep them in place. Now I use it as a speed lathe for polishing and drilling small deep oil holes. jsw -Lower the leadscrew instead. The holes for it are part of the bed casting and 21" apart, and I don't have a horizontal boring machine. jsw -The reason I mention is because I did the same thing back when I was about 22 years old... -Finally ended up drilling the mounting holes in the screw support brackets a tad oversize so as to provide the -needed clearance. I used it as the excuse to buy a South Bend Heavy 10, and don't need the leadscrew on the AA any more. jsw |
#23
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Grinding lathe bed.
"Jim Wilkins" wrote in message ... "PrecisionmachinisT" wrote in message news:QoGdnSLRdekSUcnMnZ2dnUVZ_vydnZ2d@scnresearch. com... "Jim Wilkins" wrote in message ... "PrecisionmachinisT" wrote in message ... "Jim Wilkins" wrote in message ... I remachined a well-worn Sears 109 on a big horizontal mill in the high school shop night class. It did a nice smooth job with four passes of a new angle cutter, without having to unclamp it and lose parallelism. Lowering the ways lowered the saddle, and drops the half nuts out of line with the leadscrew. I thought I could shim the saddle back up with 0.025" sheet brass strips but they weren't flat enough after bending the ends up to keep them in place. Now I use it as a speed lathe for polishing and drilling small deep oil holes. jsw -Lower the leadscrew instead. The holes for it are part of the bed casting and 21" apart, and I don't have a horizontal boring machine. jsw -The reason I mention is because I did the same thing back when I was about 22 years old... -Finally ended up drilling the mounting holes in the screw support brackets a tad oversize so as to provide the -needed clearance. I used it as the excuse to buy a South Bend Heavy 10, and don't need the leadscrew on the AA any more. jsw Aww okay I understand now... |
#24
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Grinding lathe bed.
On Thu, 28 Mar 2013 15:58:54 -0700, "PrecisionmachinisT"
wrote: "Ed Huntress" wrote in message ... On Thu, 28 Mar 2013 14:19:00 -0700, "PrecisionmachinisT" wrote: "Ed Huntress" wrote in message news On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT" wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. If this L&S lathe bed is representative: http://www.lathes.co.uk/lodgeshipley/ ...then it's the same as my SB, only reversed back-to-front. The tailstock rides on an inner flat and an inner V, while the carriage rides on the pair of outer Vs. Actually, the carriage on the lathe in your photo seems to be using both of the outside ways for alignment, in addition to it's also being being supported by the flat way section that's located out front. I don't think so. Read the text at the site you linked me to. Oh, good grief. I see what you mean. It doesn't surprise me that they dropped it in the 1960s. Frankly, I don't believe it worked as they say. To keep the saddle from floating off of the flat horizontal way or off of one of the Vs from time to time would require vertical positioning on the pair of V-ways that was accurate to within 5 or 10 microinches relative to the flat. I don't believe they could do that. They probably floated a bit with light loads, but spring compression of the bed or the saddle might have maintained contact with heavy tool loads. Anyway, that's history. It looks to me like the classic Lodge & Shipley design (Fig. 37 in your book), which is the same as my SB only I have the Lindsay Publications version, and there's no mention of Lodge and Shipley in it anywhere so far as I can tell, and page 37 deals with tapping wooden lead screw nuts in my copy. Check the drawings on page 79 and see if we have the same version. Mine is a PDF that I got somehwhere. reversed front-to-back. The four-way support described as the "ideal form" in the book has, to my knowledge, long since been abandoned. I never claimed that it's in wide usage.... That would be a scraping/aligning nightmare. Likewise, I don't think Or that it wasn't a nightmare to recondition...I'm just saying that the author considered it to be superior...however, I'll have to add that indeed, it probably was superior, at least by his fairly logical explanation of the merits inherent in said design. the L&S supported the carriage on two Vs and an assymetrical flat, because wear would be uneven between the flat and the Vs and, again, a nightmare to keep aligned. You'd be obviating one of the two big advantages of V ways. With two flats you'd at least have more balanced wear but that isn't what a L&S has. My SB just has clearance where that screw-on plate shows in the photo I only have three engine lathes, (the rest are second op or cnc chuckers machines) but the ones I do have are as you describe...a vee and flat for the carriage, another vee and flat for the tailstock. The SB is two Vs for the saddle, and a vee and flat for the tailstock. It looks like the L&S bed only without any contact between the flat and the saddle. I linked to. I suspect that it's probably just a cow-catcher. g It may be holding a felt wiper. According Oscar Perrigo; "lathe design, construction, and operation ", this appears to have been yet another iteration in a long series of carriage bearing "improvements" that evolved over the years... Eventually, the inside vees were dispensed with altogether, settling on a design that used a pair of vees and a pair of flats in a configuration that came to be called the "Ideal Form" I don't think it's around anymore. Like I said earlier, I no longer work in a facility that has dozens of engine lathes, and so I can't really verify one way or the other.. FWIW, the problem with using 4 vees was because the underside of the carriage needed to be cut away in order for it to clear the inside pair, which weakened the carriage. --prior to the advent of the "ideal form", the outside pair of vees was invariably used to carry the carriage; this allowed the carriage to be shaped like a capital letter "H" thus providing substantial addional stability while also allowing it to get in real close to (or even underneath) the chuck and tailstock ram. Thus, if he's riding on the tailstock ways, he could get some improvement. If not, not. It'd still undeniably be a hack-job, Ed. Yes it would. === Reading the text at the lathes.uk site again, it becomes apparent that not only did the classic Lodge and Shipley design have the carriage riding on a pair of vees, it also bore against the horizontal surface clostest to the operator (which was shared with the tailstock) as well as against the inside vertical surface (also closest to the operator)... --jeez.... anyone mentioned "nightmarish to grind" lately ? -- Ed Huntress |
#25
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ed Huntress" wrote in message ... On Thu, 28 Mar 2013 15:58:54 -0700, "PrecisionmachinisT" wrote: "Ed Huntress" wrote in message ... On Thu, 28 Mar 2013 14:19:00 -0700, "PrecisionmachinisT" wrote: "Ed Huntress" wrote in message news On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT" wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. If this L&S lathe bed is representative: http://www.lathes.co.uk/lodgeshipley/ ...then it's the same as my SB, only reversed back-to-front. The tailstock rides on an inner flat and an inner V, while the carriage rides on the pair of outer Vs. Actually, the carriage on the lathe in your photo seems to be using both of the outside ways for alignment, in addition to it's also being being supported by the flat way section that's located out front. I don't think so. Read the text at the site you linked me to. Oh, good grief. I see what you mean. It doesn't surprise me that they dropped it in the 1960s. Frankly, I don't believe it worked as they say. To keep the saddle from floating off of the flat horizontal way or off of one of the Vs from time to time would require vertical positioning on the pair of V-ways that was accurate to within 5 or 10 microinches relative to the flat. I don't believe they could do that. They probably floated a bit with light loads, but spring compression of the bed or the saddle might have maintained contact with heavy tool loads. I think you're correct. If so, fitting the carriage would mostly be the same as with any other lathe that runs in a pair of vees--exception being that any actual contact occurs on the flat section(s) you'd juist scrape a smidge off, for clearance... Benefit being that during a heavy cut, the brunt falls onto the flat ways instead of wearing away the vees. Anyway, that's history. It looks to me like the classic Lodge & Shipley design (Fig. 37 in your book), which is the same as my SB only I have the Lindsay Publications version, and there's no mention of Lodge and Shipley in it anywhere so far as I can tell, and page 37 deals with tapping wooden lead screw nuts in my copy. Check the drawings on page 79 and see if we have the same version. Mine is a PDF that I got somehwhere. Aww I see...page 79, figure 37 yup looks like the same book after all. --for some reason I thought you had said PAGE 37 If you haven't already, skip to page 85, and read the text accompanying fig 43, 44, and 45 which is what I had been referring to earlier. reversed front-to-back. The four-way support described as the "ideal form" in the book has, to my knowledge, long since been abandoned. I never claimed that it's in wide usage.... That would be a scraping/aligning nightmare. Likewise, I don't think Or that it wasn't a nightmare to recondition...I'm just saying that the author considered it to be superior...however, I'll have to add that indeed, it probably was superior, at least by his fairly logical explanation of the merits inherent in said design. the L&S supported the carriage on two Vs and an assymetrical flat, because wear would be uneven between the flat and the Vs and, again, a nightmare to keep aligned. You'd be obviating one of the two big advantages of V ways. With two flats you'd at least have more balanced wear but that isn't what a L&S has. My SB just has clearance where that screw-on plate shows in the photo I only have three engine lathes, (the rest are second op or cnc chuckers machines) but the ones I do have are as you describe...a vee and flat for the carriage, another vee and flat for the tailstock. The SB is two Vs for the saddle, and a vee and flat for the tailstock. It looks like the L&S bed only without any contact between the flat and the saddle. Okay gotcha three vees and a flat on a South Bend...... --the little Prazi that's down here only has one, pretty sure none of the others have more than two. http://www.lathes.co.uk/hobbymat/page3.html === Then there's this: http://www.lathes.co.uk/manson/index.html --seem to fetch a pretty good price...should I sell it ? |
#26
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Fri, 29 Mar 2013 14:03:49 -0700, "PrecisionmachinisT"
wrote: "Ed Huntress" wrote in message ... On Thu, 28 Mar 2013 15:58:54 -0700, "PrecisionmachinisT" wrote: "Ed Huntress" wrote in message ... On Thu, 28 Mar 2013 14:19:00 -0700, "PrecisionmachinisT" wrote: "Ed Huntress" wrote in message news On Thu, 28 Mar 2013 11:37:32 -0700, "PrecisionmachinisT" wrote: "Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message . 3.70... Ned Simmons fired this volley in : He's probably running the grinder on the tailstock ways I might have to take that back... PT later on down mentioned that the L&S carriage runs on both front and back ways. That's not to imply that tailstock does not run in a separate set of ways--I simply can not remember. It's been almost 20 years now since I've worked at a place that had several dozen lathes of various make and sizes all within in the same facility. If this L&S lathe bed is representative: http://www.lathes.co.uk/lodgeshipley/ ...then it's the same as my SB, only reversed back-to-front. The tailstock rides on an inner flat and an inner V, while the carriage rides on the pair of outer Vs. Actually, the carriage on the lathe in your photo seems to be using both of the outside ways for alignment, in addition to it's also being being supported by the flat way section that's located out front. I don't think so. Read the text at the site you linked me to. Oh, good grief. I see what you mean. It doesn't surprise me that they dropped it in the 1960s. Frankly, I don't believe it worked as they say. To keep the saddle from floating off of the flat horizontal way or off of one of the Vs from time to time would require vertical positioning on the pair of V-ways that was accurate to within 5 or 10 microinches relative to the flat. I don't believe they could do that. They probably floated a bit with light loads, but spring compression of the bed or the saddle might have maintained contact with heavy tool loads. I think you're correct. If so, fitting the carriage would mostly be the same as with any other lathe that runs in a pair of vees--exception being that any actual contact occurs on the flat section(s) you'd juist scrape a smidge off, for clearance... Benefit being that during a heavy cut, the brunt falls onto the flat ways instead of wearing away the vees. Yeah, and L&S lathes were heavy-duty production machines, so it could be that it worked out well in practice. The thing that makes me skeptical is that L&S's bedways were chilled, and chilled deep. Wear, as in all lathes, is going to be preferential in the area where the saddle rides the most -- typically somewhere between the middle of the bed and the headstock. You'd wind up with a different clearance to the horizontal flat there than at any other place on the bed and it would change over time -- you couldn't count on the saddle wearing quickly into the bed like, say, the main bearings on an engine wearing in to fit the crankshaft. It doesn't sound like a way to get consistently high accuracy. But then, L&S lathes were not toolroom machines. Anyway, that's history. It looks to me like the classic Lodge & Shipley design (Fig. 37 in your book), which is the same as my SB only I have the Lindsay Publications version, and there's no mention of Lodge and Shipley in it anywhere so far as I can tell, and page 37 deals with tapping wooden lead screw nuts in my copy. Check the drawings on page 79 and see if we have the same version. Mine is a PDF that I got somehwhere. Aww I see...page 79, figure 37 yup looks like the same book after all. --for some reason I thought you had said PAGE 37 If you haven't already, skip to page 85, and read the text accompanying fig 43, 44, and 45 which is what I had been referring to earlier. Yeah, I read it. It sounds good, but.... reversed front-to-back. The four-way support described as the "ideal form" in the book has, to my knowledge, long since been abandoned. I never claimed that it's in wide usage.... That would be a scraping/aligning nightmare. Likewise, I don't think Or that it wasn't a nightmare to recondition...I'm just saying that the author considered it to be superior...however, I'll have to add that indeed, it probably was superior, at least by his fairly logical explanation of the merits inherent in said design. the L&S supported the carriage on two Vs and an assymetrical flat, because wear would be uneven between the flat and the Vs and, again, a nightmare to keep aligned. You'd be obviating one of the two big advantages of V ways. With two flats you'd at least have more balanced wear but that isn't what a L&S has. My SB just has clearance where that screw-on plate shows in the photo I only have three engine lathes, (the rest are second op or cnc chuckers machines) but the ones I do have are as you describe...a vee and flat for the carriage, another vee and flat for the tailstock. The SB is two Vs for the saddle, and a vee and flat for the tailstock. It looks like the L&S bed only without any contact between the flat and the saddle. Okay gotcha three vees and a flat on a South Bend...... Right. --the little Prazi that's down here only has one, pretty sure none of the others have more than two. http://www.lathes.co.uk/hobbymat/page3.html === Then there's this: http://www.lathes.co.uk/manson/index.html --seem to fetch a pretty good price...should I sell it ? Omigosh, that's cute. Heck, I wouldn't sell it unless I really wanted the money for something else. You could keep it under your bed. g You know, there are many ways to make a lathe bed and to achieve accuracy. I've had some long and interesting discussions about this, particularly with engineers from Wasino, and especially concerning the sub-micron-accuracy lathes they started building around 2000 (no real US market for them). IMO, and not as a lathe expert or an engineer, but as a hobbyist, it matters far more how well it's executed than how it's configured. We aren't going to wear a lathe in the way a Lodge & Shipley had to deal with production. Hardinges used dovetails; American used round ways in the '70s; Wasinos used box ways; and we've seen every combination of Vs and flats you could imagine. I don't think it's something that most of us have to worry about. -- Ed Huntress |
#27
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ed Huntress" wrote in message news On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: --even with single point diamond tooling, surface finish becomes a big factor when it comes to accurately gaging workpiece diameter.. Keep in mind that master hard-drive disks and the production disks, back when they were made this way, were single-point turned. No grinding. We built lathes especially for turning them at Wasino -- and they were all shipped to Singapore. sob Still they were nowhere near to a mirror finish. And those were flat. Moore Special Tool built special turning machines for making assymetrical lenses for the Defense Dept. They were all single-point turned, although some of them (for shorter wavelengths of light) were polished. The point of those Wasino machines I mentioned is that they were made for turning parts that could not be ground, either because of microchecking or production volume requirements. They were fast and left a polished surface. As I said, surface finish becomes a big factor... Pretty sure in this situation, the material basically liquefies--high-speed-micro-photographs would be an interesting study. |
#28
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"PrecisionmachinisT" wrote in message
news:SsqdndCiuYHgtsvMnZ2dnUVZ_uWdnZ2d@scnresearch. com... "Ed Huntress" wrote in message news On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: --even with single point diamond tooling, surface finish becomes a big factor when it comes to accurately gaging workpiece diameter.. Keep in mind that master hard-drive disks and the production disks, back when they were made this way, were single-point turned. No grinding. We built lathes especially for turning them at Wasino -- and they were all shipped to Singapore. sob Still they were nowhere near to a mirror finish. And those were flat. Moore Special Tool built special turning machines for making assymetrical lenses for the Defense Dept. They were all single-point turned, although some of them (for shorter wavelengths of light) were polished. I've watched a large aspherical Germanium front lens for a military vehicle thermal imager being diamond-turned. The tool resembled a brazed carbide bit. The finish it left looked mirror-smooth to me. They use a wavelength about 10X longer than visible light and are less sensitive to roughness. jsw |
#29
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Sat, 30 Mar 2013 07:18:24 -0400, "Jim Wilkins"
wrote: "PrecisionmachinisT" wrote in message news:SsqdndCiuYHgtsvMnZ2dnUVZ_uWdnZ2d@scnresearch .com... "Ed Huntress" wrote in message news On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: --even with single point diamond tooling, surface finish becomes a big factor when it comes to accurately gaging workpiece diameter.. Keep in mind that master hard-drive disks and the production disks, back when they were made this way, were single-point turned. No grinding. We built lathes especially for turning them at Wasino -- and they were all shipped to Singapore. sob Still they were nowhere near to a mirror finish. And those were flat. Moore Special Tool built special turning machines for making assymetrical lenses for the Defense Dept. They were all single-point turned, although some of them (for shorter wavelengths of light) were polished. I've watched a large aspherical Germanium front lens for a military vehicle thermal imager being diamond-turned. The tool resembled a brazed carbide bit. The finish it left looked mirror-smooth to me. They use a wavelength about 10X longer than visible light and are less sensitive to roughness. jsw Right. That's what Moore was making. (Thanks for correcting it to aspherical, not assymetrical. Sheesh.) -- Ed Huntress |
#30
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ed Huntress" wrote in message ... On Sat, 30 Mar 2013 07:18:24 -0400, "Jim Wilkins" wrote: "PrecisionmachinisT" wrote in message news:SsqdndCiuYHgtsvMnZ2dnUVZ_uWdnZ2d@scnresearc h.com... "Ed Huntress" wrote in message news On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: --even with single point diamond tooling, surface finish becomes a big factor when it comes to accurately gaging workpiece diameter.. Keep in mind that master hard-drive disks and the production disks, back when they were made this way, were single-point turned. No grinding. We built lathes especially for turning them at Wasino -- and they were all shipped to Singapore. sob Still they were nowhere near to a mirror finish. And those were flat. Moore Special Tool built special turning machines for making assymetrical lenses for the Defense Dept. They were all single-point turned, although some of them (for shorter wavelengths of light) were polished. I've watched a large aspherical Germanium front lens for a military vehicle thermal imager being diamond-turned. The tool resembled a brazed carbide bit. The finish it left looked mirror-smooth to me. They use a wavelength about 10X longer than visible light and are less sensitive to roughness. jsw Right. That's what Moore was making. (Thanks for correcting it to aspherical, not assymetrical. Sheesh.) -- Ed Huntress I have designed many diamond-turned optical elements and helped one vendor optimize their process for our optics. Moore and Precitech are the two main competitors in this field. Single point diamond turning (SPDT) used to only be good enough for infrared optics, but now they are being used for visible and even UV optics. It only works well for certian materials of course. The cutting tool tip is usually a tapered cylinder diamond with the larger base polished and facing up to make the cutting edge. Their are different sizes but the typical diameter is 1 mm. The cutting edge has to be perfectly circular otherwise it causes form error when cutting a curved surface. I am sure someone has studied the cutting process in great detail for all the common materials, and I am not an expert in that, but I am pretty sure it is very clean cutting with very little flow. Materials that can not easily be polished like soft aluminum can easily be diamond turned. They do not usually turn directly in aluminum though. For best results, an aluminum substrate mirror might first be rough-turned on a standard CNC lathe, then plated with about 10 microns of electroless nickel, and then about half the nickel thickness or less is turned off in the SPDT process. The nickel then has a vacuum coating applied for best reflectance. The vendor I was working with had their own in-house nickel plating facility in a clean room so they could keep out contamination and inclusions. If you want to see specs that will blow you away, check out this spec sheet for their low-end model (e.g. 16 picometer encoder resolution!) http://www.precitech.com/wp-content/...Broch_spec.pdf |
#31
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Sat, 30 Mar 2013 11:26:22 -0700, "anorton"
wrote: "Ed Huntress" wrote in message .. . On Sat, 30 Mar 2013 07:18:24 -0400, "Jim Wilkins" wrote: "PrecisionmachinisT" wrote in message news:SsqdndCiuYHgtsvMnZ2dnUVZ_uWdnZ2d@scnresear ch.com... "Ed Huntress" wrote in message news On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: --even with single point diamond tooling, surface finish becomes a big factor when it comes to accurately gaging workpiece diameter.. Keep in mind that master hard-drive disks and the production disks, back when they were made this way, were single-point turned. No grinding. We built lathes especially for turning them at Wasino -- and they were all shipped to Singapore. sob Still they were nowhere near to a mirror finish. And those were flat. Moore Special Tool built special turning machines for making assymetrical lenses for the Defense Dept. They were all single-point turned, although some of them (for shorter wavelengths of light) were polished. I've watched a large aspherical Germanium front lens for a military vehicle thermal imager being diamond-turned. The tool resembled a brazed carbide bit. The finish it left looked mirror-smooth to me. They use a wavelength about 10X longer than visible light and are less sensitive to roughness. jsw Right. That's what Moore was making. (Thanks for correcting it to aspherical, not assymetrical. Sheesh.) -- Ed Huntress I have designed many diamond-turned optical elements and helped one vendor optimize their process for our optics. Moore and Precitech are the two main competitors in this field. Single point diamond turning (SPDT) used to only be good enough for infrared optics, but now they are being used for visible and even UV optics. It only works well for certian materials of course. The cutting tool tip is usually a tapered cylinder diamond with the larger base polished and facing up to make the cutting edge. Their are different sizes but the typical diameter is 1 mm. The cutting edge has to be perfectly circular otherwise it causes form error when cutting a curved surface. I am sure someone has studied the cutting process in great detail for all the common materials, and I am not an expert in that, but I am pretty sure it is very clean cutting with very little flow. Materials that can not easily be polished like soft aluminum can easily be diamond turned. They do not usually turn directly in aluminum though. For best results, an aluminum substrate mirror might first be rough-turned on a standard CNC lathe, then plated with about 10 microns of electroless nickel, and then about half the nickel thickness or less is turned off in the SPDT process. The nickel then has a vacuum coating applied for best reflectance. The vendor I was working with had their own in-house nickel plating facility in a clean room so they could keep out contamination and inclusions. If you want to see specs that will blow you away, check out this spec sheet for their low-end model (e.g. 16 picometer encoder resolution!) http://www.precitech.com/wp-content/...Broch_spec.pdf Wow. Cool stuff. So, is Precitech what became of Pneumo Precision? I see they use a granite bed, like Pneumo did. And they're in NH, which is where, if I recall correctly after 34 years, Pneumo was. 'Same company? I wrote about Pneumo Precision back around 1980, and I was talking with them and Moore to write a substantial article. But Moore was all tied up in non-disclosures with the Defense Dept. at the time. -- Ed Huntress |
#32
Posted to rec.crafts.metalworking
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Grinding lathe bed.
"Ed Huntress" wrote in message ... On Sat, 30 Mar 2013 11:26:22 -0700, "anorton" wrote: "Ed Huntress" wrote in message . .. On Sat, 30 Mar 2013 07:18:24 -0400, "Jim Wilkins" wrote: "PrecisionmachinisT" wrote in message news:SsqdndCiuYHgtsvMnZ2dnUVZ_uWdnZ2d@scnresea rch.com... "Ed Huntress" wrote in message news On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: --even with single point diamond tooling, surface finish becomes a big factor when it comes to accurately gaging workpiece diameter.. Keep in mind that master hard-drive disks and the production disks, back when they were made this way, were single-point turned. No grinding. We built lathes especially for turning them at Wasino -- and they were all shipped to Singapore. sob Still they were nowhere near to a mirror finish. And those were flat. Moore Special Tool built special turning machines for making assymetrical lenses for the Defense Dept. They were all single-point turned, although some of them (for shorter wavelengths of light) were polished. I've watched a large aspherical Germanium front lens for a military vehicle thermal imager being diamond-turned. The tool resembled a brazed carbide bit. The finish it left looked mirror-smooth to me. They use a wavelength about 10X longer than visible light and are less sensitive to roughness. jsw Right. That's what Moore was making. (Thanks for correcting it to aspherical, not assymetrical. Sheesh.) -- Ed Huntress I have designed many diamond-turned optical elements and helped one vendor optimize their process for our optics. Moore and Precitech are the two main competitors in this field. Single point diamond turning (SPDT) used to only be good enough for infrared optics, but now they are being used for visible and even UV optics. It only works well for certian materials of course. The cutting tool tip is usually a tapered cylinder diamond with the larger base polished and facing up to make the cutting edge. Their are different sizes but the typical diameter is 1 mm. The cutting edge has to be perfectly circular otherwise it causes form error when cutting a curved surface. I am sure someone has studied the cutting process in great detail for all the common materials, and I am not an expert in that, but I am pretty sure it is very clean cutting with very little flow. Materials that can not easily be polished like soft aluminum can easily be diamond turned. They do not usually turn directly in aluminum though. For best results, an aluminum substrate mirror might first be rough-turned on a standard CNC lathe, then plated with about 10 microns of electroless nickel, and then about half the nickel thickness or less is turned off in the SPDT process. The nickel then has a vacuum coating applied for best reflectance. The vendor I was working with had their own in-house nickel plating facility in a clean room so they could keep out contamination and inclusions. If you want to see specs that will blow you away, check out this spec sheet for their low-end model (e.g. 16 picometer encoder resolution!) http://www.precitech.com/wp-content/...Broch_spec.pdf Wow. Cool stuff. So, is Precitech what became of Pneumo Precision? I see they use a granite bed, like Pneumo did. And they're in NH, which is where, if I recall correctly after 34 years, Pneumo was. 'Same company? I wrote about Pneumo Precision back around 1980, and I was talking with them and Moore to write a substantial article. But Moore was all tied up in non-disclosures with the Defense Dept. at the time. -- Ed Huntress Yes they are the same company. They also spun off their job-shop in Keene which at one time was called OFC Diamond Turning Division and is now Corning Netoptix. That was the vendor I visited. Another thing they can do nowdays is servo the tool motion to the rotation axis so they can actually turn asymmetrical as well as aspherical optics. You actually did not make a blunder your previous post. |
#33
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Sat, 30 Mar 2013 11:59:25 -0700, "anorton"
wrote: "Ed Huntress" wrote in message .. . On Sat, 30 Mar 2013 11:26:22 -0700, "anorton" wrote: "Ed Huntress" wrote in message ... On Sat, 30 Mar 2013 07:18:24 -0400, "Jim Wilkins" wrote: "PrecisionmachinisT" wrote in message news:SsqdndCiuYHgtsvMnZ2dnUVZ_uWdnZ2d@scnrese arch.com... "Ed Huntress" wrote in message news On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: --even with single point diamond tooling, surface finish becomes a big factor when it comes to accurately gaging workpiece diameter.. Keep in mind that master hard-drive disks and the production disks, back when they were made this way, were single-point turned. No grinding. We built lathes especially for turning them at Wasino -- and they were all shipped to Singapore. sob Still they were nowhere near to a mirror finish. And those were flat. Moore Special Tool built special turning machines for making assymetrical lenses for the Defense Dept. They were all single-point turned, although some of them (for shorter wavelengths of light) were polished. I've watched a large aspherical Germanium front lens for a military vehicle thermal imager being diamond-turned. The tool resembled a brazed carbide bit. The finish it left looked mirror-smooth to me. They use a wavelength about 10X longer than visible light and are less sensitive to roughness. jsw Right. That's what Moore was making. (Thanks for correcting it to aspherical, not assymetrical. Sheesh.) -- Ed Huntress I have designed many diamond-turned optical elements and helped one vendor optimize their process for our optics. Moore and Precitech are the two main competitors in this field. Single point diamond turning (SPDT) used to only be good enough for infrared optics, but now they are being used for visible and even UV optics. It only works well for certian materials of course. The cutting tool tip is usually a tapered cylinder diamond with the larger base polished and facing up to make the cutting edge. Their are different sizes but the typical diameter is 1 mm. The cutting edge has to be perfectly circular otherwise it causes form error when cutting a curved surface. I am sure someone has studied the cutting process in great detail for all the common materials, and I am not an expert in that, but I am pretty sure it is very clean cutting with very little flow. Materials that can not easily be polished like soft aluminum can easily be diamond turned. They do not usually turn directly in aluminum though. For best results, an aluminum substrate mirror might first be rough-turned on a standard CNC lathe, then plated with about 10 microns of electroless nickel, and then about half the nickel thickness or less is turned off in the SPDT process. The nickel then has a vacuum coating applied for best reflectance. The vendor I was working with had their own in-house nickel plating facility in a clean room so they could keep out contamination and inclusions. If you want to see specs that will blow you away, check out this spec sheet for their low-end model (e.g. 16 picometer encoder resolution!) http://www.precitech.com/wp-content/...Broch_spec.pdf Wow. Cool stuff. So, is Precitech what became of Pneumo Precision? I see they use a granite bed, like Pneumo did. And they're in NH, which is where, if I recall correctly after 34 years, Pneumo was. 'Same company? I wrote about Pneumo Precision back around 1980, and I was talking with them and Moore to write a substantial article. But Moore was all tied up in non-disclosures with the Defense Dept. at the time. -- Ed Huntress Yes they are the same company. They also spun off their job-shop in Keene which at one time was called OFC Diamond Turning Division and is now Corning Netoptix. That was the vendor I visited. Another thing they can do nowdays is servo the tool motion to the rotation axis so they can actually turn asymmetrical as well as aspherical optics. You actually did not make a blunder your previous post. Well, I did, because I didn't know it. d8-) That's very interesting work. It must have been 1979 or 1980 when I first saw it being done at Moore, and I saw Pneumo Precision giving demos at the tool shows. I wondered what had happened to them but I have no reason to check up on it now. Thanks for the update. -- Ed Huntress |
#34
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Grinding lathe bed.
On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT"
wrote: snip Tracking down Pneumo Precision, after Jim and anorton reminded me about that optical turning business, I came across this old paper that I had forgotten about. I'll bet you'll be interested. It's not long, and it's packed with information: "On the Design of Ultra Precise Machine Slides" http://www.praecisinc.com/PDF%20File... %20Slides.pdf --or, in short-- http://tinyurl.com/d5msovs -- Ed Huntress |
#35
Posted to rec.crafts.metalworking
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Grinding lathe bed.
On Sat, 30 Mar 2013 23:43:56 -0700, "PrecisionmachinisT"
wrote: "Ed Huntress" wrote in message .. . On Sat, 30 Mar 2013 21:10:21 -0700, "PrecisionmachinisT" wrote: "Ed Huntress" wrote in message ... On Fri, 29 Mar 2013 16:13:03 -0700, "PrecisionmachinisT" wrote: snip Tracking down Pneumo Precision, after Jim and anorton reminded me about that optical turning business, I came across this old paper that I had forgotten about. I'll bet you'll be interested. It's not long, and it's packed with information: "On the Design of Ultra Precise Machine Slides" http://www.praecisinc.com/PDF%20File... %20Slides.pdf --or, in short-- http://tinyurl.com/d5msovs Why, thank you very much, Ed... I mean it really I do. I hope it's accurate. The guys behind Pneumo Precision were considered to be experts in the field. Admittedly some of it looks sketchy...but in all, a pretty good read. I'm convinced that over the years you've come to realize how fascinated I am with tribology and kinematics....much appreciated. I thought you were. I used to cover it for American Machinist, but I never got into it very deeply. They gave me a book on tribology once upon a time and it was packed with equations. It was a slow read and I don't think I retained any of it. I always get a kick out of the gun nutz, and ballistics--for instance, you can point a gun directly towards the guy sitting next to you, or you can point it nearly straight up.... --and then there's this: https://www.youtube.com/watch?v=cxvsHNRXLjw "Intuitively one might think that the ball will go over the monkey's head due to its fast speed. However, gravity accelerates all objects downward at the same rate, meaning the monkey and the ball will meet at exactly the same point. If the ball was shot even faster, it would still hit the monkey, but higher above the ground." Ha-ha! Sometimes I think they have too much fun at MIT. g -- Ed Huntress |
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