| Page 1 of 2 | 1 | 2 |
|
|
Rollie's Dad's method
When I first set up my lathe, on a way-too-flexible floor, it took me
a long time to get it dialed in. Part of that was the floor's fault, part was that I didn't have much clue what I was doing. I did finally get the lathe lined up, but I have no idea how. I seem to remember that it involved about a million cut-and-try experiments, some intense profanity, and luck. Time to do it again, this time on -- hallelujah! -- a concrete floor. I recall from way back that some people were fans of Rollie's Dad's method of lining up a lathe. I've just looked it up and it seems sane. (See http://www.john-wasser.com/NEMES/RDMLatheAlignment.html for an explanation.) What say you? Is this a viable way to set things up? Any problems with it? 'Cause it sure looks simpler than cutting a thousand test bars. Pete -- Artful Bodger http://www.artfulbodger.net |
In article , artfulbodger says...
What say you? Go get a copy of "How to Run a Lathe" from south bend, and perform their two collar test. It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Gene Kearns wrote:
Much simpler would to be to use a precision level, parallel and gage block(s) to level the lathe ways. Yeah, but that won't do the whole job, will it? Or, let me rephrase: leveling across the ways won't do the whole job, and I can't level along the ways because, though I have a very good level, I don't have anything I can really use as a parallel. Next I would use a cylinder, turned between centers, that has a near and far diameter of exactly the same diameter (the middle is not necessarily important for a machine in good condition). Use this to set the tailstock position. Yes; tailstock's not a problem. I keep just such a bar handy, and use it to reset the tailstock whenever I've set it over for some reason. (Note that Rollie's Dad's method doesn't address the tailstock at all. It's just to get the spindle & ways lined up.) It seems the link's attempt is to correct mis-alignment between the ways and the headstock by stuffing paper under the latter.... a poor fix, at best. I grant you, the business about paper is ridiculous. But I have plenty of decent shim stock around. It does not address levelness of the machine nor any twist in the bed.... Now you've lost me. It doesn't address level, that's true; but it seems that twist in the bed is precisely what it does address. If you find vertical misalignment or that the headstock and/or tailstock axes are no longer parallel with the ways.... rescraping is in order. BTDT. Fortunately the lathe doesn't need any scraping. The shaper did, though. It took way too long, but the result was good and, God help me, I had fun doing it. A lathe bed, OTOH, I'd rather not do. I'd drink poison long before the job was done. Thanks for your help. Curious to have your further comments on Rollie's Dad's method vis a vis twist in the bed. Pete -- Artful Bodger http://www.artfulbodger.net |
jim rozen wrote:
Go get a copy of "How to Run a Lathe" from south bend Got it, but it's been a long time since I've read it. Thanks, Jim, I'll have a look. Pete -- Artful Bodger http://www.artfulbodger.net |
"jim rozen" wrote in message ... In article , artfulbodger says... What say you? Go get a copy of "How to Run a Lathe" from south bend, and perform their two collar test. It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck. Jim Well and good, I'm sure, but *start* with a properly leveled machine so it isn't leaning in any direction. While lathes will run fine out of level, if you have yours established properly before you make any fine adjustments, you will be able to rely on the machine being level for certain functions. Chucking irregular objects in a 4 jaw, using a level for setup, for example. The minor amount you may be out when you do your final tweaking would be far better than to have it out a few degrees because you sought a straight cut without concern for level setup. Harold |
Harold and Susan Vordos wrote:
Well and good, I'm sure, but *start* with a properly leveled machine so it isn't leaning in any direction. While lathes will run fine out of level, if you have yours established properly before you make any fine adjustments, you will be able to rely on the machine being level for certain functions. Chucking irregular objects in a 4 jaw, using a level for setup, for example. Hey there, Harold. The notion of using a level for setup, it's just foreign to me. Last you knew, I had my machines in the unrenovated house next door to where I was living: lathe on the sun porch, shaper in the kitchen, milldrill & bandsaw in the dining room, and all the floors were made of rubber. If I put a level on my workbench, I could walk a circle around the bench and watch that bubble go from one end of the vial to the other. I set each machine up so it was good if I stood in just the right place, and that was how I worked. Now that I'm on a decent floor, I still don't have a way to get the lathe really level. I can get it close, yeah, but to get it right I'd need a good parallel or at least a longer level than the one I've got. (I've got a Starrett, a good one, but it's only 8" long.) No matter: for the time being, I'm still working on a bench that's not bad, but not great, so perfect levelling is moot. I hope before long to weld up a good steel cabinet & put the lathe on that. Then, finally, I'll be able to level the machine for real. Until that time, it's all a matter of getting things close enough for jazz. It gripes me, but there it is. Pete -- Artful Bodger http://www.artfulbodger.net |
Gene Kearns wrote:
The *concept* of shimming the headstock is bizarre, to me! Hell, the relationship between the two was established at the factory... what caused it to change since then? Ah. Confusion. The idea isn't to shim between headstock and ways, but to shim under the lathe's feet, at the headstock end. If the method called for shimming between headstock and ways, no, I'd not do it. But shimming under the feet, well, that's just normal, innit? -- Artful Bodger http://www.artfulbodger.net |
In article , Harold and Susan Vordos says...
Go get a copy of "How to Run a Lathe" from south bend, and perform their two collar test. It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck. Well and good, I'm sure, but *start* with a properly leveled machine so it isn't leaning in any direction. While lathes will run fine out of level, if you have yours established properly before you make any fine adjustments, you will be able to rely on the machine being level for certain functions. Chucking irregular objects in a 4 jaw, using a level for setup, for example. The minor amount you may be out when you do your final tweaking would be far better than to have it out a few degrees because you sought a straight cut without concern for level setup. Ever read that book Harold? I gave my copy away a few years ago or I would sent it to you. They say: 1) mount the machine to a solid, unmoving floor. 2) level it with a spirit level. 3) once this is done, then do the final arbiter check for accuracy: the two collar method. Interestingly if you read what Hardinge says about setting their machines up, there is absolutely *no* mention of any kind of spirit level. Step one: Plunk the machine down on a solid floor. Step two: drop down the tab inside the back cabinet so the machine doesn't tip. Done. Because of the ingenious hardinge kinematic mount for their beds, a spirit level is not needed at all, nor is any bed tweaking or leg shimming. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
In article , artfulbodger says...
...Until that time, it's all a matter of getting things close enough for jazz. It gripes me, but there it is. Hold on right there because what you just said makes more sense that you realize. "Getting it close enough" actually means something. It means you've decided on a tolerance for cylindicity of the parts you make - how much larger diameter can they be on one side, a certain distance from the other diameter on the other side. And it means you have a means to measure that, and to make corrections in a systematic fashion, to improve the tolerance level. And it means you are understanding the fundamental limitations of your equipment (bench stability, floor stability) that prevents you from achieving an arbitrarily higher level of accuracy. If you stop and think about it, these are the exact same steps that any high accuracy endeavor has to deal with. Doesn't matter if it's +/- 0.005", or +/- 5 microinches. Its the same plan of action, and there are some folks who *never* figure this out, and use holy water and magic potions to line up their machines. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
On Wed, 11 May 2005 01:14:57 GMT, Gene Kearns
wrote: On Tue, 10 May 2005 21:18:27 GMT, artfulbodger wrote: Gene Kearns wrote: Much simpler would to be to use a precision level, parallel and gage block(s) to level the lathe ways. Yeah, but that won't do the whole job, will it? Or, let me rephrase: leveling across the ways won't do the whole job, and I can't level along the ways because, though I have a very good level, I don't have anything I can really use as a parallel. Next I would use a cylinder, turned between centers, that has a near and far diameter of exactly the same diameter (the middle is not necessarily important for a machine in good condition). Use this to set the tailstock position. Yes; tailstock's not a problem. I keep just such a bar handy, and use it to reset the tailstock whenever I've set it over for some reason. (Note that Rollie's Dad's method doesn't address the tailstock at all. It's just to get the spindle & ways lined up.) It seems the link's attempt is to correct mis-alignment between the ways and the headstock by stuffing paper under the latter.... a poor fix, at best. I grant you, the business about paper is ridiculous. But I have plenty of decent shim stock around. The *concept* of shimming the headstock is bizarre, to me! Hell, the relationship between the two was established at the factory... what caused it to change since then? It does not address levelness of the machine nor any twist in the bed.... Now you've lost me. It doesn't address level, that's true; but it seems that twist in the bed is precisely what it does address. That, I think, is the fallacy of this method. Once you get things bent around where the indicator is happy with the wobbling rod, how can you then trust the tailstock... which I'm sure you'll eventually need! Actually, it seems to approximate some projected spindle axis based on two points on the rod... as if the headstock was no longer pointing in the right direction. Most lathe wear is near the headstock... if you create some axis based on this wear the tailstock is not going to line up.... especially if you have shimmed something.... I think you guys are reading it wrong. I took it to mean shimming the 2 corners of the main lathe frame (the ways) to the cabinet to take out the twist. Now, if your cabinet has 4 adjustable feet, it just makes the job simpler (and my Myford base does) |
Actually, I doubt that it did change from the time it was set up. But if one
expects the tolerance of a $400 machine from China to be as close as those of a $15,000 machine, you are sadling mistaken. "Gene Kearns" Gene Kearns wrote: The *concept* of shimming the headstock is bizarre, to me! Hell, the relationship between the two was established at the factory... what caused it to change since then? |
The Colchester Chipmaster has the base mounted on 3 points onto the
floor so it is automatically free of twist Geoff |
"artfulbodger" wrote in message ... Harold and Susan Vordos wrote: Well and good, I'm sure, but *start* with a properly leveled machine so it isn't leaning in any direction. While lathes will run fine out of level, if you have yours established properly before you make any fine adjustments, you will be able to rely on the machine being level for certain functions. Chucking irregular objects in a 4 jaw, using a level for setup, for example. Hey there, Harold. The notion of using a level for setup, it's just foreign to me. And likely so to others as well, but don't discount if as a viable method of setting up strange objects. I've done it with success on more than one occasion. A good example is in setting up a part at an angle. I'm not suggesting it's something you'd do routinely, but it's yet another of the tools in the arsenal of skilled craftsmen. Don't close any doors where machining is concerned. Often the most absurd suggestion is the best solution to a problem. Now that I'm on a decent floor, I still don't have a way to get the lathe really level. I can get it close, yeah, but to get it right I'd need a good parallel or at least a longer level than the one I've got. (I've got a Starrett, a good one, but it's only 8" long.) I've never invested in a high precision level, either. I use a Starrett model 98, likely the 8" level of which you spoke. The point is, I know that my machines are not leaning by a degree or two. To ignore level before beginning to trim any machine isn't a good idea. Use what you have and hold your machines as close as possible. That's far better than ignoring the issue. No matter: for the time being, I'm still working on a bench that's not bad, but not great, so perfect levelling is moot. I hope before long to weld up a good steel cabinet & put the lathe on that. Then, finally, I'll be able to level the machine for real. Until that time, it's all a matter of getting things close enough for jazz. It gripes me, but there it is. You might be surprised to find that you can't get your machine properly leveled, even with a metal bench. All depends on how rigid the bench is, and how rigid the lathe bed is. My Graziano sits on three points and refuses to go dead level, with a slight twist at the tailstock end. The only thing that will correct it is to unbolt the bed from the heavily cast base and shim, pulling the bed in alignment with the attaching bolts. That's assuming the base didn't move, and the bed did. I'm not pleased with it, but the lathe still functions well. And it is, otherwise, *level*. That means when I lay something on a surface, it isn't inclined to grow legs and wander off. If for no other reason, machine tools should be level to avoid that very thing. Good to see you back. Harold |
"artfulbodger" wrote in message ... What say you? Is this a viable way to set things up? Any problems with it? 'Cause it sure looks simpler than cutting a thousand test bars. Compensating for misalignment of headstock to bed by twisting the bed seems like a recipe for excessive wear to me. I'd recommend buying or borrowing a precision level, get the bed levelled in both directions with mounts considerably firmer than paper. Once that is done, then any misalignment of the headstock can be corrected. Once that's done, things should stay put and work well long time. |
"jim rozen" wrote in message ... In article , Harold and Susan Vordos says... Go get a copy of "How to Run a Lathe" from south bend, and perform their two collar test. It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck. Well and good, I'm sure, but *start* with a properly leveled machine so it isn't leaning in any direction. While lathes will run fine out of level, if you have yours established properly before you make any fine adjustments, you will be able to rely on the machine being level for certain functions. Chucking irregular objects in a 4 jaw, using a level for setup, for example. The minor amount you may be out when you do your final tweaking would be far better than to have it out a few degrees because you sought a straight cut without concern for level setup. Ever read that book Harold? I gave my copy away a few years ago or I would sent it to you. Can't say as though I spent a long interval with it, but a couple years ago Susan sold one on ebay. It came in a lot of things that was auctioned from a military installation. Pretty elementary stuff, but all important for the uninitiated in the way of using a lathe, naturally. Doubtful a seasoned machinist would learn much. I had a book much like it, sold originally by Sears (one of which I bought when I purchased my first lathe in the early '50s). The book went with the lathe when I sold it way back in the late 50's., a model 109,. 6" machine with the 1/2" -20 spindle that bent easily. They say: 1) mount the machine to a solid, unmoving floor. 2) level it with a spirit level. 3) once this is done, then do the final arbiter check for accuracy: the two collar method. Exactly my point when I suggested the machine should start out level. Get it close, fine tune it by turning. Your comments, " It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck." conveniently leaves out the leveling process. I don't recommend it. I get the idea you didn't intend to say it that way, though, or you wouldn't be quoting from the SouthBend manual. Interestingly if you read what Hardinge says about setting their machines up, there is absolutely *no* mention of any kind of spirit level. Step one: Plunk the machine down on a solid floor. Step two: drop down the tab inside the back cabinet so the machine doesn't tip. Done. Because of the ingenious hardinge kinematic mount for their beds, a spirit level is not needed at all, nor is any bed tweaking or leg shimming. Jim Chuckle! I'm going to assume you know better than to think you can mount the typical machine that way. My Graziano, for one, can be placed on the floor and operated. The heavily cast base is more than rigid enough to support the bed as it was shipped from the factory----------but they *still* recommend you level the machine. It's more involved than their kinematic mount---------mass and rigidity play a huge role in stability, as you well know. I'd also suggest to you that modern manufacturing facilities tend towards quite level and flat surfaces. That's a far cry from some of the older installations, where you likely couldn't get away with such an installation. Hardinge machines are solid enough to not demand level for precision. That doesn't mean you don't benefit (albeit in other ways) by leveling. Many a machine can be operated successfully at strange angles. It's just not normally a good idea. Regardless of their ability to run out of level, leveling their machine, as well as any other, is a good idea, so things stay where you put them when you let go of them. Have you ever worked on a surface plate that wasn't level? Need I say more? Also, don't discount the fact that you may, on strange occasion, wish the machine was level, so you could use a level for setup. Maybe you haven't done that in the course of running your machines, but the day will come. It has for me. Harold |
In article , Harold and Susan Vordos says...
Get it close, fine tune it by turning. Your comments, " It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck." conveniently leaves out the leveling process. I don't recommend it. I get the idea you didn't intend to say it that way, though, or you wouldn't be quoting from the SouthBend manual. As far as I'm concerned, the levelling can be done with a carpenter's level - it's only done to keep tools from rolling around in the chip pan. The real accuracy comes from the second step. I've seen too many folks try to do precision setups with a spirit level, with the reasoning "well the machine was set up level, so if I level the workpiece then it will be cut accurate. In other words, using a level when a good indicator should be used instead. IMO most folks don't level to make their machine accurate, they do so to make their setups easier. Chuckle! I'm going to assume you know better than to think you can mount the typical machine that way. My Graziano, for one, can be placed on the floor and operated. The heavily cast base is more than rigid enough to support the bed as it was shipped from the factory----------but they *still* recommend you level the machine. Cast iron is not that rigid. The bed will twist - might not be much, but it will. And that impairs accuracy. But even with a Graziano, one should still check to see how the machine cuts once it is levelled. It's more involved than their kinematic mount---------mass and rigidity play a huge role in stability, as you well know. I would say the hardinge beds are much less rigid than your graziano. Because the headstock end is supported on two, and only to point contacts, and the tailstock end is supported by a steel ball in a V-groove, no gravitational forces can ever impart twist to the bed - and because the machine was originally set up at the factory with that same mount, all the accuracy in the initial build is available with no need for an kind of spirit level. Because my south bend 10L, which has a bed as sturdy, or even sturdier than the hardinge machines, has the older leg style bed mount, a twisting moment is invariably applied between the headstock and tailstock ends. The key to getting it set up is to get that moment to the correct level. In a new machine that means 'zero' or, rather, the amount that was there when it was set up at the factory originally. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Harold and Susan Vordos wrote:
The notion of using a level for setup, it's just foreign to me. And likely so to others as well, but don't discount if as a viable method of setting up strange objects. Oh, no, not at all! It has always seemed a very sensible (and fast) way to set up certain kinds of work. Just guessing, I'd think it'd be more often useful in milling work than on the lathe; but that's neither here nor there. Reliable people have said that setting up by level is a tremendous timesaver, and I believe them. But the idea of doing it on my old shop's trampoline floors? Ha! I remember teenut once, singing the praises of his level machines and how they made some setups a breeze; I read his message and laughed, and never considered it again. Now, I guess, with decent floors, I can revisit the idea. I've never invested in a high precision level, either. I use a Starrett model 98, likely the 8" level of which you spoke. Yep, that's the one. Pretty li'l thing and way more precise than the carpenter's levels I was used to. You might be surprised to find that you can't get your machine properly leveled, even with a metal bench. All depends on how rigid the bench is, and how rigid the lathe bed is. True. I really don't know how rigid the lathe is: I don't know what to compare it to. It's a benchtop unit, a SB 9" long bed. At the time it was made, it was way more rigid than other lathes in its class. I don't know how noodly it is next to a new lathe of its size. I do know it's juuuust a bit more flexy than some two ton Hardinge. Oh, well. Carefully set up, it's neither too worn nor too wobbly to cut straight. As for the bench, we'll see. I'm about one step away from pouring a couple of concrete pillars and mounting the lathe on them. THAT would settle a thing or two. Good to see you back. Thanks. It's nice when, for at least a while, life settles down somewhat. Finally I get to do something about all those castings in the garage. They've been looknig so forlorn. Pete -- Artful Bodger http://www.artfulbodger.net |
Don Foreman wrote:
Compensating for misalignment of headstock to bed by twisting the bed seems like a recipe for excessive wear to me. I don't get it. Almost any benchtop lathe will twist from its own weight, right? So what's unusual about shimming to correct it? (As for paper shims, you'll get no argument from me. I can't think of anything more Mickey Mouse, except maybe using a sponge.) Pete -- Artful Bodger http://www.artfulbodger.net |
Harold and Susan Vordos wrote:
Because of the ingenious hardinge kinematic mount for their beds, a spirit level is not needed at all, nor is any bed tweaking or leg shimming. It's more involved than their kinematic mount.... Could someone describe the kinematic mount? I'm a curious guy. Pete -- Artful Bodger http://www.artfulbodger.net |
On 10 May 2005 19:45:55 -0700, jim rozen
wrote: In article , artfulbodger says... ...Until that time, it's all a matter of getting things close enough for jazz. It gripes me, but there it is. Hold on right there because what you just said makes more sense that you realize. "Getting it close enough" actually means something. It means you've decided on a tolerance for cylindicity of the parts you make - how much larger diameter can they be on one side, a certain distance from the other diameter on the other side. And it means you have a means to measure that, and to make corrections in a systematic fashion, to improve the tolerance level. And it means you are understanding the fundamental limitations of your equipment (bench stability, floor stability) that prevents you from achieving an arbitrarily higher level of accuracy. If you stop and think about it, these are the exact same steps that any high accuracy endeavor has to deal with. Doesn't matter if it's +/- 0.005", or +/- 5 microinches. Its the same plan of action, and there are some folks who *never* figure this out, and use holy water and magic potions to line up their machines. Jim Jim, I tried that holy water business and the machine just rusted. Magic potions are out too. Ever seen a witch? No, what works best is Maiden Juice and epithets. I learned this from the first machine shop I worked in. Almost all the work we did was close tolerance. The boss always said to put Maiden Juice on it. And then he'd cuss until things worked out. Unless his wife was around. ERS |
jim rozen wrote:
...Until that time, it's all a matter of getting things close enough for jazz. It gripes me, but there it is. "Getting it close enough" actually means something. Yessir, it sure does. There's a lot of talk about dead level, dead true, dead flat, dead straight, and plain ol' dead nuts. It's a convenient way to talk, and fine as long as nobody forgets that it means "the best I can measure with my tools." But slang has a way of taking over, so that people think it actually means what it seems to mean. It means you've decided on a tolerance.... And it means you have a means to measure that, and to make corrections.... And it means you are understanding the fundamental limitations of your equipment.... Yepyepyep. It was a bit of a stunt to get things "close enough" for the last few projects I completed. Some of them needed careful work, and I was bumping up against the limitations of my shop (and my skill). But close enough was just close enough, and the results made me proud. Upcoming tasks are more demanding: before I'm done, I'll have had to buy a much more serious mill and probably a bigger lathe, too. $$$$$$$$ sigh. But for now, I can at least get a start on the smaller parts. Looks like I'll be able to make my "close enough" a lot closer than it was in the old shop. there are some folks who *never* figure this out, and use holy water and magic potions to line up their machines. Oh, hey, I'm all for it. Sacrificing a chicken couldn't hurt, either. Pete -- Artful Bodger http://www.artfulbodger.net |
In article , artfulbodger says...
Could someone describe the kinematic mount? The idea is you provide the miniumum amount of constraint to define the geometry you desire. My south bend lathe has the bed constrained at each end, by two bolts. So it is possible to impart twist to the bed if one tightens down the two headstock bolts, which then define the beds front/back tilt, and then tighten down the two tailstock bolts, which might want to pull the bed down to a *different* front/back tilt. Likewise when the cast iron bed expands more than the steel cabinet, the bed is going to bow up a bit in the middle. Hardinge gets around this by mounting their bed at the headstock by pulling it down onto two spherical mounting points with heavy springs. So now the bed has been constrained to have a certain front/back tilt. It's still free to tilt left and right though, pivoting around the other axis of the two spherical mounting points. The tailstock end has a single ball that protrudes from the botton (actually a steel bearing ball, sitting in a countersunk recess) which fits into an upwards-facing V-groove that is the third mouning point on the cabinet. This means the tailstock end of the bed now is restrained to give the bed the desired left-right tilt, and further that any differential contraction or expansion of the bed with respect to the cabinet (one is steel, the other cast iron) is permitted because of the transverse V-groove on the lower mounting point. Of course the tailstock end of the bed is held down with the same stiff spring setup as the headstock end. Because of the single-point mount at the tailstock, there is no way on earth there can be any twist imparted to the bed by forces that arise between the cabinet and the floor. Likewise the differential thermal expansion between bed and cabinet can not bow the bed up and destroy the accuracy. Hardinge finished their beds mounted on those same three spots, so when they are installed in the cabinets, the surfaces of the ways agree again with the factory versions. They're not twisted or bowed. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
In article ,
artfulbodger wrote: Harold and Susan Vordos wrote: [ ... ] I've never invested in a high precision level, either. I use a Starrett model 98, likely the 8" level of which you spoke. Yep, that's the one. Pretty li'l thing and way more precise than the carpenter's levels I was used to. Yes -- but you would be amazed at how much more sensitive the No. 199 "Master Precision" level is. Starrett certifies it to be 0.0005" in 12" per division. They don't even make any statements about approximate accuracy for the No. 98. (I have examples of both -- not bought at new prices in either case, and I know which I would use (and did use) for initial leveling of the lathe bed.) I put a 1-2-3 block on each of the flat ways, and put the level across those, since the Clausing has one V and one flat for the front way and one of each for the back way. (I never checked whether the narrow flats on top of the Vs was also parallel to that surface. You might be surprised to find that you can't get your machine properly leveled, even with a metal bench. All depends on how rigid the bench is, and how rigid the lathe bed is. True. I really don't know how rigid the lathe is: I don't know what to compare it to. It's a benchtop unit, a SB 9" long bed. At the time it was made, it was way more rigid than other lathes in its class. I don't know how noodly it is next to a new lathe of its size. I do know it's juuuust a bit more flexy than some two ton Hardinge. Oh, well. Carefully set up, it's neither too worn nor too wobbly to cut straight. With the No. 199 level, you can see a change when you rest your hand on the headstock of my 12x24" Clausing, and I understand that even a Hardinge shows a shift. It is amazing how flexible a lathe bed can be. As for the bench, we'll see. I'm about one step away from pouring a couple of concrete pillars and mounting the lathe on them. THAT would settle a thing or two. Yep! Good to see you back. Thanks. It's nice when, for at least a while, life settles down somewhat. Finally I get to do something about all those castings in the garage. They've been looknig so forlorn. They simply are now properly seasoned. I believe that is a requirement for any kit castings -- that they must season under the workbench for some years. :-) Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
"jim rozen" wrote in message ... In article , Harold and Susan Vordos says... Get it close, fine tune it by turning. Your comments, " It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck." conveniently leaves out the leveling process. I don't recommend it. I get the idea you didn't intend to say it that way, though, or you wouldn't be quoting from the SouthBend manual. As far as I'm concerned, the levelling can be done with a carpenter's level - it's only done to keep tools from rolling around in the chip pan. I thought I said that. The real accuracy comes from the second step. I thought I said that, too. I've seen too many folks try to do precision setups with a spirit level, with the reasoning "well the machine was set up level, so if I level the workpiece then it will be cut accurate. I didn't say that, nor do I subscribe to it. I also don't subscribe to ignoring level on a machine that is supposed to be leveled, making it cut straight by tweaking the bed. Unless, that is, the bed has an inherent twist that can't be removed by conventional methods. By the time machinery is in the hands of folks like us, as a community, it is often well worn. Tweaking the bed to get a lathe to cut straight near the headstock is hardly a solution when it involves twisting the bed to an out of level condition. The day comes when one will machine past the worn portion and the problems are then magnified in the opposite direction. Way too much emphasis is being placed on a lathe's ability to turn straight near the chuck, and not nearly enough on the fact that the machine should be able to work end to end with a minimum of error. One of the negatives of pushing the bed out of level is that the tailstock is likely to be on center at only one position, so, once again, the problems are magnified. There's no way to eliminate the wear so it's not a problem aside from a rebuild. In other words, using a level when a good indicator should be used instead. IMO most folks don't level to make their machine accurate, they do so to make their setups easier. An indicator in this case would be used for the wrong purpose. From what are you indicating? Your one and only reference point, a level bed, has been ignored, by all accounts. All conditions being correct, leveling a lathe bed properly automatically provides a proper setup. There is no need for anything else. Not until you start trying to overcome wear. Chuckle! I'm going to assume you know better than to think you can mount the typical machine that way. My Graziano, for one, can be placed on the floor and operated. The heavily cast base is more than rigid enough to support the bed as it was shipped from the factory----------but they *still* recommend you level the machine. Cast iron is not that rigid. The bed will twist - might not be much, but it will. That's exactly the point. The base has much greater mass than does the bed, and it is pulling the bed out of level on one corner. There is no doubt in my mind that the minor twist in the bed could be overcome by shimming the low spot and pulling the then higher spot down to the base casting. The mass of the base is clearly greater and stronger than the bed, which is very capable of twisting, which is exactly the condition of which I speak. The base, being more rigid, will, indeed pull the bed flat. The chief reason I've never attempted the project is that I do not have access to one of the master levels, and I do almost exclusively short work. The lathe performs to an acceptable level as it sits. I don't expect my Graziano to provide the level of precision that one would expect from a grinder. And that impairs accuracy. But even with a Graziano, one should still check to see how the machine cuts once it is levelled. Not really. Unless you choose to dismantle the bed from the base and start shimming, you gain nothing. Leveling does *not* make any changes in the bed. As I said, my lathe is high on one corner, and nothing short of shimming between the bed and base will make a difference. I can set it up with the fourth leg floating and it makes no difference. Been there, done that. I keep it adjusted so it's in contact to prevent any rocking motion of the machine, but it carries no weight. Once set, it doesn't change. My floor is 6-1/4" thick concrete. It's more involved than their kinematic mount---------mass and rigidity play a huge role in stability, as you well know. I would say the hardinge beds are much less rigid than your graziano. Because the headstock end is supported on two, and only to point contacts, and the tailstock end is supported by a steel ball in a V-groove, no gravitational forces can ever impart twist to the bed - and because the machine was originally set up at the factory with that same mount, all the accuracy in the initial build is available with no need for an kind of spirit level. Assuming you don't care if things roll around when placed on flat surfaces, that is. Personally, I do care. Level is not required for the machine to operate properly (same as the Graziano), but it is a good idea for other reasons, which is and has been my point right along. Because my south bend 10L, which has a bed as sturdy, or even sturdier than the hardinge machines, has the older leg style bed mount, a twisting moment is invariably applied between the headstock and tailstock ends. The key to getting it set up is to get that moment to the correct level. In a new machine that means 'zero' or, rather, the amount that was there when it was set up at the factory originally. And yet you continue to ignore the fact that the use of a precision level is supposed to return the machine to what most likely was factory original? Why do you suppose they suggest you start out with a level machine? I'm inclined to think it's because they know the vast majority of folks don't have access to a precision level, but they do have access to a common one. The common level gets you in the ball park, the tweaking gets you closer. That's good on a new machine, but, again, hardly a solution on a worn one. I'll stick with levels, thanks. Harold |
"DoN. Nichols" wrote:
I've never invested in a high precision level, either. I use a Starrett model 98, likely the 8" level of which you spoke. Yep, that's the one. Pretty li'l thing and way more precise than the carpenter's levels I was used to. Yes -- but you would be amazed at how much more sensitive the No. 199 "Master Precision" level is. Betcha I wouldn't. Those Starrett Masters are just gorgeous and I want one. Most Starrett stuff is pretty, of course, and my level's no exception, but yours is the level they recommend for machine setup. The 199 is good for half a thou per foot, the 98 is graduated for five thou per foot. Oh, well! It is amazing how flexible a lathe bed can be. Yeah, I always used to worry that the dog was going to sneeze in the middle of a nice finish cut and throw the whole thing off. Then I'd have to shoot him. (Okay, yeah, the floor was the issue, not the lathe; but I did finally get an appreciation for how bendy iron can be. It took me a while.) Finally I get to do something about all those castings in the garage. They've been looknig so forlorn. They simply are now properly seasoned. I believe that is a requirement for any kit castings -- that they must season under the workbench for some years. Yeah, except for the ones too big to fit under the bench. I get tired of barking my shins on them. But I finally started cutting iron the other night -- made a mess, had some fun. Whee! It's been way too long. Pete -- Artful Bodger http://www.artfulbodger.net |
In article , Harold and Susan Vordos says...
I thought I said that. I thought I said that, too. I didn't say that, nor do I subscribe to it. Harold, I think we're on the same page, honestly. There's not substantive disagreement on any of this. One of the negatives of pushing the bed out of level is that the tailstock is likely to be on center at only one position, so, once again, the problems are magnified. There's no way to eliminate the wear so it's not a problem aside from a rebuild. Yep. Folks who purchase used lathes (this encompasses a large fraction of the HSM crowd) are well aware their machines are worn when they buy them. They also are aware that they can improve performance by doing tricks that one would never consider on a new unworn machine - like shimming the bed so it cuts true near the chuck, where most of the work is done. Nobody is telling themselves "this is an unworn machine, it cuts as true as it did when it was new." The statement most often heard is, "I can make it accurate enough to get my task done, in tolerance." ... one should still check to see how the machine cuts once it is levelled. Not really. Unless you choose to dismantle the bed from the base and start shimming, you gain nothing. Leveling does *not* make any changes in the bed. As I said, my lathe is high on one corner, and nothing short of shimming between the bed and base will make a difference. I can set it up with the fourth leg floating and it makes no difference. Been there, done that. I keep it adjusted so it's in contact to prevent any rocking motion of the machine, but it carries no weight. Once set, it doesn't change. My floor is 6-1/4" thick concrete. And that is probably the *most* important issue - a base that does not move over time. I would be very curious to see how the graziano cuts for cylinder, using the two collar test. And yet you continue to ignore the fact that the use of a precision level is supposed to return the machine to what most likely was factory original? Do they use spirit levels when manufacturing machines? I know that the Connolly book discusses their use in some applications. The Moore book has literally no mention of them. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
Stress is force and strain is displacement, right?
If there were no gravity, one would merely puddle mortar or expoxy at each foot, allow to cure, turn gravity back on, then begin operations. This would assure the lowest stress mounting, and you'd figure that would produce the lowest strain mounting. Without a gravity switch, would it be right to have adjusters or shims at each foot such that a separate piece of shim stock, the same size at each foot, could be pulled with a tension meter, assuming friction conditions were the same at each foot, to even the load on each foot, or conform these loads to a chart of the way they should be, as a first step? I get this idea from taking off the front of our dryer. It's a big floppy assembly with the panel off, but when in place, it's 250 pounds and more, solid. So I was thinking that when I was replacing the rollers for the dryer, the thing to do would be to adjust the feet so the rollers contacted the drum evenly. The dryer's four feet, two fixed rear and two adjustable front, are redundant. It's a question of kinematic redundancy. A lathe with two headstock feet and a single tailstock foot would be ideal. It seems you could plunk such on a level floot and go right to work because three point contact defines the position. --Doug |
"jim rozen" wrote in message ... snip---- Do they use spirit levels when manufacturing machines? I know that the Connolly book discusses their use in some applications. The Moore book has literally no mention of them. In my mind, the purpose of a level is to duplicate the condition in which a machine tool was manufactured. That does not imply that they use levels in the process, but allows one to duplicate a condition after the fact. If you level a bed, it will be in the same plane as when manufactured, at least in theory. I think both of us would agree that it could lean in any direction (but remain in a flat plane, regardless of angle) and still perform as intended. The purpose in leveling is to establish a datum plane, or point, so one can make relative measurements (or comparisons) with ease. Machines that are not level make it very difficult because of the constant compensation for the degree of tilt. Beyond that, I don't see it as a necessity. In fact, I recall advising one fellow that he could set up his small lathe at an angle such that he could access it easily from his wheel chair. So long as the bed is not twisted, it makes no difference that it leans one way or another. What say you? Harold |
On 11 May 2005 06:05:36 -0700, jim rozen
wrote: In article , Harold and Susan Vordos says... Get it close, fine tune it by turning. Your comments, " It's all you need to do, and takes nothing besides a micrometer and a piece of stock in the chuck." conveniently leaves out the leveling process. I don't recommend it. I get the idea you didn't intend to say it that way, though, or you wouldn't be quoting from the SouthBend manual. As far as I'm concerned, the levelling can be done with a carpenter's level - it's only done to keep tools from rolling around in the chip pan. The real accuracy comes from the second step. I've seen too many folks try to do precision setups with a spirit level, with the reasoning "well the machine was set up level, so if I level the workpiece then it will be cut accurate. In other words, using a level when a good indicator should be used instead. IMO most folks don't level to make their machine accurate, they do so to make their setups easier. Chuckle! I'm going to assume you know better than to think you can mount the typical machine that way. My Graziano, for one, can be placed on the floor and operated. The heavily cast base is more than rigid enough to support the bed as it was shipped from the factory----------but they *still* recommend you level the machine. Cast iron is not that rigid. The bed will twist - might not be much, but it will. And that impairs accuracy. But even with a Graziano, one should still check to see how the machine cuts once it is levelled. It's more involved than their kinematic mount---------mass and rigidity play a huge role in stability, as you well know. I would say the hardinge beds are much less rigid than your graziano. Because the headstock end is supported on two, and only to point contacts, and the tailstock end is supported by a steel ball in a V-groove, no gravitational forces can ever impart twist to the bed - and because the machine was originally set up at the factory with that same mount, all the accuracy in the initial build is available with no need for an kind of spirit level. Because my south bend 10L, which has a bed as sturdy, or even sturdier than the hardinge machines, has the older leg style bed mount, a twisting moment is invariably applied between the headstock and tailstock ends. The key to getting it set up is to get that moment to the correct level. In a new machine that means 'zero' or, rather, the amount that was there when it was set up at the factory originally. Jim A bit different way of looking at things for setting up lathes in good condition. Think about the way many bench lathes are made. The bed is machined when it is mounted on a flat level surface but BEFORE any extra bits are bolted or mounted on it. In this state the bed is pretty symmetrical so there is little reason for twist to develop if the flat surface on which it is mounted is tilted. A plethora of strange shaped bits is then bolted or mounted on this nice true bed. It is these asymmetric bits and the drive belt tension that produces small asymmetric forces that can contribute to bed twist. Note that this is true even when the lathe is dead level so that to return the bed to its parent unstressed shape a very small counter twist needs to be applied. If the lathe mounting surface is flat but not level there will be a small change in these asymmetric forces and this would require corresponding correction to the counter twist setting (in some cases the necessary correction forces would reduce). There is no reason why this correction should be any less complete than in the dead level case. This supports the argument that a carpenters level is more than adequate for basic levelling. If you're fortunate enough to possess a precision level a useful measurement is to simply locate it along the the crossslide and note the bubble movement as the carriage is traversed from end to end. It doesn't matter whether the bubble is centred or not - the ONLY thing that counts is how much it moves. This is an interesting measurement as it makes it possible to directly measure the effect of asymmetric weight distribution on bed twist. I'm lucky to have a slightly home brewed electronic level which can read down to +/-1 min arc full scale. On a Boxford ME10 (pretty similar to a 9" swing Southbend) a 14lb weight attached to a 12" arm overhung from the tailstock end of the bed - i.e. 168 lb/inches twists the bed by just over 2 min arc in 12" of carriage movement. 160 odd lb/inches is a severely asymmetric weight distribution Because the bed twist axis is a about 6" below the headstock axis, 2 min arc corresponds to a toolpoint shift of about 0.0036" which is a serious amount. However even this much can be cancelled by appropriate adjustment of the tail stock end mounts. The interesting thing is that the correct setting of this adjustment is almost unaffected by reasonable deviations from level - a 1 deg error only changes the asymmetric force by cos 1 deg - less than 2%. Incidentally I have based these comments on forces rather than shim thickness or movement because it is the balance of forces that determines the bed state - the actual change produced by a 1 thou shim depends on both the relative stiffness of the bed and its mounting surface. It's not a recommendation to rely on a precision level for final setting up - I still think the best method is a tenths clock bearing on a reasonably straight and round test bar with eccentricity averaged out. Jim |
|
"Gene Kearns" wrote in message ... On Thu, 12 May 2005 11:26:17 -0700, "Harold and Susan Vordos" wrote: So long as the bed is not twisted, it makes no difference that it leans one way or another. What say you? Geometrically, you are entirely correct. I do find, however, that machines running coolant prefer to be level. A small point, not germane to all, but helpful if you are running coolant.. Yep! Yet another *good* reason to level machines. One should also consider that many machines have oil reservoirs that should be kept level. Harold |
On Wed, 11 May 2005 14:31:11 GMT, artfulbodger
wrote: Don Foreman wrote: Compensating for misalignment of headstock to bed by twisting the bed seems like a recipe for excessive wear to me. I don't get it. Almost any benchtop lathe will twist from its own weight, right? So what's unusual about shimming to correct it? (As for paper shims, you'll get no argument from me. I can't think of anything more Mickey Mouse, except maybe using a sponge.) That's the point: shim it so it's level and not twisted, rather than shimming it to deliberately twist it to correct another misalignment. |
In article , Don Foreman says...
That's the point: shim it so it's level and not twisted, rather than shimming it to deliberately twist it to correct another misalignment. In this case often the shimming is done to counteract the effects of wear, so the machine turns and bores straight. To put this in perspective, the shims involved in getting a small floor mounted lathe dialed in for the last thou of accuracy over, say, a six inch long part, might be 0.015 inch at the legs. So the shift in the bed is going to be a couple of thousanths or so. Not much. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
On Tue, 10 May 2005 17:33:20 GMT, artfulbodger
wrote: When I first set up my lathe, on a way-too-flexible floor, it took me a long time to get it dialed in. Part of that was the floor's fault, part was that I didn't have much clue what I was doing. I did finally get the lathe lined up, but I have no idea how. I seem to remember that it involved about a million cut-and-try experiments, some intense profanity, and luck. Time to do it again, this time on -- hallelujah! -- a concrete floor. I recall from way back that some people were fans of Rollie's Dad's method of lining up a lathe. I've just looked it up and it seems sane. (See http://www.john-wasser.com/NEMES/RDMLatheAlignment.html for an explanation.) What say you? Is this a viable way to set things up? Any problems with it? 'Cause it sure looks simpler than cutting a thousand test bars. Pete Pete, I've had to rely upon Rollie's Dad's method and it has worked very well for me. Like others have said, level the lathe using a precision level. Then, if you feel a need to check headstock alignment, use R-D-M. In my case, I bought a used lathe that was in good shape, but I knew something was amiss when I spotted a crude shim between the headstock and the bed. Many days of bluing and scraping along with R-D-M to check my work eventually paid off. I really enjoy using that lathe, now. Regards, Orrin |
In article , Harold and Susan Vordos says...
In my mind, the purpose of a level is to duplicate the condition in which a machine tool was manufactured. That does not imply that they use levels in the process, but allows one to duplicate a condition after the fact. If you level a bed, it will be in the same plane as when manufactured, at least in theory. I think both of us would agree that it could lean in any direction (but remain in a flat plane, regardless of angle) and still perform as intended. The purpose in leveling is to establish a datum plane, or point, so one can make relative measurements (or comparisons) with ease. Machines that are not level make it very difficult because of the constant compensation for the degree of tilt. Beyond that, I don't see it as a necessity. In fact, I recall advising one fellow that he could set up his small lathe at an angle such that he could access it easily from his wheel chair. So long as the bed is not twisted, it makes no difference that it leans one way or another. What say you? I think that is true. I'm just trying to imagine how for example the south bend beds were made. First cast, then probably the ways were roughed out on a planer. At this point there was possibly a level used on the planer bed - but my guess is they first got the mounting surfaces all in the same plane, then flipped it over and did the ways. So when you were done, if the planer bed were level then the part done on the planer would be also. Then the bed goes to the scraping department - and there I don't know if they simply used spotting gages or if they make more sophisticated tests. I know in the moore book they describe the use of full length test gages and even more intricate tests like autocolimators and so on. The implication is that maybe the level things before they start, but that's only the beginning, a spirit level even like the starrett master precison on simply won't come close to giving the accuracy for a machine like that. Reading between the lines, I get the impression that the south bends were pretty much Chevys, and something like a moore would be a deusenberg. g And that the things the moore folks worried about were even conceived by the guys at the south bend plant. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
In article ,
jim rozen wrote: [ ... ] I think that is true. I'm just trying to imagine how for example the south bend beds were made. First cast, then probably the ways were roughed out on a planer. At this point there was possibly a level used on the planer bed - but my guess is they first got the mounting surfaces all in the same plane, then flipped it over and did the ways. So when you were done, if the planer bed were level then the part done on the planer would be also. Based on what I have seen in the South Bend _How to Run a Lathe_ book, the ways were cut -- all in a single pass (except perhaps for the under surface used by the carriage gibs and the carriage lock), using an amazing stack of cutters on a single arbor (with lots of bearings holding it right), so all the planes of the lathe bed were cut at once, and in a constant relationship to each other. O.K. It is not in the 50th edition (which is the one which I can quickly lay my hands on), but is either in a later edition (light gray cover, instead of the black on the 50th edition), or perhaps in the similar book from Atlas. But I remember the cutters almost vanishing under the flood coolant. And another shot of the roughed lathe beds being stacked for seasoning prior to the fine cuts and the scraping. Now -- I suspect that much larger machines *were* made on planers, but for those of the proper size, the horizontal spindle milling machine would do a lot more a lot quicker. In particular, the number of setups to get the right angles on the bed ways (for the prismatic ways) would make a planer take a lot more intense operator interaction. And the time to cut to a near-finished state would be a lot longer than that horizontal milling machine with its cutters awash in chips and coolant. Of course, later machines, such as my 12x24" Clausing (1957 vintage) were flame hardened and then surface ground to final dimensions. (They probably were still run through the horizontal mill before that.) Then the bed goes to the scraping department - and there I don't know if they simply used spotting gages or if they make more sophisticated tests. I know in the moore book they describe the use of full length test gages and even more intricate tests like autocolimators and so on. The implication is that maybe the level things before they start, but that's only the beginning, a spirit level even like the starrett master precison on simply won't come close to giving the accuracy for a machine like that. I seem to remember in one of the reconditioning books a "level" made of a trough of water the length of the bed. Harder to read with a 1 to 2 foot bed length, but when you get one of those monsters with chairs on the carriage for the operator, it should be quite adequate. Reading between the lines, I get the impression that the south bends were pretty much Chevys, and something like a moore would be a deusenberg. g Yep. The same (even more so) for the Atlas ones. It is hard to believe that Clausing and Atlas are the same company, comparing my lathe to the old Atlas/Craftsman 6x18 which I also have. :-) And that the things the moore folks worried about were even conceived by the guys at the south bend plant. You mean "were *not* even conceived", perhaps? That, I can agree with. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
"jim rozen" wrote in message
... In article , Harold and Susan Vordos says... In my mind, the purpose of a level is to duplicate the condition in which a machine tool was manufactured. That does not imply that they use levels in the process, but allows one to duplicate a condition after the fact. If you level a bed, it will be in the same plane as when manufactured, at least in theory. I think both of us would agree that it could lean in any direction (but remain in a flat plane, regardless of angle) and still perform as intended. The purpose in leveling is to establish a datum plane, or point, so one can make relative measurements (or comparisons) with ease. Machines that are not level make it very difficult because of the constant compensation for the degree of tilt. Beyond that, I don't see it as a necessity. In fact, I recall advising one fellow that he could set up his small lathe at an angle such that he could access it easily from his wheel chair. So long as the bed is not twisted, it makes no difference that it leans one way or another. What say you? I think that is true. I'm just trying to imagine how for example the south bend beds were made. First cast, then probably the ways were roughed out on a planer. I would think that would be the case, perhaps with some seasoning time along the way after roughing. I also wouldn't discount them having been machined on large mills at a later date. Shapers and planers fell out of favor due to inefficiency. Perhaps no seasoning, but heat treatment ( stress relief) instead. One thing for sure, the machinery on which they were made was all leveled to a fine degree. Not that it makes any difference to how a part would be handled, but to insure that the precision surfaces of the manufacturing machinery were in a common plane, yielding straight cuts. To ease handling, I can't imagine that the beds weren't parallel with the mounting feet, which is the only thing that really matters. So long as the two surfaces are parallel, leveling the top portion would, in theory, make a proper setup. Considering you own a SB, and I don't, nor have I even seen one in years, perhaps you could tell me if the ways and base are, indeed, parallel. At this point there was possibly a level used on the planer bed - but my guess is they first got the mounting surfaces all in the same plane, then flipped it over and did the ways. So when you were done, if the planer bed were level then the part done on the planer would be also. Yeah, like that, only level isn't the consideration so much as *parallelism*. Then the bed goes to the scraping department - Maybe for the SB, but not for modern machines. I dare say there is *no* scraping involved, especially when flame hardened ways are involved. Grinding long ago took over that level of precision. While we're discussing lathes, it's more than obvious to me that Bridgeport mills had *no* scraping in their making. Flaking, perhaps, but they were either milled or ground to size, with flaking for oil control. You can see that clearly when you look at one that has not worn excessively. and there I don't know if they simply used spotting gages or if they make more sophisticated tests. I know in the moore book they describe the use of full length test gages and even more intricate tests like autocolimators and so on. The implication is that maybe the level things before they start, but that's only the beginning, a spirit level even like the starrett master precison on simply won't come close to giving the accuracy for a machine like that. Agreed. Reading between the lines, I get the impression that the south bends were pretty much Chevys, and something like a moore would be a deusenberg. g If even that. I am not a fan of SB lathes, never have been. I'm turned off by their insistence of sticking to old technology, flat belt drive, sleeve bearings, clutches that needed to be engaged by turning knobs instead of rapid levers, like that. They may have been a wonderful machine at some point in time, but failed to keep up with technology that made machines better, and easier to operate. No offense intended. It's just a personal bias. I realize that they are worshipped by many. Incidentally, your mention of a Chev as compared to a Duesenberg. Wow! You really know how to pull at my heart strings. While likely a pig to drive, the J model Duesenberg is one of the cars that has always haunted me. At one point in my life I was involved in classic cars (no, not '67 Fords, which will *never* be classics, regardless of what you may read), but the real thing------true classics. I owned a '36 convertible coupe Auburn, supercharged, with a Columbia 2 speed rear end, plus a '37 Cord, Custom Beverly Sedan, supercharged, which was a one of a kind car, authenticated by the Cord historian of the ACD Club. The car had a Berline interior, and was known to be the sole Cord so turned out by the factory. At any rate, I always coveted the Duesenbergs, which, at the time, weren't all that expensive to acquire, very unlike today. I had the privilege of working on one, a '29 Murphy sedan. It's hard to imagine the beauty of the engine, a straight 8 with dual overhead cams, 420 CI displacement. I've mentioned this before, but it's worth repeating. In the late 50's, Sperry Utah purchased a new Fosdick jig borer. It was in addition to the Moore they already had. You've never seen such scraping in your life. Having watched the machine being installed, it was a perfect opportunity to see scraping at its best. Moore, from all indications, more or less set the standard for high precision. Their lead screws were represented to be precise over 12" to something in the low millionths. Lovely machines, they were. Harold |
"DoN. Nichols" wrote:
Based on what I have seen in the South Bend _How to Run a Lathe_ book, the ways were cut -- all in a single pass.... O.K. It is not in the 50th edition (which is the one which I can quickly lay my hands on), but is either in a later edition (light gray cover, instead of the black on the 50th edition), or perhaps in the similar book from Atlas. 56th edition, circa 1966 I think, doesn't have this. The sections on lathe construction are much abbreviated. Pete -- Artful Bodger http://www.artfulbodger.net |
jim rozen wrote:
Do they use spirit levels when manufacturing machines? I know that the Connolly book discusses their use in some applications. The Moore book has literally no mention of them. Sigh. The Moore Book. Five years ago I almost bought it at $100, then didn't. Now I still want it, but it's $130. That's from Moore's own distribution; maybe I should look on abebooks & see what's available. What's in the book, Jim? And how big is it? I hear the photography is superb. True? I hear that the writing is lucid even when explaining esoteric whatnots. Yes? And it's not like in a home shop anyone's going to machine their castings in a temperature controlled oil bath, but is there anything _practical_ to be learned from that book? Or is it mainly one you read going "ooooh" and "aaah," before stepping out to your garage and bodging away as usual? By "you" above, with the bodging and all, I mean "me." Of course. So, the book, is it worth chasing down? (Ed Huntress, are you reading this?) Pete -- Artful Bodger http://www.artfulbodger.net |
Harold and Susan Vordos wrote:
I am not a fan of SB lathes, never have been. I'm turned off by their insistence of sticking to old technology, flat belt drive.... It's just a personal bias. I realize that they are worshipped by many. I have nothing to compare to: my SB9 is the only lathe I've ever used. It's old (1946), and simple, which I like; it can do good work, and it's very quiet, which matters to me more than it should. (I don't know why. I like its calm, low note as it munches through steel.) There's something fitting in using a leather-belted machine to make the hardware for a steam launch. But worship? Nooooo, uh-uh. If I could get my hands on something five times as heavy and ten times as powerful and a half-century newer, shoot, I'd do it right quick. What I don't really like on machine tools is electronics. It's an aesthetic thing, I guess. Iron lasts a hundred years, circuitry goes "bzzt" and lets you down. Once the magic smoke leaks out of a chip, that's that. But I think the real issue is that I make a living of computer geekery, and when I'm in the shop I want to get as far from such stuff as I can. I don't even like digital calipers. I know, I know.... -- Artful Bodger http://www.artfulbodger.net |
| All times are GMT +1. The time now is 09:04 AM. |
|
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter