Home |
Search |
Today's Posts |
|
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. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
If you could only use one machine tool to make ALL or ANY machine
tools you want what tool would you choose? A metal lathe a metal mill or some other? DL |
#2
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
TwoGuns wrote:
A metal lathe a metal mill or some other? DL It's hard to hold a job in the rotating spindle of a mill, but relatively easy to mount a job on the saddle of a lathe, so lathe trumps mill. In fact, a mill is a lathe, specialised for work with stationery job and rotating cutter. Jordan |
#3
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
TwoGuns wrote:
If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL Lathe. I've tried using a mill as a substitute before. Wes |
#4
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 22, 3:36*pm, TwoGuns wrote:
If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL If you want to see how flexible a lathe can be, go look at back issues of The Model Engineer. They had virtually nothing in the way of modern machiine tools and came up with a lot of ways of doing with what they had. Stan |
#5
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Sun, 22 Nov 2009 12:36:22 -0800 (PST), TwoGuns
wrote: If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL A mill. "Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton |
#6
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
TwoGuns wrote:
If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL A good lathe. It can be used for far more things than a mill. -- Steve W. |
#7
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 22, 3:36*pm, TwoGuns wrote:
If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL A horizontal boring machine with a spindle that accepts lathe chucks. jsw |
#8
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"TwoGuns" wrote in message ... If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? FWIW even at my level I seem to use a small lathe about 8 times as often as a small mill. On a Desert Island I would have a lathe, The Godfather DVD and Dylan's Highway 61 revisited... -- Michael Koblic Campbell River, BC |
#9
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"TwoGuns" wrote in message ... If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL A lathe can make another lathe, but a mill can not make another mill. No CNC's allowed. |
#10
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 23, 4:58*am, "Rick Samuel"
wrote: "TwoGuns" wrote in message ... If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL *A lathe can make another lathe, but a mill can not make another mill. *No CNC's allowed. A lathe can make shafts, bearings and threads but a mill is much better for machining ways, dovetails, etc. I've tried, it wasn't fun. I picked the horizontal boring machine because it combines elements of both, the spindle and tailstock of a lathe plus the XYZ axes of a mill. If for some strange artificial reason I had to build one machine to do everything it would resemble a horizontal boring mill with a leadscrew added for threading, but it wouldn't be nearly as easy to set up as separate turning and milling machines. jsw |
#11
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Mon, 23 Nov 2009 03:57:55 -0800 (PST), Jim Wilkins
wrote: On Nov 23, 4:58*am, "Rick Samuel" wrote: "TwoGuns" wrote in message ... If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL *A lathe can make another lathe, but a mill can not make another mill. *No CNC's allowed. A lathe can make shafts, bearings and threads but a mill is much better for machining ways, dovetails, etc. I've tried, it wasn't fun. I picked the horizontal boring machine because it combines elements of both, the spindle and tailstock of a lathe plus the XYZ axes of a mill. If for some strange artificial reason I had to build one machine to do everything it would resemble a horizontal boring mill with a leadscrew added for threading, but it wouldn't be nearly as easy to set up as separate turning and milling machines. jsw Some years back, I got playing around with me SB "A" and some CI plate. After making a milling attachment, I made a duplicator for my wood lathe, one piece of which is a piece with 14 flat sides. Gerry :-)} London, Canada |
#12
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 23, 6:05*pm, Gerald Miller wrote:
On Mon, 23 Nov 2009 03:57:55 -0800 (PST), Jim Wilkins ... Some years back, I got playing around with me SB "A" and some CI plate. After making a milling attachment, I made a duplicator for my wood lathe, one piece of which is a piece with 14 flat sides. Gerry :-)} London, Canada- I made a lathe milling attachment, and then found a South Bend one. Both work about equally poorly unless I take VERY light cuts. The problem seems to be the inadequate clamps that hold the carriage down. How did you index the 14 sided piece? A 14/28/56 tooth change gear? jsw |
#13
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Mon, 23 Nov 2009 15:55:42 -0800 (PST), Jim Wilkins
wrote: On Nov 23, 6:05*pm, Gerald Miller wrote: On Mon, 23 Nov 2009 03:57:55 -0800 (PST), Jim Wilkins ... Some years back, I got playing around with me SB "A" and some CI plate. After making a milling attachment, I made a duplicator for my wood lathe, one piece of which is a piece with 14 flat sides. Gerry :-)} London, Canada- I made a lathe milling attachment, and then found a South Bend one. Both work about equally poorly unless I take VERY light cuts. The problem seems to be the inadequate clamps that hold the carriage down. How did you index the 14 sided piece? A 14/28/56 tooth change gear? jsw It is a flat rectangle (6 surfaces) with two corners cut off to give two more surfaces, then the perimeter is chamfered. Top, bottom, six vertical faces and six bevels = 14 I clamped the piece to the milling attachment and used a fly cutter on the spindle. Gerry :-)} London, Canada |
#14
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Rick Samuel" wrote in message ... "TwoGuns" wrote in message ... If you could only use one machine tool to make ALL or ANY machine tools you want what tool would you choose? A metal lathe a metal mill or some other? DL A lathe can make another lathe, but a mill can not make another mill. No CNC's allowed. What part of a mill can't a mill make? How do you machine a lathe bed in a lathe? I think I'd prefer to use a mill to make 90% of either a lathe or a mill. And for the other 10% I think it would be easier to make a spindle on a mill than it would be to mill a cross slide table, but then again I've never seen a very nice milling setup in a lathe. RogerN |
#15
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 1:24*am, "RogerN" wrote:
A lathe can make another lathe, but a mill can not make another mill. *No CNC's allowed. What part of a mill can't a mill make? *How do you machine a lathe bed in a lathe? I think the idea is to remove the head and tailstock and use a tool bit in the carriage to plane the ways. You might want to hang the new lathe bed upside down over the old one so you can plane all the way surfaces parallel. When I needed to remachine a worn lathe bed I used a large horizontal milling machine. I think I'd prefer to use a mill to make 90% of either a lathe or a mill. And for the other 10% I think it would be easier to make a spindle on a mill than it would be to mill a cross slide table, but then again I've never seen a very nice milling setup in a lathe. RogerN You can mill cylindrical or conical surfaces on a rotary table or between indexer centers. That's how I make tubing bender dies. I suppose you could cut threads with a vee cutter or a fixed flycutter bit by gearing the indexer to the table feed. The American Precision Museum in Vermont has machine tools going back to 1820 or so. By about 1860 practical experience had shaped them into the forms we still have now. The smaller details such as quick-change gearboxes and HSS tool bits were in place by 1900. There are some versatile hybrids meant for moderate production runs such as the Lincoln miller, which would be my model for a machine that makes other machines. http://www.sperdvac.org/Horizontal%2...ne_lincoln.jpg I would make the tailstock support with two posts like the headstock to better support it for tailstock drilling. Scroll down to the bottom and look at "take-up" bearings: http://www.baileynet.com/index.php?i...tegory=1000011 jsw |
#16
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Jim Wilkins" wrote in message ... On Nov 24, 1:24 am, "RogerN" wrote: A lathe can make another lathe, but a mill can not make another mill. No CNC's allowed. What part of a mill can't a mill make? How do you machine a lathe bed in a lathe? I think the idea is to remove the head and tailstock and use a tool bit in the carriage to plane the ways. You might want to hang the new lathe bed upside down over the old one so you can plane all the way surfaces parallel. When I needed to remachine a worn lathe bed I used a large horizontal milling machine. I recall some drawings that I saw in the '70s, at _American Machinist_, that illustrated the self-replicating nature of the lathe. It was a hypothetical machine, with many components machined flat and/or bored on the faceplate and with cylindrical ways, like a chucker (American Lathe?) that gained some interest around 1978 - 1980 or so. There also were very small lathes, typically types of specialized screw machines, made that way in the early part of the last century. Some of the very earliest screw-cutting lathes, maybe even Maudslay's machine, had a V-way in front and a flat bedway in the back. The idea behind that was that the V-way didn't require perfect straightness; slight compensations could be made by filing or scraping the flat way to compensate, effectively tilting the cross slide up or down a bit. It always seemed to me that this would help only at one diameter of work, but that's the way it was done, and many of them were made by hand before planers were in common use for the purpose. The idea of the self-replicating lathe may have included an assumption that some of the work was done by hand. In any case, the running parts of a lathe depend upon round journals and bushings, and most parts can be made that way either for running or for locating, so the lathe was the most capable of self-replication. -- Ed Huntress |
#17
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 10:10*am, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message ... Some of the very earliest screw-cutting lathes, maybe even Maudslay's machine, had a V-way in front and a flat bedway in the back. The idea behind that was that the V-way didn't require perfect straightness; slight compensations could be made by filing or scraping the flat way to compensate, effectively tilting the cross slide up or down a bit. Are you sure? One vee way constrains its side of the carriage horizontally and vertically, the other flat way allows the carriage to center itself on the vee without over-constraining it. My South Bend has two inverted vees for the carriage, which will wear out any slight spacing error, and a vee plus a flat for the head and tailstocks which won't. .... The idea of the self-replicating lathe may have included an assumption that some of the work was done by hand. Ed Huntress What I've read in Holtzapffel et al suggests that the old lathe bed was largely a reference for checking the new one as it was filed, scraped and fitted by hand. jsw |
#18
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Jim Wilkins" wrote in message ... On Nov 24, 10:10 am, "Ed Huntress" wrote: "Jim Wilkins" wrote in message ... Some of the very earliest screw-cutting lathes, maybe even Maudslay's machine, had a V-way in front and a flat bedway in the back. The idea behind that was that the V-way didn't require perfect straightness; slight compensations could be made by filing or scraping the flat way to compensate, effectively tilting the cross slide up or down a bit. Are you sure? I'm sure that's the way many lathes were built, prior to the mid- or late 1800s. I'm not sure that the people explaining it got their explanation right. I've always questioned it, but I never had a lot of literature to go on. One vee way constrains its side of the carriage horizontally and vertically, the other flat way allows the carriage to center itself on the vee without over-constraining it. Well, that's true, and the V-and-flat configuration has been used for the simple reason that it requires little coordination between the location of the two ways. That was always the way that I thought it was intended, from the start. But a couple of sources that I used back when I was working on the _AM_ 100th Anniversary Issue (1977) discussed the use of the flat way to compensate for inaccuracies in the V-way. It may be that one was just quoting the other unquestioningly. I suspect that's the case, but I have no basis to question it except my own suspicion. My South Bend has two inverted vees for the carriage, which will wear out any slight spacing error, and a vee plus a flat for the head and tailstocks which won't. Yeah. My South Bend, too. g .... The idea of the self-replicating lathe may have included an assumption that some of the work was done by hand. Ed Huntress What I've read in Holtzapffel et al suggests that the old lathe bed was largely a reference for checking the new one as it was filed, scraped and fitted by hand. 'Could be. I haven't read anything about it for decades, and there's been quite a bit written about Maudslay's screw-cutting lathe. The trouble with these informal histories is that they tend to use each other as sources, which perpetuates a lot of wrong ideas. -- Ed Huntress |
#19
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 11:00*am, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message ...... 'Could be. I haven't read anything about it for decades, and there's been quite a bit written about Maudslay's screw-cutting lathe. The trouble with these informal histories is that they tend to use each other as sources, which perpetuates a lot of wrong ideas. Ed Huntress I just checked my two best sources, Holtzapffel #2 and Oscar Perrigo's 1916 "Lathe Design", Both skip quickly over the rationale for the choice of flat vs vee lathe ways, and suggest that ease of production was as much or more of a factor as sustained accuracy. jsw |
#20
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Jim Wilkins" wrote in message ... On Nov 24, 11:00 am, "Ed Huntress" wrote: "Jim Wilkins" wrote in message ...... 'Could be. I haven't read anything about it for decades, and there's been quite a bit written about Maudslay's screw-cutting lathe. The trouble with these informal histories is that they tend to use each other as sources, which perpetuates a lot of wrong ideas. Ed Huntress I just checked my two best sources, Holtzapffel #2 and Oscar Perrigo's 1916 "Lathe Design", Both skip quickly over the rationale for the choice of flat vs vee lathe ways, and suggest that ease of production was as much or more of a factor as sustained accuracy. jsw Well, yeah, we know that's why it was done later, after planers came into widespread use. It's a lot easier to make three planes work together than four. And that may be (and I agree with your conclusion; it probably is) the reason it was done from the very beginning. As I think about this, I'm remembering what I thought about it at the time, 30 years ago. I believed then that the issue was the difficulty, without planers, mills, or big surface grinders, of getting the four planes of a pair of V-ways coordinated for straight and smooth travel. One way to interpret this is that you can adjust the single plane of the flat way a lot easier than the pair of planes you have with a second V. So to say that it was simpler to correct accuracy with the V-and-flat could just mean that; if the ways are hand-finished, you're correcting accuracy, and V-and-flat is a lot easier to correct than two V's. Maybe. g -- Ed Huntress |
#21
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 1:04*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message ... I just checked my two best sources, Holtzapffel #2 and Oscar Perrigo's 1916 "Lathe Design", ... ... As I think about this, I'm remembering what I thought about it at the time, 30 years ago. I believed then that the issue was the difficulty, without planers, mills, or big surface grinders, of getting the four planes of a pair of V-ways coordinated for straight and smooth travel. One way to interpret this is that you can adjust the single plane of the flat way a lot easier than the pair of planes you have with a second V. So to say that it was simpler to correct accuracy with the V-and-flat could just mean that; if the ways are hand-finished, you're correcting accuracy, and V-and-flat is a lot easier to correct than two V's. Maybe. g -- Ed Huntress If I read Holtzapffel correctly the two sides of inverted vee ways were at first made separately, joined and aligned afterwards to fit the fixed and moving poppit heads (headstock and tailstock to us). "This slight width of base does not afford sufficient lateral support to the heads, which with only moderate force in turning are liable to vibration; while exact parallelism of the two angular edged bars is also necessary. Improvement in stability was sought by making one side of the bearers flat and broad, fig. 72, with a corresponding flat on the underside of the lathe heads; retaining one angular side, to give the direction or common axis. This arrangement also facilitated the construction, as the parallelism of the two bars was no longer essential,..." Fig 72 shows one flat and one inverted vee way on a cast iron bed. The difficulties of the early machine builders that Holtzapffel recorded aren't that much different from those of a homebrew machine tool maker today, except that we can buy ground drill rod and flat stock and they could hire cheap child labor for tedious hand fitting. jsw |
#22
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Jim Wilkins" wrote in message ... On Nov 24, 1:04 pm, "Ed Huntress" wrote: "Jim Wilkins" wrote in message ... I just checked my two best sources, Holtzapffel #2 and Oscar Perrigo's 1916 "Lathe Design", ... ... As I think about this, I'm remembering what I thought about it at the time, 30 years ago. I believed then that the issue was the difficulty, without planers, mills, or big surface grinders, of getting the four planes of a pair of V-ways coordinated for straight and smooth travel. One way to interpret this is that you can adjust the single plane of the flat way a lot easier than the pair of planes you have with a second V. So to say that it was simpler to correct accuracy with the V-and-flat could just mean that; if the ways are hand-finished, you're correcting accuracy, and V-and-flat is a lot easier to correct than two V's. Maybe. g -- Ed Huntress If I read Holtzapffel correctly the two sides of inverted vee ways were at first made separately, joined and aligned afterwards to fit the fixed and moving poppit heads (headstock and tailstock to us). Yeah. In the very beginning of modern lathes, the V-and-flat combinations were assembled the same way. The first screw-cutting lathes had wood beds with bolted-on iron ways, IIRC. (I'm doing this from memory; don't bite me. g) "This slight width of base does not afford sufficient lateral support to the heads, which with only moderate force in turning are liable to vibration; while exact parallelism of the two angular edged bars is also necessary. Improvement in stability was sought by making one side of the bearers flat and broad, fig. 72, with a corresponding flat on the underside of the lathe heads; retaining one angular side, to give the direction or common axis. This arrangement also facilitated the construction, as the parallelism of the two bars was no longer essential,..." Right. That sounds familiar. Fig 72 shows one flat and one inverted vee way on a cast iron bed. The difficulties of the early machine builders that Holtzapffel recorded aren't that much different from those of a homebrew machine tool maker today, except that we can buy ground drill rod and flat stock and they could hire cheap child labor for tedious hand fitting. Right. Maybe you've peeked at my ideas for a ferrocement lathe with steel ways. d8-) (Having finished reading Naaman's _Ferrocement & Laminated Cementitious Composites_, I'm less enthusiastic about that construction.) -- Ed Huntress |
#23
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 2:03*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message ... Right. Maybe you've peeked at my ideas for a ferrocement lathe with steel ways. d8-) (Having finished reading Naaman's _Ferrocement & Laminated Cementitious Composites_, I'm less enthusiastic about that construction.) Ed Huntress- Too late. There's one from ~1830? at the American Precision Museum with wrought iron ways mortared into grooves in a granite base. Another possibility is to make the ways rigid but not precise, like spacers blocks between two channel irons, and use a bolt-on X-Y table to control the tool. I would make the head and tailstock spindles a standard drill rod size and use a separate piece of it to align the head, tail and X-Y table axes after moving them. jsw |
#24
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Jim Wilkins" wrote in message ... On Nov 24, 2:03 pm, "Ed Huntress" wrote: "Jim Wilkins" wrote in message ... Right. Maybe you've peeked at my ideas for a ferrocement lathe with steel ways. d8-) (Having finished reading Naaman's _Ferrocement & Laminated Cementitious Composites_, I'm less enthusiastic about that construction.) Ed Huntress- Too late. There's one from ~1830? at the American Precision Museum with wrought iron ways mortared into grooves in a granite base. g Yes, there have been lots of concrete lathes, and stone-base lathes. I ran a photo of one cast in reinforced concrete in _AM_ around 1978, made in the USSR, that had a 65-foot-long bed. My never-ending project is about a lathe for hobbyists. My original idea was post-tensioned concrete. I may go back to that, based on some things I learned about ferrocement. Or I may stick with the ferro and change a few things to deal with issues. Post-tensioned concrete has its own issues. Neither ferro nor post-tensioned answers all of the problems. Another possibility is to make the ways rigid but not precise, like spacers blocks between two channel irons, and use a bolt-on X-Y table to control the tool. I would make the head and tailstock spindles a standard drill rod size and use a separate piece of it to align the head, tail and X-Y table axes after moving them. Good ideas. Lining things up is one of the issues, of course. Finish-honing the headstock bearing retainers, using a simplified honing head (closer to a lapping tool, actually) that runs on the lathe bedways, is a design I worked on in the early '80s. I still think it would work OK. -- Ed Huntress |
#25
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 2:50*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message .... Good ideas. Lining things up is one of the issues, of course. Finish-honing the headstock bearing retainers, using a simplified honing head (closer to a lapping tool, actually) that runs on the lathe bedways, is a design I worked on in the early '80s. I still think it would work OK. -- Ed Huntress I would try pillow blocks with setscrews or shaft clamps and jam two of them together to get preloaded angular contact at the working end of the spindle. Then the spindle (key-slotted shafting) could be easily swapped so you could weld a plate on one to mount a chuck, for instance. jsw |
#26
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Tue, 24 Nov 2009 22:46:10 +0000, Mark Rand
wrote: (Hardinge Dovetail excepted, that works) Indeed it does...and its actually 3 surfaces..or 5 if you are counting Gunner |
#27
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 8:38*pm, "Ed Huntress" wrote:
"Jim Wilkins" wrote in message ... On Nov 24, 6:42 pm, "Ed Huntress" wrote: "Jim Wilkins" wrote in message Interesting, but I think you'd have growth problems at the back end, unless you made the spindle float in the inner race of the backside bearing -- or had the backside bearings run right on the spindle, with clearance. I'd use a tubular bearing holder (a piece of pipe) cast into a ferrocement headstock, with floating rollers at the tail end and a pair of facing tapered roller bearings on the head end. That's one traditional setup for lathes, and it combines Z-axis stability, high load capacity, and free-floating at the tail end to deal with Z-axis growth of the spindle.. I'd have to look at what kinds of bearings are cheaply available first. Ed Huntress- So you have the drive pulley on the end of the spindle instead of between the bearings? Yeah, I worked that out in one of my first sketches, and I saw no real disadvantage. I was thinking about a pretty large (2 inch) hollow spindle.. In my original version, I didn't even have a drive or gears for threading.. It was going to use thread follower attachments, like the ones used on an old Unimat or some screw machines. The idea here was to build a little tank of a lathe with only the basics, which you could build up as you go along. First you make a speed lathe; learn some freehand turning and spin-forming; then add a tailstock; (do some wood-turning); then a cross slide (using it like a gang-turn Wasino), and eventually, a compound. You could add a power Z-axis feedscrew and my thought at the time (around 1980) was that CNC was going to become cheap enough that you might never have geared thread-cutting at all, going straight to servos for CNC threading. The reason for the ferrocement over other kinds of reinforced concrete was twofold. First, it allows free-form shapes, so you could make the headstock a hollow monocoque type, like modern lathes, rather than deal with the lack of lateral (X-axis) flexibility of old designs with pillow-block or stantion-type bearing supports. The structure of the bed would be a torque box, rather than parallel beams. That would give you rigidity throughout, without adding a lot of mass. The second reason is that it's isotropic; you don't have to engineer around the lines of tensile stress that can be tolerated. It's more like a metal than reinforced concrete in its mechanical properties. That's easier for us amateurs. It wasn't really a conventional design but it combined separate elements of well-tried lathe types. I had some suppositions about the ability of ferrocement to handle tensile loads which I've since learned, after reading Naaman's book, *are not exactly true. (It will handle the loads, but it will microcrack under tension). But ferrocement still has some big advantages over other kinds of reinforcement. It still could be the best choice, perhaps with a bit of hybridization, using post-tensioned tendons at the bottoms of the lathe bed, or maybe some fibers to prevent microcracks. 'Dunno. If I get some time, I'll have to re-think it now that I have the engineering data to help me along. That does allow a higher reduction ratio, and perhaps a crank handle for threading to a shoulder. Schedule 80 pipe might have enough wall thickness to make a bearing seat and you could clamp the bearings with bored-out pipe caps, as long as you can get the pipe to run true both ways to make the seats parallel. The idea here was to turn a piece of tubing of some sort to all of the inside and outside dimensions, including threading for the bearing retainers, to within a couple of thousandths. One hopes that you have a friend with a lathe. g Or, if it was a club-type project, these parts could be made and sold. Then make a rig that fits tightly into the bore and which has three pads that rest on the bedways to align the spindle-holding tube close enough while the structure is curing that you could hone the tube bore to final dimensions, without a lot of wasted effort. I would rather be able to adjust the spindle vertically for the Z axis milling feed, or to turn an oversized pulley or bore a taper in the spindle end. OK, there's a lot of room for variation in the basic idea. I don't see the spindle heating and expanding enough to cause a problem with the relatively light and flexible bearing support framework of a homebrew machine. In good lathe designs, I believe you'll find that the typical setup is to have a pair of preloaded bearings facing each other at the spindle-nose end. In classic designs, these were angular tapered-roller bearings in larger lathes, and angular-contact ball bearings in smaller ones. All of your Z-axis location is accomplished with these head-end bearings. Then the tail end of the spindle was held in a single- or double-row bearing that allowed linear movement -- either straight rollers, or ball bearings that allow the spindle to move. It doesn't take much heat to make the spindle grow substantially, which will either overload your bearings or unload the preload on the head-end bearings. Also, this lathe is no wimp. It would handle much higher loads than my SB-10L and would be roughly the same size, although a little wider and probably a little shorter (mine has the 54" bed). Anyway, it's been a good thought exercise for me from time to time. My ideas about it have changed a bit, but, basically, the objective is to design a lathe that a determined amateur with no experience could build at home. Some parts are tricky and will require machining; I've never worked out a really good saddle, cross-slide, and compound that can be made easily at home. As I said, I see it as a progressive design. You could start using it as soon as you complete the basic steps, learning and gaining some experience while making some fun and useful things, and then build it up in stages to a full-blown thread-cutting engine lathe. With CNC threading, no less. g I would love to see someone with more time and the ambition for it take some of these thoughts and carry it through. I've been diddling with it for so long that I'm losing heart to do it. -- Ed Huntress I used different design criteria, this machine would take on occasional jobs too large for my lathe and mill. That means it can be built lighter and cheaper than normal and only have to take finishing cuts on pieces roughed out with a saw or cutting torch. (pause to watch Mya dance) As a bootstrap machine it could make parts to upgrade itself. The other similar project is a Harig-style cylindrical and tool grinding attachment for my Toolmaker surface grinder, to make it more like a Quorn. This would resemble a small and precise lathe headstock and spindle that includes sliding motion. The 5C spindle of a spin index might be a decent start if it can be cleaned up well enough and converted to an air bearing. The grinder has a Y leadscrew so the Quorn's complexity can be reduced. I bought a Morse taper adapter with the outside ground to 1.000 OD for this project and discovered that it had bulged slightly around the release key slot. jsw |
#28
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Jim Wilkins" wrote in message ... On Nov 24, 8:38 pm, "Ed Huntress" wrote: "Jim Wilkins" wrote in message ... On Nov 24, 6:42 pm, "Ed Huntress" wrote: "Jim Wilkins" wrote in message Interesting, but I think you'd have growth problems at the back end, unless you made the spindle float in the inner race of the backside bearing -- or had the backside bearings run right on the spindle, with clearance. I'd use a tubular bearing holder (a piece of pipe) cast into a ferrocement headstock, with floating rollers at the tail end and a pair of facing tapered roller bearings on the head end. That's one traditional setup for lathes, and it combines Z-axis stability, high load capacity, and free-floating at the tail end to deal with Z-axis growth of the spindle. I'd have to look at what kinds of bearings are cheaply available first. Ed Huntress- So you have the drive pulley on the end of the spindle instead of between the bearings? Yeah, I worked that out in one of my first sketches, and I saw no real disadvantage. I was thinking about a pretty large (2 inch) hollow spindle. In my original version, I didn't even have a drive or gears for threading. It was going to use thread follower attachments, like the ones used on an old Unimat or some screw machines. The idea here was to build a little tank of a lathe with only the basics, which you could build up as you go along. First you make a speed lathe; learn some freehand turning and spin-forming; then add a tailstock; (do some wood-turning); then a cross slide (using it like a gang-turn Wasino), and eventually, a compound. You could add a power Z-axis feedscrew and my thought at the time (around 1980) was that CNC was going to become cheap enough that you might never have geared thread-cutting at all, going straight to servos for CNC threading. The reason for the ferrocement over other kinds of reinforced concrete was twofold. First, it allows free-form shapes, so you could make the headstock a hollow monocoque type, like modern lathes, rather than deal with the lack of lateral (X-axis) flexibility of old designs with pillow-block or stantion-type bearing supports. The structure of the bed would be a torque box, rather than parallel beams. That would give you rigidity throughout, without adding a lot of mass. The second reason is that it's isotropic; you don't have to engineer around the lines of tensile stress that can be tolerated. It's more like a metal than reinforced concrete in its mechanical properties. That's easier for us amateurs. It wasn't really a conventional design but it combined separate elements of well-tried lathe types. I had some suppositions about the ability of ferrocement to handle tensile loads which I've since learned, after reading Naaman's book, are not exactly true. (It will handle the loads, but it will microcrack under tension). But ferrocement still has some big advantages over other kinds of reinforcement. It still could be the best choice, perhaps with a bit of hybridization, using post-tensioned tendons at the bottoms of the lathe bed, or maybe some fibers to prevent microcracks. 'Dunno. If I get some time, I'll have to re-think it now that I have the engineering data to help me along. That does allow a higher reduction ratio, and perhaps a crank handle for threading to a shoulder. Schedule 80 pipe might have enough wall thickness to make a bearing seat and you could clamp the bearings with bored-out pipe caps, as long as you can get the pipe to run true both ways to make the seats parallel. The idea here was to turn a piece of tubing of some sort to all of the inside and outside dimensions, including threading for the bearing retainers, to within a couple of thousandths. One hopes that you have a friend with a lathe. g Or, if it was a club-type project, these parts could be made and sold. Then make a rig that fits tightly into the bore and which has three pads that rest on the bedways to align the spindle-holding tube close enough while the structure is curing that you could hone the tube bore to final dimensions, without a lot of wasted effort. I would rather be able to adjust the spindle vertically for the Z axis milling feed, or to turn an oversized pulley or bore a taper in the spindle end. OK, there's a lot of room for variation in the basic idea. I don't see the spindle heating and expanding enough to cause a problem with the relatively light and flexible bearing support framework of a homebrew machine. In good lathe designs, I believe you'll find that the typical setup is to have a pair of preloaded bearings facing each other at the spindle-nose end. In classic designs, these were angular tapered-roller bearings in larger lathes, and angular-contact ball bearings in smaller ones. All of your Z-axis location is accomplished with these head-end bearings. Then the tail end of the spindle was held in a single- or double-row bearing that allowed linear movement -- either straight rollers, or ball bearings that allow the spindle to move. It doesn't take much heat to make the spindle grow substantially, which will either overload your bearings or unload the preload on the head-end bearings. Also, this lathe is no wimp. It would handle much higher loads than my SB-10L and would be roughly the same size, although a little wider and probably a little shorter (mine has the 54" bed). Anyway, it's been a good thought exercise for me from time to time. My ideas about it have changed a bit, but, basically, the objective is to design a lathe that a determined amateur with no experience could build at home. Some parts are tricky and will require machining; I've never worked out a really good saddle, cross-slide, and compound that can be made easily at home. As I said, I see it as a progressive design. You could start using it as soon as you complete the basic steps, learning and gaining some experience while making some fun and useful things, and then build it up in stages to a full-blown thread-cutting engine lathe. With CNC threading, no less. g I would love to see someone with more time and the ambition for it take some of these thoughts and carry it through. I've been diddling with it for so long that I'm losing heart to do it. -- Ed Huntress I used different design criteria, this machine would take on occasional jobs too large for my lathe and mill. That means it can be built lighter and cheaper than normal and only have to take finishing cuts on pieces roughed out with a saw or cutting torch. (pause to watch Mya dance) As a bootstrap machine it could make parts to upgrade itself. The other similar project is a Harig-style cylindrical and tool grinding attachment for my Toolmaker surface grinder, to make it more like a Quorn. This would resemble a small and precise lathe headstock and spindle that includes sliding motion. The 5C spindle of a spin index might be a decent start if it can be cleaned up well enough and converted to an air bearing. The grinder has a Y leadscrew so the Quorn's complexity can be reduced. I bought a Morse taper adapter with the outside ground to 1.000 OD for this project and discovered that it had bulged slightly around the release key slot. Those sound like good projects, too. Regarding the big machine, things like gap-bed lathes with big swings are a natural for the ferrocement construction method. You can span long distances at very low cost. It's also a good place for cylindrical bedways. The travels typically are short, and you have plenty of room to make their diameter as large as you need. In fact, a big gap-bed lathe with short tool travels would be easier than a thread-cutting engine lathe by a wide margin. If you have to face big disks, however, the whole prospect is a lot more difficult. -- Ed Huntress |
#29
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Tue, 24 Nov 2009 20:38:12 -0500, "Ed Huntress"
wrote: In good lathe designs, I believe you'll find that the typical setup is to have a pair of preloaded bearings facing each other at the spindle-nose end. In classic designs, these were angular tapered-roller bearings in larger lathes, and angular-contact ball bearings in smaller ones. All of your Z-axis location is accomplished with these head-end bearings. Then the tail end of the spindle was held in a single- or double-row bearing that allowed linear movement -- either straight rollers, or ball bearings that allow the spindle to move. It doesn't take much heat to make the spindle grow substantially, which will either overload your bearings or unload the preload on the head-end bearings. Also, this lathe is no wimp. It would handle much higher loads than my SB-10L and would be roughly the same size, although a little wider and probably a little shorter (mine has the 54" bed). Hardinge uses a single pair of angular contact bearings, one bearing at either end of the spindle, in the HLVH headstock -- a 3000RPM spindle with 25 millionths runout. The preload is controlled by a pair of spacers that introduce an offset between the inner and outer races. The drive belt is outboard of the rear bearing. One problem with tapered roller bearings, depending on how fussy you are, is that the runout specs on standard bearings is pretty bad compared to run of the mill ball bearings. And precision grade roller bearings are horribly expensive and can be difficult to source. -- Ned Simmons |
#30
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Ned Simmons" wrote in message ... On Tue, 24 Nov 2009 20:38:12 -0500, "Ed Huntress" wrote: In good lathe designs, I believe you'll find that the typical setup is to have a pair of preloaded bearings facing each other at the spindle-nose end. In classic designs, these were angular tapered-roller bearings in larger lathes, and angular-contact ball bearings in smaller ones. All of your Z-axis location is accomplished with these head-end bearings. Then the tail end of the spindle was held in a single- or double-row bearing that allowed linear movement -- either straight rollers, or ball bearings that allow the spindle to move. It doesn't take much heat to make the spindle grow substantially, which will either overload your bearings or unload the preload on the head-end bearings. Also, this lathe is no wimp. It would handle much higher loads than my SB-10L and would be roughly the same size, although a little wider and probably a little shorter (mine has the 54" bed). Hardinge uses a single pair of angular contact bearings, one bearing at either end of the spindle, in the HLVH headstock -- a 3000RPM spindle with 25 millionths runout. Hmm. Is that right? I thought Hardinges had the classic two-bearing-front, floating rear setup. But I don't know for sure. Maybe Gunner would know. In any case, they use Class 9 bearings in their top-of-the-line, and those spindles run exceptionally cool. They aren't a good example to follow for any ordinary lathe. You'd never be able to duplicate the performance of that spindle. The preload is controlled by a pair of spacers that introduce an offset between the inner and outer races. The drive belt is outboard of the rear bearing. One problem with tapered roller bearings, depending on how fussy you are, is that the runout specs on standard bearings is pretty bad compared to run of the mill ball bearings. And precision grade roller bearings are horribly expensive and can be difficult to source. -- Ned Simmons |
#31
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Wed, 25 Nov 2009 00:18:26 -0500, "Ed Huntress"
wrote: "Ned Simmons" wrote in message .. . On Tue, 24 Nov 2009 20:38:12 -0500, "Ed Huntress" wrote: In good lathe designs, I believe you'll find that the typical setup is to have a pair of preloaded bearings facing each other at the spindle-nose end. In classic designs, these were angular tapered-roller bearings in larger lathes, and angular-contact ball bearings in smaller ones. All of your Z-axis location is accomplished with these head-end bearings. Then the tail end of the spindle was held in a single- or double-row bearing that allowed linear movement -- either straight rollers, or ball bearings that allow the spindle to move. It doesn't take much heat to make the spindle grow substantially, which will either overload your bearings or unload the preload on the head-end bearings. Also, this lathe is no wimp. It would handle much higher loads than my SB-10L and would be roughly the same size, although a little wider and probably a little shorter (mine has the 54" bed). Hardinge uses a single pair of angular contact bearings, one bearing at either end of the spindle, in the HLVH headstock -- a 3000RPM spindle with 25 millionths runout. Hmm. Is that right? I thought Hardinges had the classic two-bearing-front, floating rear setup. But I don't know for sure. Maybe Gunner would know. It's as I've described. I've been in there and have a picture here in front of me. In any case, they use Class 9 bearings in their top-of-the-line, and those spindles run exceptionally cool. They aren't a good example to follow for any ordinary lathe. You'd never be able to duplicate the performance of that spindle. The key to controlling the temperature rise is more closely related to accurately setting the preload than the bearing class. In order to get reasonable stiffness you'd probably not want to mount the nose bearings directly back to back, and the most practical way to get the required separation is with a pair of spacers. The length of those spacers is critical to setting the preload, regardless of how long they are. I've designed quite a few spindles, and I think temperature effects are way down on the list of things to worry about when thinking about buliding a ball bearing headstock on the cheap with limited equipment. The preload is controlled by a pair of spacers that introduce an offset between the inner and outer races. The drive belt is outboard of the rear bearing. One problem with tapered roller bearings, depending on how fussy you are, is that the runout specs on standard bearings is pretty bad compared to run of the mill ball bearings. And precision grade roller bearings are horribly expensive and can be difficult to source. -- Ned Simmons -- Ned Simmons |
#32
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
"Ned Simmons" wrote in message ... On Wed, 25 Nov 2009 00:18:26 -0500, "Ed Huntress" wrote: "Ned Simmons" wrote in message . .. On Tue, 24 Nov 2009 20:38:12 -0500, "Ed Huntress" wrote: In good lathe designs, I believe you'll find that the typical setup is to have a pair of preloaded bearings facing each other at the spindle-nose end. In classic designs, these were angular tapered-roller bearings in larger lathes, and angular-contact ball bearings in smaller ones. All of your Z-axis location is accomplished with these head-end bearings. Then the tail end of the spindle was held in a single- or double-row bearing that allowed linear movement -- either straight rollers, or ball bearings that allow the spindle to move. It doesn't take much heat to make the spindle grow substantially, which will either overload your bearings or unload the preload on the head-end bearings. Also, this lathe is no wimp. It would handle much higher loads than my SB-10L and would be roughly the same size, although a little wider and probably a little shorter (mine has the 54" bed). Hardinge uses a single pair of angular contact bearings, one bearing at either end of the spindle, in the HLVH headstock -- a 3000RPM spindle with 25 millionths runout. Hmm. Is that right? I thought Hardinges had the classic two-bearing-front, floating rear setup. But I don't know for sure. Maybe Gunner would know. It's as I've described. I've been in there and have a picture here in front of me. Ok, then maybe it's just the HLVH? Because I used a cutaway drawing of a Hardinge spindle once to illustrate exactly what we've been talking about here, and, although I don't remember the drawing perfectly, I do remember what I wrote for the caption. Are you familiar with the earlier Hardinges? In any case, they use Class 9 bearings in their top-of-the-line, and those spindles run exceptionally cool. They aren't a good example to follow for any ordinary lathe. You'd never be able to duplicate the performance of that spindle. The key to controlling the temperature rise is more closely related to accurately setting the preload than the bearing class. In order to get reasonable stiffness you'd probably not want to mount the nose bearings directly back to back, and the most practical way to get the required separation is with a pair of spacers. The length of those spacers is critical to setting the preload, regardless of how long they are. I've designed quite a few spindles, and I think temperature effects are way down on the list of things to worry about when thinking about buliding a ball bearing headstock on the cheap with limited equipment. Aha. Are you saying you'd run opposed, preloaded bearings at opposite ends of the spindle on a lathe like we've described here? Because I was once pretty familiar with bearing layouts in machine tools, and it just goes against everything I was taught. I'm not saying you're wrong, but there is a pretty fair amount of work behind the things I thought I learned when I was writing about it. If it's all wrong, I have some work to do here in a hurry. The preload is controlled by a pair of spacers that introduce an offset between the inner and outer races. The drive belt is outboard of the rear bearing. One problem with tapered roller bearings, depending on how fussy you are, is that the runout specs on standard bearings is pretty bad compared to run of the mill ball bearings. And precision grade roller bearings are horribly expensive and can be difficult to source. -- Ned Simmons -- Ned Simmons |
#33
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Tue, 24 Nov 2009 23:36:11 -0500, Ned Simmons
wrote: On Tue, 24 Nov 2009 20:38:12 -0500, "Ed Huntress" wrote: In good lathe designs, I believe you'll find that the typical setup is to have a pair of preloaded bearings facing each other at the spindle-nose end. In classic designs, these were angular tapered-roller bearings in larger lathes, and angular-contact ball bearings in smaller ones. All of your Z-axis location is accomplished with these head-end bearings. Then the tail end of the spindle was held in a single- or double-row bearing that allowed linear movement -- either straight rollers, or ball bearings that allow the spindle to move. It doesn't take much heat to make the spindle grow substantially, which will either overload your bearings or unload the preload on the head-end bearings. Also, this lathe is no wimp. It would handle much higher loads than my SB-10L and would be roughly the same size, although a little wider and probably a little shorter (mine has the 54" bed). Hardinge uses a single pair of angular contact bearings, one bearing at either end of the spindle, in the HLVH headstock -- a 3000RPM spindle with 25 millionths runout. The preload is controlled by a pair of spacers that introduce an offset between the inner and outer races. The drive belt is outboard of the rear bearing. One problem with tapered roller bearings, depending on how fussy you are, is that the runout specs on standard bearings is pretty bad compared to run of the mill ball bearings. And precision grade roller bearings are horribly expensive and can be difficult to source. They can be..yes. Good post btw. Gunner |
#34
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Wed, 25 Nov 2009 00:47:42 -0500, Ned Simmons
wrote: Hmm. Is that right? I thought Hardinges had the classic two-bearing-front, floating rear setup. But I don't know for sure. Maybe Gunner would know. It's as I've described. I've been in there and have a picture here in front of me. Very early Hardinges had the 2 bearing front..1940s-early 50s vintage..but since the late 50s..all have been as Ned said. Thats for manual and microswitch automatics. Gunner |
#35
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Tue, 24 Nov 2009 19:09:44 -0800, Gunner Asch
wrote: On Tue, 24 Nov 2009 22:46:10 +0000, Mark Rand wrote: (Hardinge Dovetail excepted, that works) Indeed it does...and its actually 3 surfaces..or 5 if you are counting Gunner Oops. Miscounted there. I don't know where the extra one crept in from... Very definitely only three guiding surfaces on the dovetail beds of the Brothers Hardinge. Regards Mark Rand RTFM |
#36
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Wed, 25 Nov 2009 09:29:32 +0000, Mark Rand
wrote: On Tue, 24 Nov 2009 19:09:44 -0800, Gunner Asch wrote: On Tue, 24 Nov 2009 22:46:10 +0000, Mark Rand wrote: (Hardinge Dovetail excepted, that works) Indeed it does...and its actually 3 surfaces..or 5 if you are counting Gunner Oops. Miscounted there. I don't know where the extra one crept in from... Very definitely only three guiding surfaces on the dovetail beds of the Brothers Hardinge. Regards Mark Rand RTFM G Gunner |
#37
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 11:36*pm, Ned Simmons wrote:
On Tue, 24 Nov 2009 20:38:12 -0500, "Ed Huntress" ... One problem with tapered roller bearings, depending on how fussy you are, is that the runout specs on standard bearings is pretty bad compared to run of the mill ball bearings. And precision grade roller bearings are horribly expensive and can be difficult to source. Ned Simmons- Does bearing runout matter as much if you finish the spindle nose - after- keying and clamping it in place? For my version you swap spindles rather than making precise threads and tapers on the nose, so keying or at least putting the clamp setscrews back in the same depressions is important. jsw |
#38
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 24, 8:04*am, Jim Wilkins wrote:
On Nov 24, 1:24*am, "RogerN" wrote: A lathe can make another lathe, but a mill can not make another mill. *No CNC's allowed. What part of a mill can't a mill make? *How do you machine a lathe bed in a lathe? I think the idea is to remove the head and tailstock and use a tool bit in the carriage to plane the ways. You might want to hang the new lathe bed upside down over the old one so you can plane all the way surfaces parallel. When I needed to remachine a worn lathe bed I used a large horizontal milling machine. I think I'd prefer to use a mill to make 90% of either a lathe or a mill. And for the other 10% I think it would be easier to make a spindle on a mill than it would be to mill a cross slide table, but then again I've never seen a very nice milling setup in a lathe. RogerN You can mill cylindrical or conical surfaces on a rotary table or between indexer centers. That's how I make tubing bender dies. I suppose you could cut threads with a vee cutter or a fixed flycutter bit by gearing the indexer to the table feed. The American Precision Museum in Vermont has machine tools going back to 1820 or so. By about 1860 practical experience had shaped them into the forms we still have now. The smaller details such as quick-change gearboxes and HSS tool bits were in place by 1900. There are some versatile hybrids meant for moderate production runs such as the Lincoln miller, which would be my model for a machine that makes other machines.http://www.sperdvac.org/Horizontal%2...ne_lincoln.jpg I would make the tailstock support with two posts like the headstock to better support it for tailstock drilling. Scroll down to the bottom and look at "take-up" bearings:http://www.baileynet.com/index.php?i...tegory=1000011 jsw The picture of the "Lincoln miller" seems to have a "Pratt & Whitney" logo on the bed. |
#39
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
In article ,
"Ed Huntress" wrote: "Jim Wilkins" wrote in message ... On Nov 24, 1:04 pm, "Ed Huntress" wrote: "Jim Wilkins" wrote in message ... I just checked my two best sources, Holtzapffel #2 and Oscar Perrigo's 1916 "Lathe Design", ... ... As I think about this, I'm remembering what I thought about it at the time, 30 years ago. I believed then that the issue was the difficulty, without planers, mills, or big surface grinders, of getting the four planes of a pair of V-ways coordinated for straight and smooth travel. One way to interpret this is that you can adjust the single plane of the flat way a lot easier than the pair of planes you have with a second V. So to say that it was simpler to correct accuracy with the V-and-flat could just mean that; if the ways are hand-finished, you're correcting accuracy, and V-and-flat is a lot easier to correct than two V's. Maybe. g -- Ed Huntress If I read Holtzapffel correctly the two sides of inverted vee ways were at first made separately, joined and aligned afterwards to fit the fixed and moving poppit heads (headstock and tailstock to us). Yeah. In the very beginning of modern lathes, the V-and-flat combinations were assembled the same way. The first screw-cutting lathes had wood beds with bolted-on iron ways, IIRC. (I'm doing this from memory; don't bite me. g) "This slight width of base does not afford sufficient lateral support to the heads, which with only moderate force in turning are liable to vibration; while exact parallelism of the two angular edged bars is also necessary. Improvement in stability was sought by making one side of the bearers flat and broad, fig. 72, with a corresponding flat on the underside of the lathe heads; retaining one angular side, to give the direction or common axis. This arrangement also facilitated the construction, as the parallelism of the two bars was no longer essential,..." Right. That sounds familiar. Fig 72 shows one flat and one inverted vee way on a cast iron bed. The difficulties of the early machine builders that Holtzapffel recorded aren't that much different from those of a homebrew machine tool maker today, except that we can buy ground drill rod and flat stock and they could hire cheap child labor for tedious hand fitting. Right. Maybe you've peeked at my ideas for a ferrocement lathe with steel ways. d8-) (Having finished reading Naaman's _Ferrocement & Laminated Cementitious Composites_, I'm less enthusiastic about that construction.) Significant work has been done on concrete-filled fabricated metal frames for precision machine tools. The place to start is MIT professor Alexander H. Slocum (http://meche.mit.edu:16080/people/index.html?id=80). A good discussion and many references may be found in his book "Precision Machine Design". Joe Gwinn |
#40
Posted to rec.crafts.metalworking
|
|||
|
|||
Which tool is needed. . . ?
On Nov 25, 7:37*am, "Denis G." wrote:
On Nov 24, 8:04*am, Jim Wilkins wrote: ... Scroll down to the bottom and look at "take-up" bearings:http://www.baileynet.com/index.php?i...tegory=1000011 jsw The picture of the "Lincoln miller" seems to have a "Pratt & Whitney" logo on the bed.- Here's a little of the interrelationship between the machine builders of Hartford, which somewhat like Maudslay's group in England: http://www.hogriver.org/issues/v02n03/miracle.htm jsw |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Another tool ID needed XXV | Metalworking | |||
Another tool ID needed VII | Woodworking | |||
Another tool ID needed V | Woodworking | |||
Another tool ID needed VI | Woodworking | |||
Another tool ID needed III | Woodworking |