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twist on a 9A
virginiahobbyman #69441 The directions that I'm following to remove twist on my 9A have me place a precision level across the bed at the headstock end and adjust the two feet at the headstock to level the bed. Next step is to place the level along the bed and adjust the feet a second time. I happen to have the taper cross slide mounted and wonder if this would make a good base for the level for "across the bed" adjustment. http://dl.dropbox.com/u/46437435/onthecompound.pdf I'd appreciate comments on whether this is a correct base. |
Jim B. #69442 No. The bed is the bed. No guarantee the taper is the same. It is not absolutely necessary to have the bed level. The only requirement it that the tailstock and the Having said that I like mine to be level since it helps me wit setting up things on the lathe. Jim B. |
Jack Dinan #69444 OK. Then how about this. To level across the bed, it seems to me that I can stack parallels onto any number of surfaces and lay the level on these. In this photo, http://dl.dropbox.com/u/46437435/surfaces.pdf which two surfaces should I span? AE? BD? CD? jack
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Jim B. #69445 AE, makes sure there are no dings on the surfaces. Jim B. |
Davis Johnson
#69458 Actually, I think he had a good idea putting the level on the cross slide casting. In the picture the level is on the rear tail of the extended cross slide casting not the compound. Putting the level across the tops of the Vs (AE in in the photo) puts it on surfaces that are not references for anything else on the lathe. The saddle rides on the faces of the Vs, there isn't any particular reason that tightly controlling the flat tops would have had any benefit. They are probably close enough because of the happy accident that they were ground on the same machine in the same setup as the important bed surfaces. Unfortunately, on my praise-worthy 1943 clunker, the tops of the Vs are ugly at best - not an encouraging reference surface. A better reference would be the faces of the Vs where the saddle actually rides. I spent way too much time trying to come up with something to sit on the V-faces and hold the level in a repeatable manner. Then I realized that the saddle casting is a perfect level-holding fixture. I don't have the taper attachment, so all I have to do is crank the cross slide all the way to the rear until it comes off (don't loose the gib). One of the machined surfaces of the cross-slide dove tail makes a perfect place to put the level. You don't even have to touch the level when you move from one end of the bed to the other. Returning to the original poster's photo of the level on the taper cross slide. That is a flat, machined, surface that I don't have. It is one casting removed from where I propose put the level. The difference probably doesn't amount to much. Removing the taper attachment cross slide may be more difficult (I don't know). I think that should be an OK place to put the level if the cross slide nut is engaged and the taper attachment is disengaged. I suspect I'll learn something from the responses to this suggestion. toggle quoted messageShow quoted text
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Flash Gordon
#69448 Hi Jack, We have all been there. You can take the reading across the ways, but wait there is more .. read on. Taking the twist out of the bed or as some say leveling the lathe is accomplished in TWO (2) steps. Using a level is only the first step and not really that important. You could mount a lathe on a wall sideways and it will still cut accurately if you do the second step that SB has outlined. Think lathes on ships at sea in a hurricane on a dark and stormy night. Basically you need to take a test cut after the lathe is "level". The cut will not be between centers (that is a whole nother problem) After the test cut you will measure the bar and if it has a taper, you will shim under the feet at the tail stock end until the cut is perfect. Read "how to level a lathe" by SB but read all the page to get both steps. By the way you will see SB using a precision level, because they sold them. You can do the first part of leveling with any type of level. It is just a preliminary step. The proof is in the test cut. I found this out after I bought a precision level. Someday I will find another use for it. My wife has a great idea butt we will not go into that at this time. Quote SB page 20 paragraph one. " This test can also be used to perfect the leveling of the lathe Read all of pages 18 -20: http://www.wswells.com/data/howto/H-3.pdf Ed S |
Jim B. #69449 By the way you will see SB using a precision level, because I have to disagree. Without using the precision level FIRST I would NEVER get where I need to go, or at least I have tried all the other ways and I get best results just using a precision level and calling it quits. I have tried to "twee" and wind up worse off. Your mileage me vary. Jim B. |
Flash Gordon
#69450 Jim S As you say "to each his own". I should always start with "in my humble opinion". But someday I will hang my 405 on the wall and level it. LOL Ed S PS I did start with a precision level and I check it every week to satisfy my wife and to justify the purchase price. toggle quoted messageShow quoted text At 07:20 PM 3/19/2012, you wrote: By the way you will see SB using a precision level, becauseI have to disagree. Without using the precision level FIRST I would NEVER get where I need to go, or at least |
Jim B. #69451 On 3/19/2012 7:39 PM, Ed S wrote: PS I did start with a precision level and I check it every week to Have you noticed a change over time? When I first leveled my 9" after moving it to its present site, and its on a REALLY stiff metal stand, it drifted for almost a year. -- Owner: |
Flash Gordon
#69454 Jim B. It seems to change with temperature or the earth quake we had in Ohio ( due to a gas drilling and injecting in Youngstown area ). Right now it is out in an unheated pole barn with a concrete floor. My plan is to move it to the basem*nt.. someday. I do not adjust it unless it is a critical part and I do not get very many of those. From a co-worker who taught construction; "Concrete cracks The earth is moving all the time. Ed S |
Jim B. #69455 On 3/19/2012 8:26 PM, Ed S wrote: "Concrete cracks In a similar vein, since concrete has little strength in tension and very good strength in compression, concrete does not hold bricks together it holds them apart. -- Owner: |
David Rysdam #69457 On Mon, 19 Mar 2012 18:55:22 -0400, Ed S <eschwerkolt@...> wrote: Read "how to level a lathe" by SB but read all the page to get both I already knew you could test for planarity with only the second test, 1) Tools, especially precision tools, are cool! 2) At my level of skill and amount of free time, it could take me |
Jim B. #69459 On 3/19/2012 9:53 PM, davis@... wrote: Then I realized that the saddle casting is a perfect level-holding fixture. I don't have the taper attachment, so all I have to do is crank the cross slide all the way to the rear until it comes off (don't loose the gib). One of the machined surfaces of the cross-slide dove tail makes a perfect place to put the level. You don't even have to touch the level when you move from one end of the bed to the other. The issue there is that the front and back ways do not wear evenly. The force of cutting puts more pressure on the front way causing it to wear faster. Since the tailstock does not wear much this wear tilt would actually result in a bed twist. I dont like using the tops of the ways either but I use a 6" wide piece of ground stock to average out imperfections. I always draw a very fine file over the top to get rid of any dings. About 3 weeks ago I was machining a shaft to hold the cluster gear on my MG gearbox. It needed to be about 9/16 diameter and about 7-1/2" long. I found a piece in the scrap box that I had put a taper on, in preparation to making a tap for. It never worked out. I turned it down to 9/16. There was less than 0.001 taper over the 7-1/2" length and my ways are not pristine. -- Owner: |
Jack Dinan #69460 This jibes with a statement that I saved from an Turk message from a while ago. It read So any SB lathe built during and after the war the top of the V ways may or may not be even close to the same horizontal plane as the V and flat ways are. The only true way to use a level on a three V-way SB is to build two identical blocks that rest on the V and not on the small top surface. If you make up a set of these blocks then you will be resting the level on the surface the lathe uses. Even then wear will affect any reading you get. toggle quoted messageShow quoted text
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sblatheman
#69461 The tops of the vees were groundin the same set up as the rest of the bed. The top of the tailstock vee was ground .002' lower than the saddle vees. All this was done to accomadate using a level. Ted toggle quoted messageShow quoted text -----Original Message----- This jibes with a statement that I saved from an Turk message from a So any SB lathe built during and after the war the top of the V ways The only true way to use a level on a three V-way SB is to build two > |
Jim B. #69462 On 3/19/2012 10:07 PM, Jack Dinan wrote: The only true way to use a level on a three V-way SB is to build two Again, Jack, the front V, near the headstock will wear faster than the rear V. Even with ground identical V-blocks the front one, near the headstock will sit lower, but the front one near the tailstock will not sit low. -- Owner: |
Flash Gordon
#69463 I agree and that is what I told my wife. I also bought a used one.. level that is not wife. Ed S toggle quoted messageShow quoted text I already knew you could test for planarity with only the second test, |
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