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Lathe - Power Feed/Reversal

 
 

 

 
 
Carriage feed (Jan 3, 2003) Reversing (Aug 4, 2004)
SB 9A Feed questions (Apr 25, 2003) Reversing lever mod (Sep 1, 2004)
Interesting feed screw fix (Apr 28, 2003) Reverse lever plate 9c (Dec 13, 2004)
Longitudinal Feed Rates (Nov 18, 2003) Power feed (Jan 13, 2005)
Screw feed rate modification (Dec 11, 2003) Reversing a lineshaft driven lathe (Feb 1, 2005)
Reversing old lathes (May 12, 2004)  
 
Carriage feed
What do I have to do fix my carriage feed for turning. I engage the feed and it will start moving and sometimes pops out. I have a 16" south bend serial 12645 HKX 15. I am new and need elementary education on these things. Lenny (8467)
According to your serial number, H = 16" swing, K = Quick change gearbox, X = "Special" spindle and/or swing type. I am assuming that you have a lever type apron clutch. I have attached a scan of the maintenance/adjustment of this type of clutch. If you were having a "sticky" clutch, I would say that you need to flush your clutch (with kerosene). It couldn't hurt to do this anyway. Webb (8468)
I got the scan from you Bill and tried to adjust clutch. Still won't stay in. I took the handle off and if I wedge a screw in and apply some pressure it will move. What next? Am I out of adjustment? The back side of the scan you sent is supposed to be for replacing discs. Can you send that one also? (8602)
SB 9A Feed questions
I couldn't find this in the How to run books. When threading I know to use the half nuts to move the carriage. When turning down stock should you engage the feed lever to start the cut or engage it first then use the star nut to start and stop carriage? Same ? for power cross feed also. (10448)
The star knob engages a clutch. This clutch feature is useful for turning up to a shoulder. I engage the proper feed gear, longitudinal or crossfeed, and then turn the clutch knob until the tool starts moving and maybe a scoche more so it won't hesitate if the gibs are a bit tighter at one end or the other. I keep one hand on the knob so I can quickly disengage when the end of the cut is reached. If you come up to a shoulder and are sleeping on the job the clutch should start slipping and not ruin your part. I don't like to depend on this, though. Some people have reported sticky clutch problems when the apron has not been cleaned out or flushed with kerosene for 60 years. Make sure it all works as I described befor you start taking a 1/2 diameter reducing cut on an expensive piece of metal. Glen (10451)
Interesting feed screw fix
My Model A was built in 1952, so was old when I got it. Since I got the lathe, I have manufactured about 2,000 parts that are 8" diameter, and faced on 3 sides(!). One power feed pass to clean the casting and make a datum surface, then the part is flipped on the vacuum chuck, and faced. The first face is then refaced to assure plane/parallel to In the course of this product manufacture, the power crossfeed has therefore cycled more than 6,000 times at a slightly more than 4" excursion. On E-Bay I got a screw and nut from a Model C. Upon removing my crossfeed screw and comparing them I could only stare dumbfounded. The very thread profile in the worn region did not resemble an Acme screw, but rather something with a very thin (-.008) form! So knowing the Model C had no power crossfeed I reasoned that the wear could not be as bad, and it certainly is not. So I intend to use the Model C screw to run the lathe so I can part off the gear section from the Model A screw, and then bore the gear to .441 and press and pin (Or silver solder it) the to correct portion of the Model C shaft. Sounds like fun. I'll let you all know how it works out. I may photograph the process and put it on my site. The Model A screw assembly is a total loss, anyway, as there is radial slop in the crank bearings! Otherwise, I would be trying to rustle up a 12 tooth 20 pitch pinion. (10544)
I am good. 45 minutes, being careful, and it works great! One thing, though. I confess to sweating bullets when I checked the bottom of the gear teeth, that is the ID of the pitch circle. I only had .018 wall after boring the .441. Whew. Drink Time. With my Foredom and a slitting wheel, I put longitudinal grooves on the mounting surface to insure silver solder flow, 6 equispaced .010 deep, approx. I heatsunk the screw to prevent annealing. So this fix was a piece of cake. Without power crossfeed it appears the Model C screw was nearly new it had a MUCH easier life than the one in my 1952 Model A. (Or a lazier owner..haha.) Got a nut also. It amazed me how much the Model A assembly rattled around when shaken...the original was really, really beaten up. I wonder if the PO was machining ceramics on it or something. (10545)
Longitudinal Feed Rates
I recently acquired a 9 inch junior model lathe to help me relearn the basics (which I barely learned 20 years ago). I need help in determining/calculating longitudinal feed rates to use for basic turning operations. The brass gear chart on the machine only indicates the thread counts produced by the various gear combinations, not the longitudinal feeds. I appear to have the complete set of change gears, including the 81/18 combination gear. Ralph (15070)
You need to start with the pitch of the lead screw. The pitch is 1/tpi. This is the feed for one turn of the screw. Now count the number of teeth on the spindle and the number of teeth on the lead screw gear. The ratio is then the number of turns the spindle will make for one turn of the screw (assuming that there are NO compound gears in the train, only idler gears). Example: 8 threads per inch screw is a 0.125 feed per turn of the leadscrew. Given a 24 tooth spindle (I don't know what a JR has) and a 104 tooth gear on the screw this requires 104/24 = 4.333333 turns of the spindle to move 0.125 inches or 1/4.33333*0.125 = 0.02885 inches per turn of the spindle. If you put in the 81/18 compound gear, this is a 4.5:1 reduction and this would give 0.0064" feed per turn of the spindle. I hope I have been clear enough. I need to go through this every time I figure it out and I am using gears that are on my 9" . However I have two compound gears a 2:1 and a 7:1 In this case I take the basic spindle to lead screw ratio 104/24 ( The idler gears don't count) and reduce the feed rate by (1/2*1/7) 0.5*0.143 = 0.071 times the basic feed of 0.02885 = 0.002" per turn of the spindle. Jim B. (15071)
Screw feed rate modification
I have a 1940ish 14-1/2" Engine Lathe and need to modify the lathe feed rate to give obtain about 0.333 threads/inch or lower (yes that is a pitch of 3"). The machine will not be operating very fast. Any suggestions on how to modify and/or a company to contact would be greatly appreciated. Discussions with with South Bend and LeBlond Limited have not been successful. I was expecting to modify the quick change gear box or the "end gear" attached to the lead screw. Gerald (15534)
With great care to not overload the gearing, etc, this type of work requires driving the saddle **from the leadscrew**. Any screw cutting below the leadscrew pitch must be accessed for this problem of over straining the gear setup especially if using a QC box. For 3" P I would definitely use a direct drive lathe (no QC). RichD (15538)
Rich, I have no choice but to use the current lathe. My max. Saddle speed will be about 1/4"/second. If necessary it will go about 1/8"/second. I hope that is below any overload situation - will be careful with it. I admit that I'm not a seasoned lathe operator (yet) and do not follow your suggestion: the leadscrew**. I need the saddle to be in-sync with the spindle; would this still happen? Gerald (15542)
Gerald, but, it's not the speed!!! It's the torque reaction. The feed gearing cannot move the saddle under cutting load without enormous strain at large pitches. In fact, I wonder if it will move at all! NO load. There is another yahoo group that is involved in the building of a universal cutter grinder. A feature, of which, is a column with a 1" pitch thread. The original author/builder had to resort to leadscrew drive even for that pitch. RichD (15543)
Reversing old lathes
Lathes with threaded spindles have an inherent danger related to reversing the spindle. The chuck can unscrew from the spindle causing unpleasant things to happen. Ill leave the things to your imagination. There are techniques that can be used to allow opening the splitnut without benefit of a threading dial. Those methods are mentioned in some of the lathe manuals referred to in a recent post on the subject. RC (18997)
Reversing
I personally don't believe in reversing a "screw nose" lathe. One need only have one escaped chuck experience to be convinced that its a bad idea. I know one old machinist who installed a pin arrangement in his 24" LeBlond regal so he could reverse it without fear. The installation was quite involved since that machine has a hard spindle. Most single phase motors cant be "plugged" or reversed quickly although they make special ones for that purpose. I'm not sure how they work. RC
(20332)
I thing the saving grace for reversing a "screw nose" lathe is the use of a single phase motor. Knowing that a 3 phase motor has greatly more starting torque than a single phase motor I probably would never use reverse as a brake on a 3 phase machine, especially if it was connected to a real 3 phase line. As to how an instant reversing single phase motor works, It is essentially like any other capacitor start motor except it has a direction sensing centrifugal switch which disconnects the appropriate starting winding depending on which direction the motor is running. This keeps the opposite direction starting winding connected so that when switch is thrown to the opposite direction The start winding is energized until the motor reaches running speed in the other direction. Wayne (20349)
Reversing lever mod
Has anyone adapted a plunger type reversing lever to a bolt type head on a 9 inch lathe? Jim (20733)
Sure have. You need a 10K reversing unit (the 9 gears can be swapped to it). This is just a swap one for the other. I have a drawing of the plate when you are ready. RichD (20734)
Rich, thanks for the quick answer and the kind offer of a drawing. I'll let you know when I get ready. Jim (20741)
Reverse lever plate 9c
I remember seeing a drawing to make a plate for mounting a reverse lever on a sb 9 c. I did print it out but have since lost the drawing. I've been trying to search archives files and photos, but can't find it here. Can anyone steer me in the right direction to that drawing again. Mike (22924)
Mike, RichD of this group has the drawing that you want. Might pull up the members file and E-mail him. I made one from his drawing and its slick. You'll be glad that you went to the effort for it. Jim (22944)
Thank you, that was exactly what I was looking for. I converted my c to an a and this will be the final touch. I wouldn't have done it without this forum. I have to thank all the knowledgeable people here that share such good information. I just got a Clausing 8520 mill to go with my sb. These are two great machines to work with. Mike (23009)
Power feed
I have a quandary with my 10L. It will longitudinally feed with the thread gears, but will not feed using the clutch. Tightening up the star handle for the clutch does not seem to do anything. I did remove the carriage and apron when I disassembled it to bring it home, but caught the key and reinstalled it when I ran the carriage back on. Brian (23940)
There is a key in between the lead screw and the gear in the apron - I would make sure that isn't missing. (23947)
Kevin, Yup, it fell out when I was disassembling for transport, but I put it back in when I got it home and put it back together. Is there anyway that thing will fit in there and everything run except the feed and the key not be in properly? It has those two ears on the ends. Brian (23950)
I can't think of a way you could get the key in there incorrectly but it's been a while since I have had the apron off. Have you looked at the parts diagram? Kevin (23963)
Brian, Did you get this resolved? If not, maybe if you provided more info. When you say it doesn't feed, where is the stoppage? Can you shift the long/cross feed lever up and down to engage? Does one work and not the other? With the lathe off, does tightening the star wheel lock or at least impede movement of the engaged feed? With the lathe off and a feed engaged, does the star wheel turn when you move the engaged axis? The idea is to find where the stoppage is. If you can't engage the feeds, then the half nut/power feed interlock may have come adrift. If the star wheel spins with movement of the engaged axis, then the feed clutch or the worm gear are the problem. If tightening the star wheel constricts movement, then your clutch is at least partially working and your issue is still in the worm gear drive. You could try spinning the lead screw by hand (lathe off, tumbler lever in neutral) while looking behind the apron- I think you can see the end of the worm gear and verify it is turning. I would look at my 10L but it's really cold in the garage now. I could be wrong about the star wheel turning while the power feed is engaged- I remember this is the case from my misspent youth but my present lathe has the lever clutch. Even so, the rest of the tests should work. The idea is to work back from both ends and identify where your motion is disappearing. If you find something new or figure it out, please keep us posted. Everyone loves a mystery. Bill (23964)
Yes, Kevin, I have the parts book. I guess I need to pull the apron and have a look inside. Brian (23977)
Bill, the star wheel does not turn at all with the lathe running, even with the threading gears engaged. It seems to tighten up when you turn it clockwise, but it is not having any effect. Both levers move up and down through all three positions just fine. Brian (23978)
There may be something missing in the apron, but lets just get all this straight. Threading is done by engaging the half-nuts, that's the lever on the right of the apron. It only has two positions, open or closed, disengaged or engaged, off or on, etc., and in this case should remain disengaged, open or off. Feeding is done by means of the feed selector which is in the middle of the apron and has three positions, cross feed, neutral, and longitudinal feed, with a pin to positively engage the lever on one of the three positions. The feed clutch is a star-wheel at the bottom of the apron that engages the clutch by tightening it clockwise, (righty-tighty, lefty-loosey). Finally, there is a feed reverse lever at the left side of the head-stock with three positions, forward, neutral and reverse. In order to have the feed on, the the feed reverse lever at the left of the head-stock must be either fully up or fully down, the levers in the QC gear-box must be fully engaged which will result in the lead-screw turning when the lathe spindle is turning. Then, the feed select lever on the apron must be either fully up or fully down and the clutch star-wheel tightened. At that point the star-wheel should be turning as well as the feed when the lathe is on. If that isn't the case, the apron is missing some clutch discs or an intermediate gear. Roy (23982)
Words are a poor substitute for direct vision. Got to: http://www.zetagraphics.com/shop/sbparts/sbparts.html and open file 910D for a PDF of the 10L apron. Also check out: http://www.swayzephoto.com/lathe/index11.html These pics are of a larger lathe but the parts are similar. Where the drawing is confusing, the picture helps. On the 10L PDF, the worm gear 16 drives the roller 4. The roller is also the outside hub for your feed clutch. When engaged, the clutch locks the roller 4 to the small gear 1. 1 and 4 are coaxial with the star wheel 48. The feed lever 37 controls the position of gear 36 by rotating the eccentric shaft 35. Gear 36 is always engaged with the inner clutch gear 4. Lifting lever 37 engages gear 36 with gear 20, driving pinion 32. The pinion meshes with the rack on the bed and provides long axis travel. Gear 20 is also constantly engaged with gear 33- the handwheel gear. Dropping lever 37 engages gear 36 with gear 22. 22 drives 23 which stands proud of the apron and drives the cross feed screw. Notice the notch in the "near" side of part 35? This notch aligns with the tip of part 50 when the feed lever is in neutral. Engaging the half nut drives part 50 forward into the notch, locking the feed lever. Conversely, when the feed is engaged, lever 50 can't move forward so the half nut can't close. For reference, in the third picture down on the left side, you can clearly see the half nut holder above and left of lever 50 (much different shape here). Center gear 4 below worm gear. The fabled gear 37 is behind the worm. Upper left is the small drive pinion 32 in front of gear 20. The handwheel gear 33 is at the lower right. Not installed are gears 22 and 23- the hole above the left worm saddle is for their shaft. Simple, Eh? From what you describe, I would guess that gear 36 has somehow come loose from shaft 35. Just a guess, though. Bill (23983)
That sounds about right. The only way I can get the feed to work at all is to thread at what? 224 TPI?, which makes for a really slow feed. The star wheel does not turn, and the lathe will not feed no matter what the setting of the levers unless I make the lathe think it is threading. Sounds like clutch problems. Brian (23988)
I had a similar problem with my 9". The only way that I could get the apron to advance at all was to engage the half nuts. I could not even get the crosslide to work under power. I took the whole apron apart, cleaned it up and found that the clutch was frozen. What turned out to be the culprit at least I think it was was a little spring that spreads out two half disks against the clutch itself. It was badly worn, or disfigured or possible that somebody tried to bend it back to shape. I cleaned up the apron and reinstalled the bad spring while I was waiting for a part from Rose and it kind of worked, but not great. The minute I fully replaced the spring with a new one, I was off to the races. The clutch engaged, disengaged with a minute turn of the star shaped wheel. In fact somebody with a 10" lathe was amazed at how little turning force was necessary to engage and disengage the clutch. Mark (23989)
The star wheel is the clutch control. It doesn't turn unless you turn it. Do you mean it is frozen? (23992)
On the 10L and larger lathes, the star knob also turns (rotates) when the clutch is engaged and turning (with the turning of the leadscrew). The long screw on which the star knob is threaded has a pin that engages a slot on the clutch sleeve. When the clutch sleeve turns, that long screw turns with it and so does the star knob. Arne (23997)
Ed, From what I'm reading here, it should turn while feeding with the clutch engaged. It is not doing that, as it will not feed. The only way I can advance the saddle is to engage the thread function. The wheel turns freely, it is just apparently not doing anything. Brian (24001)
Arne, we had a 10L and a 13 SB in our shop and I "remembered" the knobs turning. I took a quick look at the zetagraphics page 9A/10K apron and it is an entirely different beast. So I'm not completely senile yet. That was 25 years ago. Bill (24004)
Brian, Per Arne's point- the star wheel shaft is keyed/pinned to the driven clutch feed gear. In other words, any time you have the cross or long feed engaged, the star wheel should turn when that axis moves. Engage the cross feed then turn the cross feed handle- the star knob should turn as well. The only time the star knob should turn freely is when the feed lever is in neutral and the clutch is very loose. By your description, either the pin/key Arne describes is gone and you can't tighten the clutch, the star knob is stripped, or the feed gear controlled by the feed lever isn't engaging correctly. Earlier I suggested the gear train as the issue since I thought it would be most likely to be upset removing the apron. Now I would expect the key/pin or star wheel threads. I doubt this issue was caused by taking the apron off- probably broken before. Looking at the zetagraphics parts list, the clutch system on the 9A/10K is very different from the larger machines. I would not assume that a fix for one applies to the other. Bill (24006)
I am also having problems with the clutch on my 9A. Whatever position the handle is in up or down only the longitudinal feed works with the half nuts closed, and the clutch does nothing. I have removed the apron from the lathe, and striped it down so that all that remains is the clutch assembly which I cant work out how to remove. On the front of the assembly there is a slotted screw that holds the star wheel in place. I can only turn this about two turns. I looked at the parts diagram and it looks like this screw, screws into a sleeve, and the center shaft of the clutch screws in the other end. How do I take this assembly apart, and how springy is the little spring spreads the half disks supposed to be ? Nick (24097)
That is a left hand thread screw. (24102)
The screw you are referring to I think is the only left hand thread on the entire lathe. It holds that wheel on a shaft. the end of the shaft has two notches into which the two clutch plates sit in. As for springyness, it is not a coiled spring, but rather a piece of wire that fits around the clutch plates. I know that a new one really helped me. Take a picture of how it fits around the clutch plates, without it it is difficult to visualize how it fits. I got mine from Rose at Partworks. Mark (24104)
Nick, "Whatever position the handle is in up or down only the longitudinal feed works with the half nuts closed, and the clutch does nothing." I am not sure I am reading you right. Are you engaging the half nuts while trying to use the power feeds? You're NEVER supposed to engage the half nuts when using the power longitudinal or cross feeds! There is supposed to be a lock-out between the half nuts lever and the lever that controls longitudinal and cross feed so you can't use both at the same time. It is a pin in the apron casting that floats back and forth between the half nuts lever and the "shifter" (connected to the shift lever above the clutch). There are notches in both of these parts and the pin is just long enough so that when one of the levers is engaged, the pin is pushed into the notch of the other; preventing it from moving (locked out). Webb (24116)
Webb, Unfortunately you are (sort of) reading me right. I never engaged the half nuts while the lathe motor was turning, but engaging the half nuts was the only way to get any of the feeds to work. I have traced the problem to the outside of the half nut cam being damaged (the previous owner must have hit it with a sledge hammer). You can see that here: http:// www.matterpd.com/shop/southbend/apron/ I still am not able to undo the screw on the star handle (30 and 31 in the exploded view at the bottom of of the page), although somehow, and I don't know how I have managed to get something to move so that part of part 19 is now poking out the front of the apron. It looks like part 24 also screws into part 19, but since there is nothing to grab hold of I don't know how I would unscrew that. Any help would be really appreciated here, as the internal spring 20 doesn't appear to be very strong and I guess that might be part of the problem. Nick (24134)
I think that the screw is left hand and the star is a right hand thread. I have a heavy ten clutch in my hand. Tighten the star and loosen the screw. Then loosen the star. (24138)
Nick, From the pictures, it looks to me that someone tried to force the half nuts lever over the lock-out pin (part no: 44 in the drawing). I would check to see it that pin is damaged. That pin should be free to slide back and forth in the hole in the casting. If it is bent and jammed in the hole, it may be blocking the shifter from moving. Does the shifter lever move up and down all the way to its detents? As others have mentioned, the star clutch knob retaining screw (part no: 30) is left hand thread. The clutch knob (part no: 37) is right hand threaded onto the shaft (part no: 24). You may have to reinstall the worm and its lock ring in order to stop the worm gear, clutch and shaft assembly from turning when unscrewing the screw. Also you will have to tighten the star clutch knob too. that should lock the shaft so that you can get the screw out. Webb (24139)
I have a 13inch SB that is having a similar power feed problem. The star wheel will not engage the clutch. The interlock between the half nut lever and the power feed is working but the clutch will only randomly engage. The star wheel turns freely when it does not engage. I see that the 13inch has a different clutch with plates instead of two shoes like the 9inch and 10 inch. Has anyone had a similar problem and found a solution? Chip (24190)
Chip. When I first got my 13" SB the power feed acted very sticky and it would engage then not engage , and sometimes at the worst time it would not disengage it was just cruded up and by draining the oil and flushing it out with Kero a couple times it started working great. Just a thought? Now mine is the lever engage and not the wheel however inside I think they are the same? Dee (24191)
Reversing a lineshaft driven lathe
I was wondering when SB's where driven by lineshafts how did they reverse the feed when they finished a cut? Now we have the drum switches on electric motors but how did they do it pre-electric motors? Did they just slacken the drive belt to stop the drive? Rick (24508)
I remember seeing this, but I don't remember where. There is a main source of power. It drives shafts that run through the shop. The shafts have pulleys with individual belts going to each machine. Now these drive pulleys can be reversed with some sort of a clutch mechanism. I remember seeing something like dogs moved in and out with a wooden "fork" like stick. As I remember you were supposed to relax the belt before doing this. For the life of me I cant remember where I saw this. Jim B.(24524)
The "fork" straddles a sleeve which is rounded on both ends. When the sleeve is pushed one way the rounded end pushes against the fingers of a pair of brake like clutch pads which run inside one of a pair of flat belt pulleys. When pushed the other way it engages the fingers on the pulley on the other side while disengaging the first one. (In other words, the sleeve and fork slides on the shaft between a pair of flat belt pulleys, one on the right and one on the left.) The trick is that one belt is twisted to reverse the direction. Thus by engaging one or the other of the two flat pulleys you can change direction. (24525)
Try the HTRAL. Also if you ever get a chance to go to the Henry Ford Museum/Greenfield Village in Dearborn there are a couple of shops still running lineshafts. The sliding dog engages the pulleys. Reverse is accomplished twisting one of the two belts that drive an intermediate or lay shaft with the cone pulley. The intermediate shaft is on an eccentric mount that relaxes belts for both reversing or changing lathe speed (cone pulley set) (24526)
Given the time it would take to reverse the lathe due to inertia. I would guess you have to develop a "feel" for when to the reverse the lineshaft? Rick (24528)
Ok, another lineshaft question, if a belt off of the mainshaft breaks, do they shut down the whole shop or fix it while in motion? Rick (24530)
Just after Army service in 1959, while looking around for a better job, for a few months I worked in Ewart Chain Belt in Derby, England. They made MASSIVE chain belts, like big bike chains, for use in the mining industry. I worked a six bank horizontal drilling machine, drilling the cotter hole in the link pins. If the lineshaft belt broke, we fixed it without the rest of the line stopping. You just shift it over to the free wheel pulley with the fork and get on with it, no danger. If it flew right off, a maintenance man brought pole with a sort of clevis on the top and a gripper handle at the bottom (bit like a long handled pruner), and flopped it back over. The belts BTW, were thick braided canvas looking stuff, which we dressed twice a day with rosin in a cardboard tube. The tube wore away as the rosin was used up. Len (24531)
Interesting stuff, must have been a racket with all the belts going in a lineshaft shop. Rick (24533)
And the 50 ton presses that cut and joggled the link sides from bar, some as much as 1" thick! The ground shook and before the days of "health and safety" so no ear defenders etc. Len (24550)
 
     
 

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