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That's really smooth.
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How Are You Mounting Your Pm1340gt Lathe?
- Thread starter sanddan
- Start date
I thought I had some on my iPad but I may have saved them to my laptop. If I find one I will post it up. 
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- Jun 12, 2014
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Rio,
I have a BX-24 for the low speed BX-25 for the high speed pulleys, shouldn't make a difference. The run out in the pulleys is minor, the pulleys would have to be significantly off to cause significant vibration. I doubt it is the drive train. I do not have a problem with any of my chucks, so something else is going on here, but this is what I am using:
Bison 7-848-0800 - 8" 4-Jaw Plain Back Combination Chuck (Scroll plus and Independent) Poland, I machined the D1-4 backing plate on the machine to fit this chuck. Probably my favorite chuck, takes no time to 0 the TIR, but if I have a lot of repeat machining I use the PBA. This chuck is considered more of a fringe product, and is costly. I bought it when I did not have a 4J independent, I do a lot of repeat turning on odd size metal.
Pratt Burnerd America 0625300 - 6" 3 Jaw Setrite Chuck (Sroll) UK with a PBA Setrite D1-4 backing plate, really nice chuck, Bill has the 8" and swings his up to the machine max RPM.
Precision Matthews - 8" 4 jaw (independent) Taiwanese D1-4, Really nice clean casting and machining, even has balance weights on the inside of my chuck, it is right up there with the Bison and the PBA in quality.
LatheMaster 5C Collet D1-4 Tru-Setting
The first three chucks, I can recommend, the LatheMaster 5C less so, you can dial in the TIR to near 0, but the chuck body wobbled and I had to turn the body true. My runout at 6" from the chuck with the PBA and Bison is well under 0.001", the LatehMaster is under 0.002" for what it is worth. My experience so far with the Chinese chucks, is that they make good doorstops, that's about it. These days Grizzly is probably the best option for PBA and Bision, QMT also carries Bison. If Grizzly, I purchased my PBA from them using a discount code. The Bison dealer I purchased the Bison combo from is out of business. They have gone up about 20% since I purchased mine.
Nobody has mentioned if the Hz display is staying stable, it should not flicker or change at all with the programming settings I have posted, nor if either Dan or Rio are seeing vibration with just the motor alone spinning. I wanted to rule out that maybe the motor support is not locked down or moving causing the belt to flutter/vibrate. The splash pan is thin steel, it twists up a bit when mounted ( have the same thing on mine), what really counts is where the lathe is bolted too, ant his should be absolutely rigid with no rocking trying to move the machine back and forth. . If you do pull your lathe off the cabinet, you might check if there is any warpage in the cabinet where the lathe mounts, the other consideration is accurate leveling with a precision level. This may just be cabinet flex or the lathe is not sitting level on the cabinets, I have my cabinets tied together at the top and bottom, the chucks set on the lower shelf, metal on the upper. About 200Lbs on the shelves another 100Lb in the cabinets.
Maybe go out buy some sand bags and put them on the bottom of the cabinets and see if that does anything for you. I do not have anything further to suggest beyond what has already been mentioned. I am sorry guys, but I am going to bow out at this point, I am pretty new to this stuff and there are more seasoned machinist that have a lot more experience and can provide better guidance.
Mark
I have a BX-24 for the low speed BX-25 for the high speed pulleys, shouldn't make a difference. The run out in the pulleys is minor, the pulleys would have to be significantly off to cause significant vibration. I doubt it is the drive train. I do not have a problem with any of my chucks, so something else is going on here, but this is what I am using:
Bison 7-848-0800 - 8" 4-Jaw Plain Back Combination Chuck (Scroll plus and Independent) Poland, I machined the D1-4 backing plate on the machine to fit this chuck. Probably my favorite chuck, takes no time to 0 the TIR, but if I have a lot of repeat machining I use the PBA. This chuck is considered more of a fringe product, and is costly. I bought it when I did not have a 4J independent, I do a lot of repeat turning on odd size metal.
Pratt Burnerd America 0625300 - 6" 3 Jaw Setrite Chuck (Sroll) UK with a PBA Setrite D1-4 backing plate, really nice chuck, Bill has the 8" and swings his up to the machine max RPM.
Precision Matthews - 8" 4 jaw (independent) Taiwanese D1-4, Really nice clean casting and machining, even has balance weights on the inside of my chuck, it is right up there with the Bison and the PBA in quality.
LatheMaster 5C Collet D1-4 Tru-Setting
The first three chucks, I can recommend, the LatheMaster 5C less so, you can dial in the TIR to near 0, but the chuck body wobbled and I had to turn the body true. My runout at 6" from the chuck with the PBA and Bison is well under 0.001", the LatehMaster is under 0.002" for what it is worth. My experience so far with the Chinese chucks, is that they make good doorstops, that's about it. These days Grizzly is probably the best option for PBA and Bision, QMT also carries Bison. If Grizzly, I purchased my PBA from them using a discount code. The Bison dealer I purchased the Bison combo from is out of business. They have gone up about 20% since I purchased mine.
Nobody has mentioned if the Hz display is staying stable, it should not flicker or change at all with the programming settings I have posted, nor if either Dan or Rio are seeing vibration with just the motor alone spinning. I wanted to rule out that maybe the motor support is not locked down or moving causing the belt to flutter/vibrate. The splash pan is thin steel, it twists up a bit when mounted ( have the same thing on mine), what really counts is where the lathe is bolted too, ant his should be absolutely rigid with no rocking trying to move the machine back and forth. . If you do pull your lathe off the cabinet, you might check if there is any warpage in the cabinet where the lathe mounts, the other consideration is accurate leveling with a precision level. This may just be cabinet flex or the lathe is not sitting level on the cabinets, I have my cabinets tied together at the top and bottom, the chucks set on the lower shelf, metal on the upper. About 200Lbs on the shelves another 100Lb in the cabinets.
Maybe go out buy some sand bags and put them on the bottom of the cabinets and see if that does anything for you. I do not have anything further to suggest beyond what has already been mentioned. I am sorry guys, but I am going to bow out at this point, I am pretty new to this stuff and there are more seasoned machinist that have a lot more experience and can provide better guidance.
Mark
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- Joined
- Sep 13, 2015
- Messages
- 61
Next test: I just dialed in (with a Mitoyo .0005 indicator) a Krieger 26 inch match barrel blank through the headstock to absolutely running perfectly true in the four jaw and the spider, then ran the machine.
Whatever is out of balance reveals itself most-pronounced in high range and high gear at 40hz. The entire machine is shaking, the work light, the DRO, and literally the whole headstock - SHAKING. Wait until you see the video tomorrow.
Something is just badly out of balance. Yes, if it was bolted to a 3000 lb stand bolted to the center of the Earth, one might not notice the shake, but the ROOT of the problem is something is running badly out of balance. What a disappointment. Wish I would just find out I'm doing something wrong and it's not the PRECISION Matthews lathe I just paid a premium for that's the problem, or this "high precision", Preferred-package 4J chuck that might be the problem. But, I ran the machine with nothing but the dead center in the headstock, and it still shakes. Even with it bolted to the floor.
I hope somehow I did something wrong, and I can find out and fix it. Otherwise, I got a lemon.
Sounds like SANDDAN might be in the same boat.
Too far down the rabbit hole, too many hours, too much money to turn back now....What's next? Matt?
Whatever is out of balance reveals itself most-pronounced in high range and high gear at 40hz. The entire machine is shaking, the work light, the DRO, and literally the whole headstock - SHAKING. Wait until you see the video tomorrow.
Something is just badly out of balance. Yes, if it was bolted to a 3000 lb stand bolted to the center of the Earth, one might not notice the shake, but the ROOT of the problem is something is running badly out of balance. What a disappointment. Wish I would just find out I'm doing something wrong and it's not the PRECISION Matthews lathe I just paid a premium for that's the problem, or this "high precision", Preferred-package 4J chuck that might be the problem. But, I ran the machine with nothing but the dead center in the headstock, and it still shakes. Even with it bolted to the floor.
I hope somehow I did something wrong, and I can find out and fix it. Otherwise, I got a lemon.
Sounds like SANDDAN might be in the same boat.
Too far down the rabbit hole, too many hours, too much money to turn back now....What's next? Matt?
- Joined
- Dec 26, 2015
- Messages
- 2,079
I'd love to see the pulley & belt side of the machine in a second video running through the same tests. What I'd like to see is how the belt is tracking and flapping. Any chance you'd do another one? (he asks with hands over ears). Also, what happens if you take it out of gear (between gear positions) such that the drive shaft is turning, but the headstock is not?
David
David
- Joined
- Nov 11, 2014
- Messages
- 111
The fact that it kept shaking after you stopped the spindle leads me to believe the lathe is not well anchored to the chip pan/cabinets. If you give the head stock a hard push does the lathe continue to vibrate? If so then hunt down where it's flexing and see if you can tighten or shim it to give a tight setup.
- Joined
- Sep 13, 2015
- Messages
- 61
Rich,
Good insight. All it takes is a really light bump with the palm of the hand to the headstock, and it visibly shakes for about 15-20 seconds.
See my post earlier with a picture with yellow writings and arrows. I'm thinking of putting a solid 1/2 inch metal plate under the chip pan, the entire size of the chip pan itself.
Still something is out of balance in the gearhead of the machine, which is the root problem.
Good insight. All it takes is a really light bump with the palm of the hand to the headstock, and it visibly shakes for about 15-20 seconds.
See my post earlier with a picture with yellow writings and arrows. I'm thinking of putting a solid 1/2 inch metal plate under the chip pan, the entire size of the chip pan itself.
Still something is out of balance in the gearhead of the machine, which is the root problem.
- Joined
- Mar 22, 2013
- Messages
- 497
I second Davids suggestion. Also, post a video without the chuck on. Or with it just in between gears so the chuck is not turning.
I am betting that it is either the top/larger pulley, as it is is cast iron, or settings with the VFD, or a combination. Just had a conversation with someone at the factory, and they say to replace that top cast pulley with a fully machined pulley since you put the VFD on. They also said be sure not to go above 60HZ on the motor settings, because the stock setup and motor only go that fast.
I don't have a problem with a little faster than that, but that is up to you guys. Just don't run it at 400HZ and tell me the headstock is getting hot and the 4 jaw chuck flew apart.
And good point Rich, but Rio that drawing you made about the fulcrum is outside of where the lathe bolts down though. Maybe get someone to push on it and look at the machine. See where its moving.
If there is a problem with the machine, it WILL be taken care of. But just remember, I don't build them, I am not a magician or a mind reader that can tell you in an email what it is.
But whatever the problem is, I am here to help figure it out and get it taken care of. The hardest part is that these both have VFD's on them, so that part of it changed from the factory, so there are just a few extra variables in it. But if it ends up being a VFD related issue, I am billing everyone for the time I am spending trying to figure this out (Kidding, it will be good knowledge for future customers)
- This is sort of how I can not for the life of me figure out how when I plug my phone in to charge in my truck, the radio goes to static, but only when I am not moving. When I am driving, it is OK. But when stopped, static. Unplug the phone, and it goes away.
I do wish that I could see it in person to get an idea of the shake though. Because from me looking at it in the videos, it is about 1/10th of what I was first thinking we are chasing down. But it is so hard to tell in a video if its a lot worse than I am thinking, or if its a lot less than is being described, compared with what is in my head. I remember back when I was 18 years old, guys at work running the Warner Swasey Lathes and having their Coffee sitting on the headstock. I never thought to look in the cup to see if there were ripples, but I do remember that they wanted to run jobs on the newer square headstock machine so the coffee cup didn't fall off. And they were all stained had a permanent coffee/cigarette smell baked in to them.
I do feel like that if I was there in person, I could almost look at it and tell if its the pulley or not though. But it sure sounds like it is to me.
But I agree with the factories suggestion, to use a completely different pulley. They do use a different pulley (Fully Machined) with our larger models that come with a factory VFD. (See picture included)
I asked Dan about it and he said it is as cast inside, and told him feel free to true it up on his other lathe if he wanted to try that, I have another one coming to him anyway. I am not sure if that was done though.
But as the factory suggested, use a different pulley, not the factory pulley for a setup that has been changed to a VFD controlled machine.
And Lafe, you did not waste time bolting that machine to the floor, like you said it is a lot easier to level, but it does make a difference. But you have not cut with your machine yet, so you may not notice as much. You can mess around with that later on to appreciate it more
.
I am betting that it is either the top/larger pulley, as it is is cast iron, or settings with the VFD, or a combination. Just had a conversation with someone at the factory, and they say to replace that top cast pulley with a fully machined pulley since you put the VFD on. They also said be sure not to go above 60HZ on the motor settings, because the stock setup and motor only go that fast.
I don't have a problem with a little faster than that, but that is up to you guys. Just don't run it at 400HZ and tell me the headstock is getting hot and the 4 jaw chuck flew apart.
And good point Rich, but Rio that drawing you made about the fulcrum is outside of where the lathe bolts down though. Maybe get someone to push on it and look at the machine. See where its moving.
If there is a problem with the machine, it WILL be taken care of. But just remember, I don't build them, I am not a magician or a mind reader that can tell you in an email what it is.
But whatever the problem is, I am here to help figure it out and get it taken care of. The hardest part is that these both have VFD's on them, so that part of it changed from the factory, so there are just a few extra variables in it. But if it ends up being a VFD related issue, I am billing everyone for the time I am spending trying to figure this out (Kidding, it will be good knowledge for future customers)
- This is sort of how I can not for the life of me figure out how when I plug my phone in to charge in my truck, the radio goes to static, but only when I am not moving. When I am driving, it is OK. But when stopped, static. Unplug the phone, and it goes away.
I do wish that I could see it in person to get an idea of the shake though. Because from me looking at it in the videos, it is about 1/10th of what I was first thinking we are chasing down. But it is so hard to tell in a video if its a lot worse than I am thinking, or if its a lot less than is being described, compared with what is in my head. I remember back when I was 18 years old, guys at work running the Warner Swasey Lathes and having their Coffee sitting on the headstock. I never thought to look in the cup to see if there were ripples, but I do remember that they wanted to run jobs on the newer square headstock machine so the coffee cup didn't fall off. And they were all stained had a permanent coffee/cigarette smell baked in to them.
I do feel like that if I was there in person, I could almost look at it and tell if its the pulley or not though. But it sure sounds like it is to me.
But I agree with the factories suggestion, to use a completely different pulley. They do use a different pulley (Fully Machined) with our larger models that come with a factory VFD. (See picture included)
I asked Dan about it and he said it is as cast inside, and told him feel free to true it up on his other lathe if he wanted to try that, I have another one coming to him anyway. I am not sure if that was done though.
But as the factory suggested, use a different pulley, not the factory pulley for a setup that has been changed to a VFD controlled machine.
And Lafe, you did not waste time bolting that machine to the floor, like you said it is a lot easier to level, but it does make a difference. But you have not cut with your machine yet, so you may not notice as much. You can mess around with that later on to appreciate it more
.
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- Jun 12, 2014
- Messages
- 4,810
I was going to bow out of this, but there is one major factor that is being missed in all this. Rio run the video with the gear train disengaged. This is the feed direction knob on the gearhead must be in the center position. You have your machine with the gear train engaged which significantly increase the rotating mass and components in the drive system and vibration nodes. So the whole drive train is turning even though your gearbox feed selector is not engaged. If I run my machine as you have your setup, it is guaranteed to have vibration nodes at specific speeds and it gets noisy with speed, as this is an open gearbox. You can also hear the open gearbox drive gears ringing. My machine will run exactly like your machine and shake at specific speeds, there are just too many gears with different masses going in different directions. I just avoid the nodes, or switch gears and adjust the VFD speed. It has never been an issue with getting a clean cutting finish. You would need every gear and component in the gearbox machined to high tolerance and in perfect balanced and a much heavier lathe to dampen some of the vibration. Even then, all machines have vibration nodes at certain frequencies, this is specifically why VFDs are setup with skip frequencies. Every rotating system will have nodes, when running a VFD, you can always find a speed that will excite a vibration node for that system.
My machine will have similar vibration nodes just like yours if run with the feed direction engaged, but if you disengage the gear direction train feed, that will tell you if the drive and spindle system are running true. Looking at the light shake is not relevant, it is bolted to thin sheet metal on the back and it has it's own resonant frequency, I beefed up my mounting so it wouldn't shake so much. With the feed drive and gearbox spinning, you just will get vibration nodes, this also explains the change one would see with the different pulley ratios. Different masses in the system will affect those nodes, my 60Lb chuck has more mass that decreases some of the vibration through gyroscopic affect. Also placing a water cup on top of the head, is where the vibration would be the worse, if you put it on the carriage, where your cutter is, I doubt it will barely move if at all.
Getting the correct belt tension is often critical, if the belt is too tight it will vibrate, especially if you are using the full weight of the motor to tension the belt. Run it slightly loose, but so the belt dose not flop or vibrate with speed. With the gear feed direction engaged, getting the right spacing between the large and small drive gear is also critical. If I recall it is suppose to be about 0.004" or the thickness of a piece of paper. Without the belt cover on, it makes a big racket.
Please rerun your video with your directional gear feed not engaged. Just the spindle turning, not the gear train drive. Make sure you are running sensorless vector and you autotune your motor (especially Rio, because your motor properties are different). If you want me to walk through any of the VFD setting, give me a call.
Rio, you did a real nice job on your VFD install, looks really good.
Mark
My machine will have similar vibration nodes just like yours if run with the feed direction engaged, but if you disengage the gear direction train feed, that will tell you if the drive and spindle system are running true. Looking at the light shake is not relevant, it is bolted to thin sheet metal on the back and it has it's own resonant frequency, I beefed up my mounting so it wouldn't shake so much. With the feed drive and gearbox spinning, you just will get vibration nodes, this also explains the change one would see with the different pulley ratios. Different masses in the system will affect those nodes, my 60Lb chuck has more mass that decreases some of the vibration through gyroscopic affect. Also placing a water cup on top of the head, is where the vibration would be the worse, if you put it on the carriage, where your cutter is, I doubt it will barely move if at all.
Getting the correct belt tension is often critical, if the belt is too tight it will vibrate, especially if you are using the full weight of the motor to tension the belt. Run it slightly loose, but so the belt dose not flop or vibrate with speed. With the gear feed direction engaged, getting the right spacing between the large and small drive gear is also critical. If I recall it is suppose to be about 0.004" or the thickness of a piece of paper. Without the belt cover on, it makes a big racket.
Please rerun your video with your directional gear feed not engaged. Just the spindle turning, not the gear train drive. Make sure you are running sensorless vector and you autotune your motor (especially Rio, because your motor properties are different). If you want me to walk through any of the VFD setting, give me a call.
Rio, you did a real nice job on your VFD install, looks really good.
Mark
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