# 1340gt surface finish problem



## rherrell (Feb 3, 2017)

O.K. guys, and gals, I've tried every speed/feed combo, every carbide insert I have, every HSS tool I have, I've even put  vibration isolation pads between the stand and the floor...nothing seems to work.

Here's what I get...
	

		
			
		

		
	










Please excuse my photography skills.

You can not only SEE the ripples, you can FEEL them.

I 've also tried changing the motor drive belt, I have a link belt on there now. The link belt helped a little(very little)

There doesn't seem to be any unusual vibration problem, a glass of water shows nothing.

Please don't tell me I need a VFD, a lathe of this caliber should not be doing this. However, if a VFD is the only cure then I guess I'll have to install one because I can't be sanding and polishing every part that comes off the lathe.


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## Dan_S (Feb 3, 2017)

Can you show a close up shot? 

That looks like your tool height is to high, or you had to much sickout, or maybe a little of both.


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## rherrell (Feb 3, 2017)

Dan_S said:


> Can you show a close up shot?
> 
> That looks like your tool height is to high, or you had to much sickout, or maybe a little of both.


Tool height is exactly right and the amount of stick out doesn't do anything. The photo is 5/8" round stock with 1.5" stick out, does the same thing with .5" stick out.

That shot is as close as I could get and still be in focus. I'll try and get a better photo if I can.


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## jbolt (Feb 3, 2017)

Just a though, but the pattern suggests to me it is mechanical. I would try mounting a TDI on the carriage, put the tip on the ways (top & side) and run the carriage under power to see if you are getting any oscillation. If that is dead smooth I would then start looking at the spindle.


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## JimDawson (Feb 3, 2017)

I has a similar problem with my lathe, snugged up the spindle bearings a bit and that fixed it.  Your mileage may vary.


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## firbikrhd1 (Feb 3, 2017)

What is your feed rate? That almost looks like threads. If the radius of your tool is small and your rate of feed large you get a pattern like threads which is what that looks like in the picture.

How much is your work extended out of the chuck? Unsupported thin work can result in patterns like that.

Check gibs for proper adjustment, lead screw feed shaft possibly bent.

Tool on center without enough clearance.


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## DrAsus (Feb 3, 2017)

Tagged for interest.

DrAsus

Sent from my XT1575 using Tapatalk


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## mikey (Feb 3, 2017)

That looks like chatter to me. I would suggest reducing your tool lead angle first and see if that helps. If not, try reducing your cutting speed and increasing feed. Chatter is a resonance issue but that assumes everything is tight - gibs, tool holder, etc so check that everything is solid.


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## JBowlin (Feb 3, 2017)

Looks like threads/chatter... stupid question but I have to ask, are you using half nuts for auto feed instead of power bar?


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## rherrell (Feb 4, 2017)

I put a half thou DTI on the carriage and on the ways, it vibrates between two lines which means a little less than half a thou. When I do it by hand it's dead flat smooth.

The photos above are 770rpm and a .005" feed rate, I've tried them all and nothing helps.

These next photos are the same piece of aluminum with half of it turned at 475rpm with the slowest feed rate of .0027"

I'm not a camera guy so this is about as good as it's gonna get!




















You can't really see it but the lines are still there but closer together due to the slower feed rate.


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## rherrell (Feb 4, 2017)

I figured out how to get into Super Macro mode, these aren't very good but they're closer


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## davidpbest (Feb 4, 2017)

Looks to me like the material is being forced off CL as it's being cut - like the tool is deflecting the stock as it rotates.   That could mean bad or loose spindle bearings.   Try putting a DTI against stock in the chuck and pushing on the chuck  horizontally with the weight of your body to see if you get deflection on the DTI.


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## qualitymachinetools (Feb 4, 2017)

Any way you can post a video of the cut? Or of the settings?  Does it do it on the cross feed too? Im running alum. in a 1340GT this morning, single phase machine. Its not the single phase doing that much.         Those feed rates do look like what jbowlin said, that looks like a much more coarse feed than .002 or .005  Double check the settings here:    http://www.machinetoolonline.com/files/PM-1340GT_v1_6-2016_indd.pdf

 The patterns also look to be going the opposite way of each other, were they cut in different directions?  

I get this question about 10 times a week, normally its a setting, tool, feed or speed, etc.


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## rherrell (Feb 4, 2017)

I put a piece of 1" stock in the chuck and put the DTI 1" from the jaws. When I push on the chuck with my hand it moves .0005" with just moderate pressure. When I push as hard as I can it moves .0015".


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## qualitymachinetools (Feb 4, 2017)

You mean .0005 right?   Thats normal. Its going to move a little.  Please try to post that video, and even a picture of the settings. Dont even look at the bearings until you check that all out.  Im not saying that they might not need adjusted after some time, they are tapered rollers.    But what I am seeing there is not anything to do with bearings.         Please post that video if you can of it taking a cut, from as far back as you can so I can see the whole carriage and cutting tool.


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## rherrell (Feb 4, 2017)

Matt, can I post videos here or do you want me to put it on You Tube?


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## qualitymachinetools (Feb 4, 2017)

I think if you put it on youtube and then post the link here is the easiest.


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## rherrell (Feb 4, 2017)

Here's a photo of the piece that's in the video...






It's got the same pattern to it. Here's a link to the video...  




WARNING!..I'm not any good at videos so don't laugh too hard. I hand held the camera, I can use a tripod if you want a steadier shot.


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## qualitymachinetools (Feb 4, 2017)

In that picture above, it just looks like a machined finish with a sharp tool to me.        Try the setting on E and 8, also whats the radius on the insert?   The tool also looks high to me, but that might just be the camera angle.


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## rherrell (Feb 4, 2017)

The insert is a CCGT 32.51 but I have the same problem when I use a HSS tool with a large radius. The HSS tool I use for brass has about a 3/16" radius and it does the same thing.

My carbide inserts are all either 32.51 or 32.52 and they do the same thing.

I forgot to mention that I have the same problem with hand feeding as I do with power feeding so I doubt if the problem is with the power feed.

The power feed for facing gives a better finish but it's still has some fine ridges in it.

I have to leave now but I'll be back tomorrow to check on the thread.

THANKS for all the input, keep it coming if you have any ideas.


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## Bob Korves (Feb 4, 2017)

qualitymachinetools said:


> In that picture above, it just looks like a machined finish with a sharp tool to me.        Try the setting on E and 8, also whats the radius on the insert?   The tool also looks high to me, but that might just be the camera angle.


In both the coarse and fine "threads", the lead looks like it is many times larger than the feed, like multi start threads.  It is interesting that it is not parallel to the feed, but does change lead angle with the feed.


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## Doubleeboy (Feb 4, 2017)

I have seen this problem a couple times on otherwise good working machines, both times it was a chip under toolpost or toolpost (nut) block sitting a thou proud in the slot.   Pretty easy to check and rule out.


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## mksj (Feb 4, 2017)

Your feed rate is very high, in the video the gear selection suggests 0.006 IPR where you should be around 0.002.  The usual feed rate is 0.001-0.003 IPR. Try slowing down the feed, like E-7, move the left gear lever to the next position "E". Most of the time I use E-8 and E-7 for a better finish, E-6 or E-5 to remove more material. This equates to around  0.002-0.0035 IPR.


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## HBilly1022 (Feb 4, 2017)

Don't know if this would have any effect on it but shouldn't the turning speed be way higher, like 3000 rpm since he is turning aluminum?


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## pstemari (Feb 4, 2017)

Yes, that looks to be about 1" diameter aluminum, so 2,400 rpm would be reasonable. Figure on 600-1,200 sfpm for aluminum and carbide.

A traveling rest might help, too. IIRC once you get over 8:1 length/dia, you start getting a surprising amount of deflection from the work bending.

Sent from my Nexus 6 using Tapatalk


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## mksj (Feb 4, 2017)

rherrell said:


> I forgot to mention that I have the same problem with hand feeding as I do with power feeding so I doubt if the problem is with the power feed


Missed this comment, I still would slow down the feed rate as noted by Matt. I routinely turn aluminum 1"  stock at 700-900 RPM with carbide inserts and can easily shave a few thousandth off at a couple of inches out. I normally run about 1/2 the published SFM, as this is often based on industrial machines with more rigidity. A 1" D at 1000 RPM is ~260 SFM.


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## HBilly1022 (Feb 4, 2017)

Post #3 notes that he is turning 5/8" rod, so even at 1/2 published speed it would be 1500 rpm for HSS. He is running at 475 and 770. Maybe a higher rpm combined with a slower feed would help but I'm no expert. I only started turning a year ago and only do it for a hobby. I have a lot to learn. So I am just throwing this out to see if it makes sense. I'm sure one of the more experienced members will know.


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## rherrell (Feb 5, 2017)

mksj said:


> Missed this comment, I still would slow down the feed rate as noted by Matt. I routinely turn aluminum 1"  stock at 700-900 RPM with carbide inserts and can easily shave a few thousandth off at a couple of inches out. I normally run about 1/2 the published SFM, as this is often based on industrial machines with more rigidity. A 1" D at 1000 RPM is ~260 SFM.


Several of the previous photos show two speeds side by side, .0055" and .0027", the .0027" is the slowest feed this machine has. All it does is make the ridges closer together and it also seems to change the angle of them as well. That seems odd to me,* why would the angle of the ridges change direction when you change the feed rate???*

I just tried the slowest feed with the highest rpm(1800)and there is no improvement.

I also tried lowering the tool bit and it didn't help.


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## dieselshadow (Feb 5, 2017)

I believe you're dealing with something loose. Machines all have inherent resonant frequencies at which they vibrate. If you change the speed or mass, the frequency changes. I think the change your seeing is because you're changing speed of the feed. Finding what's loose should cure this issue.


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## rherrell (Feb 5, 2017)

That makes perfect sense, the problem is WHAT is loose! I've checked the motor and the external gears, the only thing left is to tear it apart. I shouldn't have to do that on a machine that's only 3 months old!


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## dieselshadow (Feb 5, 2017)

Have you tried different materials? How about a different diameter? 

Is your tool post tight to the compound? Your toolholder tight? what about tightening the lock on the compound. That should be snug anytime you don't use the compound.


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## Rich V (Feb 5, 2017)

The spirals on your stock are classic resonance marks. The stock is vibrating at a set frequency and the tool is alternatively cutting deeper then shallower as the cutting tool moves down the stock.

Try a larger diameter piece of stock, say 1.5''OD bar, and start turning no more than 3 diameters from the chuck. If it gives a smooth cut surface then the lathe is probably fine just too much overhang for the stock diameter. If the cut is still rough then you have a lose tool/tool holder or something is out on the lathe.

Is this a new problem or did it just start?


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## HBilly1022 (Feb 5, 2017)

A good place to start is holding the compound and trying to twist it from side to side, back and forth and try rocking it. You might find a loose gib this way. It could be on the compound, the cross slide or the saddle. If you feel or hear any clicking you have likely found the culprit.


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## Badspellar (Feb 5, 2017)

I had the same problem with my PM1440E-LB.  I tried every combination of material, tools, speeds and feeds and nothing helped.  I did some searching and found the following post by Forrest Addy.

http://www.practicalmachinist.com/v...ase-motors-their-effect-lathe-finishes-73684/

To try to prove the single phase motor was my problem I did the following 2 experiments
1. I cut a short distance to establish the pattern and turned off the motor leaving the feed engaged.  I then hand turned the chuck  and I got a good finish with no pattern.
2. I made an adapter that fit inside the motor pulley that I could chuck up in my 1/2 inch drill. (My pulley extended about a half inch beyond the motor shaft.)  I again ran the lathe to get a pattern and turned off the motor and spun the lathe with my drill.  Again a good finish with no pattern at all.

I bought a new Baldor single phase motor and installed it with rubber vibration mounts and have had no problems since.

This was the finish I was getting before the motor swap


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## Bob Korves (Feb 5, 2017)

rherrell said:


> That makes perfect sense, the problem is WHAT is loose! I've checked the motor and the external gears, the only thing left is to tear it apart. I shouldn't have to do that on a machine that's only 3 months old!


The lathe should still be under warranty if it is only 3 months old.  Matt, the owner of Quality Machine Tools, is posting in this thread.  Contact Matt off group and get some help from the source until the lathe works to your satisfaction.  From the posts I see here on H-M, Matt appears to be a good seller who helps his customers after the sale.  We here on H-M are of course willing to help you as well.

Try looking at the drive and driven pulleys and the belt(s) while the machine is running, and while the machine is feeding and look for runout or other issues in the pulleys and for other than smooth running of the belt(s).  A pulley may also be loose on it's shaft.  Something loose between bed and tool could also be the problem, as posted multiple times already to this thread.

You did not state if your issue has been happening since new, or if it has started after you used the lathe for a while.  If it is something new, think about anything you had changed around the time it started happening.


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## rherrell (Feb 5, 2017)

WOO HOO!!!!  THANK YOU BADSPELLAR!!  I did as you suggested, turned a little with the power feed and then shut it off and continued by spinning the pulley with a drill motor, here's the result...






On the left is with the motor engaged and on the right is the lathe being turned with a drill motor.

Man, what a load off, I know I just created another EXPENSIVE problem but at least I know WHAT the problem is.

I guess the next step is another single phase motor, if that doesn't work then maybe a 3 phase motor and a VFD, if anyone has a cheaper option I'm all ears!


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## dieselshadow (Feb 5, 2017)

If you read the attached link he included, there are alternatives to replacing the motor. I would inspect the current motor, mount, pulleys, and belt for tightness, condition, alignment and adjustment. A new link belt may solve your issue.


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## mksj (Feb 5, 2017)

A bit surprising, although I have seen a number of posts with a similar finish issue with the single phase G4003G, just haven't heard of it with the 1340GT.  In addition to belt/pulley issues, I am wondering if there is a problem with the motor run capacitor if this would cause a problem?  You could do a 3 phase motor with an RPC, cost wise it would be similar to a VFD with a single relay setup. The latter requires rewiring the control system. There are a number of different options.

If going to a 3 phase motor, there are a very limited number of 2Hp 3 phase motors that will fit, and they all require some redrilling of the mounting holes motor/mount to fit and a different pulley (or bore the stock one to 7/8"). These motors are all TENV, these are ones that others have used Marathon E467, Y551, Y526. The Y551 and Y526 have a small encoder shaft on the back of the motor that needs to be cut off. The motors come up on eBay occasionally, and I have seen the Y551 (145THTN6046) new, go for as little as $100 plus shipping,
https://www.mrosupply.com/ac-motors/severe-duty-motors/2270020_e467_marathon-electric/
https://www.mrosupply.com/ac-motors/inverter-vector-motors/2270267_y551_marathon-electric/


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## rherrell (Feb 5, 2017)

I have a link belt installed right now, I bought several different kinds of belts while trying to fix the problem. All the motor mounts are tight and lined up correctly, the motor sounds and looks fine while running without a belt. Even with the belts on it all sounds and looks fine, no excessive vibration or anything that looks out of place.
 If I can find some rubber washers I might try that but it's still under warranty so I think I'll ask Matt what he wants to do.


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## rherrell (Feb 5, 2017)

mksj said:


> A bit surprising, although I have seen a number of posts with a similar finish issue with the single phase G4003G, just haven't heard of it with the 1340GT.  In addition to belt/pulley issues, I am wondering if there is a problem with the motor run capacitor if this would cause a problem?  You could do a 3 phase motor with an RPC, cost wise it would be similar to a VFD with a single relay setup. The latter requires rewiring the control system. There are a number of different options.
> 
> If going to a 3 phase motor, there are a very limited number of 2Hp 3 phase motors that will fit, and they all require some redrilling of the mounting holes motor/mount to fit and a different pulley (or bore the stock one to 7/8"). These motors are all TENV, these are ones that others have used Marathon E467, Y551, Y526. The Y551 and Y526 have a small encoder shaft on the back of the motor that needs to be cut off. The motors come up on eBay occasionally, and I have seen the Y551 (145THTN6046) new, go for as little as $100 plus shipping,
> https://www.mrosupply.com/ac-motors/severe-duty-motors/2270020_e467_marathon-electric/
> https://www.mrosupply.com/ac-motors/inverter-vector-motors/2270267_y551_marathon-electric/


Do you think I ought to try another single phase motor first? It's still under warranty so Matt would probably send me one.


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## pstemari (Feb 5, 2017)

I'd go through the motor mount and stand first to see if something is loose. 

Capacitor is unlikely an issue—this should have a start capacitor, not a run capacitor, and it should drop out of the circuit after the motor comes up to speed.

Sent from my Nexus 6 using Tapatalk


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## T Bredehoft (Feb 5, 2017)

rherrell said:


> why would the angle of the ridges change direction when you change the feed rate???



You're dealing with a harmonic, not a physical effect. the vibration causes the progression (or regression) of the "groves", which are really tiny chatters.

Is the drive belt tight? if not it may be flopping around.

A lot transpired between the time I wrote this and the time it got posted, Probably my fault for not checking for recent posts.


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## qualitymachinetools (Feb 5, 2017)

The thing that I have always noticed, on the machines where the single phase motor is causing that problem, you get a definite audible hum. And you are saying that it sounds quiet.        I run one of these all the time, in single phase, and its not a problem just being single phase.    On a Chinese motor, yes possibly, but not on this one, well never yet anyway.     Not saying that there couldnt be a bad one, but it will be a first on one of these.   Can you post a video of the just the motor running? 

 And yes of course its under warranty, (Thats not loose bolts though), but if there is something wrong with that motor, yes, absolutely no question about that. There is nothing you have to tear apart.

But if you can answer these:

1. Is it a new problem, or has always happened?
2. Are you sure the motor sounds fine? Maybe send me or post a video of just that? Any time I have seen a machine with that classic single phase hum, you can hear or feel it. Maybe not anything extreme, but if its going in to the work piece, any time I have ever had it, you could hear it right away. Possibly without anything to compare with though, maybe its hard to tell.  Maybe a video of the motor itself, and then one of the whole machine running from pretty far back.     

 I can check that motor out / swap motors that is no problem at all, but just want to get a little more info before.  If it didnt do it when new but started later and no change to the sound, or if its been doing it since new, (Not sure when you started using it)    Turning with the drill motor can be a good indication, but its also turning at a completely different speed, so there could just be more to it than that.  Let me know the answer to these if you can, and we will get it taken care of tomorrow.


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## qualitymachinetools (Feb 5, 2017)

Actually as I listen to that video again, whats that high pitched noise?  Or is that just something in the video that is not really there? (That happens to me all the time when I make videos)


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## qualitymachinetools (Feb 5, 2017)

Here are a few videos, first of just the motor running, and then of it cutting on about the same diameter alum.  This is my 1340GT, Single Phase. Just a quick cut, going away from the chuck so I didnt crash it as I was taking the video ha ha.


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## qualitymachinetools (Feb 5, 2017)

First picture shows the finish with about the same feeds and speeds you were at, pretty good on that one.





The one below was with a much faster feed rate, what I thought the others looked like at first, but thats been ruled out long ago.


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## qualitymachinetools (Feb 5, 2017)

A few more things I thought of to check:

1. Check the bar that tensions the belt (Holds the motor up)  Make sure its not loose, if it is add a washer to tighten it up.
2. Make sure the headstock bolts are tight to the bed. (Not sure if you aligned it yet or not)
3. Just a general overall check of the headstock area bolts to make sure its all tight. 
4. Also the answer above about if it just started, or it always did it.

 My idea is since I have a known good running machine here, we can swap parts back and forth until we get it.    Like if you send me your tool and work and I turn it on this one, or we swap motors, or whatever.  We will get it, don't worry about that.


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## rherrell (Feb 5, 2017)

It's been this way from the start, the reason it's taken so long to mention it is I've been trying to troubleshoot it myself. I'm kinda stubborn and I wanted to try everything I could think of before I asked for help.

When I did the test I ran it with my *corded* 1/2" drill motor which has a top speed of 800 rpm, I ran the lathe at 770 rpm under power  so the two speeds are almost the same.

I'll get a video of just the motor and post it here in the morning


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## rherrell (Feb 6, 2017)

Here are the videos you wanted Matt.  I checked all the bolts on the motor mount and everything is tight, including the adjusting bar.


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## sanddan (Feb 6, 2017)

Have you checked the gear lash on the banjo gears? I'll have to go check mine but I don't remember hearing that much gear "whine". My shop's never that quiet so I could have missed it but it seems louder in the video.


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## rherrell (Feb 6, 2017)

You too?  Yeah, that was the first thing I did after I made the video. I'm guilty of playing my tunes WAY too loud so I didn't notice it, especially with the cover on. I tightened it up with a piece of printer paper for a shim, all better now!


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## rherrell (Feb 6, 2017)

I thought I'd better make another video with the gears adjusted, just in case Matt couldn't hear what he needed to hear.


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## Bob Korves (Feb 6, 2017)

The motor definitely has a hum to it, but I don't know if that noise is what Matt was talking about.  All motors seem to hum some.  The brush and plate for the centrifugal start switch is sure making a lot of noise.  On my Kent 13x40 I took the motor apart, polished the contact brush and where it rubs on the contact plate, and it was gloriously quiet -- for about five hours of run time.  Now the noise is back, but not as bad.  It was never as noisy as yours is, unless it is just the video making it seem louder and scratchier...


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## mksj (Feb 6, 2017)

You can see your belt resonating back and forth, I would try to tension the belt a bit more.  You also may consider a notched belt such as the Gates Tri-Power, you would need both a BX24 and BX25 belt. I would also be curious if you see the same cutting issue on the low speed belt setting.


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## jbolt (Feb 6, 2017)

The motor squeal when the power is turned off doesn't sound right. The 2hp single phase motor that was on my PM-1440gt was a lot quieter all around and did not squeal.


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## rherrell (Feb 6, 2017)

mksj said:


> You can see your belt resonating back and forth, I would try to tension the belt a bit more.  You also may consider a notched belt such as the Gates Tri-Power, you would need both a BX24 and BX25 belt. I would also be curious if you see the same cutting issue on the low speed belt setting.
> View attachment 225675


I've tried every belt except the notched one like in your photo. I have 5/8" and 1/2" V-belts and 5/8" and 1/2" link belts, no difference in any of them.
 I have it tensioned exactly how it's recommended, this is copy and pasted from the manual...

Raise the motor


to de-tension, reposition the Vee belt, then lower the motor

to re-tension — not fully weight bearing, just enough

to drive reliably without slipping.



I've tried even less tension than that and as much tension as I could get, no difference.

It does the same thing on both HIGH and LOW pulleys.


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## qualitymachinetools (Feb 6, 2017)

Yes I agree with Jay, that squeal COULD be something with that motor. Ive also seen motors with just a very very slight rub on the motor shaft, but that one does sound like something.      Will get the motor on the way, see if that fixes it.  If not, (Or now) also check the spindle bearings, also as Jay  said earlier. Ive just never had that cause anything, but hey there is always a first for everything. (Like if its the 1340GT Mot0r, never once had that)


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## rherrell (Feb 6, 2017)

Thanks Matt, I'll let you know when it arrives.


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## woodchucker (Feb 6, 2017)

Have you tried locking or tightening both cross slide and compound to eliminate that


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## qualitymachinetools (Feb 6, 2017)

Yes another good idea, and also I think it was already mentioned, make sure the tool post is pulling down tight. Just saw a machine this morning that has an Aloris on it, the T Nut was a little too thick, so it was tightening down on the T Nut, but not actually sitting tight on the top of the compound, so you could tap it back and forth.     Similar problem, fixed that immediately.


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## tmarks11 (Feb 6, 2017)

rherrell said:


> The photos above are 770rpm and a .005" feed rate, I've tried them all and nothing helps.
> 
> These next photos are the same piece of aluminum with half of it turned at 475rpm with the slowest feed rate of .0027".



WAY WAY too slow on the spindle speed. Aluminum likes speed.

RPM = 4*sfm/D = 4*500/ (5/8") = 3200 rpm!
sfm for Aluminum with carbide 500-1000 (1/4 that for HSS)

If you don't like doing math, then get HSMAdvisor or G-Wizard.

The above is really for using with coolant, but I would be cutting that 5/8" aluminum rod at a minimum of 2000 rpm.  Aluminum likes high speed, and it doesn't like low speed.

What about DOC?  Start with at least a 0.030" DOC, and you will get a mirror finish... except when you run the carriage back to the right, you will get a spiral on it.  Then take a spring pass.

Try a feed of 0.004ipr (too small a feed rate can be just as bad as too high a feed rate.... you end up rubbing instead of cutting, and that destroys your surface finish).


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## rherrell (Feb 8, 2017)

qualitymachinetools said:


> Yes another good idea, and also I think it was already mentioned, make sure the tool post is pulling down tight. Just saw a machine this morning that has an Aloris on it, the T Nut was a little too thick, so it was tightening down on the T Nut, but not actually sitting tight on the top of the compound, so you could tap it back and forth.     Similar problem, fixed that immediately.





tmarks11 said:


> WAY WAY too slow on the spindle speed. Aluminum likes speed.
> 
> RPM = 4*sfm/D = 4*500/ (5/8") = 3200 rpm!
> sfm for Aluminum with carbide 500-1000 (1/4 that for HSS)
> ...


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## rherrell (Feb 8, 2017)

I locked everything down, no difference.  The toolpost is down all the way and tight.


This lathe has a top speed of 1800 rpm, I've tried that speed at .010", .020", .030", .040", .050"and .060" doc, no difference.


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## Bray D (Feb 8, 2017)

I'm having the same issues with my South Bend 9c, but it appears to only happen with I feed with my compound. I haven't messed with it to see what's going on. The lathe is well used (early '35-'47 model I believe), and it's done it for as long as I've had it (not quite 1 year yet). 

No suggestions for you, but I'm following along to see what you find.


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## qualitymachinetools (Feb 11, 2017)

I believe he fixed it if anyone is wondering, said he put some washers on the motor mounting plate. New motor was sent and changed out, a motor that was tested good here, didnt change anything so that was not it, he can comment more on the details, but since people keep emailing me about this, wanted to put an update on here.


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## DrAsus (Feb 11, 2017)

Thanks for the update.

DrAsus

Sent from my XT1575 using Tapatalk


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## rherrell (Feb 12, 2017)

The rubber washers took about 50% of the ripples out but it's still not right. I'm going to try a 3 phase motor with a VFD , I've tried everything else and nothing has worked. I'll get back here in a few weeks to let you know how it went.


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## qualitymachinetools (Feb 13, 2017)

Make a list of everything thats been checked if you would, headstock bolts, and any other bolts, check spindle bearing tightness, and the stand its mounted on.

 Also try a different chuck, but make sure to check everything thats been talked about, and list it if you can.

 If the washers helped, and thats a known good motor that was checked on another machine here, something is loose somewhere there, thats all it can possibly be.  Yes of course a 3 phase motor/vfd is always better, but if it didnt do it on a machine here, and it does there, it isnt the motor, something is loose somewhere.          And there are only really 4 things to check between the motor and the part, you already changed the belt, so the motor mount, the headstock mounting bolts, the spindle bearings, the chuck, and the stand its mounted on.


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## bench (Feb 13, 2017)

Maybe the spindle is misaligned a lot.


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## rherrell (Feb 14, 2017)

Matt, everything you have listed has been checked. All the bolts are tight, and it does the same thing with a collet chuck or the 3-jaw.

When I push on the chuck with moderate pressure the deflection in only .0005", when I push as hard as I can it's .0015".

The only other variable is the stand.
	

		
			
		

		
	













The stand is made from 2"x2" steel tubing with 2"x4" steel tubing for the uprights. The stand is NOT sitting on the wheels, I jacked it up and put 3" round solid steel  under it. There are adjustable feet threaded into the steel rounds but you can't see them in the photo. The floor is 2x10 studs with 3/4" plywood that has been reinforced under where the lathe sits. It also sits on a piece of 3/8" solid steel plate.

Let's all not forget the elephant in the room, when I turn the lathe using a drill motor I get a perfect finish. To me that says it's electrical.


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## qualitymachinetools (Feb 14, 2017)

I dont see a problem with that stand at all, that looks nice and solid, no problem there.  And yes I know that you are getting a good finish with the drill motor, but so was I with that motor on a lathe here. 

     BUT I did not know that it was on a stud floor like that. I just assumed concrete, never even crossed my mind. I ran in to this same exact problem a few years back (actually 10 years or more probably now) with a customer putting a machine in to a trailer for a mobile shop. He used an aluminum plate to save weight, but other than that, almost the exact same set up. That has to be it, its the same problem that he was having, and we even swapped machines back then because we went through everything and I didn't know much about VFD's back then. I tested the heck out of the replacement lathe before sending it out, sent to him, and same thing.  His came back here,I set it up, and and it cut fine. It was the PM-1236.        He ended up coming up here and I eventually got him set up with a PM-1127V at the time, and it worked just fine in a trailer. Its a variable speed DC motor on that one.      That has to be it, and I bet that VFD will be a big help though.   That just has to be it, its the same thing.       I didn't even think to ask that, looked like a concrete garage floor to me.


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## qualitymachinetools (Feb 14, 2017)

Is it possible to wheel the lathe out to a concrete floor just to test? (If its not on the same level to just wheel it out then dont do it, but if it is easy, give that a shot)


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## Dan_S (Feb 14, 2017)

are the gibbs on you cross-slide and compound tight?


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## pdentrem (Feb 14, 2017)

Place a glass of water on the floor and run the lathe. Any vibrations will be seen on the water surface. Any vibration shows that the floor is not stiff enough.
Pierre


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## bench (Feb 23, 2017)

rherrell said:


> Several of the previous photos show two speeds side by side, .0055" and .0027", the .0027" is the slowest feed this machine has. All it does is make the ridges closer together and it also seems to change the angle of them as well. That seems odd to me,* why would the angle of the ridges change direction when you change the feed rate???*



This can be understood if we assume a forward-backward vibration of the stock at the tool tip. The slanting direction of the lines depends on the feed speed. If the feed speed is above a certain critical speed that is proportional to D/T, where D is the stock diameter and T is the period of the vibration, the lines slant backward and if the feed speed is below the critical speed they slant forward. The horizontal distance between the lines equals feed speed times the period of the vibration. This gives a rough estimate of the vibration frequency of about 1 Hertz from the pictures of the pattern and feed rate. This frequency is way below the motor frequency of about 30Hz (assuming 1800RPM), so motor cannot be a direct source of the problem, even though it provides energy to the vibration. This suggests converting to VFD may not help, unless it somehow reduces the energy transfer of the motor to the vibration.  Harmonics of a few Hertz must be of mechanical origin, so as Matt suggests, putting the machine on a firmer floor may help.


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## sanddan (Feb 24, 2017)

I have a question on the stand, are the uprights connected in the area marked in red? It looks like the frame is a "C" shape with that area an open span.


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## Doubleeboy (Feb 24, 2017)

The drill motor does not necessarily mean its electrical problem, it could easily be that the drill motor does not deliver near as much torque, hence setting up less vibration.  I like Matt's idea, roll that lathe out to some concrete and turn it on.  If you are going to be on wood floors I suspect you need a lighter weight table top machine, I believe the 1340 is too heavy to sit on a flimsy floor.  Matt listed the variables to check, when they are all checked, moving lathe to solid footing should rule out the last likely source of trouble. Ten thousand small southbend lathes run on single phase motors and cut fine, I seriously doubt a 3 phase set up is going to solve this for you.


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## Dan_S (Feb 24, 2017)

Doubleeboy said:


> I believe the 1340 is too heavy to sit on a flimsy floor.



I wouldn't say its to heavy, more like to powerful.

My little 8x14's bench migrated back against the wall once, and just the intermittent contact with the timber wall caused harmonics similar(not as severe) to this. I moved the bench back out away from the wall and the problem was solved. Something like the 1340 can probably turn the floor into a sound board.


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## Badspellar (Feb 24, 2017)

Not all single phase motors are built the same.  When I took the cheap 2 pole single phase motor off my 1414E-LB and replaced it with a quality 4 pole Baldor single phase motor my problems went away.  Before the switch I tried everything mentioned in this thread and nothing corrected the problem.  Since the motor change nothing I can do will make the pattern return. I can cut any speed, depth or feed rate and do not get the pattern.  I'm totally convinced a good quality motor will solve his problem.


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## Dan_S (Feb 24, 2017)

Badspellar said:


> I'm totally convinced a good quality motor will solve his problem.



They already tested a known good motor, and it had no effect, on the issue. Buying an expensive replacement would be a waste of money.


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## bss1 (Feb 24, 2017)

Once the motor and floor are eliminated, if the problem still exists, I would look at adding another set of vertical supports and feet to the stand at the area under the right side of the headstock.  I think that may be where Sanddan is headed with his comment above.


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## bench (Feb 24, 2017)

If the problem is the floor, not the stand, then putting the entire stand on a thick, wide metal sheet of perhaps half-inch thickness may help. This will spread the entire weight of the machine and stand across the area of the sheet, which will reduce pressure on the floor.


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## rgray (Feb 24, 2017)

I was gonna chime in earlier about a statment from a brown and Sharpe cylindrical grinder owners manual.(I suspected the floor as the problem)
It is under the "work shows chatter finish" trouble shooting. It states as one cause "Machine located on insufficiently rigid floor, or floor transmits vibration to machine"

and then says see page 20...on page 20 is "isolation mountings" "these mountings eliminate the need for expensive machine foundations where external vibrations are a problem. 

And it is a 2400 lb machine.


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## pdentrem (Feb 25, 2017)

This why I suggested placing a glass or pan of water on the floor. Any vibrations will show up and prove the floor is the issue.
Pierre


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## qualitymachinetools (Feb 26, 2017)

So many good replies here, lots of good information. I wonder how we ever made is through life before these forums existed internet ha ha. Im thinking that the 3 phase/VFD Will solve it. But that doesnt mean it was the motor, had the old motor come back here too, put it on my machine, and cuts just fine. (And while these arent Baldor motors, they are still pretty decent motors from Taiwan)               What I believe is since the single phase motors are just not quite as smooth as the 3 phase w/VFD (Although in most cases smooth enough on this model for a good finish) and since its on the stud floor, its not absorbing that vibration, it might even be magnifying it. And the 3 phase will have less vibration, so not as critical what kind of floor its on, so hopefully that takes care of it.


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## ziptie (Mar 1, 2017)

Sorry,late to the party. There is a strap,or gib, on the back of the carriage which rubs under the back flat way of the bed. Hand lift up or gently pry up on the back of the carriage and indicator check to be sure the gib (strap) takes up all the play without causing a lot of drag.


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## Alan H. (Mar 2, 2017)

sanddan said:


> I have a question on the stand, are the uprights connected in the area marked in red? It looks like the frame is a "C" shape with that area an open span.
> 
> View attachment 227144


Like many, I have been following this thread.  I hoped the OP would answer Dan's query here.

If there are no tension/compression members in the stand's upper end where Dan marked the photo, this leaves the verticals without proper lateral support.   In addition, the loading on the verticals appear to be eccentric.  With this they will tend to deflect/bend inward.  Without the support Dan marked, the system could vibrate and this could be the source of some of your vibratory problems.


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## willthedancer (Mar 2, 2017)

I'm late to the party too.

I have a similar issue with my lathe. Mine is in the spindle. I have a threaded spindle nose, and none of my chucks seat properly. Additionally, the spindle is mounted on class 3 bearings which have an intrinsic .0003 run-out.

Have you compared chucked work to work run between centers, with the head center mounted directly in the spindle bore? Have you tested the fit on your camlock taper?

Sent from my Moto G Play using Tapatalk


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## Alan H. (Mar 2, 2017)

willthedancer said:


> I'm late to the party too.
> 
> I have a similar issue with my lathe. Mine is in the spindle. . . . . . ..


Will, I am curious as to the make/model of your lathe.


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## willthedancer (Mar 2, 2017)

I'm running a Clausing 111/4800. Date 1948. I'm right now making a D1-3 spindle for it.

Sent from my Moto G Play using Tapatalk


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## rherrell (Mar 12, 2017)

I'm disabled and have to sit while working, the crossbar in front was moved back 6" so it wouldn't hit my knees, you can see the bottom of it in the photo.

The lathe is also sitting on a 3' x 6' x3/8" steel plate on top of the REINFORCED wood floor. All the joists have shims between them and the ground  to keep them from bowing. They also have been sistered with an additional 2x10 on either side, making each joist 4 1/2" wide. THEN, all the spaces between the joists were filled in with more 2x10's laid flat and screwed down to the sistered joists. (the sistered joists were left 1 1/2" from the top of the original joists)

A glass of water on the floor  AND on the headstock show no vibrations at all.

I'm installing a Marathon Black MAX  Y-551 inverter motor and a VFD, I'll keep you posted.


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## petertha (Mar 18, 2017)

Late to this post but I had a very similar issue on my Taiwan King 14x40 GH lathe when new. Turns out the power feed shaft was slightly bent. When shaft was removed service guy rolled it on a very flat table & the wow was visible. Suspect it occurred behind the scenes in transport or who knows, even factory. Anyway, with new straight shaft the finish turned into a mirror, resonance gone. The reason why this is fresh on my mind is my clutch is giving me some grief, which is on exact same shaft adjacent to headstock. The ball/spring/detent assembly is starting to click under power feed & I am seeing some surface finish issues. Nowhere near as extreme as before but that kind of slight 'threading overlay' looking issue. It could be picking up some mechanical scuffing or intermittent junk motion from any number of places in power feed drive train - including inside the apron where bar rotates through the gear traversing assembly?

About all I can think of to suggest is replicate your same material & tooling setup. Power up & then traverse the carriage by hand as constant as you can as though you were a robot. Helps to put a bit of friction on the carriage wheel with your left hand. Try some different rpms. If finish consistently looks smoother, at that at least it points you to power feed drivetrain & maybe not motor & bearings & other factors. Keep us informed & good luck.

*edit my apologies I saw you tried this in post#20*
_I forgot to mention that I have the same problem with hand feeding as I do with power feeding so I doubt if the problem is with the power feed._


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## rherrell (Mar 21, 2017)

Houston, we no longer have a problem!

Thanks to Mark Jacobs, the VFD guru, I can report that all of my surface finish problems have GONE AWAY! I used the Marathon Black Max inverter motor and WOW, does this thing have power. I can take a .050" doc(.100" on the diameter) and it cuts like butter. I can take more but I'm happy with that, I don't like to push any of my machines.

Here are some pics....
	

		
			
		

		
	





































This last image shows my solution for the motor support. It hit the motor using the original position so I cut it down and flipped it over so it comes up from the bottom, it was a simple fix and it seems to be working well.

Again I want to thank Mark, I screwed up a few things and when I asked him for help he solved the problems IMMEDIATELY.

I also want to thank everyone who posted comments, without this forum I can't even imagine where I would be right now.


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## Tozguy (Mar 21, 2017)

Mark, this content is way over my head but when a fella like you is so generous with his knowledge it inspires me tremendously.


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## wrmiller (Mar 21, 2017)

Once I get some 240v in the new garage in the next couple weeks or so, I may have to contact Mark and ask him how much he'd charge for a complete setup from motor to control panel with the auto-stop feature for my 1340. I will admit that I kinda did a hack job on mine when I was in CO as I was impatient to get started...  

It needs to be done right this time.


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## petertha (Mar 21, 2017)

rherrell said:


> . I can take a .050" doc(.100" on the diameter) and it cuts like butter. I can take more but I'm happy with that, I don't like to push ANY of my machines..



That's awesome that your problem went bye-bye & we all benefited by seeing your end result. Congrats.

I'll offer another one. My Taiwan 14x40 is generically very similar to yours. Its actually had a pretty easy life until I started doing more machining lately. Recently I have been fighting what I thought was a clutch issue kicking out, strange noises & related surface finish problems. The carriage assembly was finally dismantled yesterday with some help from a good buddy who volunteered his time. We discovered the worm wheel in the apron on the power drive rod was slowly eating its way into the cast iron U bracket that contains it, so it developed lateral end play slop. I was only taking 0.015" DOC passes in 1144 SP steel when the racket started. Now, this was probably coincidental timing that loaded the power drive a bit more than usual, like the straw that broke the camels back. I will take some pics & fully document this so others can see. And I think this assembly can be improved. In fact in a Keith Fenner video series, this is exactly what he dealt with on his lathe & he silver soldered a bronze thrust washer which is probably the most straightforward option. I'm considering tossing the cast iron POS altogether & making an entire new block with some better features.

So my amateur machinist precautionary words of wisdom are: maybe your motor is capable of plowing big time metal but there may be a weaker link in the system, at least in stock lathe form. I'm pretty sure my clutch was set conservative up until now, so somehow the wear still slowly occurred on the driveline. My read (hope!) is its reacting to the bad friction in the worm gear issue. Not to dilute your great post, but just curious if you consider 50-thou type DOC is something a lathe like this should be able to handle no problem over extended life?


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## mksj (Mar 22, 2017)

Rick, it is interesting that you had this surface issue problem, but glad it was resolved going to 3 phase. I have heard of  similar issues with single phase lathes (of this size), but seems to be sporadic and have not seen it reported with 3 phase lathes. One consideration, is that when we start changing the mounting structure of the machine, it changes the harmonics/vibration nodes which can be exacerbated with rigidity. I saw this on my 1340GT, where changing to solid feet and stiffening the base exacerbated the vibration peak at 650RPM and 1250RPM. This only occurred with heavier chucks, so this size machine is more sensitive to any imbalance in the system. Also, VFD's variable speed allows RPMs where you will always find a resonant peak for the structure. In larger machines with VFDs, this can often lead to catastrophic failure if the system is completely rigid, and often they program the VFD to have skip frequencies to avoid the resonant peak RPMs. It may be that the stiffer support frame you made may have transmitted the single phase motor pulsations, which showed up on the surface finish. In many cases, individuals have isolated the motor from the machine with rubber feet, and this issue has been resolved. I like your idea of using a drill motor to power the machine and evaluate the surface finish, I think that tells the tale that this was a single phase motor issue. I still think it is important to check the other mechanical issues that others have mentioned, especially with an older machine. Regarding DOC, I see no issues with taking a 0.100" diameter cut with this size machine, but the motor/VFD combination you used is surprisingly powerful and I wouldn't want to test which will break first on deeper cuts.

I still feel 3 phase is the way to go with these machines, either using an RPC or a VFD. The BlackMax motors are killer on these lathes, but the stock 3 phase motors performs quite well also. Glad I could help you out with your lathe. Very nice install on your VFD enclosure, your lathe is now on steroids.
Mark


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## figgman7 (Mar 26, 2017)

Best guess is that the nut for the crossfeed is loose.  You should be able to tighten with no more than removal of the compound.


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