# Surface Finish Issues On 12x36 (long Post) + Kb Electronics Vfd Install



## Muskt (Jul 30, 2016)

I have a couple of problems, and I now submit them to the group.  I shall attempt to thoroughly explain the problem and my methodology.  Please be patient.

First, the obligatory disclosure:  I have not contacted Matt, or QMT.  I am not upset.  I am not PO'd.  I just want to get it fixed.

There, I feel better already.

Next, a bit about me.  I am not a complete machining rookie, nor an expert.  I consider myself to be somewhat of an advanced amateur.  I used a Grizz 9x20 for 10+ years, and this PM 12x36 for just over a year.  I also have a PM 932 mill.

OK, on to the problems.

I have never been totally satisfied with the surface finish obtained with this 12x36.  I have used CRS, HRS, 6061, Brass, Bronze, 1144, & 12L14.  What is wrong with the finish?--It generally looks as though the material has been very very lightly hammered with a tiny ball-pien hammer.

I have used Carbide inserts, Brazed Carbide, & HSS tooling.

I have several TCGT inserts which (with the 9x20) provided nearly mirror finish on Aluminum and also the 12L14.  The finish retains the hammered appearance on Aluminum on my 12x36.  HSS tooling is not wonderful, either.  I will freely admit that my tool grinding skills are not the best--although, good  enough  (in most instances) to get by with.

So, I started investigating.  The first thing I did was to observe the belts with the guard removed--please do not tell the safety Nazis.  The 2 belts were not tensioned evenly.  I checked the alignment of the motor pulley to the input pulley and made small a adjustment.  No improvement.  I removed both belts (one was way too loose) and obtained 2 new Gates belts--No change.  One of the new belts is also a bit too loose.  I removed the loosest belt and rechecked the alignment--hammered appearance was better, but not yet right.  Next, I obtained some of the Link Belting and created one to fit.  Better again, but still not good enough.

I'm beginning to get a bit frustrated.

I put the DTI (B&S--0.0005) on the spindle taper & hand rotated the spindle--No perceptible movement.  This should eliminate a spindle bearing issue.

Next, I put the DTI on the machined surface of the motor pulley--Very little (almost none) movement.  This should eliminate a motor issue.

Next, I put the DTI on the machined surface of the input pulley---Whoa--High to Low = 0.006.  Further, I can easily deflect that pulley further with gentle hand pressure.  I know someone will ask, so here is how I set up the indicator.  

As you face the lathe on the gear train end (looking toward the tailstock), the DTI pointer is in the machined (belt) groove at the 9 o'clock position--with the pointer oriented parallel to the indicator (vertical).  If I grasp the pulley at the 9 & 3 position and push-pull (not in & out) the indicator will change about an additional 0.003.  In-out movement is non-existant. Up-down movement is non-existant (I repositioned the indicator).  
Oh yes, I did remove the pulley to check the input shaft for variations or bending, & found none.  All of the rotating was done via the motor pulley (by hand) with the belt still in place.  I now suspect that the input pulley is not correctly machined.  The machined surfaces where the belt runs are very rough (like sandpaper), too.  All 4 grooves in the input pulley exhibit nearly the same amount of wobble.

So, what say you?  Do you think that the 0.006 of wobble on the input pulley could cause the hammered appearance that I have described?

Since I cannot re-machine the pulley on this lathe (my only one), I will need to either contact Matt for a replacement or proceed to the next step, below.

Before I get too terribly involved in a repair, I am considering a toothed belt and pulley system to replace the current system.  Is this a good or bad idea?  If a good idea where would be a good source for the replacements?

I realize that this has been exceedingly long.  I thank you for your patience.
Jerry in Delaware


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## qualitymachinetools (Jul 30, 2016)

Hi Jerry, I just happened to be on here now. Any way you can post a picture of the finish?     I would say that the link belt pretty much eliminated it being that pulley, since they float pretty well in any groove, .006 seems like a lot to a machinist, but it really isnt that much (Although I would prefer .0005 on everything like that)         But if was that, I THINK that the link belt would have made it go away,if it was from the way it rides in the groove, the link belt would have eliminated that.         Just for the heck of it, we can try another pulley, but I don't think thats it. I am only 99% sure, not 100%, but I just do not think that would be it.        If you can post a picture, or even a video of it cutting, that might help a lot.


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## Muskt (Jul 30, 2016)

Sorry to hear about the phone problems, Matt.  I hope you get it fixed soon.

Here is a still of a piece of 6061 that I just cut.  
It is approximately 7/8 in diameter.  Ran at 700RPM and the finest (0.002) feed rate.  The cut was with the TCGT insert.
The roughness is small, but plainly visible in the reflections of the lights.
	

		
			
		

		
	







Oh, nearly forgot.  Thanks for the response, Matt.  

Jerry in Delaware


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## wrmiller (Jul 30, 2016)

Forgive my butting in, but this doesn't look like a ISV (instantaneous speed variation) issue like a wobbling belt or bad pulley. This looks more like the tool is moving ever so slightly, making what appears to be 'flats' in the finish. Or I could be absolutely full of it and have been staring at your picture too long...


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## Muskt (Jul 30, 2016)

No problem, Bill.  Any/all ideas gladly accepted.  
I get similar results with HSS, also
I checked the compound for looseness--none.  The gibs on the cross slide are snug, also.
I have not checked the rack or any of the apron items--hoping for an easier fix.

Jerry in Delaware


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## wrmiller (Jul 30, 2016)

Yea, I figured you checked the tool/holder/compound as I would have checked those as well. The worst case scenario would be flex/looseness in the saddle or apron. Or feed screw?

Question: Does the finish change when manually feeding vs. power feeding?


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## Muskt (Jul 30, 2016)

I cannot say that I have ever observed closely a hand-feeding scenario.  I shall go out to the shop & try.  Should be back in less than 10 minutes.

Jerry in Delaware


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## Muskt (Jul 30, 2016)

Did a hand-feed cut without changing anything--No perceptible difference.
While out there, I also checked all of the rack bolts for tightness, and the 4 apron bolts--All tight.

Jerry in Delaware


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## wrmiller (Jul 30, 2016)

Well that's that.  

Rethinking my earlier comment, I'll walk back my comment about ISV not contributing to this because I started wondering what effect ISV would have on cutter loading, etc.. It's possible ISV is causing tool flex, i.e., putting those little 'flats' in the workpiece. I'll be honest and say I've never seen something like this, but then I'm no expert in anything.


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## Muskt (Jul 30, 2016)

Thanks, Bill.
If/when I get it figured out, I will definitely post here. 
I anticipate more responses, and am completely open to suggestions.

Jerry in Delaware


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## Muskt (Jul 30, 2016)

Well, I'm really grasping now.
I am thinking, "If the pulley is causing the problem, how about if I increase the vibration/deflection a bit?"
So, I place a piece of Black Gorilla Tape on one side of the groove ( in a random location) of the input pulley.  Tape goes all the way to the bottom and is approximately 2 inches long.
Here is the original pic (Top) and a new one (Bottom) after the tape is in place.  I could not duplicate the exact lighting & distance.  
It actually, to me, looks slightly better with the tape in place.  Go figure???









Jerry in Delaware


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## qualitymachinetools (Jul 30, 2016)

Do you still have the link belt on?   Try to loosen it up as much as you can, with it still being tight enough to spin it. 

  Its hard for me to see it in the pictures, and I know its hard to take a picture too though.       

 Does it change with speed?     

             If it was something in a pulley, I would think that the link belt really should eliminate it. Or I would think there would have been a drastic difference, not just slight.          I've seen some pretty bad pulleys on different things over the years, and no bad effect that I knew of from it.  I would think so anyway.

  I will have to think for a while to see if I can come up with anything else.  Anyone else please reply if you come up with anything too.      I like these threads, we all usually end up learning something.


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## mikey (Jul 30, 2016)

Just thinking here, Jerry, but looking at the pics immediately above, it looks like the defects in the highlighted parts repeat at regular intervals. I'm talking about the little oval-like dimples that are in the highlighted band roughly in the middle of the top picture. I took a caliper and marched out toward both ends and can convince myself that the pattern repeats.

This argues that this is a transmitted harmonic. This phenomena is not unheard of on lathes. If the tape you applied altered this pattern, which it seems to have done, then that supports that something to do with the pulley is creating that harmonic. Have you tried indicating the pulley one full turn? If the pulley is out of round then that would show it. 

As an aside, link belts (at least Fenner belts) are said to reduce vibration by up to 50%. That doesn't mean they cannot vibrate. I'm sure you realize that a new link belt feels like its too small - difficult to get onto the pulleys. If you matched the diameter of the link belt to the rubber belt when you made up the linked belt then the linked belt is likely too long; remove a link or two and try again. If the harmonic is due to the belt then it should show an improvement.

I am assuming that your motor spindle is running true, which may not be the case. It is entirely possible that the output bearings are loose. I'm not sure how you would test this because it has to be checked dynamically, I think, and you don't want to put a dial indicator up to a moving shaft. Maybe UlmaDoctor will chime in with his thoughts. 

Interesting discussion.


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## Tony Wells (Jul 30, 2016)

Tried using a center in the tailstock? Even on a stubby part like you have there. What about feeding away from the chuck?


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## coffmajt (Jul 30, 2016)

Muskt said:


> I have a couple of problems, and I now submit them to the group.  I shall attempt to thoroughly explain the problem and my methodology.  Please be patient.
> 
> First, the obligatory disclosure:  I have not contacted Matt, or QMT.  I am not upset.  I am not PO'd.  I just want to get it fixed.
> 
> ...


While you could have a harmonic coming into play, if your bed is supported evenly I would not suspect this as a problem.  Even though you used an indicator on the spindle nose I would suspect the spindle bearings as the most likely issue.  If any of the bearing components are damaged it could result in a bad finish under load.  Good hunting -- Jack


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## wrmiller (Jul 30, 2016)

Good idea. Any way to verify the bearings are the culprit without just shotgunning?


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## coffmajt (Jul 31, 2016)

wrmiller said:


> Good idea. Any way to verify the bearings are the culprit without just shotgunning?


If you have an I phone there is a vibration analysis app that will help you identify high frequency vibrations that would tell you your bearings need service. Jack


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## Muskt (Jul 31, 2016)

I'm an Android guy; however, there are apps for vibration analysis for us also.  I tried several, with varying results.
Most were able to graph the x, y, & z axes separately.  By playing with the phone a bit, I was able to determine that Z is up-down.
Z showed the most deflection; however, the results could have been in waffles per toolboxes (squared) for all I know.  As with most phone related stuff, documentation is sparse to non-existant.  Anyway, I tried the apps at varying speeds, and with/without the feed rod engaged.  I did not remove the belt--big PITA to get it reinstalled & adjusted correctly.  I tried the phone resting on the HS, & on the cross slide (oriented the same for each test).  I placed the headstock between speeds (neutral).  I ran in both forward & reverse.  I tried it while cutting the same piece of 6061 with the same TCGT insert.  Essentially all the results were very similar.  The amplitude did not look great--but again, there is no apparent way to determine how much there actually was.

I was just informed that since today is our anniversary, there would be "NO shop playing" this afternoon.

I guess that possibly tomorrow, I will remove the belt and run just the motor to see how it reads on the vib tester.

Thanks for all the ideas.
Jerry in Delaware


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## tmarks11 (Jul 31, 2016)

Just for reference, you don't need two belts.  Leave one off.  The single belt is more than capable of transmitting all the power the motor can provide.  Unless you get perfectly matched belts, that second belt is going to hurt your finish.

A gear headed lathe is never going to give you as nice of a surface finish as a bet driven spindle.  Some people solve some of this problem by putting vibration mounts on the electric motor and/or replacing the inducation motor with a 3 phase motor (vibration mounts help a lot, 3 phase motor helps a little).


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## wrmiller (Jul 31, 2016)

Just a thought, but if I had a two-belt drive I'd figure out how to replace it with a 12-ribbed belt and pulley system, assuming I could get a belt of proper length.  Even if I had to make the pulleys myself.


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## qualitymachinetools (Jul 31, 2016)

I dont think its anything bad with the spindle bearings, it really doesnt seem like that. Maybe try to snug them up just a little, see if there is any change? I've only ever seen one bad set of spindle bearings causing problems in my life, and it was every turn. What you have doesn't look like that at all. At least what I am seeing in the picture.

   I will have to try some parts on a machine this week too.          If you didnt have good results on another machine, I would say it could be too light of a cut or in the tool, .002" feed rate is pretty much just rubbing. Any time I get a mirror finish on a part with carbide, its a lot faster feed rate, and I don't use the triangle carbide inserts, never had much luck with them.     But you said it worked fine on the smaller 9x20, but I also assume that one was a belt drive machine?

 At a .002 feed rate, any time I do it with carbide, or really any tool, even HSS, I get tears in the surface and just a bad finish overall. 

  I just can't look at the pictures and decide if its really bad, or if its nowhere near as bad as I might think, I wish I could see it in person, so I can compare with a cut I'd take.       When you have time, try the thing with the link belts, leaving it as loose as possible to get it to still turn OK.     Just trying to eliminate that pulley.  Or like I said we can swap them out, but the pattern looks to me like its a lot farther apart than one turn of the pulley. 

 Any way you can post a video of the cut in action?        

  I know a lot of people go to the 3 phase and VFD to get the Best finish. Lots of option out there,  I am just thinking out loud here really, but if its something as simple at that pulley, thats easy.


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## tmarks11 (Jul 31, 2016)

Muskt said:


> Here is a still of a piece of 6061 that I just cut.
> It is approximately 7/8 in diameter.  Ran at 700RPM and the finest (0.002) feed rate.  The cut was with the TCGT insert.



What was your DOC?  Even with that sharp insert, a shallow DOC can make the insert skip on the surface, given a poor finish.  Try a minimum of 0.020" DOC.

700 RPM is very slow for cutting aluminum with carbide.  T6061 is recommended to use 650 sfm, which means 2900 rpm... bump your speed up to at least 1200 or 1400 rpm and you will get better results.  

You have a more powerful machine, don't be afraid to push it a bit harder than your 9x20.  Carbide likes deep cuts and fast speeds.

What is the tip radius of your insert?  I would also say speed up your feed rate to 0.004 ipr.


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## Muskt (Jul 31, 2016)

I'll try some of those things tomorrow. 

I have read about and tried many different inserts.  I understand about getting aggressive with carbide.  However, these TCGT inserts are designated for aluminum and are close to razor sharp--Seriously.  I don't recall the radius, but it is pretty small.  They are not recommended for steel at all; however, I have used them successfully with very light cuts and obtained extremely good results (on the little 9x20).  I can't locate an actual pic of one on the web, & I had better not get caught sneaking out to the shop tonight.  But really, after getting a part close to dimension, this insert will bring of a whisker that is "finer than frog hair".  But I digress.

Thanks again,
Jerry in Delaware


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## wrmiller (Jul 31, 2016)

The razor sharp inserts for aluminum do great with light cuts. I can pull tenths with them. Leaves a bright finish on aluminum as well. Haven't tried them on steel. May try some light cuts to see how they work.


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## Bamban (Aug 1, 2016)

wrmiller said:


> The razor sharp inserts for aluminum do great with light cuts. I can pull tenths with them. Leaves a bright finish on aluminum as well. Haven't tried them on steel. May try some light cuts to see how they work.



I settled on inserts for aluminum turning SS barrels and crowning.  I tried and spent few bucks searching for the best combination till I finally settled on razor sharp uncoated inserts DCGT 32.51, or CCGT 32.51 for turning and VCGT 110302 for crowning. They are fragile, use cutting oil.

Here is a crown chucked up in the 6J set thru after cutting, unpolished.









I use these inserts on Aluminum on my 9x20, as the OP mentioned on doing on his own 9x20, with great results.


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## mrbasher (Aug 1, 2016)

Damn nice. The finish is nice but the parts I like are the super sharp edges. It's leaving almost nothing behind. Thank you for giving the info on the actual inserts you're using. There are so many out there.

I had a thought about what might be going on with Muskt's surface finish, mainly due to the change when putting tape on the belt but I'm no expert so I'm going to wait. I'm curious.


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## Muskt (Aug 1, 2016)

Here is a pic of the actual insert I have been talking about.
I should have shot one from the side, too---it does have a good clearance angle, thus contributing to its fragility.
	

		
			
		

		
	






Jerry in Delaware.  

PS.  I am working on a short video--I am gaining more respect for the guys on YouTube who produce all the videos most of us enjoy.


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## jbolt (Aug 1, 2016)

These are my preferred inserts for aluminum. 

http://latheinserts.com/CCGT-3251-INSERT-FOR-ALUMINUM-1-03-000329.htm


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## wrmiller (Aug 1, 2016)

Yea, the real bright and shiny ones. Those will slice your thumb in a heartbeat. Don't ask how I know this...


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## qualitymachinetools (Aug 1, 2016)

Yes those are the same exact inserts that I use too, they work really well. I just got about 5,000 of them in.       Jerry, I will be in your area in about a week or 10 days, I can't promise anything, but I might be able to swing by. If you are located where your profile says you are.

 But go ahead post the video if possible too, that might help a lot.


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## tmarks11 (Aug 1, 2016)

Bamban said:


> ...CCGT 32.51 for turning and VCGT 110302 for crowning.



Do you go with the VCGT insert for crowning because the geometry of the cut makes it easier to get in there with that insert?


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## Muskt (Aug 1, 2016)

I attempted to shoot a video late this morning.  When I attempted to upload it, it was rejected due to file type problems???  I attempted to use the Windows Store to download a different movie software program.  I ended up nearly killing my computer--story is long, & several unpure thoughts and words followed.  Anyway, I finally got it straightened out--still no video editing software--I'll work on that later.

Matt, I would never ask you to come by; however, if you desire to stop in, I would be absolutely thrilled to meet you and learn from you.
My actual location is just outside of Milford, De. which is approximately 15 miles south of Dover.  Are you on the way to Ocean City?

If you are in this area, you are very welcome to come by--send me an email (jmakpilot@gmail.com) or PM me for a real address.


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## Enderw88 (Aug 1, 2016)

Muskt said:


> If you are in this area, you are very welcome to come by--send me an email (jmakpilot@gmail.com) or PM me for a real address.



Very off topic, but fill us in on the Alaska Pilot stuff!


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## Muskt (Aug 1, 2016)

WOW!!  I would never even consider asking you to come by.  However, I would not be opposed to a visit, either.  
My actual location is just outside of Milford, De--about 15 miles south of Dover.  

If you want to stop by, just shoot me an email (jmakpilot@gmail.com) or send a PM for a real address.

I attempted to shoot a video late this morning (Monday) & it was rejected because of a file type error????  I attempted to download some software from the Windows store & somehow I almost killed my computer.  I got back up & running late in the afternoon.  I will attempt the video again, tomorrow.  Really, the finish is not Gross, it is just not as good as I think it should be.

Tomorrow morning, I am going to Electric Motor Wholesale in Clayton, De. t pick up my new Leeson 3 Phase motor for the 12x36.  This has been on the table for some time, and I finally just decided to do it.  The finish problems are really not related to my decision.  This company has the best prices I have seen for the motor that Ray C. said was a good replacement.  I already have purchased a VFD, and most likely will be contacting MKSJ to pick his brain.  Man, this almost like an early Christmas.

Jerry in Delaware


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## Muskt (Aug 1, 2016)

OOPPS!  Looks like in the excitement I made a double post.  Sorry 'bout that.

What do you want to know about flying in Alaska?  I did 3 years in the Air Force up in Anchorage (1979-1982).  I did one year flying a civilian stretched C-130, & 25 years flying light twins (Recips, Turboprops, & Jets) for a charter company all over the state, all out of Anchorage.  I did not do floats or off-airport, although some of the places we went into (by Lower 48 standards) would qualify.  

Well, I tried to upload 2 different videos. One was a wmv & the other an avi.  Both were refused by the forum.  Maybe tomorrow.

Before anyone gets upset, I will not continue this type of thread here, I promise (unless there are LOTS of requests).


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## Muskt (Aug 1, 2016)

OK, I found my archive copy of video editing/conversion software.  Here is, I promise, the only one of these "Way Off Topic" posts I'll make.  VLC Player plays it just fine.

This really is pilot porn.

I was the instructor in the right seat during this one.  Been there many times.

This is at a USAF remote radar site in central Alaska.  The runway is 12% uphill at upper half (yes, twelve percent).  For those of you who know about flying, check the Vertical Speed Indicator and compare it to the airspeed indicator near the end after landing.  It shows 500 feet rate of climb at 5o knots--that is not your everyday normal airport.  This was in a Cessna 441 twin engine turboprop (ten seats)--cruise speed at 28,000 ft = 300 knots.

That is all, really.
Jerry in Delaware


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## Enderw88 (Aug 1, 2016)

Muskt said:


> That is all, really.
> Jerry in Delaware



Sweet thanks.


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## Bamban (Aug 1, 2016)

tmarks11 said:


> Do you go with the VCGT insert for crowning because the geometry of the cut makes it easier to get in there with that insert?



Yes, I still ground a more bottom relief so I can go I can deeper on recessed target crown


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## juiceclone (Aug 2, 2016)

I have a suspicion based on personal experience....humor me?  Please post a pix of the tool post and compound .


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## Muskt (Aug 2, 2016)

"I have a suspicion based on personal experience....humor me? Please post a pix of the tool post and compound ."

To whom & what are you referring?

Jerry in Delaware


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## Greebles (Aug 2, 2016)

jbolt said:


> These are my preferred inserts for aluminum.
> 
> http://latheinserts.com/CCGT-3251-INSERT-FOR-ALUMINUM-1-03-000329.htm



These are GREAT for aluminum!


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## KevinMaiorka (Aug 2, 2016)

Muskt said:


> "I have a suspicion based on personal experience....humor me? Please post a pix of the tool post and compound ."
> 
> To whom & what are you referring?
> 
> Jerry in Delaware


I believe he is referring to you and a pic of your tool post and compound slide as well. I'm pretty sure he is thinking that there might be a rigidity issue there. I don't personally see how a belt issue can cause a poor finish when your headstock is running true. 

Sent from my LGLS991 using Tapatalk


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## jbolt (Aug 2, 2016)

Have you checked if the head stock to bed bolts are tight?


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## juiceclone (Aug 2, 2016)

KevinMaiorka said:


> I believe he is referring to you and a pic of your tool post and compound slide as well. I'm pretty sure he is thinking that there might be a rigidity issue there. I don't personally see how a belt issue can cause a poor finish when your headstock is running true.
> 
> Yes, that was on my mind.. I had a finish similar to his when I installed a Chinese QC tool post.  Found the bottom surface was not "flat" and when tightened down the actual load bearing area was right around the bolt.  (imparting a microscopic rocking)  Just ground off tiny amount of metal all around the bottom surface almost out to the edge, and it cured it immediately.


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## Muskt (Aug 2, 2016)

A couple of answers.

I have not checked the bolts, yet--very good thought--I will do that tomorrow.

About the QCTP--another excellent idea--I experienced that exact problem with a Phase II on my 9x20 several years ago and even wrote about it on the 9x20 forum.  I used nearly the same procedure for the repair--I turned it in the 4-jaw instead of grinding.  

Since is is past 10PM now, I'll check both of those things tomorrow, & report back.

Thanks,
Jerry in Delaware


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## Muskt (Aug 3, 2016)

On with the story.

This morning, I went to the shop & did some inspections.

1.   Headstock bolts-----All tight.
2.   Compound top surface---Not pristine, but not terrible, either-------Wrapped 600grit wet or dry around a large ceramic stone & polished (gently) the top surface.
3.   QCTP bottom surface------really difficult to tell, so I placed a sheet of 600 wet or dry on my granite plate & a few drops of oil and gently rubbed the QCTP around (letting gravity do the downward pushing)---Wiped it frequently & continued till the bottom was about 90% shiny.

Tried another test cut on same material at the same speed/feed & with the same tool----NO CHANGE! 
Repeated the test cut with the compound and the cross slide locked----NO CHANGE!   

Next, I just let the machine run without the feed engaged---small vibrations evident (not huge, just a bit of vibration).
1.   Checked the floor pads and made a tiny adjustment to one of them---very small improvement in the vibration.
2.   Fussed with the floor pads till the minimum vibrations observed.
3.   Removed the chuck & repeated the run listed above---still vibrating about the same.
4.   Removed the drive belt & repeated---vibration gone.  HMMMMM!!!

OK, I still haven't made a video.  I am just about out of ideas.  

Let me restate that the surface finish I am observing is not gross, or terrible.  It is just not what I think it should be.
One more time---I am not terribly upset, PO'd, or any number of negative things--I just am hoping to get it all squared away.

I think I will just stop for a while & cut the grass.

Jerry in Delaware


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## KevinMaiorka (Aug 3, 2016)

Jerry, thanks for letting us all know how it is going and I am interested to find out what it is that is causing your issues. 

Hoping for a simple fix but I am personally out of ideas. 

Sent from my LGLS991 using Tapatalk


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## francist (Aug 3, 2016)

That make for a great life axiom -- "Sometimes you should just stop and cut the grass"


-frank


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## Muskt (Aug 3, 2016)

Well, I'm not sure if they will be of any benefit; however, here are three short videos of the 12x36.  Attempting to create these has given me an increased appreciation of what guys like Abom & K. Fenner & others do on a regular basis.

Just for reference:  spindle speed = 700.  Feed rate = 0.002.  DOC = 0.005.  Insert = TCGT.  Material = 6061 @ approx 11/16 diameter.

Be Gentle, now.

Jerry In Delaware


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## Muskt (Aug 3, 2016)

I guess (in retrospect) I should have left the camera run after the cut was finished in the 2nd video.  It looks exactly like it does before the cut started.

Jerry in Delaware


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## mksj (Aug 3, 2016)

This type of surface finish issue has been discussed in a number of posts, not uncommon with the G4003G and 1236 machines with single phase motors. Sometimes they are solved other times not. If everything else is tight, spindle bearings are set correctly, then the most common source of the problem is belt tension/alignment/matching, and issues surrounding the single phase motor and isolating it from the machine. You have done a very thorough job on the belt concern, checking the usual culprits. Although a lot of people favor the linked belts, there have been some tests on vibration/smoothness of cut and a good cogged belt was found to work the best overall. I like the Gate Tri-Power, but any decent belt should work. The stock belts on most of these machines should get tossed up front. Most of these were pointed out previously: http://www.hobby-machinist.com/threads/lovejoy-coupling-for-lathe.38870/

The insert you are using, tool post, etc. all look good and should work well. You might put you hand on the side of the tool post and see if there is any flex or chatter, also check the gibs, or try to lock the tool post and cross slide and see if there is any difference. Make sure the insert is well seated, and there is no tooling flex. Next step would be to try to do some form of motor isolation, some discussion in the second link below. It could be a balance issue in the motor or just the cogging of the single phase. Three phase gives a much better finish, but I would not want to do the investment and find out it didn't fix the problem, but 3 phase with a VFD have a lot of other upsides. I do recall an issue with the spindle bearing tension causing vibration, and readjusting it helped. But I would go there as a last resort.

Last but not least, if you haven't already dons so, you might look into different feet, improving the rigidity of the bases, and or mass loading the bases with some sand in bags. Check the lathe leveling and the feet are similarly loaded.

If you are seeing the same type of cutting pattern in different metals and with different tooling holders, then very unlikely to be the insert. If you only have one insert holder, you might try another type/design, I like the CCMT/CCGT types as my main insert.

http://www.hobby-machinist.com/threads/grizzly-g4003g-belt-vibration-video.22308/
http://www.hobby-machinist.com/threads/g4003g-motor-vibration-surface-finish-issues-fixed.42604/


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## Muskt (Aug 3, 2016)

Mark, thanks for the response.  I was in the process of sending you a PM to see if you have any info available about 3 phase & VFD on the 1236.  I "fat fingered" something, & lost it. 

Anyway, I already have a new Leeson motor and a KBDA29 drive.  I have connected them on the bench and so far, all is well--no magic blue smoke.
Tomorrow, I will pick up the add on IODA board for the drive.  It allows for remote switching & speed controlling.  I have manuals, but the knowledge to use them is somewhat lacking.

I followed your post about using mostly stock parts on the 1340, and that is the route I desire to pursue, also.  No need for light power or coolant power, either.

If you have the time and inclination, maybe we can work something out so that I can proceed.  PM??

Thanks,
Jerry in Delaware


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## tmarks11 (Aug 3, 2016)

Again, if your are cutting Aluminum with carbide, you will get a much better finish if you speed it up.  7/8" or 1" diameter part at 1400 rpm should cut better than 720 rpm.


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## mksj (Aug 4, 2016)

Hi Jerry,
Let us know if you have the same cutting pattern issues when turning other materials, I often use 600-800 RPM on 3/4-1" aluminum, and have not had any issues with the finish cut, but for real nice finishes I use very sharp positive rake uncoated carbide inserts (like CCGT) and can get close to a mirror finish. 

I started to put together a suggested parameter change worksheet for you, and then ran into the issue that this VFD states an "IODA Option Board required" to run any of the commands by external inputs.  I see that you are going to pick this up. I had KB VFDs in the past, but switched to full function VFDs because of the additional costs when you start adding all their modules. Still, it should work fine in this application.

With the IODA module, you would use a 5K pot for speed control, using the voltage sources which is the default jumpers on the board. Connections are per page 52 in the manual. I would use inputs 1, 2 and 3 for Forward Reverse and Multispeed 5Hz for Jog. I have attached my recommendations on the parameter files.

You could use the stock For/Rev contactors (after disconnecting all the HV wires to them) to switch the VFD signals and wire the jog as a separate contact to the I/O board. The PM1236 comes with coolant/light so you would need to put that on a separate circuit/controls if run through the contactors. You could use the stock system breaker or fuses to provide power to the VFD, motor connections would be direct connect to the VFD. Also note that I have not had much success with using used contactors switching low level signals. The contact resistance tends to be too high because of the burnt contacts. But you can give it a try.  The contactors could be replaced with relays.  You would not need the thermal oveload for the motor. I have built completer systems for the PM1236, it was a bit more challenging and time consuming than usual. You also need to wire in all the safety interlocks.

Going to 3 phase should help a lot, and the Leeson motors have been very good in this application. You can pm me if you have questions,.

Other threads worth reviewing:
http://www.hobby-machinist.com/threads/pm-1236-vfd-conversion.11649/
http://www.chaski.org/homemachinist/viewtopic.php?f=42&t=96363


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## Muskt (Aug 4, 2016)

Thanks Mark for the reply.  I just got in from picking up the IODA board and taking the wife shopping.  I have not had a chance, yet, to study your procedures. 
I noticed that the KB drives were significantly more expensive, also.  I had already ordered the 29 drive from EBAY before learning that the IODA board was extra (live & learn).  It was new old stock, & I got it for $249.  The IODA was $75 at ELECTRIC MOTOR WHOLESALE  here in Delaware (about a 40 minute drive from where I live).   (http://www.electricmotorwholesale.com/)
I am not affiliated with them in any manner; but, can truthfully state that they are fantastic to deal with.  Their facility is actually a large (barn-like) structure way out in the country.  I have dealt with 4-5 of the employees and cannot say anything negative about them.  Then, and this is a biggie, their price on the Leeson motor (in stock) was about $50 less than any other vendor I found on the web.  The IODA board (in stock) was $75.  So I am into an American made drive for about $325.  It appears that a large portion of their merchandise is drop shipped from the manufacturer or other location.  Also, Delaware has no sales tax to contend with.  Anyway, if I can get it all together It should be a very good system.

Thanks again for all the info.

Jerry in Delaware


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## tmarks11 (Aug 4, 2016)

So as long as you are replacing the motor, take a look at Coolidge's thread on sound mounting the motor on his 4003g, and think about doing that as well when you bolt on your motor.

http://www.hobby-machinist.com/thre...solation-mounts-surface-finish-fix-2-0.42943/


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## Muskt (Aug 5, 2016)

Good idea, Tim; however, I think that I will look into that after I get the other mess taken care of.  My reasoning is to only try one or two things at a time so as to be able to identify where the problem actually lies.  That is one of the reasons behind not upping the RPM as you had earlier suggested.  If I change too many things at once, I'll probably not know what (if anything) fixed the problem.

Another thing that I finished up today on the lathe.  There are 4 bolts for holding the headstock to the base cabinet.  There is no way on Earth, or any other planet, to install the furnished bolt (the one closest to where the lead screw & feed rod come out).  These bolts are the metric version of 1/2 inch (maybe they are 1/2--but it doesn't matter--STILL WON'T GO IN!!!).  These bolts thread into strap steel bars welded to the top of the cabinet.  The one described will simply not go into the hole let alone getting the threads started.  My solution is a 3/8 grade 5 bolt with washers inserted from below.  The clearance is so tight that a 3/8 nut sitting on top of a flat washer will not fit either---AHHHH!!!!--I have a nut thinner (lathe).  So I turned about 3/32 off of a nut & now I have 4 bolts holding the HS to the cabinet.

Mark, I thoroughly read (& re-read) your info.  I have already reset the programming on the VFD (still on the bench with the motor & IODA board connected).
I have the schematic that Ray C. posted, also.  I will be attempting to follow that--using your info where applicable.

I have not attempted to check the switches (contactors) for fwd/rev yet.  I have been experiencing a small, but irritating, oil leak on the front of the HS since I changed the oil.  So I tore into that.  Since I needed (or thought I needed) to remove the face plates to access the switches & sundries, I figured it was a good time to locate & hopefully repair the oil leak.  It turns out is was around the gasket on top of the HS.  The gasket was in good shape, so a good cleaning & a layer of Blue RTV, & I'm just idling while I give the RTV some time to cure prior to snugging it down.

Back to the project, now.  What would you recommend for wire (gauge??) to run to the IODA??  I was thinking telephone wire, but have not a clue.  I liked the phone wire idea since it is solid, contained (sheathed), easy to identify, and readily available to me.  Ideas, opinions, recommendations???

One thing I forgot to mention yesterday about the VFD--It came with the waterproof connectors, and the on/off switch which total to about another $5o if purchased separately.  All in all, unless something catastrophic occurs I don't feel too bad about this purchase.

Thanks to all for the ideas.
Jerry in Delaware


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## Andre (Aug 5, 2016)

I have this problem on my South Bend 13. Why? It's not the motor, although it is single phase. It's because of inconsistent carriage speed causing a constant frequency in toolpost deflection. Basically, the tool post nods in and out. This is caused from the heavy carriage/bed wear in my lathe, and now the pinion that moves the carriage is spaced out from the rack, causing a bumpy motion. My advise for you is to remove the rack gear under your bed, and shim it downwards slightly. This might help.

Sent from my XT1053 using Tapatalk


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## mksj (Aug 6, 2016)

Do not use solid wire for the connections, it will fatigue and fail over time. I use standard 18-22G wire in the control box for low voltage connections and use crimp pins for the VFD end, spades for other ends.  I tend to use 18-24G stranded shielded cables, the drain wire is attached at the VFD end only.  This would be for VFD level signals. It all depends on how you wire everything up. I often use flexible Beldin shielded cable, something like this: 
http://www.ebay.com/itm/25-Belden-9...-Low-Capacitance-Cable-9C-24AWG-/262239125129
http://www.ebay.com/itm/24-9-24-gau...Quabbin-8195R-Belden-9539-50-Ft-/322007638873

I use shielded cable between the VFD output and the motor connections because of the electrical noise generated, shield is connected at the VFD, ground wire at both ends. So something like 14/4 shielded. But it is hard to source VFD specific cable, and it needs to be a minimum of 600V rating.
Example would be http://www.ebay.com/itm/Alpha-Wire-...ielded-Cable-Robot-Comp-25-roll-/232019607914


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## Doubleeboy (Aug 6, 2016)

I will just throw this out as a possible cause.   Toolpost mounted in a nut that is too high or very close to compound surface and then a chip getting caught between and post not sitting perfectly flat.  I have had this problem and took for ever to figure it out.  A toolpost rocking on top of a chip will leave a poor finish, with a hammered look to it.  Not to be rude or insult your experience but could it be your tool is a few thou above center, I would look for the simple, easily overlooked issue.

cheers
michael


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## Muskt (Aug 8, 2016)

The saga continues--Mostly in a positive fashion.

I have been debating about starting another thread about installing and setting up the VFD & 3 Phase motor on the 12x36.  I have decided, that the VFD install actually falls into the surface finish realm, and therefore am leaving it as one thread.  I will attempt to rename the thread to include VFD install in it in case anyone else attempts this.

As a pilot, I would rather fly an instrument approach to minimums with a 20 knot crosswind & one engine out than mess with electric & electronics--I'm not afraid of it, I just don't enjoy it.

Anyway, I obtained the IODA board for the KB VFD and have it installed.  I followed MKSJs programming and setup notes that he so generously provided, and was able to get the motor spinning nicely using the VFD controls.  Then the fun started.  My next challenge was to set up for remote operation. Remember, I am electrically challenged (severely).  I hooked it all up as best I thought I knew how.  I couldn't figure out why the motor wouldn't run.  I read & reread the manual--which is very good--not written in Chinglish.  I was just not clever enough to figure out which of the situations I was attempting to set up.  I called KB tech support & got through to a tech almost instantly.  He first asked what I was using the drive for.  I told him a metal lathe and his response was "That is too much drive for a lathe--kind of like putting a jet engine on a Toyota Corolla".  After we had a good chuckle, he walked me through the setup, & wished me luck. 

So, back to the bench.  Let me interject here a bit--I have the motor & drive on a workbench.  I have been using jumpers to simulate the switches.  That leaves the lathe contactors completely out of the equation, for now.  OK, moving on.  I reprogrammed the parameters per the techs instructions, & NOTHING!!

Started over, did all the programming again, & checked the jumpers--still NOTHING!!

Another call to tech support, & I actually spoke to the same tech again.  He asked a lot of additional questions this time, & I was able to provide the answers that he desired, & he pointed me in a whole new direction--This time including the external potentiometer. The manual has a very clear diagram that even I could follow.  He apologized for not sending me to that section initially.  I went through the programming again, hooked up the jumpers, & now I have the motor running both forward & reverse, and with variable speed in each direction.  One more hurdle cleared.  I even took notes of how it is wired for when I get it installed on the lathe.

Now, I want to check the FWD/REV switch on the actual lathe.  MKSJ told me that the contactors might be too corroded to function with the low voltage supplied by the VFD.  I got lucky--Both directions work great.

My next big hurdle is all the safety switches.  Tracking down the foot brake was easy.  The case door, also easy.  The EStop, not so easy.  There are lots of wires in that panel.  So, after a bit of detective work, I finally have all the switches figured out.  They are all normally closed.  So, I am guessing that if I connect them all in series and in series with the common wire to the FWD/REV switch on the apron, that all should be happy.  I am just a bit hesitant to do it right now.  Kind of basking in a small success--afterglow.

So, that's it for now from Delaware.

Jerry


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## mksj (Aug 8, 2016)

Hi Jerry,

Most likely the VFD was programmed for external controls and the speed pot, if not connected it won't operate. The safety switches are all NC, so just connect them serially, usually before the stop switch. You can use an ohm meter to trace each one or follow the cabling back to the control box.  Nice that you are making headway, took me quite a few tries the first time I wired up a VFD, and then there was the programing. But you are getting there. The KB should work fine with this size motor, it is not a big lathe, nor heavy duty. Some of the more industrial VFDs can take a much higher overload for short periods and can provide a bit better motor control,  but you should get the benefits of the 3 phase and a smoother motor.


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## Muskt (Aug 9, 2016)

IT LIVES !!!!!

This afternoon, late, I removed the old motor, & all of the required stuff needed to hook up the VFD & new motor.  Quite the job.  I had to shorten the link belt by one link in order to get the new motor to clear the drip pan.  No Biggee!  Got everything lined up nicely & fired it up.  Ran the first time.  Now, you must envision this in your mind--cuz I'm not going take a picture of this mess.  I have the motor mounted, temp wires everywhere, & the VFD lying on a work table nearby.  I was clever enough to ground it all together.

OK, I can't wait.  I set the VFD for 60 Hz & let it run a while at 840RPM.  I'm on the high speed range for the belt.  Still almost the same amount of total vibration as before--a tiny bit less, but not much.  840RPM is as close as I can get to the old motor settings without redoing the belt, etc.  Close enough.
Same insert, same feed rate, same piece of aluminum--Some very, very slight hammering still visible--I would estimate the intensity to be less than half as much as before.  When looking at it, it is noticeably better. 

So, after I get everything back together and get permanent wiring installed, I can then start playing with speeds, feeds, & RPM settings to locate the sweet spot.
Overall, at this point I feel that I made a positive step forward.

I wish to thank each of the members of this forum for all the ideas & encouragement to undertake this project.

Jerry in Delaware.


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## tmarks11 (Aug 9, 2016)

Now it is time to get some vibration mounts.



There is always one more job to do...


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## Muskt (Aug 12, 2016)

Moving Forward With the Project!!

Yesterday, & today, I worked at fabricating and installing a bracket to hold the VFD for the 1236.  This VFD is huge!.  So, in the following pics, you can see what I created.

The first pic is of the bracket to hold the VFD to the lathe.  It is constructed from 1.5 inch square aluminum tubing--nice sharp corners--not rounded--3/16 thick.  A bit overkill, but all that was available in the salvage yard that I frequent.  The reason for the offset will be clearer later.  I used my TIG to assemble it.  My aluminum welding still leaves a lot to be desired.  It still needs to be cut to length.







This is a front view--I was back & forth several times about whether left side or right side was best--Right side finally won.  The black cable coming through the splash shield is for the light power.  I have a 12-volt wall wart that plugs into a receptacle on the back of the splash shield.  I still do not have the left side of the lathe back together, yet.  It all functions properly except for one important item--More on that a bit later.






This is a side view of the whole assembly.  There is a piece of the aluminum tubing inserted and bolted into the steel  base that I built soon after acquiring the lathe.  The upper support is bolted on 2 sides to the cabinet with large thick washers to help with possible "oil caning".  It seems pretty rigid after a bit of test running--no actual machining yet.  In the next Pic, you can see the offset to go around the splash shield.  The bracket is not connected to the aluminum channel on the rear of the splash shield yet, but if needed for vibration reduction, I will do it later.






OK, I mentioned one important item that does not function--or function properly.  I need some help with this one.  I have eliminated about 95% of the factory electrical stuff from the cabinet.  Actually, I disconnected it, it is still physically in there--another day's project.  I used mostly existing wiring for this install plus a 9 conductor cable from the VFD to the electrical box on back of the head stock.  I wired all of the safety switches (except for the chuck guard) in series with the common power line that feeds both forward & reverse for the main motor.  They all work as normal except for the foot brake switch.  It works, but as soon as I remove my foot from the brake, it starts up again--NOT GOOD!!  Any ideas how to cure this issue?  When formulating an answer, you need to realize that there is no power other than VFD control power (low voltage) in the electrical box--NONE!!!!!

As always, Thank You All for your inspiration & support.
Jerry in Delaware


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## mksj (Aug 12, 2016)

Jerry, we would need to know how you wired up the VFD. If the brake switch restarts the system when reset, the same would occur with all the other safety interlocks and E-Stop.  If it is only the brake switch it might be that the wiring is wrong, or it has a dual switch (3 wires), one NC and the other NO that might be wired into the system incorrectly. If you are not using any reset/power relays, then it will restart when the fault is correctly. I can look at the VFD settings and see if there is a programmable function that requires the VFD to be reset, but the spindle will engage immediately once the fault is corrected. You most use some form of power relay that requires a reset. I designed a system for a Grizzly lathe awhile ago and several people have used this schematic on their machines.
Regards,
Mark


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## Muskt (Aug 12, 2016)

That is correct, Mark.  They will all restart--However, only the brake is important.  Example--you cannot remove & then replace the gear end cover accidentally,  or the E-Stop, either--no problems with those.  I took the chuck guard switch out entirely.  As you guessed, I wired the 3 switches in series with the common wire for the fwd/rev switch.  I never thought to see if there is a stop function that would require other action for restart that could be used for the brake.  I'll go through the manual again.  I also need to determine if I can set up one of the sections for a jog switch.

I suppose that I could (with a lot of coaching) configure one of the relays for the brake switch.  I am really not too thrilled about running another circuit into the lathe for that one switch, though.

Thanks, 
Jerry in Delaware


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## mksj (Aug 12, 2016)

Hey Jerry,
How is the VFD input terminals wired to the lathe, if directly connected to the spindle switch, then what you will have this restart issue and a risk. It is possible to wire in a latching relay, that when it trips requires the reset button to be pressed. If I recall this is how the standard G$003G is setup. I did a post elsewhere that use the contactors as relays for the VFD For/Rev, just removing the high voltage to the contactors. It should work exactly like the stock machine.
Mark


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## fixit (Aug 12, 2016)

E-STOP switches are normally PUSH TO STOP & must be PULLED to permit restart
fixit


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## Muskt (Aug 12, 2016)

You are correct, Fixit.  What I meant by my statements in post #67 was that I could not inadvertently or accidentally restart the lathe via the E-Stop or Cover (it requires some actual attempt to restart it).  However, with the Brake, if I remove my foot, it starts right back up.

Gonna require some more thinking.

Jerry 
in Delaware


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## Muskt (Aug 14, 2016)

Greetings, group.

I still haven't decided what to do about the foot brake situation.

I spent a good portion of yesterday afternoon getting most of the lathe back together.  I have encountered another oil leak on the head stock.   My repair of the cover gasket is working nicely.  The new leak is around one of the shifter shafts (top right as you face the machine).  I don't feel up to tearing the machine apart just yet to determine what type & size of seal (if any) lives in there.  The manual lists one, but a project for another day.

I obtained one of the digital tachometers from Amazon last week.  Fabbing a small bracket to hold the pick-up was a relatively simple task.  I used electrical tape to hold the magnet to the left end of the spindle.  Another 12 volt wall wart for power, and I have a temporary digital speed readout.  It worked the first time.  The displayed speeds differ quite a bit (up to about 100RPM) from the placarded speeds on the lathe with the frequency set at 60 hertz.  I think that I will base any/all speed considerations off of the tach instead of the placard.  Now, I need to construct some type of case or holder for the tach body.  That should occupy my Sunday afternoon--unless the DSU (Designated Spousal Unit) has other plans.

I am actually having quite a good time with this project.

Wow, I nearly forgot one of the main purposes for this post.  SURFACE FINISH!!  I played with some CRS shafting (grade unknown) yesterday.  I was able to see a marked improvement in the surface finish since the 3 phase/VFD install.  I tried both HSS & Carbide inserts--both showed improvement.
I also tried some 6061--it also showed improvement.  I experimented briefly with speed adjustments--more of that as I gain experience with this "new" system.

So, here is the breakdown of costs for this project:

Leeson 3 phase motor (*192205.30*)---------$213
KB Electronics VFD (inc shipping)-----------   269
KB Electronics IODA Board (required)------      75
9 conductor shielded cable--------------------      20
Power cable--------------------------------------     23
Speed control pot + knob----------------------       6
Aluminum (VFD mounting bracket)---------      18
__________________________________
Total-----------------------------------------------$624

Of course, nuts, bolts, eye terminals, etc are not included.

I could have acquired a cheaper VFD; however, I thought I was getting a great deal until I discovered that the IODA board was required for remote operation of the drive.  The Leeson motor (and the IODA) was sourced locally here in Delaware (I picked them up at the dealer)--incidentally, their price was the best I could find on the internet.  (electricmotorwholesale.com)

Jerry in Delaware


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## tino_ale (Nov 8, 2016)

Hi Jerry,

Just a thought, have you tried locking the compound, locking the cross-slide, locking both ?
Has any of these 3 tests changed anything in the finish ?

Sorry if you have tried that, I may have missed it.


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## Muskt (Nov 8, 2016)

I normally lock the compound when doing any turning, even threading, so that isn't part of the equation.  I do not have a lock on the cross slide, yet, & rarely lock it--might be something new to try.

Overall, the VFD/3 Phase install made a significant improvement in the finish.  I have found that RPM changes as small as 20-25 will make a difference.  So, if I have the option of a test cut, I can locate the sweet spot to minimize the "roughness".

Matt mentioned something to me when I was chasing this problem around.  He said that the term "vibration" that I was using might be more accurately described as "shake".  I think that that is a better term.  I have observed the light while using the lathe, and since it is on a long flexible neck, the shake is intensified.  I have observed (going from memory now) that the most pronounced shake occurs around 675 RPM.  That speed is obtainable with the VFD at more than one gear setting--it always seems worse at that speed.  I tried with & without the chuck installed with no significant change.

That is about all for now.
Jerry in Delaware


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