# Max spindle speed G0602 VFD...



## GunsOfNavarone (Jun 16, 2020)

So I did the VFD mod on my G0602Z some months ago. I got a wild hair to put the belt on the highest pulleys (AC3) and see what max speed is like. I dig the 15rpm for threading, max speeds gotta be great for titanium or?..... I know the VFD version of this machine is 100 to 2000 rpm. Mine stock is 150 to 2400, so I'm just curious, what does 4800rpm look like. Yeah, around 3000 I was just uncomfortable. Everything was smooth, no real issue, but what can the spindle bearings/drive train handle? Thoughts?


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## darkzero (Jun 16, 2020)

GunsOfNavarone said:


> max speeds gotta be great for titanium or?



Depends on the grade but recommended sfm for Ti is slower than SS, closer to speeds for tool steel or slower.


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## DavidR8 (Jun 16, 2020)

No idea but I can tell you I cringed as I watched Clough42 spin his Grizzly lathe to 3000 2400 rpm with an empty chuck...
Edit: reviewing the video he took it to 2400 rpm.


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## darkzero (Jun 16, 2020)

GunsOfNavarone said:


> so I'm just curious, what does 4800rpm look like.



Holy crap! I'm curious too on a manual lathe. Please post a video if you do!


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## GunsOfNavarone (Jun 16, 2020)

@darkzero Dude....I expected you to be the voice of reason.....not egging me on!


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## GunsOfNavarone (Jun 16, 2020)

@DavidR8 So you don't believe the spindle can handle the 4800rpm?
That's the question, what can it take, what upgrade is possible to go to that rpm? It doesn't seem better bearings are possible for that lathe...


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## DavidR8 (Jun 16, 2020)

GunsOfNavarone said:


> @DavidR8 So you don't believe the spindle can handle the 4800rpm?
> That's the question, what can it take, what upgrade is possible to go to that rpm? It doesn't seem better bearings are possible for that lathe...



No idea to be honest as I don’t know much about that model. I would think that any bearing worth it’s salt could take a 100% increase in speed. I have no data to back that up, 

Looks like bearings have been swapped in that machine. 

Grizzly G0602/G0752 Spindle replacement








						Grizzly G0602/G0752 Spindle replacement
					

Hi Everyone, Im hoping someone can answer me on how to remove the spindle on my G0752 Lathe. I have removed the nuts, gears, etc on the left side of the lathe. It looks like the spindle should just push out the other side but it is pretty much stuck. I didn't want to force it without checking...




					r.tapatalk.com
				





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## GunsOfNavarone (Jun 16, 2020)

@DavidR8 Bearings were swapped in what machine? I remember reading that thread some time ago. I thought they came to the conclusion there really isn't a better bearing out there for the G0602/0752.. Unless you really want to jack with it, and at that point, you may have better bearing, but installed in a way that you loose precision on the wonky mounting technique.


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## DavidR8 (Jun 16, 2020)

GunsOfNavarone said:


> @DavidR8 Bearings were swapped in what machine? I remember reading that thread some time ago. I thought they came to the conclusion there really isn't a better bearing out there for the G0602/0752.. Unless you really want to jack with it, and at that point, you may have better bearing, but installed in a way that you loose precision on the wonky mounting technique.



Sorry, I guess I didn’t read it closely enough. I thought that better bearings were found. 


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## darkzero (Jun 16, 2020)

GunsOfNavarone said:


> @darkzero Dude....I expected you to be the voice of reason.....not egging me on!



Normally I would be but I'm curious too & want to see!  

But to be serious, be careful! Aside from the bearings probably not rated for those kinds of speeds pay attention to your chuck(s). Semi-steel/cast iron body chucks have a lower RPM rating than forged steel body chucks. Backplate matters too. Also the bigger the chuck the slower the max rated RPM.

For example, my Bison 6.3" forged Set-Tru 3-jaw is rated for 3500 rpm max. My Bison 6.3" forged Set-Tru 6-jaw, basically the same chuck but more jaws & heavier is rated for 2500 RPM. My  8" 4-jaw semi steel direct mount is only rated for 1800 RPM. Same with my 9" drive plate, direct mount with only a couple of slots but cast iron, 1850 RPM max.


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## GunsOfNavarone (Jun 16, 2020)

@DavidR8 
look here
Bearing thread


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## fitterman1 (Jun 16, 2020)

GunsOfNavarone said:


> So I did the VFD mod on my G0602Z some months ago. I got a wild hair to put the belt on the highest pulleys (AC3) and see what max speed is like. I dig the 15rpm for threading, max speeds gotta be great for titanium or?..... I know the VFD version of this machine is 100 to 2000 rpm. Mine stock is 150 to 2400, so I'm just curious, what does 4800rpm look like. Yeah, around 3000 I was just uncomfortable. Everything was smooth, no real issue, but what can the spindle bearings/drive train handle? Thoughts?


 Hi Guns, reference speed used by SKF in their general Catalog is 7000 rpm, limiting speed is 8500rpm.
If your lathe doesn't shake itself to death i suggest spare undies in close proximity just in case.


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## darkzero (Jun 16, 2020)

fitterman1 said:


> If your lathe doesn't shake itself to death i suggest spare undies in close proximity just in case.



Heck if it were me, I'd build a blast shield to stand behind along with a remote switch!


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## GunsOfNavarone (Jun 16, 2020)

At 3000k, when I hit the brakes....I really felt like failure was eminent. I mean it was smooth but the change gears sounded like a freight train. 2nd time I dropped it between gears....I was keeping clear for a reason. I'll do it again and post, but most likely wont go to 4800. I had a over load error as turning up potentiometer down too fast threw the code. too much fast spinning mass...brake couldn't handle it. It's like traveling at light speed, weird stuff starts to happen.


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## GunsOfNavarone (Jun 16, 2020)

fitterman1 said:


> Hi Guns, reference speed used by SKF in their general Catalog is 7000 rpm, limiting speed is 8500rpm.
> If your lathe doesn't shake itself to death i suggest spare undies in close proximity just in case.


Thanks mate! So the stock bearings in this thing are SKF's? I gotta say, I would be surprised!


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## DavidR8 (Jun 16, 2020)

GunsOfNavarone said:


> At 3000k, when I hit the brakes....I really felt like failure was eminent. I mean it was smooth but the change gears sounded like a freight train. 2nd time I dropped it between gears....I was keeping clear for a reason. I'll do it again and post, but most likely wont go to 4800. I had a over load error as turning up potentiometer down too fast threw the code. too much fast spinning mass...brake couldn't handle it. It's like traveling at light speed, weird stuff starts to happen.



Same thing happens on my mill if I have the brake time set below 10 seconds. 
Three, four-step cast iron pulleys and the spindle is waaay too much mass for the internal brake to quickly slow down. 


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## Ulma Doctor (Jun 16, 2020)

the gearing will be the limiting factor, don't exceed 2500 rpms with gears attached


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## fitterman1 (Jun 16, 2020)

GunsOfNavarone said:


> Thanks mate! So the stock bearings in this thing are SKF's? I gotta say, I would be surprised!



No, the standard brgs are cheap chinese.
I just looked up my skf book, their brgs are rated at that speed. I would say any similar branded brgs would be capable of those speeds. I happened to replace mine with FAG's ( 32009 ) because thats what my brg supplier can get. I think even 2400 rpm on this lathe would be somewhat a hairy proposition considering the threaded spindle. I barely push my 0602 over 1000 rpm, no need to.


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## GunsOfNavarone (Jun 16, 2020)

fitterman1 said:


> I barely push my 0602 over 1000 rpm, no need to.


I have 2 words for you.... ceramic inserts!


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## fitterman1 (Jun 16, 2020)

GunsOfNavarone said:


> I have 2 words for you.... ceramic inserts!


I'd like to use them, but to justify their cost I'd like a larger lathe to take advantage of them.


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## GunsOfNavarone (Jun 16, 2020)

For sure...they are for huge CNC monsters with 24000 rpm spindles, way out of my league. 
SO....other than a video, I will not be using over 2500...MAYBE 3k. Good idea to change the bearings, but that's not gonna save my sorry back side.
Got it.
Thanks guys!


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## Buffalo21 (Jun 16, 2020)

darkzero said:


> Heck if it were me, I'd build a blast shield to stand behind along with a remote switch!


Reminds me of video the turbo charged Mazda rotary engine on the test bed, in a safety chamber, they just kept turning up the turbo boost and the fuel, then there was a  SUPER LOUD BANG, there was shrapnel everywhere, most of the pieces were the size of a baseball, but as the test operator said, it made roughly 1200-1300 hp for about 3 seconds.............


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## GunsOfNavarone (Jun 16, 2020)

@Buffalo21 what I took from that? There is a sweet spot on that rotary engine when it was amazing and probably...I dunno, 900 hp to be mild. SO...
Maybe my sweet spot IS 3k, but DON'T dare go to 3150rpm!


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## darkzero (Jun 16, 2020)

So I guess what we got out of this is don't/can't always turn it up to 11!


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## GunsOfNavarone (Jun 16, 2020)

That's crazy...I was gonna quote Spinal Tap..assumed no one would get it.
Nice Work Dark!


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## RJSakowski (Jun 17, 2020)

I wouldn't want to push my 602 to 5,000 rpm.  Even if the bearings are up to the task, the spindle lubrication system on the 602 leaves a lot to be desired.  There are no oil seals and no provision for metering oil to the bearing.  Any oil added will run through the bearing and out fairly quickly.  at high rpm, centrifugal force will throw the oil more rapidly, leaving the bearings starved for lubrication.   Minimally, if I were running at high rpm, I would replace the OEM ball oilers with an oil cup and a wick so oil could be delivered through the course of operation.

In addition to the spindle bearings, there are ball bearings in the belt tensioner and a bushing on the 60 tooth gear.  The gear bushing turns at 2/3 the spindle speed but the tensioner is turning at around 2.5 x the spindle speed.


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## GunsOfNavarone (Jun 17, 2020)

I have the 1st few parts of James' ELS, so building will begin sometime soon. That will take the change gears out the equation, but yeah, nothing about this is safe for >3000rpm. I don’t need it anyway, it’s just since I don’t have to changes belts anymore, what would happen if I did? (Rhetorical question at this point) I don’t think I’ve ever used 2400 prior to VFD TBH. 
A question about magnet placement for RPM gauge. When I get to 2k, it sure seems like ALOT more. My magnet placement can’t have that much effect can it??


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## Buffalo21 (Jun 19, 2020)

Yesterday, I was changing chucks on the Jet 14 x 40 lathe, while off, I spun the naked D1-4 spindle, at 2000 rpms. Damn!! That looks fast!! The lathe made a slightly unhappy sound, almost like “Hey, what the hell are you doing”. I put the Bison 6-1/4” chuck back on and ran it a “normal” speeds, all was well.


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## GunsOfNavarone (Jun 19, 2020)

I had my chuck on, I no longer need the splined belt, but I did find the nylon gear just below the spindle nylon gear, really has play & tracks at an angle...gets a bit noisy. I’d like to redo that shaft & gear with something more precision. Right now I’m working in the ELS.


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## RJSakowski (Jun 19, 2020)

GunsOfNavarone said:


> I had my chuck on, I no longer need the splined belt, but I did find the nylon gear just below the spindle nylon gear, really has play & tracks at an angle...gets a bit noisy. I’d like to redo that shaft & gear with something more precision. Right now I’m working in the ELS.


If you can figure a way to drive the encoder, you wouldn't need the 60 tooth gear.  The 40 tooth spindle gear could be replaced with a gear belt pulley.


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## GunsOfNavarone (Jun 19, 2020)

At least initially, I want to keep the option of change gears, once I am happy with the performance (assuming I can get it built and working) I will do away with all that...perhaps the transmission entirely and mount the stepper/servo where the transmission was. That nylon gear mounted on the dead stud needs to go, it is the least "precision" part of the whole machine in  my opinion. Am I remembering correctly and you have Clough's ELS @RJSakowski  ? I am quite sure I will need help as computer lingo and building boards and getting them talking is outside my pay scale.


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