Maximum Safe Rpm For A Grizzly G4003g

Xiansheng

Xiansheng

Congming
Registered
Joined
Mar 8, 2014
Messages
41
Hi Everyone,

I am planning to install a VFD speed controller on my lathe, which is the equivalent of a Grizzly G4003G. I plan to use a speed range of about 25 to 2,500 RPM, but I will be grateful for any advice about the higher limit. Is the lathe capable of being run at 2,500 RPM?
 
Last edited by a moderator:
2500 I would say OK, but 25000 NO WAY

fixit
 
/\/\/\/\ I concur with fixit.

2500 is plenty for what you would want to do. 25 rpm is an awesome slow speed!
 
In my opinion, just because your car and go 100 mph is it safe to do all the time? I recommend 70% of top end for all the time, otherwise your car will wear out prematurely. Your lathe will thank me also, if you use the same advise.
 
Hi Everyone,

First, I apologise for my typo where I suggest that I want to run the lathe at 25000 RPM. I realise that even it it were possible and needed, it would be insane and a rather nasty smash would be inevitable. I also don't plan to regularly run the lathe at 2500 RPM, but would like the capability for very small parts. As for the 25 RPM, I want to be able to do screw-cutting at what I consider a safe speed, especially if forced to keep the half nuts locked and stop the lathe when cutting metric threads. Years ago I used to use lathes with back gears that permitted that sort of low speed which was very comfortable, whereas this lathe's minimum RPM is 70, which is too fast for some screw-cutting or other operations. To illustrate what I mean, when winding a inductor coils or making springs, a slow speed is very preferable. Regards Xiansheng
 
Not sure as to the actual experience of anyone running a 4003G at 2500 rpm, but it capability of doing so will depend upon factors like how well the spindle is balanced (or not) what type of bearings are used in the headstock, and what the remainder of the gear train can support.

I would look at the gears (quality, mesh, etc.) and other components more closely if you intend to do a large number of small parts at 2k+ rpm. If you are thinking of doing this only occasionally, then the geartrain is less critical. You still may need to upgrade the spindle bearings though.

Just thinking out loud... :)
 
The max speed on a G4003G is only 1,400 rpm I don't think it would be wise to assume it can take 2,500 rpm you might take a piece of casting or gear to the face.
 
When threading, just turn the speed pot down as you get to the end. Otherwise add an electrical stop switch and use the vfd electrical brake. I use a proximty sensor, postion stop is better than 0.001. Probably max speed of 2000, other than mechanical issues, lubercation may also be an issue. You will also get a better finish going to 3 phase.
 
I don't think you will take a casting in the face, but you will accelerate bearing wear. That being said, I doubt that the spindle bearings will be overstressed at 2500 rpm... the spindle bearings are quality NSK, and are rated for a significantly higher rpm.

Now will your chuck hand that speed is a different question. Four jaw chucks are generally only rated for slower speeds than three jaws. Cast iron chucks for lower speed than steel. If you don't know the speed rating of the chuck, than don't chance it.

You would definitely have no problems with a 5C chuck at those speeds.
 
Mine has P5 NSK bearings. I don't think the spindle and bearings is the issue. I think it will come down to gear quality and alignment in the headstock. Wish they had helical cut gears.
Dave
 
You must log in or register to reply here.
Back
Top