# New G4003G Lathe - Spindle/Gearbox Break-In Data



## frostheave (Nov 1, 2013)

Hi G4003G owners.  If anyone is interested, here are the results of my spindle/gearbox break-in.  These are the results only from another post.

First I did the break-in with oil in the gearbox  measuring bearing temperatures, rotational speed, and gearbox noise.   After the break-in was complete, I put new oil and 16oz, one bottle, of  Power Punch in the gearbox.  The gearbox noise was then measured again.   Below shows the test setups and the resulting data.





Gearbox Noise Level Measurement.






Added 3 pieces of reflective tape to chuck for checking speed with laser-tach.  Divided readings by 3.






Inboard Bearing Temperature Measurement.






Outboard Bearing Temperature Measurement.






Motor Pulley Bearing Temperature


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*G4003G Headstock Break-In
* *Chevron GST 32 Oil - Equivalent to Mobil DTE Light* *No Power Punch* *10/29/2013**Running**Outboard**Inboard**Motor**Speed**Time**Bearing**Bearing**Pulley**Headstock**Tach**RPM*
*Direction**Minutes**Temp F**Temp F**Bearing Temp F**Noise dBA**RPM*70Fwd20585686688570Rev206158966785200Fwd20676110172236200Rev20696410271236220Fwd20716510368255220Rev20716610267255270Fwd20736810274307270Rev20767010372307360Fwd20807210470421360Rev20817410470421600Fwd20897710473708600Rev20927910574708800Fwd20978110476920800Rev209985103769201000Fwd20113871057711671000Rev20111901067911671400Fwd20122931068015111400Rev2012694109781511


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*G4003G Headstock Break-In
* *Noise Comparison Before and After Power Punch* *Chevron GST 32 Oil - Equivalent to Mobil DTE Light* *10/29/2013**Without PP**With PP**Noise**Speed**Headstock**Headstock**Difference dBA**RPM*
*Direction**Noise dBA**Noise dBA**With PP*70Fwd6867-170Rev6766-1200Fwd7270-2200Rev71710220Fwd68691220Rev67681270Fwd74740270Rev72764360Fwd70711360Rev70722600Fwd73752600Rev74773800Fwd7675-1800Rev767711000Fwd7775-21000Rev797901400Fwd8078-21400Rev7880-2

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So it appears, in my case, the Power Punch essentially made no  difference in gearbox noise, if anything, maybe a little louder.  I  wonder If I added too much and should have gone with only 8oz.   Regardless, the gearbox isn't too noisy and I am pretty happy with it so  far.

I thought the laser-tach speed readings were pretty interesting.   According to the manual for the tach, the accuracy is, +-0.05% +1 Digit.   Therefore, at say 1000 rpm, the tach should accurately read between  997 and 1003 rpm.  The nameplate on the motor says 1720 rpm.  I measured  the motor speed at 1793 rpm.  A difference of 73 motor rpm does not  account for the difference in measured and set spindle speed.  I was  going to count the number of gear teeth inside the gearbox and do the  math to see if the numbers would jive, but I ran out of time.  Ok, yeah,  I was too lazy to do it!

Bob J


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## Mike Nash (Nov 1, 2013)

The speed differences look more like the nameplate is for 50Hz line frequency.

I'm still trying to figure out why there is a 4-3/4 TPI gear when that seems to give no useful thread in imperial or metric. The older US lathes had 5-3/4 which at least gives 11.5 TPI for garden hose fittings. Near as I can tell, someone somewhere cloned one wrong and we're all stuck with copies of that clone. (Mine is a Harbor Freight 12x36.)

As for the oil, I just wish mine would stay in the gearbox and apron. It costs too much to use the lathe occasionally when I have to pour in 1/4 gallon each time 

Have fun with yours!


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## Ray C (Nov 1, 2013)

Thanks Bob.  Kinda confirms my general instincts about additives.  Anyhow, there is no rocket science in these gearboxes -none whatsoever.  Provided you are using the proper hydraulic oil, there's not much more you can or should do to improve things.  If you were so inclined, you take out each gear and balance them.  In my lathe, the pressure angle on the involute crowns is 14.5 degrees which is common for maximum power transmission.  You could go with 20 degree gears and if you were really up for it, each gear would be cut with a cutter that matches exactly the pitch for that gear.  Of course, this is all just pie-in-sky dreaming -it simply isn't worth the hassle.  These are the differences between hobby-oriented machines and pro-line equipment.  High end gear sets like that are very costly.

As for the speed differences, maybe things are closer once there's a cutting load.  Honestly though, I wouldn't let it get under my skin.  It works, it cuts metal, it's yours -use it.


Ray


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## frostheave (Nov 3, 2013)

Mike Nash said:


> The speed differences look more like the nameplate is for 50Hz line frequency.
> 
> I'm still trying to figure out why there is a 4-3/4 TPI gear when that seems to give no useful thread in imperial or metric. The older US lathes had 5-3/4 which at least gives 11.5 TPI for garden hose fittings. Near as I can tell, someone somewhere cloned one wrong and we're all stuck with copies of that clone. (Mine is a Harbor Freight 12x36.)
> 
> ...



Thanks Mike.  I did check the motor nameplate again and it does say 60hz.  I guess you better buy that oil in bulk!

Bob J


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## Mike Nash (Nov 4, 2013)

frostheave said:


> Thanks Mike.  I did check the motor nameplate again and it does say 60hz.  I guess you better buy that oil in bulk!
> 
> Bob J



Right, but I suspect the spindle speeds plate is for operation at 50Hz, so everything shipped to the US then runs 1.2 (60/50) times faster.

Usually no big deal but I have seen industrial blowers overloading due to the extra speed. Had to have a VFD added to slow them down.


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