New G4003G Lathe - Spindle/Gearbox Break-In Data

[frostheave]

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
	70	Fwd	20	58	56	86	68	85
	70	Rev	20	61	58	96	67	85
	200	Fwd	20	67	61	101	72	236
	200	Rev	20	69	64	102	71	236
	220	Fwd	20	71	65	103	68	255
	220	Rev	20	71	66	102	67	255
	270	Fwd	20	73	68	102	74	307
	270	Rev	20	76	70	103	72	307
	360	Fwd	20	80	72	104	70	421
	360	Rev	20	81	74	104	70	421
	600	Fwd	20	89	77	104	73	708
	600	Rev	20	92	79	105	74	708
	800	Fwd	20	97	81	104	76	920
	800	Rev	20	99	85	103	76	920
	1000	Fwd	20	113	87	105	77	1167
	1000	Rev	20	111	90	106	79	1167
	1400	Fwd	20	122	93	106	80	1511
	1400	Rev	20	126	94	109	78	1511

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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
	70	Fwd	68	67	-1
	70	Rev	67	66	-1
	200	Fwd	72	70	-2
	200	Rev	71	71	0
	220	Fwd	68	69	1
	220	Rev	67	68	1
	270	Fwd	74	74	0
	270	Rev	72	76	4
	360	Fwd	70	71	1
	360	Rev	70	72	2
	600	Fwd	73	75	2
	600	Rev	74	77	3
	800	Fwd	76	75	-1
	800	Rev	76	77	1
	1000	Fwd	77	75	-2
	1000	Rev	79	79	0
	1400	Fwd	80	78	-2
	1400	Rev	78	80	-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

 

[Mike Nash]

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!

 

[Ray C]

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

 

[frostheave]

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!

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

 

[Mike Nash]

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.