G4003g Vs G0750g Machines

I looked at the same two lathes a year ago. Didn't go with either, went with a Grizzly G0709 14x40 instead. What sold me on the G0709 was the universal gear box for threading. My lathe QCGB has one knob that is set to the left for power feeds, turned to the middle for English threads, turned to the right for Metric threads. No fiddling around with changing gears on the quadrant. All three lathes inconveniently require two nuts to be removed to access the back side of the head stock and the quadrant. On the plus side for the G0709, it's primarily done to access the oilers for the quadrant gears. My background aside, back to the original post question . . .

Advantage of the G0750G is an enclosed QCGB, no oil dripping on the chip pan. Probably runs a little quieter since the bottom of the gear box is closed.

Advantage of the G4003G is the Norton style QCGB which allows access to all threading/feed combos without having to remove to head stock back side cover to change quadrant gears. Download the G0750G manual or look at the picture from page 55 of the manual below. Row 'b' shows the quadrant gear needed for each of the tpi to be cut by the QCGB. Lots of potential gear changes on the quadrant to change tpi. Cut a 5/16 - 18 thread, then want to cut a 1/4 - 20? You guessed it, gotta pull the head stock cover and change from a 'b' gear of 54 teeth to a 'b' gear of 60 teeth. On the plus side, it would force the discipline of removing the cover and oiling the quadrant gears on a regular basis! There's a pic of the G4003G threading chart below also. Want to change from 18 to 20 tpi? Move the RH QCGB lever from position 2 to position 4.

Other spec differences are minor: G0750G has an inch less travel on the cross slide (5 5/16" vs. 6 1/4"), less tail stock quill travel (3 3/4" vs. 4") and fewer feed rates and English tpi (32 vs. 40).

I'd go with the G4003G lathe over the G0750G. However, if you can scrape together another $1500, go with the G0709G. I absolutely love the universal gear box. I have to admit to being a little lax on oiling the quadrant gears however. One of these days I'll plumb in some remote oilers and/or revise the head stock cover and add a hinge like the G0776G lathe.

Bruce

G0750G threading chart
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G4003G threading chart
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I have the G4003G and love it. At this price point I haven't seen another lathe I would prefer.
 
I got to believe the 4003 is better. I noticed the differences which you have so effectively pointed out. That extra travel on the compound
is a real "life saver" sometimes.
I just bought the 4003. Its heavier and a good size for my small shop.

Thank you all.
 
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