What made you upgrade from the g4003g to a 709? im also looking at that as a possibility
Hang onto your hat this will be lengthy...
Relative to the G4003G I needed the larger swing for a project close to 14 inches in diameter. That cemented the minimum swing size. I wanted more weight (mass) and a more stable stand. I wanted an enclosed quick change gearbox (vs the G4003G open QCGB) with minimal required gear changes. Pay particular attention to that because the differences are substantial. Some lathes require far more frequent swapping around of the quick change gears for different feeds and threads. The G0824 is a good example of what to avoid. The G0709 only has 2 gears to swap to cover the entire range of feeds and threads. Other lathes have a whole stack of gears you need to swap around. Both of the G0709's change gears are always installed on the lathe which hints at how good the QCGB design is. The factory default gear config covers pretty much all the feeds and threads I'd use. Unless I'm trying to turn acme threads or something oddball I'll never need to swap gears. The G0824 in contrast, read the reviews, people have complained about how frequently they have to swap gears noting they would have purchased a different lathe if they had known.
Other considerations -
1. Having experienced the surface finish issues on the G4003G I knew I would be isolating the motor from the lathe casting with rubber isolation mounts on day one. I would also be upgrading the motor to a USA Baldor. This would require a custom aluminum motor mount. Since the motor and motor mount would be on a shelf never used I didn't want to spend more money for a Taiwan motor.
Some quality issues, the G4003G motor mount was hilariously poorly drilled resulting in the motor pulley hanging half off the motor shaft to get it to align with the spindle pulley. (face palm) Also the G4003G motor pulley was a complete joke. It was machined so poorly it wobbled like a cartoon. Examples of China not giving a crap about quality. Grizzly did send me a replacement pulley which was fine but the Baldor motor swap would require a new pulley anyway for the 7/8" shaft (vs the Grizzly metric pulley). At this point I was starting to build a case for saving money by going with a less expensive China lathe vs spending a lot more (upwards of $2k) for a Taiwan lathe of the same capabilities and swing.
2. Surface Finish Issues - This sucked all the fun out of owning my first lathe. So the G4003G was fine at first, great finish I was altogether happy. Then the lathe started breaking in and loosening up a bit and whammo surface finish issues appeared. A geometric pattern started to appear on the surface of turned parts vs the smooth clean finish I had been getting. While this only measured in 10ths and could not really be felt it looked like absolute TRASH. Troubleshooting this was maddening.
Researching I saw that others had reported the same surface finish issue. I tried changing speeds and feeds and materials, no improvement. Some had discussed maybe it was the cheap China motor so I upgraded to a USA Baldor motor, this had no effect on the surface finish issue. That said the Baldor motor was night and day smoother than the China motor. The China motor was not even in the same zip code quality wise as the Baldor. Next I started thinking spindle bearings. I wasted a LOT of time checking, adjusting spindle bearings. Then cross slide gibs, the gibs on the back of the carriage etc. no improvement.
Finally I came across a post from someone who had isolated the motor from the lathe bed casting with rubber isolation mounts so I decided to try that. The G4003G (and G0709 and many other lathes in this class) bolt the motor directly to the lathe bed casting metal on metal. This imparts a LOT of vibration from the motor into the lathe. Not really belt vibration, though I had also replaced the factory belts with USA Napa cogged belts then with linked belts to reduce belt vibration. Side note, the China belts are garbage, the belt dust wow. Instead the vibration was from the single phase pulsing of the motor, it's a higher frequency buzzing type vibration. Place your hand anywhere on the lathe and you could feel the lathe buzzing. I put a Mitutoyo 10th's test indicator on the lathe chuck, you could measure the vibration in 10ths.
So I ended up building a new aluminum motor mount for the G4003G utilizing rubber isolation mounts from McMaster-Carr. A new motor mount was required because simply adding the rubber mounts to the factory cast iron motor mount resulted in the belt jamming into the lathe end cover as it positioned the motor a couple inches further to the rear. Plus as discussed above the factory cast iron mount was a hot mess in any case.
I fired up the lathe with the isolated Baldor motor and WOW the vibration was reduced to almost nothing. Placing a hand at several locations on the lathe it felt very quiet and calm, a substantial improvement. So I turned some aluminum to test...drum roll...BAM the surface finish issue VANISHED without a trace!!! VICTORY!
3.
DRO - I knew I would be installing a good quality DRO and had owned several DroPros with magnetic scales. So I did not want to pay for some lesser quality DRO like the Grizzly thing on the G0824 knowing I'd just remove it. That was initially the nail in the coffin of considering the G0824 before I learned of the QCGB issue. This cemented the G0709 as my baseline lathe choice. Compared to similar 1440 lathes across China and Taiwan models across many different brands the G0709 was about $2,000 less expensive. That's $2k I could put towards chucks, tooling, DRO and planned upgrades. Suffering sticker price shock at DroPros I looked into the PM MagXact DRO's. Short version, this is pretty much the same DRO that DroPros sells yet cost hundreds less. I have been super happy with the PM MagXact so a big thumbs up to PM on this. Note the computer screen of the MagXact vs the less expensive model's 1980 numerical type display has been nice. So much easier to read with my 62 year old eyes.
4.
Variable Speed - After consultation with my brother who had owned a $250,000 Mori CNC lathe we decided I really didn't require variable speed. The 8 speeds on the G0709 would meet my needs fine. This narrowed down the list of lathes. Also cemented a single phase Baldor motor upgrade, eliminating a 3 phase motor and all the other gear required to convert to variable speed on the G0709. Side note, some PM lathes have double the number of speeds via a high/low motor/spindle pulley option. I guess that would have been a nice to have, something to consider.
5.
Chucks & Tool Posts - I knew I would be upgrading to Bison forged steel SetTru chucks as I had done on the G4003G so once again, I saw no reason to pay more for Taiwan chucks since I'd put the Grizzly China chucks on a shelf never to be used. I also would be upgrading to a Dorian QCTP so the least expensive China tool post was fine since it also would get put on a shelf.
With the G0709 cemented as my baseline choice I shopped 1440 lathes up through $12k-$13k. When the smoke cleared, for my needs the G0709 with my planned upgrades was the logical choice. I could not justify spending more for minimal gain. Did I run into several quality issues on the G0709? I sure did but none have been major and I expected this going in. That was part of my reasoning for spending less on the G0709. I had also noticed that people who had spent more, also ran into quality issues. Simply spending more on a Taiwan lathe was no guarantee, though certainly the Taiwan lathes have a lower frequency of issues. But not none.
Hope this was helpful.
