The Grizzly 4003G wasn't out yet when I bought my Birmingham or yes, I would've bought it.
The 4003G has four primary features that set it above the 4003 and the Birmingham.
1- beefier spindle being D1-5 with 6 pins instead of D1-4 with 3 pins.
2- different/better spindle bearings
3- tailstock clamping via torque wrench
4- cabinet stand is much better than the 4003 and Birmingham
I think those are the only differences. Everything else is the same as the 4003 and my Birmingham 12x36.
Steve Bedair has one of the 4003G. He's a gun guy. I've had email with him about his Grizzly mill as it's the same as mine except his is 1 phase 5 speed. (I like mine better).
http://bedair.org/Grizzly12x/GrizzlyG4003G.html
his mill
http://bedair.org/Mill/6760mill.html
Once you hit 13" swing on a lathe the $$$ starts climbing. I could've gotten the 14x40 but didn't see a real point to it. I'd lived 30 years with a 15x60 so I knew what you could and couldn't do with either. With an antique 15x60 there's very little you can't do as long as you can figure out a way to chuck it up or attach it to a face plate. I machined the front hub of a Ford F250 4x4 once. That dude was pretty heavy and big but the 10" Union 3 jaw chuck took it in stride.
These smaller lathes like the 12x36 are not heavy duty lathes. The Atlas 10x36" that I owned for 25 years was capable of good work. It was a light duty lathe but could do a great deal. The 4003 and Birmingham are "semi-medium" duty lathes. Certainly capable of more grunt work than the Atlas but nothing like the bigger beefier lathes. I've run 18" LeBlond in college and I think that was the biggest I've run. Big lathes are fun.
Buying used American iron is risky. My Von Wyck was only 75 years old when I bought it in 1979 but it had a lot of wear and tear on it but it cost only $500 in '79. Best money I ever spent, too. But older South Bend and Logan and those are/were great machines. But you might have to spend a great deal of time repairing older machines. There was no place to buy parts for the Von Wyck so either I made it or adapted something or did without. Fortunately in 30 years of use I didn't need anything major.
You need to research an awful lot if you were going to shop for a used South Bend Heavy 10, for example. I'd prefer a 14" or 18" South Bend. You could machine truck brake drums on a 18" lathe. I did disc rotors on the Von Wyck but it was close.
For a couple years I also had a Clausing 6300 12x36 lathe in my home shop. My brother bought it and I ended up with it. It was a very accurate lathe. The Birmingham sort of emulates the Clausing. But the Clausing 6300 was a very nice lathe. The earlier 4900 and... there was one other model.. they are also very accurate and capable machines. But to find one that doesn't need some upkeep.... maybe not so easy. A really nice 6300 could run $3,500 still. And they're fairly old lathes now. The 4900 even older.
this is the Clausing 6300. I had the variable drive setup.
http://www.lathes.co.uk/clausing/page2.html
LeBlond Regal. 19". This is the one I used in college. FYI My Von Wyck 1903 was made with a LeBlond patented carriage drive. The co-owner, Roach, was the superintendant at LeBlond at the turn of the 20th century. The Von Wyck was a very good lathe.
http://www.lathes.co.uk/regal/page5.html
It wouldn't hurt to spend a lot of time reading the lathes.co.uk website. It is the most awsum machinery website in the world. My old Index mill is featured on this page:
http://www.lathes.co.uk/blankbuxton/
Here's a pretty clean South Bend 10". $1800. I have no doubt it's a very decent lathe. But will a 10" lathe give you the capacity for what you may want in the future?
http://cgi.ebay.com/South-Bend-Lathe...item2ead78e24b
Another Heavy 10" South Bend. I wouldn't be afraid to buy this one and plug it in and start turning. You'll learn as you go.
http://cgi.ebay.com/10-South-Bend-La...item35acc9dcf3
12x30 Hendley.. pretty good looking. $4100. But a very beefy lathe. I would say this has twice the beef as the 4003G.
http://cgi.ebay.com/HENDEY-12-X-30-E...item3cac4ffbc7
LeBlond Regal $1100 start bid. 14X42". I'll say this much: At least it's CLEAN. It's BEEN cleaned. Some are fithy.
http://cgi.ebay.com/HENDEY-12-X-30-E...item3cac4ffbc7
14x48 Clausing. Very clean. $4750. You see? American = $$$$$.
http://cgi.ebay.com/CLAUSING-VARIABL...item19bfdb4d3e
15x42 LeBlond Regal mfg 1964. This dude is very nice, very clean, very well taken care of. It's also $5950. Is it worth that? Yes, I think so. Of course it's been painted but it was painted nicely, carefully and the ways look very nice. It also has DRO. When you get done looking that $6000 isn't all that much more than a new Chinese 14x40. I rather like this one
. Study the carriage and compound surfaces. It's not beat up or abused. That's the kind of thing you look for in a used lathe. Abuse and neglect. This LeBlond is darn nice for just coming across it.
http://cgi.ebay.com/15-x-42-cc-LEBLO...item1e5e5e66c1
Here's an old Cincinnati 15x54" for $100 starting bid. A HUNDRED bucks. It's in Paramount, Calif. That's by Compton... Inglewood... places you'd need a gun to visit
. I was born in Inglewood.
http://cgi.ebay.com/Cincinnati-lathe...item415336070e
Another darn clean LeBlond 15" Regal $3500.
http://cgi.ebay.com/15-LeBlond-Regal...item563f78db51
And finally... a totally cool Monarch 15". $1800 BUY-IT-NOW and darn nice looking for a lathe that old. This is a flat belt lathe. The headstock is very simple. It looks like a 6 speed back-geared lathe. This is a very capable lathe. Very heavy duty. Much beef. This could be as late as 1940s era World War 2. I'm not up on the dating of these but they are a very well thought of lathe.
http://cgi.ebay.com/MONARCH-LATHE-15...item45f5798177
Older used lathes you have to know what can go wrong and how to find parts and fix it. Or you need somebody experienced to shop with you. Finding a use lathe via a machine shop that wants to get rid of one is not a bad way to go as long as you can take somebody with you and spend sometime inspecting it UNDER POWER.
And this is why lathes like the 4003G sell so good.
Dutch