More newbie lathe questions.

[franco]

Clinthub,

Quote: "Since you have had yours for 10 years I wonder if it isn't a Taiwanese product. Just curious."

Definitely China. It has "Made in China" prominently on the front panel, and, curiously, on the back of the lathe where it is obscured by the motor mount to the point it is almost invisible, "Shaoxing". It was made by the Shaoxing Tongli Machine Tool Company in 1996.

While some people on forums have reported problems with the generic 12x36s, there are a lot of satisfied owners too. The machines are very obviously built to a price, and are certainly not industrial quality. I bought mine with some misgivings to supplement my sixty year old flat belt drive 9x18 after looking intermittently for five years for a good condition second hand lathe locally in this size range with no result, and have not regretted it - it's much better than no lathe at all!

franco

[oldtiffie]

Machines on "island" benches

Deleted/erased-out

[Clinthub]

Clinthub,

While some people on forums have reported problems with the generic 12x36s, there are a lot of satisfied owners too. The machines are very obviously built to a price, and are certainly not industrial quality. I bought mine with some misgivings to supplement my sixty year old flat belt drive 9x18 after looking intermittently for five years for a good condition second hand lathe locally in this size range with no result, and have not regretted it - it's much better than no lathe at all!

franco

Franco,

Yeah that is where I ended up too. I would love to have a mint SB or Clausing that was owned by a little old lady but decided that I am as likely to be elected Pope as to win the lathe lottery. I looked at these two machines at the Grizzly showroom in Pennsylvania and got the manuals for both beforehand, which I think is a must-do before buying. The G4003 manual is actually quite good and is written by someone fluent in English. The G9249 manual is a sparse little document riddled with typos and often doesn't reflect reality. The lathe has apparently changed since it was made in Taiwan but the manual was never updated. I was unduly influenced in the showroom by the apparently better quality of the castings on the G9249 than the G4003. Now I realize that the guys who made it are just more artful with Bondo and paint. After the heroic UPS guy and I wrestled the crate up my driveway and into the garage and I got the crate open, I discovered the bottom of the crate covered with a layer of sand. It looked like one of our Delaware beaches after the tide went out. I was at first horrified but then decided to look on the bright side and be thankful that the sand wasn't still in the castings. Of course how much remains in the castings is a good question. I guess shipping it half way around the world and dropping it off a few loading docks is actually therapeutic as far as ridding the castings of sand goes, but that may be what knocked the headstock out of alignment.

The bottom line as you say is that it is better than nothing. I knew going in that I would be making some mods just like I did to my mini lathe, which ended up after the mods being a pretty good little machine. I still have it. I just didn't think there would be so many needed for what I thought was a "real" lathe. It also points out that all Chinese made tools are not created equal. The quality of the Sieg made "mini" tools is clearly better than my Miss Bondo. Anyway in the next life if I come back with the same vice it will be a G4003G for me.

Clint

[J Tiers]

On that G4003, I'd be more worried about other things and not the feed. (see below)

You can always juggle gears to change feed rates etc, if you really need to.

I rarely use power feed anyway, because I rarely turn long shafts etc. There the power feed is far more consistent than your hand feeding will ever be. But for small items, it's almost more trouble to use the power feed.

With hand feed, you can feel what is happening, and adjust on the fly. With power feed, and a large depth of cut, you may have trouble finding a good rate and end up feeding by hand anyway.

If you need to turn an inch of a 0.375 shaft down to 0.093 (counterbore pilot, for instance) you'll probably do that in one step, with a high rake tool, and you'll hand feed unless you have really fine power feed.

If you are turning up to a shoulder, as in the pilot example, you'll need to hand feed the last bit anyway.


The real problem:

The g4003 has a slowest speed of 70 rpm. MIGHTY FAST for a 12" lathe.

Doing quick calculations, for a piece of CRS that wants about 100 f/min surface speed, your largest blank you can turn and maintain that speed is 5.5" diameter. Not even close to 12". Any larger, and you go over the 100 f/min. At max diameter, your speed is double that.

They give you a 10" faceplate, what do they think you will do with it?

If you ever work with tool steel, at 40 f/min, it better be a small piece. Anything over 2" diameter and you are above 40 f/min. Now, if it was very stout, and could run carbide to max, that wouldn't be a problem, but I doubt that's true.

These asian imports seem not to ever have real back gears. That 70 rpm is actually slow for them, I have seen as high as 150 rpm minimum, on a 10" machine.

That's almost a "second operation" or "speed" lathe, good for polishing, finish cuts etc.

My cheapo 10" Logan has a back gear speed of about 30 rpm. It swings almost 11" at maximum. The equivalent max diameter for 100 f/min is over 12" diameter, larger than will fit. So it's set up fine to use the max diameter on typical stuff.
For 40 f/min tool steel, max size is 5", as large a punch as I am ever likely to work on.

[BadDog]

I'll second the low speed problem, though I don't know if it is more important than feed and other considerations, that would be a personal application matter. Still, it was one of the bigger complaints with my old Griz. My current 11" Rockwell is rated down to 50 rpm on the plate, would actually go to around 45 stock, and now goes down to ~40 with a slight mod to the Reeves drive. And that does not even include the use of VFD which could take me easily to 20 rpm if desired, though torque would likely be a problem given the diameter that would be the likely source to require such low rpms. A VFD would help some with the 70 rpm min, but again, you really need the mechanical reduction to bring the torque to where it needs to be on large diameters.

[Rumbledoll]

I also did the too close to the wall, thing, but managed to get it wired non-the less. The headstock room, though - I had a wall to the left, set the lathe down with a couple of feet to spare, so that the cover would open. There is a window in the wall, and just in case, I cocked the lathe a little, and made a taller stand, so that a piece of stock would just clear the window sill. I did have to grind out a little of the window frame, but it has made a nice bearing. All was fine until one morning early, I had a pretty long shaft - had to be done by 8.00 am. Opened the window, tried to shove the shaft in - the shop is 5' from the property line, and there is a tree just on the other side of the property line - no way. I took the tailstock off, and confirmed one more time that a shaft would not bend past the mill, and into the small lathe headstock. It took about five minutes to decide, but with the help of an extension and a Milwakie self-feed bit, I soon had a nice self-standing, wooden outboard headstock support (tree). Over the years, that hole in the tree has been used more than once - although when I added on for the bigger lathe, the wall - and the wall across from that - had holes built into them.

Good Luck,

Mike

[J.Ramsey]

Tree Rest

What are you going to do when the tree grows and changes your center height ?

[Clinthub]

[QUOTE=J Tiers]On that G4003, I'd be more worried about other things and not the feed. (see below)

Mr. Tiers,

You are quite right about the "low" speed. That was the main deciding factor for me in buying the belt drive Griz with a back gear speed of 50. I would rather have 35 for threading to a shoulder and turning to a .45 inch reamer, but 50 was better than 70. Before buying the big lathe I spent some time on my mini-lathe with a tach and variable speed motor trying to thread to a shoulder on a section of M14 barrel. At 50 RPM I could cope. At 60 (JET BDB speed) I had to hussle but it was possible if risky. At 70 I couldn't keep up. So 70 seemed to fast for a career amatuer. It seems that buying a lathe is rather like buying a car, no single unit has all the features you want. If I had the gear head G4003 I would probably have to convert to 3 phase and VFD. As it is I shall be spending much time now learning how to turn the carriage hand wheel REALLY slowly.

Regards,
Clint