Opinions on purchasing a Grizzly G0750

[epanzella]

The issue of a lathe only doing 54 vs 112 or 200 TPI comes up a lot. I think it's a bogus parameter to compare lathes.


The challenges of making anything finer than 54 TPI would prevent any sane person from attempting this on a benchtop machine. The spacing of threads at 112 or 200 TPI is approaching the resolution of the pixels on your computer monitor. Most PDF files have a resolution of 72 Dots Per Inch and I don't think it's possible to cut threads at 112 or 200 TPI in a homeshop. At 112 TPI, you will need to use a sewing needle as a cutting bit -and most chucks cannot hold a piece of 18 ga wire.

Not trying to ruffle any feathers, Ray. The man asked for info on the G0750. The Grizzly catalog doesn't show the thread range of the G0750 so I thought that info might be of use to him. I did say" I think you'll be happy with either one".
Ed P

 

[Ray C]

No worries... Feathers not ruffled... Only stating that 112 and 200 TPI is a ridiculous (take that back, ludicrous) paramter by which to judge a lathe. And yes, both are fine.

Ray

Not trying to ruffle any feathers, Ray. The man asked for info on the G0750. The Grizzly catalog doesn't show the thread range of the G0750 so I thought that info might be of use to him. I did say" I think you'll be happy with either one".
Ed P

 

[kd4gij]

There's only three "significant" differences. One is 4" longer than the other. The 36" unit has a max spindle speed of 1500 and the other was 2000. One is 1100lbs, the other is roughly 1340lbs. The extra mass is nice sometimes...

For benchtop lathes of this sort (and for what they're generally used for) 1500 RPMs as the top speed is fine. BTW: These units are carbon copies of the Precision Matthews 1236 and 1440.


Ray

One outher big diff. is the G0709 has a foot break the outhe does not.

 

[epanzella]

No worries... Feathers not ruffled... Only stating that 112 and 200 TPI is a ridiculous (take that back, ludicrous) paramter by which to judge a lathe. And yes, both are fine.
Ray

I would imagine that the power feed would be coarser as well. I noticed that the G0750 comes with 10 change gears instead of 6 so there are some difference in how the enclosed transmission works vs the traditional one. The on line manual has a lot of pop-up boxes over the feed chart so it was hard for me to figure out the feeds.

 

[Ray C]

Possibly so but when I set mine down to 0.001x range of IPR, I get finish surfaces that look like it was ground with a tool post grinder. If it went any slower, I'd fall asleep in the middle of the cut. Also, it's a double edge situation... when the IPR is down real low, there's more time for a vibration to setup and ruin the finish. I usually go much faster than the low-end speeds.

Ray

I would imagine that the power feed would be coarser as well. I noticed that the G0750 comes with 10 change gears instead of 6 so there are some difference in how the enclosed transmission works vs the traditional one. The on line manual has a lot of pop-up boxes over the feed chart so it was hard for me to figure out the feeds.

 

[epanzella]

Possibly so but when I set mine down to 0.001x range of IPR, I get finish surfaces that look like it was ground with a tool post grinder. If it went any slower, I'd fall asleep in the middle of the cut. Also, it's a double edge situation... when the IPR is down real low, there's more time for a vibration to setup and ruin the finish. I usually go much faster than the low-end speeds.

Ray

Ditto. I haven't been using the slowest feeds much because I've been using carbide and it seems the harder I push it the better it works. When it comes to carbide I'm like a kid in a candy store because my previous machine wasn't rigid enough to use it causing chattering and chipping of the inserts.

 

[Ray C]

I'm not sure which machine you have but on mine, there is a speed doubler selector lever that controls the feedrod and leadscrew... Sometimes I wish it has a 1, 1.5 and 2x position instead of just 1 and 2x... That middle position would be really nifty... Oh well...


Ray

Ditto. I haven't been using the slowest feeds much because I've been using carbide and it seems the harder I push it the better it works. When it comes to carbide I'm like a kid in a candy store because my previous machine wasn't rigid enough to use it causing chattering and chipping of the inserts.

 

[epanzella]

I'm not sure which machine you have but on mine, there is a speed doubler selector lever that controls the feedrod and leadscrew... Sometimes I wish it has a 1, 1.5 and 2x position instead of just 1 and 2x... That middle position would be really nifty... Oh well...


Ray

I've got the old fashioned QC Trans with the detents and the pins that's been around since Picasso. I'm having fun but I don't know enough to know what I don't know......yet.

 

[Ray C]

Well, you've got the right idea about pushing carbide a little faster than HSS. When the top of your hand is covered in small blisters, you're working the carbide just right ).

I've got the old fashioned QC Trans with the detents and the pins that's been around since Picasso. I'm having fun but I don't know enough to know what I don't know......yet.

 

[eac67gt]

Just an update....grizzly did not have in stock, locally, the lathe my son wanted so he is not getting one right now. His intentions were while he was home on summer break he would get lathe and help me set it up. He still fully intends to get one but not this week. We are making the trip up to grizzly anyway just to take a look and drool on equipment. I will let you know what the next move is on buying a new lathe. Thanks for everyone's input.
Have a great day!
Ed

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