G0709 for mcdanlj

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mcdanlj

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As I have been preparing my shop for my PM-30, I started thinking about a larger lathe, too. I started looking at various 1340s and 1440s and thinking about maybe a few years out. Then, just to see what the local market looked like, I glanced at CL—and saw that someone local had a reasonable deal on a G0709 with only a few years under its belt. So much for "a few years out..." The main thing it's missing for me are DROs. The DROs on my PM-30 seem reasonable, so PM's DRO kits are certainly an option.

Today, with the help of two dedicated and wonderful friends, I moved it into my shop!

I think I've read all the G0709 threads on this forum to prepare, so hopefully I'm set to get started. When I want more variety in speed, or better surface finish, or am bored, I may consider a 3Ø with VFD conversion. I've been looking at the schematics and it doesn't look like it would be super hard, and in fact would probably make the foot brake even more effective as a bonus.
 
The G0709 is definitely a very nice lathe, especially in good shape and just a few year old. A proper VFD conversion for a single phase lathe is a bit more complicated then you may anticipate, when a VFD is used, typically it is either used for braking or the mechanical foot brake is used but not both. They will fight each other as the VFD wants to brake the machine in a prescribed fashion as setup in the parameter file, so jumping on the mechanical brake (which can stop the machine very quickly) the VFD may slow down that process if you were to use something like a 3 second stopping time. What is typically done is to change the foot brake electrical switch which shuts down the motor contactors, to a 2 pole version. One side is configured NC which connects to a power relay which shuts down the VFD run inputs, the other NO pole issues a free run command to the VFD so it does not brake. This allows you to use the mechanical brake independently of the VFD braking. I have built numerous lathe VFD systems this way.

Some lathe manufactures have done away with the mechanical brake altogether, they just used the foot brake to send an emergency stop command to the VFD, which will brake it at the fastest time possible without tripping it into an over voltage error.

You will need to look for a 3 phase motor that will fit the machine, I recommend what is known as a Vector/inverter motor which ate typically TENV type for this size machine. I have been using the Marathon BlackMax, Lincoln, and Baldor IDNM/ZDNM types.
 
Congratulations on picking up a G0709. I've had mine just over 3 years with no issues other than what's been documented here. I have a TPACTools DRO on mine.

Bruce
 
mksj said:
A proper VFD conversion for a single phase lathe is a bit more complicated then you may anticipate...
Click to expand...

Thank you for all those specifics! How kind! I wasn't sure what would be faster; mechanical brake or emergency stop on a VFD with a properly-sized braking resistor. At any rate, I'll be investing in more tooling before I play with electrical upgrade. ☺ But now I can daydream more realistically! :grin:
 
BGHansen said:
Congratulations on picking up a G0709. I've had mine just over 3 years with no issues other than what's been documented here. I have a TPACTools DRO on mine.
Click to expand...

I'm trying to make sense of the differences between DRO packages out there. The set on my PM-30 seem good, so the Precision Matthews 8x40 lathe DRO package seems like a contender. The TPACTools DRO package looks pretty similar and sells for a similar price. The DROPros sets are $800-$1000 for the various 8x40 sets—so roughly twice the price. I haven't put together a spreadsheet to compare all the measurements from the provided drawings and probably I'll wait until I finish some work on my shop itself before I start seriously looking into it. In the meantime what factors have y'all considered for comparing the available DRO packages appropriate for a 14x40 lathe? Any other vendors I should be considering when I get there?
 
Hi mcdanlj,

Here's the thread on the DRO I installed on my G0709 from TPACTools. Frankly, haven't shopped for another DRO since I'm not currently looking for another one. I chose TPAC originally for a mill 4 years ago because of a friend's recommendation. Had a good experience with that one, so went with them for my G0709.

Bruce

https://www.hobby-machinist.com/threads/grizzly-g0709-lathe-dro-install.49902/
 
The manual says to make sure to use a rubber tip ball oiler to avoid damaging the ball oiler ports. On a google search, I see lots of folks saying that they have trouble finding rubber tipped ball oilers. I can find plastic junk with reviews saying "this broke on my first day using it" and things like that, but I haven't found what the manual tells me to use. Do folks mostly just use rubber hose over the tip of a metal oiler to make a seal without pushing the ball too far in? Also, I guess I could turn a tip from something soft like PE. Or does everyone ignore the manual?
 
In order to get the spindle better aligned with the ways, I'm having to take basically all the weight off the middle feet and use only the end feet to hold the lathe up. This doesn't make a lot of sense to me; why would there be six feet if I'm really only using four? But I'm sweeping a turning test bar and with runout around 1-2 tenths, I'm seeing 2-3 tenths per inch rise in the test bar towards the tail when I have similar weight on all four headstock feet. By transferring essentially all the headstock weight to the outside feet, I reduce that rise to 1-2 tenths per inch.

I think I saw the same thing indicating both against the top and bottom of the test bar, but I guess I could have misread. I suppose I should mic the test bar to make sure it has consistent diameter, not a gentle taper.

That's on the order of ~2 thou / foot error, which doesn't seem terrible. Is it a reasonable plan to let the lathe settle for a few days on four feet and then put some weight back on the middle feet for the long term? I'm still leveling it daily as it settles in.
 
mcdanlj said:
The manual says to make sure to use a rubber tip ball oiler to avoid damaging the ball oiler ports.
Click to expand...

I use an allen wrench (1/16") to push the balls open and a regular oiler and watch until a drop has run down into the oiler. I found this easier the trying to use the tip of the oiler to push on the ball.
 
mcdanlj said:
The manual says to make sure to use a rubber tip ball oiler to avoid damaging the ball oiler ports. On a google search, I see lots of folks saying that they have trouble finding rubber tipped ball oilers. I can find plastic junk with reviews saying "this broke on my first day using it" and things like that, but I haven't found what the manual tells me to use. Do folks mostly just use rubber hose over the tip of a metal oiler to make a seal without pushing the ball too far in? Also, I guess I could turn a tip from something soft like PE. Or does everyone ignore the manual?
Click to expand...

The Reilang oil gun is awesome. The Reilang products are not cheap, but much cheaper than the result of not getting oil to where it needs to be. There are any number of other options for delivering oil into the oil fittings (less expensive) - several of which I tried. I would have been money and fussing ahead if I'd followed the advise of Forums similar to this one and got a quality oil gun (also called a "hand push oiler") right off the bat.

Regardless, make sure the oil is getting to where it needs to be.
 
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