G0791 Combo Lathe / Mill

mglenar

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Aug 4, 2015
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Hello all,
This machine is the first i have owned where metal working is concerned. My first impression on delivery of the robustness of the castings and overall weight was good. My shop is in the basement, so thank god the house is a split level with ground level access. This being said, it was half a day getting the machine into the house and in place. That was a month ago, and initial set up was fairly strait forward. I was unable to level and tram the machine right away because i did not have jacking feet on hand. I used this as my first project. The initial set came out in less than desirable condition so i made a second set that was acceptable. On install of the jacks, i was able to level and tram the machine Because i allowed the lathe to sit un-level while i made the jacks, once i leveled and took my first alignment cuts on my test piece, i discovered a .004" taper. I shimmed the bed to take out the twist which, im assuming, was introduced by not having the lathe sitting on a true surface. after two days i was able to remove all but .0002" using a 3" dia test piece with measuring surfaces spaced 4" apart. Next i proceeded to align the tail stock at .0017 over a 24 inch span. all in all, im seeing these measurements as quite good. I will work the lathe for a couple more weeks and readjust once the machine has found its set.
A couple of items i have found over this span of time being (1). I had to replace the motor start capacitor after the second weekend, which i concede, was probably my fault due to running the machine to hard.
(2) There is no power feed while running the milling attachment, which basically throws speeds and feeds out the window. (3) With the milling attachment vertical pillar placement, the cross slide range of movement is limited when the axis of the cross slide is coincident with the pillar.
Other than these issues, and with my limited experience, this lathe will work fine for my needs. I have a couple items in mind to modify the machine, but im going to stew over them for the time being before i run them across you guys.
If anyone has any advice or suggestions please feel free to post your comment here!
Thanks ahead of time and "Good Machining"
 
can the lathe and mill work simultaneously ?
i had a HF mill/drill/lathe.
to use the longitudinal and cross feeds for the mill , you'd switch the mill on and the lathe was switched on as well.
you'd use the lathe's crossfeed and longitudinal feeds under power for the milling operations.
maybe your set up is similar???
 
Hey Mike !
That was my first thought also. I tried it and the magnetic switching kicks the power to the machine off. I have to turn off the mill and the lathe before i can reset the power switch to on.
I was thinking there may be a way to bypass this feature. i have yet to look in depth at the wiring diagram and load specifics in the control panel. Safety then becomes a concern at that point though.
Thanks for the suggestion mike, all is appreciated.
 
This is the same machine I am looking at as well. I've been bouncing around to various forums for over a year now looking at my options. I have been scouring craigslist and my local buy sale trades for over a year as well.

I kept thinking someone would want to get rid of something too large to move themselves and would come off the price. It turns out that is not exactly true.

So I've been through the info looking at the pros and cons of an integrated machine. My application is mostly gunsmithing orientated. I want to start truing rifle actions and fitting 1911 handguns for competition use. I do a lot of shooting and reloading but enjoy the gunsmithing as much as the target shooting. I have a couple approved ATF Form 1's to manufacture my own suppressors and want to get started on them. All in the name of good, honest fun and learning.

I found a lathe locally that seemed like a good deal but I believe the owner was trying to hide a crack around the main bearings and play it off as a paint defect. After all this, I'm back to looking at new machines and have continuously come back to the Grizzly G0791. Their Mossouri facility is less than 4 hours from my house.
 
fixer, This is not a post to bash 3in1 machines so with that out of the way let me make a comment. If you have room separate machines are the way to go. I have a Shoptask 3in1, with out it I never would have been able to start in this hobby. The thing is the switching from milling to turning and back again is a pain. the other issue is getting the work to a height that you can do your work. Nice work can be done do not get me wrong but to me the lathe is pretty decent but the mill portion is lacking. I still use the lathe part but have purchased a PM727 mill so no more stacking blocks and hoping I can do a tool change.
 
fixer, This is not a post to bash 3in1 machines so with that out of the way let me make a comment. If you have room separate machines are the way to go. I have a Shoptask 3in1, with out it I never would have been able to start in this hobby. The thing is the switching from milling to turning and back again is a pain. the other issue is getting the work to a height that you can do your work. Nice work can be done do not get me wrong but to me the lathe is pretty decent but the mill portion is lacking. I still use the lathe part but have purchased a PM727 mill so no more stacking blocks and hoping I can do a tool change.

Thanks for the advice. I did put off ordering machine and continued the watching locally. Lathe #2 that was serious about and went to look at was also a problem that I didn't want to take home. I'm pretty tired of looking at clapped out machines locally. I would need a good lathe to fix the lathes they are looking to sell... Which would be GREAT deals if I had the lathe to fix them. I'm probibited by my hoist from anything larger that 2 tons at the moment. I've come to realize that buying antique machines or machines that spent their previous lives in shops is not necessarily the best route for a beginner like myself to learn on.

I circled back to considering this machine the OP posted but am disappointed that they would put a 3/4hp gear-head mill on a 2hp lathe. I was looking at ordering the 4003G (same machine minus the milling head) since I'm more interested in the 13x36 lathe. Since I am not in any hurry, I decided to focus on finishing my 30x70 shop that conveyed with the interior partially finished before adding more machines to move around during the mess *unless I was to come across a deal on a used machine, which is unlikely.

On the plus side, I've had more time to educate myself. I do recommend a short read called "The Milling Machine For the Home Machinists". Its's saved me quite a bit of money buying a bunch of tooling that would be more convenient than required. For a 3-in-1 machine, this book plus the old Southbend reprint of "How To Run a Lathe" would make great companions.

Of all the combination machines out there, I do like that this one does not jam the mill head into the gear head of the lathe. It is similar to Bolton's setups. I'm sure Smithy figured this all out and got their machines working smoothly but I'd rather have separate drives at a minimum. I also have experience with some of Grizzly's other equipment and found their customer service adequate.

All that being said, I suspect the OP got a decent machine and one that would likely do everything I demand, although it would be at the cost of convenience and wear/tear on tools that have to make at least twice as many passes. I am curious if the mill head has a power downfeed, which would make it a 3-in-1 vs a 2-in-1. Grizzly does not list it as such and I don't see the traditional quill indicator that the usual suspects of power downfeeds have but they don't list a lot of features. Also, I'd add that Shop Fox and Grizzly are branding the same host lathe that is used for this machine.

I also noted Grizzly showing out of stock on both their facilities for this combo machine. They must be selling well although you'd be hard pressed to find a true review of the machine anywhere.
 
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Thanks for the recommendations. I stuck with the local searches; expanded my "local" search areas and finally came across the lathe I was hoping for. It wasn't the 4003"G" but it is the 4003, which lacks tapered bearings and a spyder. I ended up with a 3 axis Shooting Star DRO (1 axis was is setup on the tailstock) and a ton of assorted tooling that he procured from an aerospace plant that shut down. For about 1/2 of the price of the new machine with shipping and a 2 hour drive. He was even kind enough to load it in my 1-Ton truck for me because I was a little busted up.

It's all in excellent shape with the exception of an intermittent contactor. Every once in awhile, it doesn't want to power up from what he explained to me. I did some checking with a meter and found the main control power contactor (not to be confused with the motor overload) continuity was reading all over the place from one cycle to the next. One's already arrived at the house for me to swap.

Unfortunately, I took a spill from the shop ceiling I was finishing and ended up with 5 broken ribs so I haven't had a chance to really set it up before getting cleared by medical to get back to work offshore for the month.

Next up is a knee mill, which was my first goal before realizing I need a lathe to break into this game. I have a lead on one that is setup with a centroid conversion if I can get the guy to email me back.

All in all, it's taken over a year of being patient but things are coming together. I have no immediate "need" for everything so my patience paid off. I used my time to bone up with books, pick up some good deals on indicators and layout tools so I can hit the ground running. When I get back home, I'll be finishing that shop (injury free this time) and putting together my machine side of the shop.
 
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