[slakwhere]

OK guys, i just took delivery of a used G0704 mill in great shape with a GMT vise. Tooling is on the way. it's completely original. I've been reading lots of threads here by people that have gone way off the deep end, and it's fantastic but not really what i think i need (at least not yet). I've come up with a hit list for a CNC build on this machine and i would love input on anything else i should do while it's apart, things i shouldn't bother with, etc. any suggestions would be appreciated!

i am fairly new to machining, so i think i'd rather buy someone's kit pre-fab rather than try to make mounts from scratch since i don't have access to a second mill once i've taken this one apart. I have the hoss plans from a while back but i haven't really been through them in great detail yet.

1. 3 axis CNC with retention of manual mode for simple operations. this is a big one for me. not everything i do in the shop should require programming.
2. Y motor in the back with a pulley so i have a front handle and it doesn't stick out a ton. seems this requires drilling the column which i'm ok with.
3. Y travel upgrade. suggestions here? spacer blocks? i know hoss has some info here.
4. Conversion Kit - i sort of want to buy a kit because i know it should all work together, but i don't want to waste cash if it's going to be full of parts i can't use. this seems like a decent kit for $1k all in, but are these the controllers you guys like? have a better recommendation?
5. Software - i've got LinuxCNC running in a VM while i build a dedicated PC so i can play with it a bit. i'd throw down for mach3/mach4 but it sounds like LinuxCNC is very stable, which i like. For the CAD/CAM side it'll be mostly Fusion360, free is hard to beat.

i'm sure there will be a build thread soon as i actually get started with all of this. I'm overwhelmed by the knowledge and generosity of this place, thanks for sharing all your hard work!

[arizonavideo]

The need for handles goes away real fast. You can use the on screen MPG just fine for manual jobs, I do it all the time.

If you really need longer travel in every way you should start out with a larger mill. That being said a 1.5" column spacer and head spacer will help to stop the vice from hitting the column.

Really the largest drawback is the low spindle speed. A belt drive is a good idea.

[slakwhere]

are you just setting a feed rate in the display and holding a feed direction digitally with a keyboard/pendant/mouse? that's for sure an option i guess, but i'd like to not even have to power up the computer just to take a pass or drill a hole. a manual machine sure is handy sometimes for non-critical operations.

i don't NEED longer travel, but if it's apart and fairly easy to do, i'm going to do it while it's apart. i know RusStuff on youtube didn't and really regrets it. it seems like a pretty low hanging fruit item.

would you say the belt drive for the spindle is easy enough to do later after sorting out the rest of the CNC stuff? or a big enough change that it should be done while the machine is apart for ball screws and steppers/servos?

[Connor]

If you plan on using ball screws, handles won't work. The Z will most likely slide down, and you would have to lock the gibs for drilling, and for manual milling, the screws could back off.. Get yourself a $100.00 drill press.

Software wise, I prefer LinuxCNC. Don't do CAD/CAM on the Machine Controller. Use a laptop or desktop for that. Keep you Machine Controller as clean and simple as you can.

are you just setting a feed rate in the display and holding a feed direction digitally with a keyboard/pendant/mouse? that's for sure an option i guess, but i'd like to not even have to power up the computer just to take a pass or drill a hole. a manual machine sure is handy sometimes for non-critical operations.

i don't NEED longer travel, but if it's apart and fairly easy to do, i'm going to do it while it's apart. i know RusStuff on youtube didn't and really regrets it. it seems like a pretty low hanging fruit item.

would you say the belt drive for the spindle is easy enough to do later after sorting out the rest of the CNC stuff? or a big enough change that it should be done while the machine is apart for ball screws and steppers/servos?

[slakwhere]

well i guess that means no handles :/ i'll have to get a pendant down the road then.

software will be LinuxCNC on the Machine Controller and nothing else. Isolated from everything. CAD/CAM will be done on a windows machine with Fusion 360 (which to my knowledge doesn't run in nix anyway)

[xdnok]

Sounds like you have a good start, I had fun with my G0704 and it's a great way to get started with a new addiction, I mean hobby..... I went with automation technologies complete kit that put the y axis on the back which is a very clean setup. The kit I got had a g540 controller, it worked ok, but the z axis was little weak and wished I had gone with Hoss's heavy duty recommendations so don't skimp there. Limit switches, get some good ones as you will use them a lot, the inexpensive ones did not work well or last long for me. Automation direct has some nice ones. I left my x/y wheels on without the handles and took the z off at the flange, easy to put back on for a quick cut. Downside is with ball screws the z axis falls like a rock when not powered on. I also regret not extending the y axis on mine as well when I had it down for conversion as I had doubts on removing more material from the base at the time. If you have modest needs the immense pride you get from remaking the machine is awesome and the parts made from it even more so. My needs grew quickly (kinda like when your friends realize you have a truck and you can't say no) and now I have moved on to a 770 Tormach and my G0704 sits in the corner waiting on me to put it up for sale for someone else to start their project. The one thing that really stands out to me now after getting the new machine is the faster spindle speeds, a belt drive from someone like Benchtop precision and a different motor for the G0704 would make a world of difference in cutting aluminum.

[hoss2006]

There's a simple solution for a dropping Z and all it takes is a relay or switch.
Hoss

https://www.youtube.com/watch?v=21LY6y5xf-Q

[slakwhere]

that is an awesome solution! so you just flip it down to short A+ and A- when not in use? do you power down the rest of the control box / PC when not in use?

thanks for the help, hoss! i've been studying your plans and videos, and you're the main reason i'm about to embark on this journey. thank you for all your contributions to the community over the years!

There's a simple solution for a dropping Z and all it takes is a relay or switch.
Hoss
]

[slakwhere]

heavy duty being a bigger stepper on Z?

Limit switches are for sure going to have to happen. i will probably bite the bullet and get good sealed ones just in case i ever go to flood coolant.

as for growth, i have a truck but my friends know not to call me to use it unless there's something in it for me... i expect the CNC to be the same way. i've told very few people about it just yet to help keep it quiet.

Once i get the rest of the machine back together i may have to look into a motor and belt drive upgrade for this box. i'm trying to tell myself now that going slow is ok (no flood coolant, slow drive on the OEM motor) but i know once i get into it it'll snowball into the whole 9 yards.

Sounds like you have a good start, I had fun with my G0704 and it's a great way to get started with a new addiction, I mean hobby..... I went with automation technologies complete kit that put the y axis on the back which is a very clean setup. The kit I got had a g540 controller, it worked ok, but the z axis was little weak and wished I had gone with Hoss's heavy duty recommendations so don't skimp there. Limit switches, get some good ones as you will use them a lot, the inexpensive ones did not work well or last long for me. Automation direct has some nice ones. I left my x/y wheels on without the handles and took the z off at the flange, easy to put back on for a quick cut. Downside is with ball screws the z axis falls like a rock when not powered on. I also regret not extending the y axis on mine as well when I had it down for conversion as I had doubts on removing more material from the base at the time. If you have modest needs the immense pride you get from remaking the machine is awesome and the parts made from it even more so. My needs grew quickly (kinda like when your friends realize you have a truck and you can't say no) and now I have moved on to a 770 Tormach and my G0704 sits in the corner waiting on me to put it up for sale for someone else to start their project. The one thing that really stands out to me now after getting the new machine is the faster spindle speeds, a belt drive from someone like Benchtop precision and a different motor for the G0704 would make a world of difference in cutting aluminum.

[CL_MotoTech]

I use a 25lb air spring to support my Z. It never drops and it never misses steps. Cost was maybe $20 from McMaster. I made a bracket out of some .5" aluminum bar stock.

Belt drive, motor, spindle bearings are big. I run my machine at 6k RPM (that maxed out) for almost all of my work which is almost totally in aluminum.

Forgo Lovejoy couplers. They are junk IMO. Go straight for Ruland Oldham couplers, they can be had cheap on Amazon.

Beyond that it's all butter. Lot's and lot's of tweaks to improve many things.

[slakwhere]

is your air spring set up parallel to the column i assume then? that seems like cheap piece of mind!

belt/motor/spindle bearings are going to be phase2 for me once i know i have the machine working the way it should be. it'll also give the illusion i didn't spend as much money if i space it out over time.

Ruland Oldham couplers, got it! jam nuts on all ballscrews as well.

tweaks i'm good with, i just don't want to miss something while it's apart that i should have done (like Y travel increase)

great list, thank you!

I use a 25lb air spring to support my Z. It never drops and it never misses steps. Cost was maybe $20 from McMaster. I made a bracket out of some .5" aluminum bar stock.

Belt drive, motor, spindle bearings are big. I run my machine at 6k RPM (that maxed out) for almost all of my work which is almost totally in aluminum.

Forgo Lovejoy couplers. They are junk IMO. Go straight for Ruland Oldham couplers, they can be had cheap on Amazon.

Beyond that it's all butter. Lot's and lot's of tweaks to improve many things.

[CL_MotoTech]

It's fairly close to parallel. Close enough that I've never had any issues with binding of the column. Before I assembled the ballscrew assembly I was able to move the Z-axis up and down fairly effortlessly by hand which indicates that I got a fairly good balance I think.

[slakwhere]

good enough for what i'm going to be doing with it for sure it may also allow me to keep manual mode, which would make my shop mate happy.

[CL_MotoTech]

I actually installed the air spring when I was using the machine manually. After lots of machining my right arm would totally be destroyed. The air spring helped my arm fatigue in that at least going down and up required the same effort whereas up was fairly tiring beforehand. When I did the CNC conversion I initially took the gas spring off. After fighting with missed steps, the annoying falling column when powered down (easily solved with a wood block), and a few other minor problems I reworked my bracket and installed it again. It solved a lot of those problems in a very simple and economical way. Sure there are fancier methods out there, but for the time and money investment I'm not sure it can be matched.

[taiwanluthiers]

One thing I found that worked well and can be done out of the box:

Flip mod.

Basically remove the head, then the slide that holds the head to the column. Reinstall it backwards and you will have added at least 6" to the table to spindle distance, I have not tested if it increases Z axis range but it seems to add a few inches to the Z axis range... Doesn't really affect the operation of the machine other than looking kinda funky with the lock lever on the wrong side and all... as well as the head being displaced about 1/4" to the left. But it adds a LOT more room for things like a big vise with swivel, a rotary table, long drill bits/tools, shell mills, face mills, taps, etc.

If you're going the manual route (no CNC) a DRO will really help. I'm doing this mod now but you can also buy the G0759 which has DRO included (but if you're going to do the flip mod you may need to modify the Z axis scale). In fact if you're going the manual route add a DRO before you tinker with belt drive, because honestly you can manage your machining technique to deal with lower RPM but DRO will help with accuracy especially when you're following a plan. Though expert machinists will tell you to count handwheels, it gets tiring and if you lose count, you start over. That's also not accounting for the fact that leadscrews have worse accuracy than DRO scales...

[coherent]

Even if you think it not a necessity, consider a belt drive down the road. The "plastic"gears that drives spindle will eventually become an issue. The plastic gear will eventually go. Believe me.. almost every G0704 owner has "been there done that". If nothing else, order a couple extra of the plastic 37 tooth gears that drive the secondary drive off the brass motor gear. Bet better yet, look as Hoss's belt drive info and make the upgrade. I think it's just a matter of time before you either need it or wish you had it. Have fun with the mill. It's a great mill. Lots of info and upgrade info and lots of mods you can do yourself.

[taiwanluthiers]

I always wonder about the rationale of plastic gears, are they there to protect the mill if something jams up?

I used mine a bit but never got to the point of stripping or destroying the gear.

[slakwhere]

with just flipping the head (no machining of the column) you get the extra travel? no need to remove material on the column to still have tooling reach the table? i was planning on a Y extension for sure, CNC almost 100% for sure (just have to work out the details) and the Z flip looks straightforward enough.

One thing I found that worked well and can be done out of the box:

Flip mod.

Basically remove the head, then the slide that holds the head to the column. Reinstall it backwards and you will have added at least 6" to the table to spindle distance, .

[slakwhere]

i will consider a belt drive for extra RPM and such, but it won't be part of phase 1. probably a good idea to order extra plastic gears in the mean time!

[taiwanluthiers]

Unless you're using very stubby tooling, without any extension (collets, not end mill holder) I seriously doubt it will be a problem. Hoss's video did show that he had to remove some material from the slot to increase the travel but honestly I found it unnecessary because I can always use the quill. Otherwise the 2" of distance from the table would be easily taken up by any end mill holder...