Newbie G0704 - build planning advice requested


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Thread: G0704 - build planning advice requested

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    Default G0704 - build planning advice requested

    Hi everyone,

    Long time lurker, first-time poster. I've been running my G0704 manually off and on for the past 3 years and tore it down for a move a year ago. I'm planning to put it back together CNC'd in a basement utility room. I bought Hoss' full set of plans, and I've read through quite a few build threads here over the years, but when it comes to finally settling on my own design choices I find my head spinning a bit with all the options. My current goal is to machine some astronomy parts, so I think I need as much precision as I can squeeze out. I know I want the build to eventually include ballscrews; I'm unsure on extending the Y and Z travel. I need an enclosure, so I'm leaning toward rear-mounting the Y stepper with a belt drive. I'm unsure on belt driving the X and Z, but it seems to be considered a popular choice at 2:1; is that right? I'd appreciate others' thoughts on the following --

    * 3d printing the "phase 1" parts. Hoss mentioned most of the STLs being "untested" in his documents, but have they been tested since? Is it a viable plan to print those parts, assemble the mill with CNC, and then machine the phase 2/3 mounts? possibly doing extension mods as part of the upgrade? Are there recommendations on infill for the prints?

    * ballscrew vendors. Is automationtechnologiesinc.com still a preferred vendor for screws and electronics? same question for linearmotionbearings2008 on eBay? Are there newcomers worth checking out?

    * automatic oiling of ballscrews. When I have ballscrews, how critical is an oiling system? Is it viable to manually lubricate the screws and ways, and how often would it need to be done? I only have the one mill so I can't really mill the machine itself... any issues hand grinding and drilling the oil channels into the ways?

    * downsides to all the "grind away" mods. The Y and Z extensions have you cutting away what appears to be a substantial chunk of iron; the rear-mounted Y has you drilling through the column; I've seen some Y extensions that include a large aluminum spacer between the base and column... do these mods add up to a loss of rigidity that will affect the quality or life of the tool?

    * do either of the Y or Z extension mods from Hoss' plans change the length of the lead screws used? I know the plans evolved over time so I've been putting together my parts lists starting with the Phase 3 folders and working backward, but the only mention of screw lengths I've seen is in reference to the C7 screws from eBay and appear to predate the rear-mounted Y, and Y and Z extension mods.

    * milling indoors. Going with a full enclosure should solve most of my concerns about tracking chips through the house, but is there any advice specific to running a CNC mill indoors?

    Thanks in advance for your thoughts!

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    Default Re: G0704 - build planning advice requested

    Just starting you have a lot to learn, give yourself some time to get up to speed and decide what mill will meet your needs.

    If you get into modding the mill a lot and have few tools you will have a long time before you have something that works. If you know you will need longer travels than a 704 offers then plan on getting the next size larger mill. After years of reading the post here I have never read a post of someone who was sorry they bought too big of a mill.

    You can make accurate parts with the hobby mills but working inside a .003" window is not to be expected. Most part don't need to be that good but I don't know what astronomy parts might be.

    The 704 for its size is quite nice and for smaller parts or most anything that fits on a 5" vice its good.

    Your final accuracy will be determined by the overall setup and tramming, How well you ways and Gib strips fit and the slop from the ball nuts , end bearings and the cutting process and tools selection. The stock C7 screws can be good or have lots of backlash. Some couplers have lash, some end bearings have lash, some ways and gibs don't move smooth.

    Their is the larger Weiss 30 for sale now and the other RF clones. If you want to do a lot of mods grab a RF-31 used. They are a great drill press and OK mills and you can make all you might need to do a custom mill. They go for $600 often and you can re sell it later for the same.

    youtube videos of the G0704 under the name arizonavideo99


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    Default Re: G0704 - build planning advice requested

    Thanks for responding arizonavideo. I already have the G0704, and unfortunately there's no room in my house for a second mill or a larger mill... so the decision is to reassemble my G0704 as a manual mill, or CNC it. I'm familiar with some aspects of CNC... I've scratch built 3D printers, a CNC engraver (a mill, but tiny), and worked with CAD, CAM, and controllers; but I know I still have plenty to learn. The "grind away" extension mods are just interesting right now because a) the mill is already in pieces, and b) who knows how much capacity I'll wish I had some day. I think I've decided to pass on them for now, for the reason you stated - I don't want to be out of commission for a really long time. But I'm still interested in how the performance of the machine is impacted by removing all that material.

    I started 3D printing the motor mounts from Hoss' DVD yesterday because it's basically a free step in the right direction. If they work out I can buy electronics and assemble the mill with CNC. Assuming they prove insufficient I'll reassemble the mill to factory spec, and machine aluminum mounts for his 'phase 2' plans with ballscrews. All my prior questions stand, but it will be a while before I make any final decisions. Thanks again!



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    Default Re: G0704 - build planning advice requested

    I printed out the phase one mounts from Hoss although I didn't use them and decided to fabricate aluminum mounts and use the double ball nuts & screws. I simply didn't want to have to tear it apart twice and had another mill available to use. I'm sure they (the 3d printed mounts) would work well enough to at least allow you to cnc your aluminum parts, but personally if I had an operational mill like you do, I'd just use the G0704 in manual mode and make aluminum ones and get it over with and just do it once. The 3d ones printed fine as is from his files. I wouldn't expect them to hold up for any lengthy period or extended use though. All of your other questions are answered in the forums. I realize there is a lot of info to read regarding the G0704 on here, but it really is the best way to get a firm understanding of what it can do, what mods or upgrades you want and how to go about making them.



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    Default Re: G0704 - build planning advice requested

    * 3d printing the "phase 1" parts. Hoss mentioned most of the STLs being "untested" in his documents, but have they been tested since? Is it a viable plan to print those parts, assemble the mill with CNC, and then machine the phase 2/3 mounts? possibly doing extension mods as part of the upgrade? Are there recommendations on infill for the prints?

    * ballscrew vendors. Is automationtechnologiesinc.com still a preferred vendor for screws and electronics? same question for linearmotionbearings2008 on eBay? Are there newcomers worth checking out?

    * automatic oiling of ballscrews. When I have ballscrews, how critical is an oiling system? Is it viable to manually lubricate the screws and ways, and how often would it need to be done? I only have the one mill so I can't really mill the machine itself... any issues hand grinding and drilling the oil channels into the ways?

    * downsides to all the "grind away" mods. The Y and Z extensions have you cutting away what appears to be a substantial chunk of iron; the rear-mounted Y has you drilling through the column; I've seen some Y extensions that include a large aluminum spacer between the base and column... do these mods add up to a loss of rigidity that will affect the quality or life of the tool?

    * do either of the Y or Z extension mods from Hoss' plans change the length of the lead screws used? I know the plans evolved over time so I've been putting together my parts lists starting with the Phase 3 folders and working backward, but the only mention of screw lengths I've seen is in reference to the C7 screws from eBay and appear to predate the rear-mounted Y, and Y and Z extension mods.

    * milling indoors. Going with a full enclosure should solve most of my concerns about tracking chips through the house, but is there any advice specific to running a CNC mill indoors?


    I did Hoss' conversion to my G0704 over the course of more than a year, part of that was from starting with phase 1 and switching to 3. I finished the conversion back in February and use it now. There's a lot of good advise in Arizonavideo's answer about overall setup, tramming and such. I was never able to get to zero back lash, but have .001 on Y and the worst is .004 on Z. There's a lot of details that you'll need to research and some times design yourself.


    If I may try to answer a few:

    1) Don't have a printer, so no idea about 3D printing the parts. I've seen someone do it as a stop gap until they could make metal parts. I made my metal parts on a combination of the G0704 itself before taking it apart and on my Sherline mill.

    2) I used Automation Technologies (ATI) and LinearMotionBearings 2008. ATI will sell you kits that sub for making your parts; it's basically Hoss' design. They'll also sell your a complete, modified mill for $4k.

    3) I use automatic oiling on X and Y, but not Z, because the fittings don't fit inside the Z-column. I'm thinking of pulling the Z-column again and trying to get something in there. As it is, I shoot some oil onto the the ballscrew now and then. The oiling system was a bit of an ordeal to get running right, it really took me a couple of months to get it to stop leaking on my floor. (The secret is not to use PTC connectors on the pump. Use barb fittings or something with hose clamps).

    4 and 5) This is a big one. I did a front mounted Y motor, but see some issues with it now. I think I actually have less Y travel than when it was manual, and one of the extensions on the back is a better way. Because I didn't do this, I can't say anything about the system's rigidity, but if you look at Hoss' drawings, you'll see three different Y-axis ballscrews, and you need to make sure you get the right one for what you're doing. I ordered my ballscrews directly from Chai by email, and when I said "G0704" he basically answered with a standard kit. At that point, I didn't even realize there were many options and that I needed to specify one, I just bought what he offered.

    6) My system is indoors, and I built the enclosure for it. Be careful here, too, because there's a couple of versions of the chip tray and you'll want to build the big one. I had issues putting the enclosure together, too, and had to kludge a fix to get it to even close. I opted to go with a Fogbuster instead of flood coolant because the thing just ain't going to be watertight. Maybe it's just the way I built mine, but even with a bunch of patches to the enclosure to keep splashes from out, I didn't think I could keep the base from leaking. I don't think anyone will say their coolant is safe for people and pets in our lawsuit-driven society, but I care about that with it being in a garage shop that's essentially inside the house. I bought some Kool Mist water-soluble oil because it's supposed to be "non-toxic". I understand Koolrite is good, too.



    Hope that helps,
    Bob

    Shop-built 4 axis CNC Sherline mill with A2ZCNC extended XY and CNC Sherline lathe.
    4 axis CNC Grizzly G0704 - based on Hoss' plans Manual Sherline 4400 and LMS 3540 lathes


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    Default Re: G0704 - build planning advice requested

    3.) I manually oil mine. It really doesn't take much to get an oil film where needed. I oil mine at the start of a run and if the run is longer than 2 hours I oil again during a tool change or between setups. May not be optimal but mine seems to be working so far. I use way oil on both the ways and on the screws. I made a little device that holds a sponge full of oil against the bottom of the table ways to oil the X and the Y and Z I pour on out of a oil can.

    4-5.) I have a rear mount Y motor and the positive is the table is much closer to the front of my enclosure when setting up and taking off parts. The down side is there is no adjusting the column tram without removing the motor and motor mount.

    6.) Mine lives in the garage and as much as I thought through the design of the enclosure it still has a pan under it as coolant magically finds a way to escape. On long fly cutting runs the splashing of coolant on the enclosure itself occasional drips out the joint at the corner of the 8020 and hits the floor. That's very minor though compared to what escapes around the chip tray opening. In a 3 hour run I end up with about a cups worth of coolant in the pan that I soak up with a sponge and drop back into the tank. If you are running full flood you are going to have a leak somewhere it's just inevitable.



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    Default Re: G0704 - build planning advice requested

    How do you oil the Z-axis ballscrew? Hold the sponge vertically, or just shoot it with a spray of oil?

    Shop-built 4 axis CNC Sherline mill with A2ZCNC extended XY and CNC Sherline lathe.
    4 axis CNC Grizzly G0704 - based on Hoss' plans Manual Sherline 4400 and LMS 3540 lathes


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    Default Re: G0704 - build planning advice requested

    Thank you so much for the replies coherent, Bob, and Kenny.

    Bob, your insights into the oilers and Y axis are much appreciated. Kenny, thanks for chiming in with a manual oiling solution. I've been reading through builds but hadn't come across anyone explicitly oiling manually. coherent, I'm reading what I can, but "a lot to read" is the understatement of the century. Doesn't help that I get sucked into threads and dragged off into tangents only to look up and discover my evening's free hours are spent with no progress and no answers. I really appreciate the Zone communy's willingness to respond to my questions, even if they've been asked before.

    I definitely like the closer setup table with a rear-mounted Y, but I'm still apprehensive about putting the column on the other side of an aluminum block. I'm thinking I'll live with stock Y (after removing flashing) and a rear mounted Y stepper. I'll try to tram the column as best I can before mounting the motor - thank you again Kenny for pointing out the tramming issue.

    The enclosure is my current brain teaser. I've settled on flood coolant, and the mill has to be indoors, but plenty of better builders than I have said "it is going to leak". My current best idea is to make a one-piece pan out of fiberglass and marine paint. I suspect that coolant, being an oil, will get through any joint through capilary action, so I'll need to look into gaskets for all the joints between walls and pan at least. I've found expired patent references to using Teflon pieces or coatings to defeat oil's capilary action as well. I'll certainly share whatever I come up with!



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    Default Re: G0704 - build planning advice requested

    Quote Originally Posted by CFLBob View Post
    How do you oil the Z-axis ballscrew? Hold the sponge vertically, or just shoot it with a spray of oil?
    I lower the head and oil the top of the screw and the slides with an oil can. The raise the head.



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    Default Re: G0704 - build planning advice requested

    Quote Originally Posted by jiggerinc View Post
    The enclosure is my current brain teaser. I've settled on flood coolant, and the mill has to be indoors, but plenty of better builders than I have said "it is going to leak". My current best idea is to make a one-piece pan out of fiberglass and marine paint. I suspect that coolant, being an oil, will get through any joint through capillary action, so I'll need to look into gaskets for all the joints between walls and pan at least. I've found expired patent references to using Teflon pieces or coatings to defeat oil's capillary action as well. I'll certainly share whatever I come up with!
    I'll point you at my thread that includes the stand build to give you some ideas. I did a full one piece fiberglass pan and somehow coolant still finds it's way to the floor.

    http://www.cnczone.com/forums/bencht...uestion-2.html

    It's very clingy to surfaces and can migrate sideways. You'll see I have that problem concerning drain holes in the chip tray. The coolant would cling to the bottom of the drawer and make its way sideways before dropping off onto the floor. When I say it leaks its not mop the floor sized leaks. On mine like I said the main leak is around the area that the coolant returns to the tank through the ship drawer and that was easily controlled with a big mechanics drain pan. Nothing actually hits the floor via that leak. The small one around the 8020 only happens under certain conditions like fly cutting. I do have a couple of simple ideas to fix that one it's just so infrequent that it's not really a problem. I lose more coolant to evaporation than I do to leaks.



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    Default Re: G0704 - build planning advice requested

    Quote Originally Posted by Kenny Duval View Post
    I lower the head and oil the top of the screw and the slides with an oil can. The raise the head.
    Thanks - that's what I've been doing. I was thinking of making the accordion folded cover for the Z-screw removable and oiling the bottom.

    I was concerned the plastic bushings on the ballnut were keeping the oil from getting in to where the balls actually are, and that's where we need the oil.

    Shop-built 4 axis CNC Sherline mill with A2ZCNC extended XY and CNC Sherline lathe.
    4 axis CNC Grizzly G0704 - based on Hoss' plans Manual Sherline 4400 and LMS 3540 lathes


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    Default Re: G0704 - build planning advice requested

    Those Teflon seals don't fit tight enough on mine to keep the oil out plus the way oil clings pretty well to surfaces so it's pulling some of it in as the screw turns. I could be wrong and causing premature wear on mine but since it's not running 24 hours a day or even multiples days a week I'm not too concerned.



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    Default Re: G0704 - build planning advice requested

    This is why I use grease. My way covers do an excellent job at keeping out chips and grease doesn't contaminate my coolant like oil does which eliminates the need for a skimmer. I use cheap synthetic grease (Mobil 1) which I've found doesn't get waxy or dry like traditional greases and apply the grease every 10-15hrs of run time. Though the ways and screws are always still in nice slippery condition when I do. I don't even use a grease gun, rather I just apply directly to the screws and ways with my finger. Takes just a minute or two. I've rebuilt my ball nuts a few times simply to check their condition, they are always cleans and well lubricated at tear down. Would I want to use this option on a machine that runs 24/7, absolutely not, I hate being covered head to to toe in grease after each rebuild/adjustment cycle and with grease an automatic system would be expensive, but for my shop and the parts I make I have experienced excellent results. I do think that because the temperature inside my shop remain very consistent at about 70 degrees (it's a basement) the grease is more easily considered than shops that see larger temperature swings.



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