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Grizzly G0704 Cnc Conversion

Discussion in 'MACHINE BUILD LOGS' started by cozmogeek, Jan 9, 2016.

  1. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Yeah, I kinda resigned myself to making most of it new and ordered all the parts (I think!) from McMaster and VXB bearings. Then I was watching the phase 2 videos and find the first thing he says on the X-axis video is that the phase 2 parts would work, and the phase 1 motor mount I made is the same in phase 2. After looking at lots of prints, I think I'm going to make new phase 3 hardware.

    But if you're a hobby machinist, there's nothing bad that can come from machining extra parts. I just won't have the Griz done and running quite as soon as I wanted.
     
  2. TomS

    TomS Active User H-M Supporter-Premium

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    Have you installed your ball nuts and screws? I'm curious what your backlash is and any other comments you have about the screws and nuts. I'm thinking of buying these double nuts to replace the single nuts on my mill. I have more than .003" backlash on X axis and a bit less than .002" on Y.

    Tom S.
     
  3. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    I haven't installed them, yet, and it's going to be a while. I'm needing to make all the new phase 3 hardware.

    I wish I could estimate how long it will take to be ready to move on to that step, but I don't have a clue.


    Bob
     
  4. TomS

    TomS Active User H-M Supporter-Premium

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    Thanks for replying. Keep us posted on your progress.

    Tom S.
     
  5. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    I've made the first piece, the X-Axis ballnut mount.
    X-Nut_on_ballscrew.JPG

    It's a bit off center, [edit to add: the curved cut out area isn't exactly centered on the piece] but it seems to fit where it needs to. The only issue I have with it is that Hoss talks about putting a pin in those holes, with the side facing the ballnut turned down to .216. According to my calipers, the mating holes are .208 - and a .216 pin in a .208 hole just ain't gonna happen. I'm not sure what goes in that spot right now; if I just turn a piece of aluminum down smaller, go to a #12 screw, or just what.

    The space where it goes in the base of the mill is tight, and I don't think there's room for a screw head on either side, which is probably why Hoss used the pins.
     
    Last edited: Apr 22, 2016
  6. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    I see I haven't updated this in a while. I've been working on all the pieces for the phase 3 conversion and have everything roughed out. Had a talk with Hoss to ensure I'm building the right parts and was actually on the way to a wrong piece for the Y axis spacer. That was easy to solve; the blank I cut was too big, so I just took some more off with the bandsaw.

    I resolved the issue from the previous post (pins too small) by turning down a couple of small pieces of 1/4" brass rod I had. That finishes the X-axis ballnut mount. Then I completed the Y axis ballnut mount. The Y axis part is mounted to ballnut with 10-32 screws in this picture, as it will be in use. The X-axis part is just sitting there so you can see the pins.
    X&Y.JPG

    The pins will get blue Loctite. The screws will, too, but it's more mandatory on the X-axis. Those pins will fall out if you hold the aluminum and shake it a bit.

    The Z-axis ballnut mount is larger than this Y axis piece and brings some challenges of its own. For the Y-axis, I bored the 1.110" hole on the lathe. All the bulk stock removal was done on the G0704, and the Sherline mill was used as a precise drill press.

    Still plenty of work to do, but progress is better than no progress.
     
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  7. cozmogeek

    cozmogeek United States Active Member Active Member

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    You've made more progress than I have. I've been busy killing myself in the yard. I might not get back to the cnc conversion until fall at this rate.
     
  8. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Florida is completely backwards from the rest of the country. When you're going inside because it's too cold to be outside, that's our prettiest time of year and I want to spend most of my time outside. When you're getting outdoors for the summer to enjoy the long days, I'm moving more into the shop to avoid the sun.

    I took a week off for a trip up to visit family. I'll do an update tomorrow.
     
  9. MontanaAardvark

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    My only real accomplishment since the last update, showing the completed X and Y axis ballnut mounts, was to complete Z-axis.

    The Z mount was the biggest piece I've done yet, and I had to learn a few new things to get it completed. As I mentioned, to bore the large (1.110") hole in the Y axis mount, I put it in the four jaw chuck on the lathe, turned a plug to fit the hole I had drilled in it, centered it, and bored it on the lathe. The Z- axis piece has an even larger hole, 1.420", and the size/shape of the part wouldn't fit in my four jaw (well, maybe there's a way, but I didn't see it). Instead, I put it on the G0704 itself and used my boring head.
    Boring_Mill.JPG

    You'll note the large chamfers on this part. I cut these on the G0704 as well, clamping the piece down after using a combination square to position the part so that straight cuts took off the excess material (those chamfers are 0.375 on a side from the square corners).

    Then came drilling and tapping the 1/4-20 holes. For the first time, I barfed this up. The holes were far enough off that I could get only one screw in the ballnut.
    Z-axis-problem.JPG
    Now what? I've never relocated holes before, but it really is a fundamental skill we should all have. I know in commercial shops they may drill it out larger and put in a PEM nut, or use a welder to fill it, but I don't have a TIG welder and wouldn't know how to use it if I had one. So acting on the advice of a friend, I got a half inch aluminum rod, turned it down to thread and made 1/4-20 aluminum screws to plug the holes with. Used red LockTite to hold them in place, sawed them off with a slitting saw on my Sherline, then milled them just a little proud of the surface (like .002) with the G0704. This is on the Sherline, before I milled them.
    Z-axis-fix1.JPG
    I think my error was in setting my zero on the Sherline before I drilled, because after flipping the part, finding zeroes again, and putting a small peck at each hole with a center drill, the marks all appeared to be in the right place.

    The same friend suggested that since I have the master location (the ballnut that has to mount), why not make a tool to fit in the hole that will better center a drill and mark it that way? So I turned down some more of that 1/2" aluminum bar to fit the holes in the ballnut, then center drilled them on the lathe for a 1/16" drill bit. I made four and put them in the four corner screw holes in the ballnut, and clamped the ballnut to the mount with C clamps. Drilled holes with a 1/16 bit. Broke the first bit and while muttering obscenities and looking for the next size up to continue, found that "someone" had bought and stashed three 1/16 bits. No more excitement because I remembered to use just a tiny dab of tapping fluid. Once the four were drilled, I moved two tools to the center holes, re-clamped, and drilled them.

    Moved it to the Griz and mounted my drill chuck. Carefully centered the bit three times, using a 7/64 bit, then three more times using the bit that came in my old Craftsman drill and tap set for 1/4-20. While doing the larger holes, I could feel that some times it felt way too easy. Turned out two of the aluminum threaded screws had backed out. So I put them back with more Locktite. The result: perfect fit.
    Done-Z.JPG
    The little tools are in the lower right.

    So that's where I am now. I'm down to four parts to make: the X and Y motor mounts, the Y axis spacer and the X-axis end cap. The end cap has a lot of machining that needs to be done, and I think I'll do that last. I spent three weeks on this part, though, so I hope I pick up some speed.

    Every part is a puzzle!


    Bob
     
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  10. cozmogeek

    cozmogeek United States Active Member Active Member

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    At this point I wish I could just pay someone else to make these parts for me. I'm probably not going to get to it until winter at this rate.
     
  11. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Yeah, I get the same feeling. I think Hoss could add to his business if he did that. Even if he had someone from China.com make the parts and he just sold them. I'd be curious just how big the market is. I mean, how many of these does Grizzly sell in a year, and how many get converted to CNC? If you had a machine shop make 20 sets of the parts that you sold, how long would it take to sell them?

    Automation technologies sells a kit for BF20L mills -
    http://www.automationtechnologiesinc.com/products-page/g0704-kit/bf20-cnc-conversion-kit-set

    There are others, too. Just Google G0704 CNC Conversion or BF20L CNC Conversion.

    I'm not out of the woods on this job. I don't think I even get into the woods until I take the G0704 apart. I have no clear picture in my mind of how this all goes together, or how I'm going to get to the finish line. Right now, I'm drilling holes and using the G0704 itself to cut the big ones. Once it's apart, and I'm back to handheld tools, along with my Grizzly drill press with terrible run out at the bit, and my small Sherline/A2ZCNC mill, it's going to be like walking a tightrope for the first time - without a net.

    Meanwhile, I finished one more part, the Y-axis extension. I didn't chamfer the corners. I might do that and might not.
    Y-Spacer.JPG

    Down to the two motor mounts (X and Y - the Z-axis motor mount I made for Phase 1 is still usable), and the X-axis end cap.
     
  12. markba633csi

    markba633csi United States Active Member Active Member

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    For somebody without any machining experience you're doing pretty good- looks like fun too I'm jealous :D
    Mark S.
     
  13. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Thanks, Mark.

    Yeah, I'm having fun. Spent a few hours drilling some holes in those motor mounts. Well, spent a good chunk of the time figuring out how to fixture the first piece. They're an odd shape, really an irregular pentagon, and nothing I had with my small CNC setup looked like it was going to work. Finally figured out an approach that's working.

    Should have them done in a couple of hours.


    Bob
     
  14. jbolt

    jbolt United States Active User H-M Supporter-Premium

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    Work holding is half of the machining process. Back when I was working in an R&D shop we regularly had to make half a dozen or more fixtures to completely machine a part. I enjoy the challenge though it can be frustrating when making one-off parts.

    The thing I found invaluable when I did my mill conversion was making all the parts in Solidworks before I ever cut metal. It required that I mostly disassemble the machine to measure all the parts to model but that really helps you understand the machine. Also the great thing about modeling in 3D is the ability to make different iterations to see which works best for your own requirements. If Solidworks had not been available to me I would have used AutoCad Fusion 360.

    The whole conversion process is a huge amount of work but very rewarding when done.
     
  15. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Oh, absolutely! I haven't been making metal things for very long, but I've had that rammed into my brain often enough that it stuck. Like you say, with these one-off parts, it's pretty tempting to do it all with one fixture, and I generally have been able to. With these mounts, I used a clamping kit with the clamps just "above" (toward the top in this view) the two holes at the widest point.

    G0704_stepper_mount.jpg

    Likewise, I've put everything into Rhino 3D, my 3D CAD program. Now, I bought Hoss' DVD and he supplied .DXF files of all the parts and that helped a lot, but I've used those files to create a datum, add dimensions that aren't immediately obvious to me, and a bunch of other things. Some parts have been made by CNC on my modified Sherline mill, but most have been made on the G0704 itself, using those drawings and "old school" layout techniques.
     
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  16. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    I'm back here after a rude interruption, and still working the CNC conversion. I think I've decided I need to redesign one of Hoss' parts.

    The last part to build is the X-Axis endcap, which is a large part. It's about 7.1 x 2.2 and the motor mount area is left 1" thick. The rest of the cap is thinned to 0.5" thick. That's a lot of stock to remove, and made me wonder what the best way to do that is. On Hoss' DVD, he makes that part on his "phase 2" CNC G0704, and it's a workout for a machine with flood cooling and pretty fast motion. Since I don't have flood cooling or CNC control, it would be manual and take quite a while.
    X-axis-endcap.jpg

    I think the way to do this part is to make it out of two 0.5" thick sections screwed together at the middle. There are already three tapped holes for the motor mount, and room for me to add a couple of tapped holes to attach my two pieces together. That turns it into one big (X/Y) piece and another, smaller piece that's almost a copy of the motor mounts I've already made. It adds the chance for tolerance stack-up and design-type issues, which is most of what I'm thinking about. Now I'm stacking a motor mount on top of two parts instead of just one.

    Sure would love some comments and sanity checking.

    Bob
     
  17. cozmogeek

    cozmogeek United States Active Member Active Member

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    If you do, share it with me. I don't want to make that part either!
     
  18. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    It's 10 days later and time for an update. I have what appears to be a usable Rev 1 of the two piece X-axis end cap.

    X-endcap-Rev1.JPG

    This is a half inch thick piece mounted on top of another half inch piece, and held together by the two black SHCS screws at the 2 and 10 o'clock positions of the big bearings. It's an easy mod to do in any CAD program to copy the hole pattern and then flip it; when you do so, the top hole overlaps the bottom edge, so I deleted it. Of course that leaves only two screws to hold the parts together. The stack-up of two bearings with a shim between them fits perfectly, and stand slightly proud of the top surface (didn't measure). The next part is a motor mount and stepper motor support that mounts on top of this. The motor mount's bore is considerably smaller than the bearings, sized 0.800" while the outer bore at the bearings here is 1.024". The motor mount compresses the bearings to help control backlash.

    I started with the Hoss DVD drawings that I purchased for the end cap, and then split them in two. One became the small top piece while the other became the 7x2 (-ish) bottom. I partitioned features between them so that when the two pieces are joined, the result should be the same as the one piece end cap. For example the original part had a dual diameter bore for the bearings: 1.024" that went down 0.638" and the rest of the hole is 0.875". I split that into the top and bottom pieces, so the top is all 1.024 diameter and the bottom piece has 1.024 for 0.138" depth and 0.875" the rest of the way through.

    There's a goof up here - in those three holes around the bearings you can see in the top piece. Those are not threaded and are sized to clear an 8-32 screw. The base of the end cap has those holes threaded. That's wrong. The top piece should be threaded. I moved the threaded portion down from the top piece without it registering in my mind that the screws need to thread into the bottom piece but can't because they're not long enough to make it to the bottom piece. What I missed is that motor mount I mentioned that goes on top of this piece. The stack up looks like this (the parts are just stacked - no fasteners - just sitting on the Grizzly with my boring head still mounted.
    X-axis-full-assy.JPG

    The motor mount is 3/8" thick, the top of the end cap is 1/2", so a screw has to go through 7/8" of metal before it gets to the threaded holes, and you'd want some engagement there, like another quarter inch (1 1/8). So instead of 3/4" screws, I need three longer screws. No big deal, but if I was starting again, I'd just thread the holes in the top piece and not drill them into the bottom piece at all.

    There's another problem lurking in this piece, which is that when I transferred the base (7x2 piece) from the Sherline, where I drilled all the holes, onto the big mill for boring the holes, I flipped it upside down! So the "top view" you're seeing has the two mounting holes left and right of the 1" thick area counterbored on the bottom - backwards. I think that's also going to be fixed by two new screws.

    This part doesn't have the stylish tapers that Hoss' part has. I'll have to see if I can figure out how to add those without barfing anything up.

    Getting close to time to take the Grizzly apart and add all this stuff.


    Bob
     
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  19. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    I think I see how to cut the tapers.

    Kind of a DIY sine vise. Make the 16 degree cut into a straight horizontal cut.
    (The black plastic clamp is just there to keep the angle indicator from sliding off, and won't be there during cutting).
    CuttingTheTapers.JPG

    I'm pondering whether I have a good way to add a clamp in the bored hole. Or if I need to, since all the cutting is in that roughly two inches over the center of the vise.

    Two 16 degree cuts, then two 45 degree cuts to clean it up near the bearing holder.
     
  20. JimDawson

    JimDawson Global Moderator Staff Member Director

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    If your purpose is to reduce chatter, then this is the way I do it. Just clamp a piece of something heavy to the work. There is a lot of material sticking out of the vice in your picture above, so yes, I would add some mass.

    upload_2016-7-16_11-24-8.png
     
  21. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Thanks. Had not thought of just adding mass to the piece. I was thinking of clamping it to the table. Your approach sure seems more feasible.
     
  22. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    And Ta-Da...

    X-axis-EndCap-Final.JPG

    Since this part is visible once the conversion is complete, I think I'm going to paint it. Powder coat.

    Bob
     
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  23. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Well, two weeks later and time for an update.

    It turns out I wasn't ready to powder coat. I thought I was until I started test fitting pieces in my little toaster oven, and found they didn't fit. I had "back to the old drawing board" moment that lasted four or five days until I figured out how to do it, and some unavoidable junk that took up time.

    Anyway, everything that gets painted is now painted.
    All_Painted_parts.JPG

    There are four vertical (more or less) pieces of blue rod in the background. Those are holding up the replacement rack I had to build for the toaster oven. The built in rack wouldn't get high enough. And yeah, those are fishing lures on the right. It's a busy bench.

    I bought the powder coat gun in about '05 but only did a couple of little things. I had to relearn, and some of these aren't a cosmetic "10". I'll deal with it. The 10 year old powder I bought at Sears still acted fine, it was my technique on some of them.

    Now I think it's time to start taking the G0704 apart and start working on the real conversion.


    Bob
     
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  24. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Has anybody here done the phase 3 conversion?

    There's something I need to do with the Y axis ball screw/nut combination and I could use some advice. There's an issue with the Y-axis ballnut mount we make and the Linear Motion ballnut. The problem is that the ballnut overhangs the edges of the mount, and Hoss recommends they be ground away with an angle grinder. There's a similar issue on the X-axis, and Hoss had the Linear Motion guys do it so that the x-axis ballscrew was modified when I bought it.

    I was thinking of using the mill to remove the extra material before I take it apart. I have carbide end mills. The ball nut is hardened steel, so it will be tough, but I think a carbide half inch end mill would take that off, a few thou at a time.

    The disadvantage to using the angle grinder is I'll have to work outside (where it's about 90 to 100 heat index all day) and there's no way to hold the work out there (no vises, benches, etc.). It will take quite a bit of setup to be able to do it. Plus, I'll need to completely wrap up everything in blue painters tape - ballscrew, nuts, everything except the two little areas I'm grinding so I can keep the metal dust from finding a home deep inside the ballscrews where it will eventually ruin them. Not to mention I've never used an angle grinder before - although I've got to cross that bridge some time. I need to work outside to keep the dust from contaminating all the tools inside the shop!

    I honestly don't know if it's "fair use" to show this pic clipped from Hoss' DVD, so I'm going to post it and moderators feel free to take it down (or tell me to) if it's not OK.

    Yaxis-trim.jpg

    You can see the straight vertical edge on the right ground away, cutting into one of the screw holes, and you can see what it originally looked like originally.

    Does it make sense to try to mill that away with the G0704 itself? Can the carbide end mills cut the hardened steel, or do I need something more exotic? I know there's a lot of meanings for "hardened steel" and carbide, so it's a tricky question.

    Especially, if you did this conversion, what did you do?


    Bob
     
  25. JimDawson

    JimDawson Global Moderator Staff Member Director

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    The first thing I would try is a file. If you can file it, you should be able to cut it. Keep the feed rate up so the tool is cutting not rubbing.

    Taping up everything is a good idea if you need to grind. Anchor the part to something, even if you have to take your vice outside and bolt it to a piece of plywood. Set up so you can work in a comfortable position so you are not over reaching or in an awkward position.

    Just as a side note, I grind in my shop all the time. I just make sure the sparks are not flying towards precision tools or something flammable, they are pretty directional and drop out pretty quick. Normally aimed out the door where possible.
     
  26. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Thanks for this, Jim.

    Tried the file and it kind of skates over the edge, so I think that means it time to try the grinder. I bought a Horrible Freight angle grinder just for this. (If that doesn't inspire confidence, I don't know what will.


    Bob
     
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  27. coherent

    coherent United States Active Member Active Member

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    I completed the phase one cnc conversion about 8 months ago. I quickly decided I wasn't happy with the backlash with the stock screws and ordered the ballscrew/nut set from automation technology and all the bearings etc. (I ended up with the double nut set). I simply used an angle grinder per Hoss's instructions for the ballnut. I removed the balls and plastic guides from the nut simply because i wanted to ensure I didn't overheat or melt any of the insides so the grinding went pretty quickly. I initially tried really shallow cuts with a carbide end mill and it just didn't work well on the hardened steel casing. maybe it would be do-able with a big knee mill, but not on a G0704 or LMS Mill. Once you complete the project, you realize it isn't that difficult, just time consuming and a little confusing until you've "been there done that". The same with the belt drive conversion. Hoss's plans unfortunately don't include a "step one, step two etc process" instruction layout which would simplify things. When you first look at the files, it's a bit daunting and confusing (at least it was for me), but once to study things a bit not too bad. He's great about promptly answering questions if you have them. Oh and for those who plan on a belt drive conversion, upgrade to some good AC bearings while you're tearing stuff apart anyway. I was able to find the pulleys, belts and bearings on Amazon. Mine ran much, much cooler than with the stock bearings.
     
    Last edited: Aug 2, 2016
  28. coherent

    coherent United States Active Member Active Member

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    I learned my lesson a couple of years ago when sparks hit a whole roll of fuse (like for small cannons and such) I had hanging on the pegboard behind my vice. scared the crap out of me. Luckily I keep a small fire extinguisher in my shop. One of those things that happen and you can only hang your head, feel foolish and be glad the house didn't burn down. A lesson so basic that I shouldn't have needed it to be demonstrated. Duh!
     
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  29. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Thanks. I'm in the process of setting things up to do it. Right now, I'm trying to get anything done I might possibly need the Grizzly for before I take it apart. Nothing worse than needing it when it's a pile of parts. I'm sure this will all make more sense after it's done. Everything always makes more sense the second time.

    Did you make the ballnut removal tool Hoss made to remove it without chasing ball bearings around the shop? If so, out of what? In the videos, it looks like a plastic or 3D-printed thing.
     
  30. coherent

    coherent United States Active Member Active Member

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    I have a 3d printer so I printed one. Quick, simple and it worked great. In the past when building a CNC router, I simply used a piece of paper towel tubing cut to size (slit it length ways to adjust the diameter). Just get it close and wrap a piece of duct tape around it. I've seen posts where others have measured and headed to the local home improvement store and found a piece of pvc tubing or wood dowel sized close enough to work also It doesn't have to be a perfect fit to hold the ball bearings in place for removal/install.
     
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