Grizzly G0704 Cnc Conversion

I'm sure if we spent a few days reading hundreds of pages of Hoss' g0704 posts we might understand it all.. I bought all the stock and bearings to do this, I just need to do all the CAM and get it done. Once I'm done with the Y axis bearing block it's on to the ballnut mount pieces and that big X end cap.

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.
 
Got my leadscrews from Chai today. I have to compliment him on the turnaround time. Chai knows about the cuts to the X-axis ballnut assembly that Hoss did and includes that.

I think having these things in hand will help sort through all the options that Hoss puts up. I was looking at those folders on the DVD and getting really confused. I think I see which holders to make now.

Left to right, that's X, Y, Z, for anyone who cares.

View attachment 126513

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.
 
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.

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
 
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

Thanks for replying. Keep us posted on your progress.

Tom S.
 
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.
 
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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.
 
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.
 
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.

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.
 
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
 
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.
 
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