[CFLBob]

Same idea, but by buying a 1/2 down to 3/8 adapter I could use my half inch breaker bar (15"). I was able to break them free with that.

I should have had one all along, but only had the one that goes from 3/8 up to 1/2.

[coherent]

Mine were really tight also. I had to use a large breaker bar. Squirt a little break free or kano kroil around it and let it sit for a little while. Mine finally came loose but it look a bit of leverage and I was worried the bolt head would snap before it did, but finally success. Just make sure you use a quality allen wrench or allen head socket that won't bend or snap on you.

[CFLBob]

I did the modifications to my base and still get just the original range 6-7/8", maybe a bit less. I certainly don't get 8 or 9 inches.

I cut out the 1-1/4" square and cleaned it up with a grinder as well as went hunting for stuff on the underside of the base to grind away. To my mind, the front was rather smooth to the touch and well finished, especially compared to the back.
Attachment 347234
I removed some flash along the sides of the cutout, but none of it would have hit the ballnut.
Attachment 347236
The back required a lot of grinding. I used a saw to remove some of the big lumps (destroyed a jig saw blade in the process), but still ground through a full battery on my drill/driver.
Attachment 347238
That's still lumpy, but the ballscrew comes 3/8" short of that wall and I don't how much farther I could cut that back - if I could cut it back. I'd hate to have balls falling out if that ball nut mount moved too far to the back and off the end of that screw.
Attachment 347240

In the front, it appears the ballnut, which is about 2 3/4 long, is hitting the casting. I suppose I could gain about an inch if I could cut away the front wall of the base in that area and into the Y axis extension.

If anyone else did a front-mounted motor conversion, I'd like to know what your Y-range is.

[hoss2006]

Well any pics of it assembled to see exactly where the ballnut is hitting? Guessing it is the front of the casting where you didn't remove material to within 1/4 inch of the front as shown in my post on the previous page. I explained this in the video "06 G0704 Double Ballnut C7 X and Y Axis Prep Part 2" on the dvdrom.
Hoss

[CFLBob]

From the picture, I got the impression the work on the underside was to remove lumps and bumps that might hit the ballnut and make it stop early, not take out the front wall. The underside up to the front wall had no bumps, so I thought it was OK.

Here's the ballnut. It hits the front wall, like I thought. (looking at the positions of everything and the length of the ballnut, it all worked out with a ruler. )

Attachment 347256

Here's an overview. I can fit a 3/8" Allen wrench between the end of the ballscrew and the back of the casting.

Attachment 347258

I don't think I have a tool that would cut out that front wall, but the most I could pickup would be about 5/8" (the wall looks to be about 7/8). If I could drill a hole large enough to pass the whole ballnut, I'd pick up the full thickness of the wall. until the ballnut and mount hit the front edge of the 1-1/4" cutout. I don't know how much it's worth spending to pick up that 5/8". No matter how much travel you have you'll always end up needing 1" more than what you have.

[hoss2006]

Yes as you can see if you removed the extra nut section it would travel the extra inch or so like a standard nut where the flange of the nut would hit the edge of the section you cut out like is called for on phase 2 with a standard nut. the double nut needs the extra material removed to allow the flange to go as far. drilling out the hole big enough to allow the ballnut to pass thru would be a good alternative.
Hoss

Something I just noticed is it looks like you are using the standard length ballscrew, that's definitely not the extra long y bearing mount speced for the extended travel y axis front mount and there should be material removed from the back of the casting to allow farther reward travel which would require the longer extended travel y ballscrew in the plans. expecting to get 9 inches of travel with what you are using is unfeasible, the standard y screw will get the standard 7 inchish y travel.

Just an fyi in case you don't realize but any amount of travel over 7 inches will require a correspondingly thick column and head spacer for you to be able to actually use that extra travel. If you are getting nearly the stock 7 now I'd call it good if you don't plan on doing the spacers, best you get boring out the front hole is about 8 inches with that ballscrew.

[CFLBob]

Without a milling machine like the G0704, I'm limited to drill bits. For a variety of reasons, I'd need a Silver and Deming bit for my hand drill in about 1-1/4". I might be able to get away with one that's smaller, but there's no penalty for making that hole a bit bigger I can think of. I think the answer that works for me is to leave it as is for now. If I need more travel in year or so, I'll be able to make the Y-axis rear mount parts and switch over to that approach.

Don't worry. There will be more questions in the coming weeks. Although I think it's realistic to say I could have it put together in the next couple of weeks.

[CFLBob]

Yes as you can see if you removed the extra nut section it would travel the extra inch or so like a standard nut where the flange of the nut would hit the edge of the section you cut out like is called for on phase 2 with a standard nut. the double nut needs the extra material removed to allow the flange to go as far. drilling out the hole big enough to allow the ballnut to pass thru would be a good alternative.
Hoss

Something I just noticed is it looks like you are using the standard length ballscrew, that's definitely not the extra long y bearing mount speced for the extended travel y axis front mount and there should be material removed from the back of the casting to allow farther reward travel which would require the longer extended travel y ballscrew in the plans. expecting to get 9 inches of travel with what you are using is unfeasible, the standard y screw will get the standard 7 inchish y travel.

Just an fyi in case you don't realize but any amount of travel over 7 inches will require a correspondingly thick column and head spacer for you to be able to actually use that extra travel. If you are getting nearly the stock 7 now I'd call it good if you don't plan on doing the spacers, best you get boring out the front hole is about 8 inches with that ballscrew.

Right. When I contacted Chai and told him I heard he was the source for G0704 ballscrews, he seemed to know what I wanted and gave me a quote. I didn't know enough to question about ballscrew lengths, but once they came in, I was going through them trying to figure out what they were. I remember contacting you via personal email asking about this odd screw I had. You directed me to the right spacer. I always wondered why they provided a pre-ground X ballnut and not a pre-ground Y.

[hoss2006]

The Y doesn't need any grinding unless you do a specific mounting of it angled for better oil fitting access for an oiling system, not something that a majority of people need.
Hoss

[CFLBob]

If I may switch topics, I never saw how you get oil to the Z-axis ballnut oil fitting.

Specifically, do you keep a coil of tubing outside or inside the column or do you use loose tubing inside the column? Is abrasion on the tube a concern?


Thanks

[hoss2006]

Because I didn't, I did the oiling far down the road and after my handicap prevented easy access to the inside of the column. A loop of flexible tubing inside would have been my method.
Hoss

[CFLBob]

Thanks. Of course, I had no idea of the complication there.

I'd like something that didn't scrunch the tube up when the ballnut is at the top of the screw. If I could figure a way to coil up some tube and have it feed into the column when the head goes down and coil back up on the outside when it's back higher, that would be a good approach.

[CFLBob]

I went to put an oil fitting on the z-axis ballnut and ran into this:

Attachment 347690

At first glance, it looks OK. Until you look into the holes in the ballnut and see they don't line up with the holes in the mount. When I rotate the ballnut to line up the holes, the fitting bangs into the wall.

I broke one fitting trying to get around this and this is my last. I have another trick to try: just screw the 1/4" polyurethane tube into the tapped hole. If I can fix the tube to the mount with a simple clamp, it should keep stresses off the tube. Maybe it'll work well enough.

[Wiggles84]

@CFLBob,

What about something like this? (google searched m6 banjo bolt)

https://www.tyagiracing.com/products...t-for-5mm-Hose

Or if you have the means you can do what I did to my Z ballnut

http://www.cnczone.com/forums/bencht...ml#post1617000


Andrew

[CFLBob]

Thanks, Andrew. I was thinking about trying to make a bolt like that.

It has to be low profile, and I figure I need a head that's about .200 thick to drill and tap 10-32 (there are oil fittings on McMaster-Carr that size). I'd drill a hole up the axis of the bolt on the lathe, stopping short of drilling through, and then cross wise on a flat. It shouldn't be that hard to get the holes to meet in the center. I'm not sure if it would fit.

I've got a friend that says "Why bother? Just drill into the existing hole from the top surface of the ballnut and cap off the hole so the oil doesn't go both ways". That makes sense. I think with some care that could work, but chips in a place that can get into the ballnut kinda scare me. Something like this, to butcher Hoss' jpeg of the ballnut.
Attachment 347744

Then I ran across this picture while doing an image search. It's from a guy on eBay who sells some ballnut mounts that look sorta like Hoss'.
Attachment 347746

The tube is pushed or threaded into the hole. 1/4" OD kinda works in M6 since the pressures are low.


Bob

[Wiggles84]

Thanks, Andrew. I was thinking about trying to make a bolt like that.


I've got a friend that says "Why bother? Just drill into the existing hole from the top surface of the ballnut and cap off the hole so the oil doesn't go both ways". That makes sense. I think with some care that could work, but chips in a place that can get into the ballnut kinda scare me. Something like this, to butcher Hoss' jpeg of the ballnut.
Attachment 347744


Bob

This is what I did but I went thru the ballnut mount. I didn't feel there was enough "meat" to tap the new hole in the ballnut. Also but a set screw in the side ov the hole to keep the oil from leaking out.

Andrew

[hoss2006]

just an fyi the ballnut is hardened so drilling and tapping would be difficult.
Hoss

[CFLBob]

Thanks to the link to your build thread, Andrew. Good stuff in there.

[CFLBob]

OK, now I have a WTF?

Finally got everything to put my mill's base back together. Hooked up the oil distribution. Finagle the table into place. Now I get this:

Attachment 347882

Everything I can find shows the ballnut on that side of the mount - facing the back. But the table clearly interferes with the fitting and sits on the hose. It was dicey with the other side of the distribution, but tucked away nicely and safely (I think).

Attachment 347884

The only remedy I can see is to put the ballnut mount on the far side of the ballnut, which will move the oil fitting closer to the middle of the table, but that will reduce my Y travel because the back of the ballnut will hit the inside of the base sooner.

[hoss2006]

You can heat the tubing up with a hotair gun for example to give it a 90 degree bend or 2 so it clears the saddle, it will hold that shape when it cools.
Hoss