[sansbury]

Hi Guys!

So tonight I took some measurements to try and figure out how much clearance I needed to create in order to get the square Roton nuts under my X2 table. It seemed like an enormous amount and wanted to see what you guys thought.

Here is a pic. The ruler didn't come out well but you can see where I used a marker to show the interfering area. There is about 1/8" of iron left above the colored area which doesn't make me feel very good.

I can get a *little* more space by shaving the flange on the top, and the whole area can be cupped a little, but at the top it is still pretty deep. There is about 0.025" of metal left in the saddle I could mill down which would buy me that much more room, but that's not that much.

Anyway since I trust I am not the first guy to put square Roton nuts on an X2 I was wondering what other folks have seen.

FYI here is a link to the ball nuts I am using in case you want to see the dimensions. They are about 1" square.

http://www.roton.com/Mating_Componen...family=7059321

[acondit]

What about grooving the saddle and lowering the ballnut into the saddle a little bit?

Alan

[X2cnc]

My Thompson ballnuts are about 1-1/16" around, plus the ball return tube, which the CNCFusion kit located on the front side.

The roton web site says your square nuts are supposed to be 1", as you said... but I didn't have to take anything like that much metal out of my table. I have some pictures at http://www.bacomatic.org/~dw/tool/x2/x2.htm

Also note the entire length of the table doesn't have to be ground to clear the ballnut; the part that stays over the saddle just has to clear the screw. I could have saved a lot of grinding if I'd noticed that.

I'm wondering if your ballscrew is located higher than mine? If so, you might consider backing up and re-doing the screw brackets to drop it as close to the saddle as you can.

[sansbury]

Alan: I thought about that. I don't know if I can take it down all the way but it could probably buy me 1/16th or so which is significant. Beyond that the surgery may get more severe but it may well be easier/better than taking down the table. At least I still have my X1 which does quite respectably milling cast iron for these purposes.

X2: Without measurements I couldn't say. I'm basing this on the Hoss approach so the ballscrew follows the same centerline as the original screws. Given the roughness of the table casting I wouldn't be shocked if there were significant variations in dimensions of non-mating surfaces.

[hoss2006]

Knock the corners off of the top half of the ballnut (mill or grind, keep it cool).
Someone did it on here but can't remember who showed the pics.
Grind a tad off of the inside of the saddle so the screw almost rubs against the saddle
then you should only need to clean off the casting flash at the end
of the table to clear the nut.
Good Luck,Hoss

[sansbury]

And we have a winner!

Turns out that by pocketing the saddle right down to the chinny-chin-chin of the screw, I cleared enough space to make things fit! The pocket ended up being about 0.100" deep. Definitely a better approach than milling/grinding the heck out of the table!

The downside of this is that it's thrown the alignment of the screw off a bit, so it starts to bind up when the end block gets within about 2" of the nut. But it's great the rest of the distance, so I may just leave it as is for now and use the machine to make a new one when it's finished.

Other good news is this was enough assembly to take some rough backlash measurements, and I'm pretty sure I'm coming out around .003" or less. I haven't adjusted the preload on the bearings too carefully yet so I bet there's room to improve. If it comes out at that number when all is said and done I will be a happy camper.