[saabman]

Seems like a few of us are installing CNC kits. I took my mill apart to move it into the basement many months ago. Then I got layed up from an accident, now I am getting around better and have started to install mine.

I did all the recommended mods to the cast iron. Removed the cross tie on the column (more Z travel), extended the opening in the base (more Y travel in combination with table extention), and bored the hole in the base (to facilitate ball screw installation). That latter is a must do in my oppinion.

I have completed the mechanicals on the Y. One hard learned lesson is to make sure the pulley is screwed down very tightly. I failed to do this the first time around, and after preloading the ball screw there was backlash caused by the ball screw moving forward and back as the pulley started to turn. Had not noticed this on initial install because there was not enough load on the nut. Lets just say Red Locktite on that long a thread is a bear to get undone. Took a long time to preheat with my heat gone.

You will find reference to a 1/8 inch sim under the y mount done by some people. I did this too. It makes the ball screw center perfectly in the hole in the front of the base.

Chris

[RustedOut]

One hard learned lesson is to make sure the pulley is screwed down very tightly. I failed to do this the first time around, and after preloading the ball screw there was backlash caused by the ball screw moving forward and back as the pulley started to turn. Chris

I went out and bought a good quality strap wrench to use on the pulley and used two or three vise grips on the ball screw and managed to really tighten up the pulleys. Only used the blue Locktite, but once tight, it pretty much stays that way.

Bob

[jetflatline]

Yeah, those are on my list, as is possibly filling the base with some sort of granite/epoxy mix.

You will find reference to a 1/8 inch sim under the y mount done by some people. I did this too. It makes the ball screw center perfectly in the hole in the front of the base.

I'm not sure I've seen this, can you elaborate?

[saabman]

Sure, the height of the ball screw (relative to the base of the mill) is set by the mount on the saddle. As delivered by IH, the mount will locate the ball screw "high" in the hole in the front of the base. Placing a 1/8 inch shim under the mount will locate the ball screw dead center in the hole. If you have the 3 inch extender this is particularly important as the ball screw nut comes all the way out to the hole.

I discovered (by accident) that the saddle could come out so far (as I was testing travel, by hand) that the front wiper (snap on) got lodged in the hole and pulled off the ball screw nut on retraction. I will set my limit to prevent this in practice. I will also put a tie wrap on the ball screw as a fail safe.

Also of interest, if you have the Y extention you will likely not have to cut the ball screw. I think IH makes the Y screw to length for the extention. Without it you have to cut the ball screw.

Another tip is when installing the ball screw nut, put the first nut on the shaft and then rotate the second nut (still on the cardboard) so that the it can be placed as close to the first nut as possible (you will have to rotate the locking collar too). But keep both circulating tube in the same position relative to each other. Doing this will give you maximum range when you preload the ball screw. As delivered to me, the two nuts were far apart and the locking collar went way up on the threads during preload.

I had to use a chain pipe wrench to get the pulley off (pulley was wrapped with a leather strap to prevent damage). I used less loctite on the reinstallation. I did not use the wrench to reinstall but I did press the shaft forward (from the far end) and used by leather strap to get a real tight set on it. Now it is rock solid

Let me disclaim that I am learning as I go. I read as much as I could about what others have done and began my process from there.

Chris

[jetflatline]

Thanks, I think I get it. I don't remember ordering an "extension", but I bought my mill a couple of years ago so maybe it was included?

Because IH still hasn't sent me any instructions I'm working from an older set of instructions provided by someone who did this awhile back. The pictures are a little different but I am figuring it out.

One question for anyone who's done it recently: Does the guard that locks under the y-table with little pins get re-installed? Mine isn't wide enough to fit around the ball screw mount (see photo below), but a few minutes with a grinder and I could fix that.

[RustedOut]

I didn't re-install mine, but covered the ways and ball screw with a sheet metal cover attached to the front of the Y saddle. It slides back and forth with the saddle and extends out to cover the Y axis spacer and part of the motor brackets when the saddle is back towards the column. Here's a pic.

Bob