X2 mill modification for tram adjustment

zeeprogrammer · Dec 21, 2009

Rick (black85vette),

Let me know if you'd rather I post elsewhere...

Took a run at making the Z extension mod on the X2 today. Overall it went well but I wanted to post a couple of observations and I'm wondering if I did something wrong...

First the observations...

a) The template they (LMS) give you to drill the two holes at the top is not to scale. Measure instead.

b) It was not clear to me where center was. Center of the column? Or center of the dovetail. I used the dovetail but I don't think it matters other than you should use the same reference for the hole on the back of the column. But even that's not critical.

c) The instructions don't explicity say (at least I didn't see it)...but remove the motor.

d) When you loosen the rack and/or insert the new one...you will see the handles of the head turn as you push or pull the rack.

e) The Z stop is the last thing to attach. Also, at some point they talk about moving the head all the way up...if you do, you'll run off the old rack and it can be difficult to get it back on.

f) I believe the X distance given for placing the support on top of the head is too short. When all is said and done, the two shafts do not appear parallel to me.

Looks worse in 'real life' than in the picture.

[EDIT: Hold comment until I get a chance to look at this closer. I think there's a part from the torsion spring assembly in the way that needs to be removed first.

My biggest concern follows...]

[EDIT: Woke up in the middle night calling myself an idiot. (Not unusual.) I realized the lack of lower Z was due to the same problem. I needed to remove the torsion spring.]

g) Sure seems like I lost a couple of inches down below. Not that I'm unused to that...but I didn't expect it here...

That seems to be a function of where the hole is drilled in the back of the column and where the spring rod is attached.

So that's the bit I'm wondering if I did right...

Anybody else who's done this see that?

You would think it could go another 4" but if you do, then there won't be enough spring rod at the top end. Maybe 2"? In other words...instructions say to put the hole at 12" from top...what did you guys do?

For all that...you get maybe 2" at the top...but if that's at the loss of the bottom...I'm not so sure this is worth it.

rudydubya · Dec 22, 2009

Good info zee. Got one ready to be installed, but I think I'll wait to see what you find out. Thanks for sharing.

Rudy

tel · Dec 22, 2009

Isn't that kit supposed to come with the longer rack, that allows the head to come down more?

TimGS · Dec 22, 2009

I have performed this modification on an X2 with a cncfusion ballscrew upgrade already installed.

To determine where the hole in the back goes...
1) Mount the new rack on the Z-Axis.
2) Mount the solid bar, rod, and air spring mount on the mill head per the instructions.
3) Move the mill head to the top most position
3a) From the back of the z-Axis:Hold the top of the air spring to the top air spring mount (from step 2)
3b) Mark where the bottom of the air spring mount touches the back of the z-Axis
4) Lower the mill head to the bottom most position
4a) From the back of the z-Axis:Hold the middle +1in or +25mm of the air spring to the top air spring mount (from step 2) (this simulates fully compress air spring....try it yourself but be careful)
4b) Mark where the bottom of the air spring mount touches the back of the z-Axis
5) Select a point between the two points you marked in steps 3b) & 4b) and centered horizontally in the z-axis column....That's where you should put the hole.

The air spring at the top most position will not be fully extended or bottomed out if you do this

...Good Luck...and don't forget to support the head when you remove the torsion spring

)

zeeprogrammer · Dec 22, 2009

I edited my post. I woke up in the middle of the night giving myself a head slap.

The lack of lower Z was due to the same problem as the parallelism...that is, I needed to remove the torsion bar. There's a rod that goes through the column in X and the upper portion of the spring bar hits that.

The instructions aren't not clear about how you go about removing the torsion bar other than they say to remove the pivot pin at the end of bar first.

I then removed the nut on the main assembly...but not sure if that was needed. Then I removed the set screw on the other side of column. Then you can slide the whole thing off. Depending on how well made, or installed, the spring is...the spring may be stuck in the housing. Jiggling it around freed it...or there's 3 flat head Philips screws inside the housing you can remove.

I left the torsion spring housing on as well as the post that held the pivot. But you can remove them too.

This is not really a 'Z extension kit' nor does LMS call it that. You get less than inch more height. This is about replacing the torsion-spring with an air spring. And so far it does seem easier and nicer to move.

Easy enough to install.

The kit came with a small collar looking thing. It's not shown in the picture of the parts, nor is it ever referenced in the instructions.

One of the screws is supposed to be M8x20 but the provided one (and pictured one) seems more like M8x15. But it works fine.

Some of the parts come packed in red grease. I just cleaned it off with WD-40 and a brush. Pay particular attention to the rack...it looked like the teeth were packed with swarf.

The kit does not come with drills and taps. I purchased the LMS tap and tap drill kit. But I only used the 6mmx1 tap and the 5mm drill bit. If you have the tap, then you probably have everything you need.

Top of column looks a tad ugly. I'm thinking of taking the old plastic cover, putting a notch in it, and reinstalling it. It's just glued on. Which reminds me...they don't tell you how to remove the cover. I just put a screwdriver in and it popped off.

Thanks Rudy, tel, and TimGS for your responses.

TimGS...then it sounds like I can convert to CNC and leave this mod in?

TimGS · Dec 22, 2009

You will be able to easily perform the cncfusion upgrade if you left about 11mm between the air spring mill head mount bar and the z-axis column. If you use another MFR's kit you may have to modify the air spring mount and the mill head.

In any event you will also have to remove that nice new z-axis extension rack you just installed because it is just not needed.