[Kalvin]

Thanks for the fast reply Kelvin.

I'm going to move on with putting the motor and sheet metal back on tonight. I had planned on spending some more time on trying to hunt this down.


Cheers,

[Teyber12]

hey kalvin!

it seems like your conversion came out very nice frustrating about the z axis... has anyone noticed this problem with manual machining?

I would love to see some "overall" pictures of the mill if its not a hassle

And if you don't mind me asking... where and how did you decide to mount your home switches?

Thanks so much!

cheers

[Kalvin]

Hey Teyber,

Still not 100% sure whats causing the Z axis thing. I played with it a bit more tonight. If I tighten the Z gibb up alot more I can make it a lot worse. Loosening it off , the best I can make it is about .0025. I'm not really too concerned about it. I can see that much play in the head just from flex in the column, if I put a light load on it. Just curious what is causing it to move in the opposite direction initially. It always goes back to zero when I "goto Z".

I didn't get it all back together tonight. I ended up playing around with the Z a little more. When I did start to put the sheet metal on I ran into another little problem. I needed to removed about 2 mm from the sheet metal where it sits over the Z axis mount bolt heads. I just finished doing that and repainted the edge to prevent corrosion. Will put that on tomorrow and post a few pictures.


"And if you don't mind me asking... where and how did you decide to mount your home switches?"

Presently I have no home and limits switches. Still thinking this one out.

Up till now I've been playing with mach3 and a pen. Heres what I figured out. Pens break when pressed into the table too hard.

The most important limit in my opinion is the lower Z. I doubt I will ever hit the upper Z and the X-Y limits won't cause the same damage that going thru the lower Z will. The problem with the lower Z limit is that it is dependent on the tool you have installed. What I am thinking of doing is making an adjustable lower Z axis limit switch and setting it up on a magnetic base under the head. Adjust it as required after a tool install and live with that.

I've had pretty good luck with the soft limits in mach 3. (I know these are only good if the s/w doesn't hickup.) Time will see what I end up with. I will definitely have the Z lower hardware s.w. I will take a picture of it when I get it set up.


Cheers,

[HackMax]

It's been a while since I've had a chance to play with this. (Just got back from my trip to China.)

Spent the day tramming and shimming and tramming.....pretty happy, in a 4" circle I measure a total of less then .001.

The problem I'm working with right now is in the Z axis I don't think it could be defined as backlash. Here's what is happening.


I set up my test indicator (attached to the spindle) touching the table with a slight preload.

Zero the z axis and the indicator.
Move the Z axis up.
Then hit "goto Z" in Mach. (head moves down) Bang on. Right where I want it to go. Every thing zeros up fine.

Now press the step up button, one press.....approx 0.001" (0.0250mm). The dial indicator shows the head move slightly down, not up. It will do this for approx three presses.......0.003" before it starts to move in the proper direction. I would have thought backlash would show no movement before it moved in the proper direction.

It does this in the opposite direction also.



Any ideas?

The problem is a cantilever between dovetails of the column and the head mounting bracket. There is one heck of a weight put in the dovetails is this design. About the only thing to combat this is put some sort of support on the head to count the weight of the head. Even with the gibb tight it still has this cantilever. I am planning to do something similar to what another forum member found to do. I can't remember the thread but I do have a few pictures of an x2 (i think) that has used this.

Also the head is actually tilting in and out. Move the head back up to just where it stats to go back up and check the y tram. I think you'll find that it is out of whack again.

Rick

[Speedygonzales]

Kalvin and KCT
where in canada are you located?
if close (long shot) could I have a look

[Kalvin]

Kalvin and KCT
where in canada are you located?
if close (long shot) could I have a look

I'm in Calgary, Alberta. You?

Kalvin

[Kalvin]

Also the head is actually tilting in and out. Move the head back up to just where it stats to go back up and check the y tram. I think you'll find that it is out of whack again.

Rick

Thanks Rick,

I tried that last night. The tram was still good. I thought the problem might be related to play in the Z gib. I kept trying it and then tightening, then trying it again. Tightening the Z gib more and more will make it the problem worse.

If it was related to the dovetail you think it would get better with the gibbs tightened up.

The thing I can not explain is the initial reverse movement. Loosing the gib will reduce this movement down to approx 0.0025"

I can get the same reverse movement if I turn the Z ball screw by hand. Turn it in one direction a few turns. Then reverse direction and the Z still moves in the first direction. That eliminates the stepper, belt drive and pulley.

Cheers, Kalvin

[HackMax]

Thanks Rick,

I tried that last night. The tram was still good. I thought the problem might be related to play in the Z gib. I kept trying it and then tightening, then trying it again. Tightening the Z gib more and more will make it the problem worse.

If it was related to the dovetail you think it would get better with the gibbs tightened up.

The thing I can not explain is the initial reverse movement. Loosing the gib will reduce this movement down to approx 0.0025"

I can get the same reverse movement if I turn the Z ball screw by hand. Turn it in one direction a few turns. Then reverse direction and the Z still moves in the first direction. That eliminates the stepper, belt drive and pulley.

Cheers, Kalvin

I noticed the same thing on my X3 and then I looked at how the gib works and because the gib works as a wedge more than a guide this causes a pivot point at where the head will rock. When you attempt to move the head up the ball/acme nut moves up but the weight of the head works against this so it stays down and tilts in a little. Locking the gib would make it worse since there is only one pressure point holding the gib against the column in effect bowing the gib to a certain extend and an making the pivot point worse. The only way to make sure this is not what is happening is to tighten the gib adjustment screw until it has locked up the head. Even then you may have to move the head up and down .001 until you get it rock solid tight. I can picture in my mind what is happening but it is hard to explain. Others have found this issue before and the answer they came up with was what I showed in the pictures.

Rick

[project5k]

i can see what your saying, the head is in effect pivoting around the "middle" of the gib, and by adding that little block and bearing, you eleminate that pivot point, making sure that the top and bottom of the gib are in effect the contact points, not the middle.

I like that little block so much, i think im gonna make me some and add them to my machine, even tho i havent seen this issue with mine... course.. nothing i do is that precision anyway.. but it sure could get there quick... once i increase my spindle speeds.

[Speedygonzales]

I'm in Calgary, Alberta. You?

Kalvin

Toronto, Ontario. ways apart unfortunately

[Kalvin]

Teyber, here is a few pictures for you.

My one Z limit switch. I made it up last night. It's not wired in yet, I'll do that tonight.

It basically is held in a magnetic base and positioned where required. Wired into the BOB and will kill all operations if the machine goes lower then I want it to.

Cheers,

[Kalvin]

Just posting a few pictures of my controller. Reclaimed an old PC case. A few old PC heatsinks and fans. (Had to mill the heat sinks flat.)

All in all I'm pretty happy with how it turned out.

When I get some time I'm planning on making a Stainless plate to cover over the
drive bay holes and I'll mill out an array of LED holes and wire them into the I/O board, so I can see whats happening.

Kalvin.

[Teyber12]

wow turned out really nice! glad to see you took the time to finish it non ghetto

thanks for posting the pics

[Kalvin]

Missed one picture.

[Kalvin]

Thanks Teyber,

It sure beat's the 3/4 inch piece of plywood I had my temp. setup on.

Kalvin.

[Kalvin]

Wow, it has been a while since I did this thread.

Hope everyone is doing well. I'm at the stage where I would like to add a high speed spindle to the side of my milling head. The spindle I'm looking at is 80mm by 180 mm.

Anyone have a few photos of how they mounted theirs? I'm thinking on the left side of the head in front of the motor. Built a spacer to offset the spindle clamp so it will clear the back of the quill cover.


Cheers, Kalvin