Ok, got a new problem.

Ok, got a new problem. I think I know what it is and how to fix it. But I want to make sure that I am going about it the easiest way.

My Z axis is jumping and changing the zero. When it plunges it sometimes sounds like it skips with a thud. Then my zero gets off. It just started doing this yesterday. I think I have to adjust the acme tensioner on the Z axis. Is there any way to do this without taking the Z axis apart? I got excited because I thought I could get it from behind. Then turned out to be the X tensioner.

Thanking everyone in advance.

You think the nut block is too tight? I remember @Brandon_Satterfield showed a picture once of drilling a hole through the c beam (I think) to get to it using a ball end Allen wrench. Or are you plunging too fast? With the steppers turned off, can you easily turn the coupling by hand? You should be able to.

I think it might be to loose. With the power off it is easy to turn with two fingers. I could be plunging to fast but I didn’t do it before.

@Edward_Bigham hmm, think you might be able to get a quick video of it in action? I know it’s had to catch these things when you want them to happen… :-).
I have before, getting too aggressive, knocked a lock collar loose. In fact I am much more apt to do this then get the Z out of adjustment by the nut.

When I do the Z axis AcMe adjustment (only twice since the beginning) I take the bottom plate off the C-Beam, Z up till I can reach them.

I will check the lock collar and see if that is the problem. If that is not the problem I will try to video it. Thanks.

I think the lock collar was the problem. It was loose and I was able to move it up and down. I am trying to cut some aluminium now. It is not jumping around but I am having trouble figuring out the feed and speed to get it to cut. It cuts good for a pass or two then binds up and stops cutting.

Is the material “gumming” up in the tool? If so your feed rate is too low, our your tool rpm is too high. Try using some lubricant also. Wd40 works ok, or water/oil based tapping lube. You also may be talking too deep of cuts. Try shallower cuts

@Mark_Leino it was welding the aluminium but that stopped. I think it is plunging to deep. I have it set to cut .02mm per minute. But in the middle it seems to plunge deeper and just bind up.

It’s it pulling your z axis down?

Slow. What kind of bit are you using?

It just digs in and stops it. Feed rate is 300 mm/min, plunge is 10mm/min, cut is .02 mm

That is slower than I run. Are you running 800 watt spindle

How big of an end mill, how many flutes, is it a ball end?

Sorry. 6mil 3 flute. The spindle is at around 6000rpms.

Mill is has.

Mill is an hss.

I have never used one that large for aluminum. I have only used 3mm, 4mm single flute, and 1/8" two flute. Had great luck running close to the speeds your running

I have a single flute 1/8 down cut. I don’t know if that will work.

@Mark_Leino what are your settings for the single flute 1/8?

I will check when I get home. They carry them in stock at fastenal for like 8$ if you hand one near you