CNC Mill and 35/64 is not really 14mm

David G

Well-known Member
I got both the X and Y motors mounted.

The steppers have shafts on both ends, I needed to make an adapter so I can put the crank wheels back on. The motor shaft is 14mm, the cranks are made for
16mm shaft so had to make an adapter. I could not get a 14mm reduced shank bit locally, so tried a 35/64, but it is just a few thousands too small. I have to get a
bit before I can finish.

I am posting pictures of the two motors and the adapter for the crank wheels.
a151864.jpg

a151865.jpg
 
I would like some advice.

The bed on the mill has a crank to raise, and the spindle has a crank to lower it. It takes a lot more torque to raise the bed versus lower the spindle. I am thinking it is best to manually set the bed, and automate the spindle. That way I can move the bed up so the part is a standard distance from the spindle, then let it control.
 
The bed on CNC systems normally do not have a Z motion. So just drive the Z feed from the Spindle. Allow the spindle to move at least 1/2 of its travel to get to part Z Zero. The spindle should be pretty free to move up and down with little resistance. One of ours has a roller chain driven counter weight to make "up" (Z positive) as easy as Z- Jim
 
Definitely the spindle aside from the weight factor of the bed vs the spindle you have a large backlash factor in the acme thread lead screw on that mill. To hold any accuracy you would need to drop down and raise the axis back up for every z axis position change.
 
That sounds like an older Haas. The newer version uses a nitrogen cylinder that assists the ball screw as it raises the head.
 
Haas hasn't had a gas counter balance in quite awhile. Our 1999 VF2 does, but the newer ones (2008, 2014 and 2016) don't. The servo loads while stationary on Z(vertical), or Y on the horizontal are much higher than the old machine with the gas counter balance.
 
I believe you are correct. I had an older 1995 VF3 with the big weight on a chain that I had replaced with newer. I asked the install tech. where the counterbalance weight was and at the time he told me they were using pressurize gas. I had never liked the counterbalance on a chain after having the chain break on that machine and wipe out the Y axis servo and ball screw. When I sold the shop I owned 4 Haas mills oldest a 2008 to newest a 2014 and never really had any major problems with them.
 
The gas counter balance is ok until it gets some age on it and leaks off a little. Then, when you power off the machine the spindle head will fall.

If your newest machine was a 2014, then you didn't get the "privilege" of Haas's "Next Generation Control" that came out on UMCs and EC-1600s in late 2015 and the VF series mid 2016. What a nightmare! If they ever get it fixed it will be a good control, but it continues to be plagued with bugs and they will fix one problem and create 2 more in the process. We got the very 1st software version and have got 6-7 updates in the last year, but it still has several glicthes. I have talked to a guy on cnczone.com that actually sent a VF2SS back to Haas because of the control problems.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top