Stuck knee gib on Tree 325

[anitel]

Yesterday I stuck the knee on my new to me Journeyman 325...

I'm kicking myself as I have just refitted this machine with mesa / pc / emc controls and it is running like a champ. I had cleaned up all the ways except the bottom of the knee.

I put a keyless chuck in the spindle last night to drill some holes and cranked the knee down further than I ever have. When I went to raise the knee back up it got very hard to move. Of course I wasn't thinking and kept trying to move it up or down. Luckily I did not break the crank gearing.

After reading all the horror stories and advice re knee gibs on this and the OTHER forum, I looked at it with fresh eyes this morning. Sure enough, there is a small piece broken off the top of the gib where the screw holds it in place. The gib is sitting about 1" lower than the bottom of the knee. The only good news I can see is that I have several inches of clearance below the bottom of the gib.

So, after hours of reading, research, and thought, I made my first attempt at unsticking. I cut a piece of heavy steel bar and positioned it directly below the bottom of the gib to keep it from sliding further down. Then I moved the table all the way back to the limit close to the column (Y axis). I put a heavy piece of plate on top of the table, then a 1/2" piece of plywood, then a 10 ton bottle jack. On top of the bottle jack is a small block of aluminum stock.
BTW, the plate is to distribute the load as much as possible around the table and knee. The plywood is there because the bottom of the jack is not perfectly flat. The aluminum is on top because I am pushing against the underside of the casting between the column and the Z axis ball screw.

Anyways, I mounted a dial indicator on the table and began pumping on the jack. I've got the knee screw tension released. I've pumped the jack up to approximately 30 - 50% pressure, say about 6 - 10,000lbs. The dial indicator is showing 0.010 deflection but as soon as I release pressure on the jack it goes back to zero. Obviously that is deflection in the column and not movement of the knee. While under pressure I took a 5lb sledge hammer and wacked the top of the knee (protected by cribbing of course) to try and dislodge. Nothing.

So know I'm stuck. I believe that the column casting may fail before the knee becomes unstuck. I cannot afford the time required to strip this machine down and lay it on it's back to get at the bottom of the gib.

I've got a full shop of tools including a forklift. My first thought was to try lifting the knee and table up with the forklift but I think that will make the gib / wedge situation worse and likely won't do any good anyways because I will just pick the whole machine off the ground.

I've searched and I can't find any other tree owners with this problem. I really prefer not to destroy this nice machine.

Please don't flame me for using a sledgehammer, hydraulic jack, not cleaning the machine before using... I feel plenty bad about this situation already. I use this machine for making money and it needs to get fixed or broken and replaced. I know the machine is in pain and can hear it crying out to me, but this is business. I don't have weeks to mess around, tearing everything apart, trying this or that.


I'm looking for constructive suggestions relevant to the journeyman line of machines. I believe if I keep jacking against the cast iron column housing I will likely break it, I just can't think of any better options.

Any bright ideas?

Thanks in advance,
Thomas

[anitel]

I was able to get the knee unstuck this morning.

I continued jacking against column and tapping on the knee. I'd estimate I had about 8 tons of pressure on it before it broke loose.

The knee now moves smoothly up and down without binding. The next step is the repair the gib. I am going to put a plate on the bottom of the knee also to cover the bottom of the gib as an extra protection.

Thomas