Taig Mill Table "play/slop/lash"

[surrealism]

Hey guys, went to run some parts tonight, and I changed my vice. the mill was stepping the cuts (something not square). So I decieded to recheck the whole thing.
I have some table lash I would like to deal with. I made a video for ease of understanding my problem.

Any hints would be great! Thanks again guys for all the help.

(just posted it, it might take a few min to be available to stream)
[nomedia="http://www.youtube.com/watch?v=yF3ntvdfvdM"]YouTube- Taig Mill Table Lash.wmv[/nomedia]

[Andre' B]

If you want to find out where the motion is coming from you need to keep looking.

Use the indicator to check for motion between the table and the saddle.
Then from the saddle to the screw.
And then from the screw to the frame.

Or you could just adjust everything that can be tightened up and see what you end up with.

[allenj20]

Lock the table and 0 out the handle then turn it if it moves it's in the screw and the dial will tell you by how much. Do you have the newer adjustable lead screw nuts? If so then just adjust the backlash out see here http://www.cartertools.com/nutback.html

[wildwestpat]

In your video you demonstrate that the table moves when pushed and stays there – but - when you tighten the gib you have a spring action of almost the same magnitude.

The gibs on the table need to be sufficiently tight in both axis. The gib adjustment is critical and needs to be done properly making sure the gib screws are acting in their respective recesses in the gib strip correctly. If the adjustment screws including the locking screw can cause the gib to bend. A good check is to try twisting the table rather than just pushing it looking for movement with the DTI mounted from the head or mast with the sensing point as far from the centre-line of the machine as possible. IMO it is probable that the gib is either bent or not seating correctly and some careful checks with the dial test clock should quickly show where the movement spring action is coming from. I would withdraw the gib strips and inspect them for flatness – surface finish and most importantly for the adjustment screws making proper contact in the centre of each recess in the gib. The gib should not only fill the gap but also push the table down onto the flat part of the dovetail slide. If the gib is upside down the gib might be being bent as well as tending to lift the table rather than simply force the table down on to the flat. I suggest the following test before you start removing the gibs:-

See if you can twist the table with respect to the head. If you can then you have a gib adjustment problem. Do not expect to get zero movement as you can put a large force on to table compared to the normal cutting forces and any movement is magnified by the distance from the centre of the machine. Remove any sources of twist first as this will mask any other adjustments you make.

Backlash will show up when you rotate the lead screws and the clock shows that you do not get an immediate response from the table on changing direction of travel. The amount of lost motion can be derived from observing the forward and reverse action. There are numerous adjustments / fitting corrections and these include the bearings on the screw as well as the nut.

You should also check the tram of the mill after making any adjustments in view of the spring just to make sure the head is still perpendicular to the table as this is the most common cause of steps in a finish between consecutive passes.

Hope this helps – regards Pat