How / Where to shim Taig Mill

[Spokerider]

Gents,

I've been tramming the Taig Mill.

Have the X axis trammed to .001" over a span of 7.5 inches. This is good.

When I checked the Y axis / column tram accuracy, it is out .005" over the same 7.5" span [ front to back ]. For me, this means the column is tilting towards me, when I'm in the front of the mill.

Do I shim between the mill base and the column, where the round machined surfaces mate? A strip of tin foil? Pop can? or?

Or....do I shim between the column 2 x 2 tube and the Z axis ways? If I were to shim here, put a shim in the top....re-tighten the bolts.......would that just bend the ways and put an "arc" into it? Hummmm.

How / where do you shim your Taig for this?

I would like better accuracy, if possible, for when using a flycutter.

Thanks for your thots.

 

[ThinWoodsman]

I guess it sorta depends.

I would shim between the mill base and the column. I would also double-check that area is clean and smooth before shimming. Shim could be tinfoil, leaf from a spacer gauge, etc; I picked up a shim assortment from McMaster or somewhere that has increments of .001.

Of course, you will have to replace the shim every time you tram the Taig column for the X-axis, which can be onerous. The Taig gets knocked out of tram quite easily when taking heavy cuts. My workaround for this was to drill through the bench that the Taig is mounted to, and run 3/8" allthread down the column and through the hole, with nuts and fender washers on either end so that the column gets clamped in place once trammed..

Might be less work to just shim the Z-axis column once and be done with it.

Does the 0.005" reading apply at both the top of the Z axis and the bottom?

 

[Spokerider]

Thanks ThinWoodsman.

I have limited tools for checking tram.......and thus can only check tram with the Z axis at about mid travel. This is for both X and Y axis. I have a dial indicator, and articulating arm that is collet / spindle mounted. I have to measure on the mill table itself, as I don't have any 123 blocks or parallels yet.

Seems to be many threads on tramming Taig X axis, but little discussion on tramming the Y axis.

The Tram gets knocked out when making heavy cuts?? Hummm. I didn't know this. I guess I'll become very good a mill tramming........

 

[wlutz83]

Gents,

I've been tramming the Taig Mill.

Have the X axis trammed to .001" over a span of 7.5 inches. This is good.

When I checked the Y axis / column tram accuracy, it is out .005" over the same 7.5" span [ front to back ]. For me, this means the column is tilting towards me, when I'm in the front of the mill.

Do I shim between the mill base and the column, where the round machined surfaces mate? A strip of tin foil? Pop can? or?

Or....do I shim between the column 2 x 2 tube and the Z axis ways? If I were to shim here, put a shim in the top....re-tighten the bolts.......would that just bend the ways and put an "arc" into it? Hummmm.

How / where do you shim your Taig for this?

I would like better accuracy, if possible, for when using a flycutter.

Thanks for your thots.

One other approach I’ve heard about is shimming the Y base, so instead of correcting the leaning Z axis you’d be effectively pushing the back side of the Y axis up to square with the Z using shims against the mounted Y base and lower part of the machine frame. I just got a machine and am in the process of figuring this out now. I have a feeling the weight of the motor and front side of the column has a lot to do with the Z squareness issues, it seems like people regularly have the same occurrence of it leaning forward slightly, so I’m wondering whether counterbalancing might even work, or some kind of gusseting with a fine adjustment or the like. I’m hesitant to shim between the Z ways and the column because they look thin enough to just flex when tightened down, and shimming under the spindle mount obviously won’t correct the axis, just the spindle. I’ll have to do some experimenting. I’d be interested to hear how you’ve fared with it.