Tonight I did some very preliminary measuring for tramming the head and column. Mostly just practice to start wrapping my head around it.
I started with the DTI in an ER20 collet holder in the spindle. First up is checking the Y axis, fore and aft. The back measurement is down .005″ over ~7.25″, which I think means the head is tilted back.
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7959.jpg)
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7960.jpg)
Next, the X axis. I actually trammed this in by loosening the head mount bolts and tapping the head with a soft hammer, so it rotated around the boss on the Z slide. Things moved a bit as I tightened the bolts, but by doing a cross-torquing pattern and going a little at a time, I got it to be within 0.0005″ over ~7.25″. Could do better, but it was just a quick 2 minute job. No sense in going nuts since I’ll have to take it apart to shim the fore and aft to fix the error above.
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7961.jpg)
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7962.jpg)
Next up, an attempt to see how the column tilt is looking. I used my granite square, mounted the indicator on a mag base on the head, and ran the head up and down with the Z stepper. The Y direction is actually pretty good as-is, it’s not even out 0.001″ over ~9″
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7967.jpg)
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7969.jpg)
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7970.jpg)
X axis isn’t so good though. Seems like the whole column is tilted to the left, I’m measuring 0.015″ over about 8″. Guess I’ll need to shim up the left side.
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7963.jpg)
![](https://www.tangentaudio.com/wp-content/uploads/2023/06/DSC_7965.jpg)
I plan to do the measurements again, then take some other measurements so I can do some trig to get some approximate values for shimming. I picked up a shim assortment from McMaster a few weeks ago, so I should be good to try once I come up with some numbers.
Perhaps that 0.015″ I’m seeing in the left-right direction is not column tilt, but some combination of gib fit and wear in the ways. Maybe I should also expect to also see fore-aft movement if this is the case?
I’ll have to think a bit more to see if there’s a way I can determine the source of it, though there’s really little harm in shimming up the column anyway. Easy to undo if I determine it’s something else.
I do have that new, unfinished gib sitting on the shelf. I should really get that thing fitted before I go crazy with tramming anyway.