This is what I use, which is easy and convenient, as well as other options are mentioned.
ERL-1340 Cross Slide Lock for DRO Equipped Lathes
Often when doing tight tolerance work one needs to lock the cross slide to get consistent diameters along the length of the cut. My ERL-1340 was fairly tight when new, but over time I did noticed slight shifts in the cross slide position from my original setting. I am using glass scales, and I...www.hobby-machinist.com
Excellent solution DavidYou can re-mount the DRO scale/encoder to give access to the locking bolt. What I did is discussed in this thread.
DRO Install on a 1340 GT
I purchased a DRO along with my 1340GT from PM. In hindsight it might have been a good idea to pay the extra and have them install the DRO. Instead I spent the extra money on tooling and a drill chuck. Not I'm facing an install with no instructions :) For those of you who have a 1340 (or...www.hobby-machinist.com