Hardinge hlv hlv-h tfb indicator mount. Pictures 2-8 show exactly what is included in the listing. The indicator mounting hole is 0.386 diameter.
This mount comes with a delrin bushing you will put into the head of the 1/2” cap head bolt that is clearly shown in pictures 15-17. I use a small hammer and gently tap it in. Once installed and you bolt the mount to it the bushing will expand and hold the mount tight. Then the set screws with nylon tips will help secure the mount further.