That is a custom machined/tempered thread and bolt.
Are you trying to repair a damaged unit or build a tool?



http://www.peachparts.com/shopforum/diesel-discussion/324349-my-inexpensive-w123-spring-compressor.html

Homemade Spring Compressor
Homemade Spring Compressor - PeachParts Mercedes ShopForum


.

__________________
ASE Master Mechanic

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D

https://www.boldegoist.com/