Slightly off topic. I was wondering if anyone has run into 70 type coil spring terminal blocks. These were developed by Bell concurrently with 66 blocks in the late 1950's and early 1960's. I only saw them once in a Municipal Building on Staten Island ,NY. They looked like they were a pain to work with,which probably explains why they were discontinued.
Yes, I've seen them in some high rise buildings in Washington, DC, and yes, they were built in the late 50s/early 60s. I was certainly not a fan of them.
