Cast Iron registers/grates

I wanted to make a post featuring the cast iron grates we have in our home. We have 3 different styles, with the second (and most ornate) being the most common in our home. They're floor mounted on the first floor and wall mounted on the second floor. It seems our home had a coal-fired furnace back in it's day and we have a "coal room" in the basement with a coal chute cover still in place!

These grates all still work to this day 114 years later! They're now connected to our central heat/AC units!

The first photo is the old wood intake grate:

The following is the grate style we have in most rooms:

We only have 2 of these:

This is the only one of these we have:

An example of a wall mounted grate:

The coal chute door:

And as a final note, I might add while our house had a coal furnace and heating very early on, it wasn't the case when the house was first built - it must have relied solely on fireplace heat. I have determined this from the fact that there are score marks on the hardwood floors where the intake grate was cut and the floor boards removed, however in other areas, like at where our fireplace tiles are, there are no such score marks which to me, says that on one hand the fireplace tile space was planned originally where as the grate was done after the flooring was installed. However, given our grates are all Victorian, it's safe to assume to heating was a very early addition. I tried to get a photo of these score marks but they're very faint, and along with the rough and uneven edge of the cut for the intake grate, all clues that it was added after the fact.