Cast iron rods found under floorboards of home built in 1853. What are they used for?

A questioner said:

Cast iron rods found under floorboards of home built in 1853. What are they used for?

Owner said: 

Only thing giving me pause for them being paddles for a mortar mixer or the like, is their size. They’d need to be spun up by some sort of engine, not by hand I’d assume as most craftsman at the time would be using to mix mortar. And even if used within the last 100 years of the homes brick patch repair, that would be a big machine for a smaller section of foundation. And while this home was contemporarily very expensive, I don’t see them bringing in that size of machinery for that type of work.

Some of the people opinions on it:

americathon said:

They are probably Cast Iron Shaker Rocker Grates for a coal stove or furnace.

Cast Iron Shaker Rocker grates are a specialized type of grate designed for use in coal stoves and furnaces. Unlike traditional fixed grates, these grates feature a rocking or shaking mechanism that allows you to easily manage the coal bed and remove ash buildup.

The cast iron construction provides exceptional durability and heat resistance, ensuring long-lasting performance in the demanding environment of a coal-fired appliance. The rocking or shaking action facilitates the even distribution of air through the coal, resulting in more complete combustion and improved heating efficiency.

Uniqueacadia said:

r/whatisthisthing - Cast iron rods found under floorboards of home built in 1853.

Definitely shaker grates. Burning coal results in ash and “clinker” (glassified rock and sand that was in with the coal). That waste material must be shaken out of the fire box periodically because it will become insulating, so you don’t get the full benefit of the burning coal. The wouldn’t have rotated all the way, they would have just been rocked (shaken) back and forth. The gears were likely because they had one handle to shake them both together.

What do you think it is? Please let me know.