I was going though my dad's and his dad's tools and found this tool. The two iron pins can go up and down and be locked by the screws.
Is it a measuring tool? How do you use it?
Used for marking mortise and tenon joints. The yellow disk in the illustration below is the fence, corresponding to the disk shaped (hockey puck shaped) fence of OP's tool. The sharp edge of the marking disks scribe the workpiece. In some gauges the cutting disks rotate freely, and they are called marking wheels.
With two independently adjustable rods, this gauge lets you set two measurements at once, so you can quickly alternate between them when transferring or marking repetitive dimensions.
The one shown below in the pic also has an optional shaft clamp (not shown) that locks to both shafts and will allow you to keep the relative position of the shafts while shifting the fence (the large disk shown in the pic)