I'm working on a jig to hold a 360° prism at the end of a large bridge girder during assembly. My plan is to mark the centerline end of girder, then place this jig over the measure marks. Jig will be made from aluminum or strong plastic with magnets to secure it on the steel.
I will try using a Switchable Kelly Mag Mount. Not sure how well I will be able see my center mark. So I may mount this on my jig.
Looking for input and suggestions from others.
Here is video shop how this fits on girder.
Angle Retro Reflective Survey Target
That will not work when instrument is not aligned with that fixed target. I will be working radial.
What's the purpose?
Cause the engineers want it!
Assembly of 400ft spans, 3 girders wide off site many miles away. Engineers want to check bearing alignments to see if spans ' grow', is what I'm told they want. Basically looking to check before they are lifted in air.
Could you get them to tack weld a 5/8" stud to centre and knock it off after event?
If engineer requires I'm sure he could arrange that.
I'd be concerned using magents it could shift. Unlikely but possible.
If the stud shifted you would certainly know as it's most likely on the ground.
Rare earth magnets would hold it, but not sure plastic or aluminum would be tuff enough. Rare earth magnets can be brittle as well, so have to slide into position and not let it get sucked onto the metal.
You can buy them all the way up to a few hundred pounds of pull force.