J-bolts are a bit difficult to put in anyway. The tendency is to drop the bolt in a little along the bottom of the "J", rather than straight down the shaft. Once it's down, then the shaft is leaned a bit to get the exposed part on the mark.
Another problem is that once they are dropped into the concrete they have to be wiggled around in order to ensure the concrete surrounds the bolt. That also can be a factor in displacing the bolt a bit.
And, they can be placed accurately if one knows the problems and allows for it.
(J-bolts are used to bolt the bottom plate of a wall to the concrete footing. With wood it's easy. Insert the bolts, let the concrete set up, put your board in place, beat on the board so the bolt makes a mark, and drill.)
Continued good luck. They can be placed accurately, in my experience it's just not as easy as it might seem.
Arf
Off Topic » in reply to Without a template, you put your anchor bolts in. Drill out the plate.
Slight addendum.
The whole thread (37 posts)
- Question: how do you find 3 points on a plywood circle 120 degrees apart, without a protractor? (n/t)
- Without a template, you put your anchor bolts in. Drill out the plate.
- Yet another method
- Here you go, have a protractor:
- If I remember enough geometry...
- Cut a circle out of paper, exactly the same size as your plywood circle
- Yes, there is a way!
- So... tell us what you're building! (n/t)
- Why can't you use a protractor?
- It's impossible