Why galvanized anchor bolts cause problems on site
Anchor bolts are installed first and adjusted last.
If their threads are damaged, nothing fits.
Nuts jam.
Base plates won’t sit flat.
Crews start grinding threads on site.
This turns a simple erection task into a delay.
What actually damages the threads
During hot dip galvanizing:
- Zinc builds up inside threads
- Threads become tight or blocked
- Coating thickness varies
- Nut fit becomes inconsistent
If threads are not chased or tapped after coating, problems appear on site.
Why this keeps happening
- 1. No thread chasing after galvanizing
Threads are left as-coated.
- 2. Wrong nut tolerance
Standard nuts don’t fit HDG threads.
- 3. Poor galvanizing control
Uneven coating creates tight spots.
- 4. No test fitting before dispatch
Problems reach site unchecked.
What happens on site
- Nuts jam half-way
- Installers force them
- Threads get stripped
- Bolts become unusable
- Base plates misalign
How to prevent this
Chase threads after galvanizing
Use oversize tapped nuts
Test fit nuts before packing
Measure coating thickness
Reject jammed threads at factory
Final thought
Anchor bolts should make alignment easy, not impossible.
Proper thread finishing after galvanizing prevents site delays and frustration.