The most important distinction is between cast-in anchor bolts and post-installed anchors. Cast-in bolts are positioned before concrete is poured, so the layout, thread projection, and template accuracy matter early. Post-installed anchors are fitted into hardened concrete or masonry, so hole diameter, embedment depth, cleaning method, and base material condition affect the result.
This distinction matters because the wrong type can shift the risk from product cost to site labor. A bolt that looks correct on a purchase order may still fail the installation requirement if the drawing does not state embedment, exposed thread length, coating, nut and washer requirements, or the standard the buyer expects.
Start with the installation method. If the anchor is set before concrete placement, confirm the shape, bend, plate or sleeve arrangement, thread length, and required projection above the finished surface. If it is post-installed, confirm the base material and the hole preparation expected by the project specification.
Match material and coating to the environment instead of choosing by appearance. Indoor dry use, outdoor steelwork, wet concrete areas, and corrosive industrial sites may need different finishes or base materials. Hot-dip galvanizing, plain finish, zinc plating, or other coatings can change thread fit, corrosion resistance, and cost, so the mating nuts and washers should be considered at the same time.
Avoid ordering only from a rough description such as “M20 anchor bolt.” That leaves too many decisions open: total length, thread length, grade, surface finish, bend or end form, washer size, nut quantity, packaging, and drawing tolerances. For repeat work, use a drawing or previous approved sample to prevent small changes that create field problems.
The next step is to send the application, drawing if available, diameter, length, thread details, finish, required nuts and washers, quantity, and any project standard. If load performance is controlled by an engineer or local specification, share that requirement before confirming the bolt style.
