The main distinction is between cast-in anchor bolts and post-installed anchors. Cast-in bolts are positioned before concrete is poured and can be a good fit for planned foundations, base plates and equipment pedestals. Post-installed anchors are fitted into drilled holes after the concrete has cured, which can suit retrofit work, site changes and smaller fixing jobs.
That difference matters because it changes the tolerances and failure risks. Cast-in bolts need accurate setting templates and enough thread projection after the pour. Post-installed anchors depend more on hole diameter, cleaning, edge distance, embedment depth and the anchor mechanism, such as expansion, sleeve or chemical fixing. A 12mm anchor that looks correct on a drawing can still cause site rework if the thread length, nut allowance or installed height is wrong.
Start with the anchor type, not the diameter alone. A 12mm J bolt, L bolt, straight anchor rod, sleeve anchor, wedge anchor or chemical anchor stud can all serve different fixing conditions. For new concrete work, confirm the bend shape, overall length, thread length and projection. For drilled installation, confirm the hole size, embedment and whether the base material is cracked concrete, sound concrete, brick or block.
Match the material and finish to the exposure. Plain steel may be suitable for protected indoor work, while zinc-plated, hot-dip galvanized or stainless options may be considered for damp, outdoor or corrosive conditions. The trade-off is cost, coating thickness, thread fit and availability. If a nut, washer or coupling nut is required, ask whether the finish and thread tolerance will work together after coating.
Check the drawing details that often cause avoidable mistakes: total length, threaded length, thread pitch, nut and washer requirement, exposed thread above the plate, plate thickness, hole clearance and any required bend radius. For anchor bolts set in concrete, also confirm the layout tolerance and whether a setting template is needed. Small errors in projection or spacing can stop a base plate from sitting down correctly.
As a next step, send the anchor style, diameter, length, thread details, material or grade requirement, finish, quantity and application notes. If the anchor is for a structural or safety-critical connection, provide the project specification or engineer’s drawing rather than relying on a verbal description.
