How to Design a Mounting Plate
A mounting plate is one of the most useful parts you can make: a flat slab with holes that bolts a motor, sensor, camera, or bracket to something else. It looks simple, and it is — as long as you get the bolt pattern right. Here is how to design a mounting or adapter plate, step by step, and export it ready to print or machine.
Step 1: capture the bolt pattern
The whole plate is defined by where the holes go. A bolt pattern is described by two things:
- The layout — how many holes and their arrangement (a square of four, a circle of holes, two slots).
- The spacing — the center-to-center distance between holes, or the bolt-circle diameter for a circular pattern.
Measure these from the thing you’re mounting to, center-to-center, with calipers or a ruler. If you’re copying an existing plate, our guide to measuring a part for replacement walks through getting hole positions accurately.
Two patterns at once
An adapter plate usually has two bolt patterns — one to attach the device, one to attach to the frame. Measure both and put them on the same plate.
Step 2: thickness, size, and holes
Thickness
3–4 mm is plenty for a printed plate carrying light parts; 5–6 mm or metal for anything that takes load or vibration. Thicker resists flex.
Outline
Make the plate just big enough to surround every hole with a few millimetres of material, then round the corners with a fillet.
The holes themselves should be clearance holes — a little larger than the bolt so it slides through and threads into the part beneath. Our bolt hole size chart lists clearance diameters for M3, M4, and M5 so the bolts drop in without forcing. If a bolt should also sit flush, ask for a counterbored or countersunk hole.
Step 3: print it or machine it
A flat plate is one of the easiest things to manufacture. For a 3D printer, lay it flat on the bed and export a mesh; the holes print cleanly with no supports. For a stronger metal plate, export a STEP solid and send it to a shop — a plate with holes is fast and cheap to cut. Remember a printed hole shrinks slightly, so the same tolerance rules apply if the fit matters.
A mounting plate is a single part — one solid you can make in one go. If your project needs the plate and a bracket it bolts to, make each part separately; see single parts vs assemblies.
Generate your mounting plate
You don’t have to draw the bolt pattern by hand. Describe it to PartWork.ai — “a 60 mm square plate, 4 mm thick, with four M4 clearance holes on a 50 mm square pattern” — and get an editable plate, sized correctly, ready to export. See creating parts for how holes and patterns are placed, and exporting for the file.
Start with 2 free AI generations — no card required
Open the studio, describe your plate and its bolt pattern, and export the part. More credits: 100 for $4.99 (~5¢ each).