A profile projector shines light past a part and projects its magnified shadow onto a screen. Inspectors measure the outline with a moving stage and digital readout, or compare it against an overlay chart. It is a fast, non-contact way to check small turned parts, threads, gears, springs, punches and stamped parts.
Quick facts
- Magnification
- Lenses of about 10×, 20×, 50×, 100×
- Screen
- About 300–600 mm (11.81–23.62 inch) diameter
- Stage travel
- About 100–250 mm (3.94–9.84 inch)
- Accuracy
- A few microns with a good DRO
- Measures
- Lengths, angles, radii, thread forms
- Contact
- None
Main parts
- Light source and collimating lens
- Projection lens (changeable magnification)
- Screen with protractor and crosshairs
- XY stage with digital readout
- Surface illumination for non-through features
Profile projector or CMM?
| Profile projector | CMM | |
|---|---|---|
| Best for | Small flat profiles, threads | 3D features and large parts |
| Speed | Fast | Slower |
| Cost | Lower | Higher |
Need work done on a Profile projector?
Post your requirement free. Workshops that take your kind of work see it and get in touch. You only talk to the ones that fit.
Get startedRelated
Related job work
Questions
- What can a profile projector measure?
- The outline of small parts: lengths, diameters, angles, radii and thread forms, without touching them.
- Is a vision measuring machine better?
- It measures automatically with a camera and software, faster for batches, but costs more.
- Which magnification should I use?
- The highest one that still fits the feature on the screen, for the best reading.
The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 23 October 2026.