Before you add another precision tool to your dimensional metrology machine inspection setup, ask what job needs doing. If you're measuring an outside diameter, inside bore, depth, or step on a workpiece, you need a handheld digital caliper. If you're keeping a coordinate measuring machine (CMM) running and protecting its air bearings, you need a CMM pressure switch assembly. These are very different purchases even though both carry the Mitutoyo name and come from Japan.
Quick Verdict
Choose the Mitutoyo 500-196-30 Absolute Digital Digimatic Vernier Caliper when you want a portable way to measure parts directly. Choose the Mitutoyo BHN506 Pressure Switch / Sanwa Denki SPS-8T when you're servicing a CMM and need to replace the air-pressure safety component that monitors the machine's supply air.
Price and Position at a Glance
| Product | Listed Price | Condition | Role | Best For |
|---|---|---|---|---|
| Mitutoyo 500-196-30 Digital Caliper | USD 48.36 | New | Handheld digital caliper | Direct part measurement |
| Mitutoyo BHN506 Pressure Switch / Sanwa Denki SPS-8T | USD 399.00 | Used | CMM air-pressure sensing part | CMM air-bearing protection and fault interlock |
Where Each Product Wins
- Mitutoyo 500-196-30 Absolute Digital Digimatic Vernier Caliper wins when your inspection task starts and ends with a part in your hand. It is built from hardened stainless steel and covers the common reading modes you need for direct part checks, with a large LCD for clear values.
- Mitutoyo BHN506 Pressure Switch Sanwa Denki SPS-8T wins when the task is machine maintenance rather than part measurement. This genuine assembly uses the Sanwa Denki SPS-8T adjustable pressure switch to trigger a fault or interlock when CMM air pressure drops, giving the control system a chance to halt the machine before guideways are damaged.
Product Notes
Mitutoyo 150mm/0-6 Absolute Digital Digimatic Vernier Caliper (500-196-30)
For most bench and inspection work, this caliper is the straightforward pick. It is built from hardened stainless steel and measures outside, inside, depth, and step from one compact tool. The dual-unit conversion and zero/ABS function make it easy to switch between inch and metric readings on the large LCD, and the 0.0005-inch resolution keeps readings precise. One concrete reason to choose it: if you want a single, portable instrument for direct part measurements, this covers the common reading types. The limitation to note is the SPC Output: None specification, so if your quality routine expects to feed readings into a data collection system, you'll be reading and entering values manually instead of exporting them.
Mitutoyo BHN506 Pressure Switch Sanwa Denki SPS-8T (Coordinate Measuring Machine)
For shops that keep a CMM in daily use, this part addresses a specific failure point: low air pressure reaching the machine's air bearings and pneumatic counterbalance. The BHN506 assembly uses the Sanwa Denki SPS-8T adjustable pressure switch to trigger an interlock or fault signal when pressure falls below the operating threshold, giving the control system a chance to stop the machine before damage occurs. If you already have the machine opened up and need the pressure switch assembly, this is the genuine replacement part to evaluate. The main limitation is that it is a component rather than a measuring instrument; it won't measure a part, so it should be treated as a service part for CMM repair rather than a bench measuring tool.
Final Choice by Use Case
Pick the 500-196-30 caliper when you need to measure features directly on a workpiece. It lists at USD 48.36, comes in new condition, and supports outside, inside, depth, and step measurements with dual-unit conversion and zero/ABS control. Pick the BHN506 / SPS-8T pressure switch when the job is repairing or maintaining a CMM. It lists at USD 399.00, is used, and is the part-oriented solution for protecting the machine's air-bearing system. If you're not working on a CMM, the pressure switch won't help with daily part measurement; if you're not measuring parts directly, the caliper won't fix a machine fault.
