Your coordinate measuring machine's pressure switch has one job: catch a drop in air pressure before it damages the air bearings or pneumatic counterbalance components. When that switch starts acting up, you need a replacement that matches your CMM's requirements. The Mitutoyo BHN506 pressure switch assembly, built around the Sanwa Denki SPS-8T adjustable pressure switch, is one specific option listed at USD 399.00. This guide looks at who should consider it, what stands out, and where the trade-offs are.
Quick verdict
If your CMM is designed to use the BHN506 or the Sanwa Denki SPS-8T, this is a credible replacement. It's a genuine Mitutoyo part made in Japan, and it's described as a critical safety sensor for air pressure on air-bearing CMMs. The listing is for a used unit, so your comfort with a used safety component will likely decide whether this is the right path.
Who it suits
This part suits metrology labs, machine shops, and maintenance teams that know their CMM's part number and want a Japan-made replacement. It also suits buyers who need the specific SPS-8T adjustable switch configuration rather than a generic pressure switch. If your protocol requires new or recertified safety hardware, this used listing may not be the best match.
What stands out from the listed details
The standout is the combination of Mitutoyo and Sanwa Denki. The BHN506 assembly uses a Sanwa Denki SPS-8T adjustable pressure switch, and the description makes clear its role: monitor air pressure supplied to ultra-sensitive air bearings and pneumatic counterbalance components, then trigger an interlock or fault signal if pressure falls below operational thresholds. That's a focused safety function, not a general-purpose switch. It's also manufactured in Japan, which aligns with the metrology-grade expectations many CMM owners have.
Meaningful trade-offs
The primary trade-off is the used condition. Since this is a safety component, some buyers will want a new part for this duty, especially if the CMM is in continuous production. The price of USD 399.00 positions this as a specialized part, not an inexpensive generic switch. Another consideration is fitment: this is described as a part for coordinate measuring machines, so it isn't positioned as a universal replacement. Your decision should rest on whether the BHN506 matches your machine's existing switch setup.
Bottom line
If the BHN506 is the right part for your CMM and you're comfortable with a used component, this is a focused, practical choice. It provides a genuine Mitutoyo part with a Sanwa Denki SPS-8T switch, made in Japan, specifically engineered to protect guideways and axis mechanics from pressure loss. At USD 399.00, it's a serious component for a serious machine. If you need new safety hardware, you'll want to keep looking, but for a compatible CMM, this is a strong candidate.
Product note
#### Mitutoyo BHN506 Pressure Switch (Sanwa Denki SPS-8T)
This used, Japan-made Mitutoyo part pairs with a Sanwa Denki SPS-8T adjustable pressure switch. It is listed at USD 399.00 and is intended for CMM air-pressure safety monitoring. Choose it if your machine uses this switch type and you're prepared to rely on a used safety component. The limitation is the used condition: for a part that guards against pressure-loss damage, you'll want to be confident in its operational state before installation.
