THRU-HOLE / DONUT / FORCE WASHER
Through-hole load cells.
Keep the center open.
Through-hole load cells for screw thrust, bolt preload and hollow-axis machines. Define the bore, fit the envelope, then match the measurement chain.
Your shaft sets the ID.
Your machine sets the envelope.
A thru hole load cell must fit the force path as well as the space. Choose a smooth donut, bolt washer, threaded interface or large-bore annular ring.
Review a custom bore ↗FIVE SERIES / ONE MEASUREMENT CHAIN
Start with how the load enters the sensor.
Smooth donut
Ball and roller screw thrust, bearing reaction and fixture clamping
3–50 mm / 1/8–2.0 in100 N–200 kN02 / MT-THL-B↗
Bolt force washer
Bolt preload monitoring, flange clamp force and torque-to-tension studies
M4–M20 / 1/4–3/4 in2–300 kN03 / MT-THL-T↗
Threaded tension / compression
Hollow-shaft tests, center-hole jacks and cable tension fixtures
M6–M30 / flange review200 N–100 kN04 / MT-THL-LP↗
Large-bore annular ring
Robotic hollow joints, hollow-shaft motors and wafer press fixtures
50–120 mm / 2.0–4.5 in options10–500 kN05 / MT-AMP-KIT↗
Conditioning & acquisition
PLC press control, paired sensor acquisition and multi-bolt force monitoring
Matched to selected sensorSystem calibration required
MOUNTING IS PART OF THE MEASUREMENT
A flat washer is useful. A correct load path is essential.
Hardened parallel load washers can improve the contact interface when matched to the sensor. They must load the designated annulus, keep the shaft free and avoid bridging the sensing element.
For bolt preload, assess torsion, support stiffness and force shunting in the assembled stack.
Read the mounting guide →FROM THE BRIDGE TO YOUR CONTROL SYSTEM
Total force, or the load at every bolt?
A summing box combines bridge outputs. Independent USB or PLC acquisition retains individual forces so you can inspect load distribution. Specify the decision you need to make before selecting electronics.
ENGINEERING NOTES / THREE DECISIONS THAT MATTER
Check the interface before you order.
How Does a Thru-Hole (Donut) Load Cell Work?
Full-bridge strain measurement, load-path design and mounting flatness for donut load cells.
Read guide →NOTE 02Load Cells in Parallel: Summing Box or Independent USB Channels?
Compare calibrated total force with individual bolt loads, excitation current and synchronization.
Read guide →NOTE 03Metric vs. Imperial: Selecting ID / OD Clearance for Shafts & Bolts
A practical bore-clearance worksheet for M4–M24 bolts, ball screws and imperial shafts.
Read guide →Engineering review / Quote & CAD
Send the bore, envelope and force requirement.
We review the loading path, mechanical fit and signal chain before quoting. Request the configuration drawing and calibration scope with your brief.
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