Two documented release cycles · signed readings · controlled field method

Machine-Foot Movement Record

Normalize and compare repeated movement readings at each foot while preserving the instrument, mounting, bolt sequence, sign convention and acceptance-source record.

No universal 0.05 / 0.10 mm limitsNo automatic shim thicknessNo soft-foot type diagnosis

Arithmetic record only—not a soft-foot diagnosis or correction instruction. A signed indicator/laser change depends on the documented sensor direction, fixture and bolt-release procedure. The largest recorded response does not by itself prove a gap, identify parallel/angular/induced soft foot, establish cause, or equal the required shim.

Repeated movement readings

Number of recorded feet

Reading unit

Enter the signed change for two complete, independently repeated cycles using the controlled sign convention. Point or comma decimals are accepted.

FootCycle 1Cycle 2

Asset / machine ID

Foot numbering / orientation map ID

Machine configuration and movable case

Controlled measurement procedure ID / revision

Instrument / sensor model and serial

Calibration / verification ID and date

Resolution and measurement uncertainty

Sensor location, direction and sign convention

Fixture / reference and stability check

Bolt condition, initial torque and tightening sequence

Release amount / endpoint and dwell time

Coupling, piping, conduit and process state

Base, foot, shim/chock and cleanliness inspection

Machine / ambient condition and temperature

Controlled repeatability criterion / source

Acceptance source, edition, clause and scope

Technician / reviewer

Record date

Notes and observed direction/cause evidence Optional: feeler-gauge map, rocking/contact pattern, pipe response, dirt/burrs, looseness, repeat sequence, photographs

Isolation, stored-energy control, bolt release and personnel safety follow the site/OEM procedure; this webpage does not authorize work on the machine.
The sensor direction, sign convention, fixture stability, instrument condition and calibration/verification are documented and valid for both cycles.
Each cycle used the controlled one-foot-at-a-time release and full restoration sequence; coupling, piping, process, bolt and temperature state remained documented.
The output is only repeated-reading arithmetic. A qualified reviewer will use the licensed/current standard, OEM and site criteria plus physical inspection to diagnose and correct the condition.

Repeated-reading summary

Largest absolute mean response

—

Largest cycle-to-cycle difference

—

Recorded feet / unit

—

Foot	Cycle 1	Cycle 2	Signed mean	Absolute mean	\|Cycle 2 − Cycle 1\|

Equations, units and classification

m_i = (r_i,1 + r_i,2) / 2
a_i = |m_i|
d_i = |r_i,2 − r_i,1|

These are ordinary descriptive arithmetic, not formulas or acceptance criteria specified by ASA/ANSI S2.75. The signed mean preserves the entered convention; absolute mean only ranks recorded magnitude; cycle difference only describes repeatability. 1 in = 25.4 mm exactly; 1 mil = 0.001 in = 0.0254 mm exactly.

Model boundary and removed unsupported content

No universal 0.05 / 0.10 mm traffic-light table. The former thresholds had no verified edition, clause, machine scope, method, sensor direction, uncertainty or boundary rule. Exact acceptance remains NEEDS_LICENSED_SOURCE plus controlled OEM/site requirements.
No “reading = required shim” formula. A bolt-release response can include fixture motion, frame/base distortion, angular contact, debris/burrs, pipe or conduit force, bolt effects and other interactions. Correction requires geometry and cause evidence.
No diagnosis from sign. Reversing indicator direction reverses sign. A negative value alone does not prove induced/reactive soft foot, and a positive value alone does not prove a physical gap.
No worst-foot or all-feet-pass verdict. The output identifies only the largest recorded absolute mean and repeat difference. It does not establish acceptability, root cause, machine alignment or work priority.
No universal three-type/correction prescription. SKF public guidance distinguishes parallel and angular contact and recommends four feeler-gauge values per foot to determine the type; scalar movement alone cannot supply that contact map.
No unverified work instruction. Release amount, torque, sequence, coupling/piping/process state, measurement direction, safety controls and recheck criteria must come from the controlled procedure and equipment documentation.

Source traceability

Claim	Classification	Evidence
ASA/ANSI S2.75-2017/Part 1 is the current reaffirmed horizontal flexible-coupled shaft-alignment methodology; its public scope includes machinery mounting conditions that affect alignment.	Official status and public scope only	ASA catalogue: S2.75-2017/Part 1 (R2025); exact clauses and criteria require the licensed document
Acoem states that soft foot is corrected before shaft alignment and its AT-010 directly measures movement/play at the machine foot as the bolt is released.	Official manufacturer application guidance	Acoem AT-010 / True Softcheck
SKF defines soft foot as a machine not resting solidly, distinguishes parallel and angular forms, and recommends feeler gauges with four values per foot to determine type precisely.	Official manufacturer maintenance guidance	SKF Bearing Maintenance Handbook, p. 162
m=(r1+r2)/2, a=\|m\| and d=\|r2−r1\|	General descriptive arithmetic; not a standard acceptance model	Direct mean, magnitude and absolute-difference definitions shown above
1 in = 25.4 mm exactly and 1 mil = 0.0254 mm exactly	Exact unit conversion	NIST SP 811, Appendix B.8

Accessed: 15 July 2026. Public sources support scope and measurement cautions, not the former numeric limits, automatic shim value, diagnosis or pass/fail logic.

Arithmetic reference example

For Foot 1 readings +0.04 mm and +0.06 mm, the signed mean is +0.05 mm, absolute mean is 0.05 mm and cycle difference is 0.02 mm. These values demonstrate the arithmetic only; no soft-foot diagnosis, tolerance or shim thickness follows.

Questions

Why are there no green, yellow and red limits?

The former limits were not tied to a verified standard clause, measurement method, machine scope or uncertainty rule. Enter the applicable controlled criterion in the record and let the qualified reviewer apply it.

Does the largest absolute mean identify the foot to shim?

No. It only identifies the largest magnitude among the entered repeated readings. Physical contact mapping, cause investigation and controlled correction are separate.

Why preserve signed readings?

Discarding sign loses information, while assigning a universal meaning to sign is also unsafe because sensor direction and convention vary. This record requires that convention to be documented.