DGBB Engineer Guide

Use this section when reading deep groove ball bearing results. DGBB is class-first: class and gates decide meaning before score.

How To Read A DGBB Result

1. If a reference was selected, confirm it is the intended bearing; otherwise review the dimensions supplied for discovery.
2. Read class: DROP_IN, CONDITIONAL, or REJECT.
3. Check any reported hard failures and conditional flags.
4. Review the candidate warnings and required confirmations.
5. Read the supplied and candidate values in the technical snapshot.
6. Compare the technical snapshot fields for bore, OD, width, bore type, protection, loads, speed, clearance, chamfer, precision, and snap ring.
7. Decide whether the candidate is a direct candidate, review candidate, or blocked candidate.

Do

• Do treat DROP_IN as the only direct replacement class.
• Do treat CONDITIONAL as an engineering review result, not a procurement-ready result.
• Do treat REJECT as blocked by hard gates.
• Do explain which hard failure or conditional flag drove the class.
• Do use score only to rank candidates inside the same class.
• Do verify clearance, protection, speed, and load ratings when the application is sensitive.

Don’t

• Do not let a high score override REJECT.
• Do not promote CONDITIONAL to DROP_IN.
• Do not ignore unknown speed on sealed/shielded changes.
• Do not ignore snap-ring requirements.
• Do not treat a series mismatch as harmless without review.
• Do not recommend a bearing with lower required load capability.

Status Next Actions

Status	Engineer action
OK	Read class first, then gates, conditional flags, score, and evidence.
AMBIGUOUS_MATCHES	Ask for exact bearing designation, suffixes, dimensions, or protection code.
INPUT_RECHECK_REQUIRED	Resolve conflicting dimensions, suffixes, or bearing identity before using candidates.
NO_REFERENCE	Request part number, ISO designation, dimensions, or datasheet.
ERROR	Treat as no result; retry or escalate.

Tag Next Actions

Tag	What to do next
BEARING_TYPE_MISMATCH	Reject for DGBB substitution unless product family was misclassified.
MISSING_CORE_*	Collect the missing core dimension before deciding.
CORE_DIM_MISMATCH_*	Reject or verify measurement/source if the mismatch looks like bad input.
BORE_TYPE_MISMATCH	Confirm cylindrical/tapered/special bore requirement.
PROTECTION_DOWNGRADE	A reported protection downgrade is a hard failure; review the rejection and the actual application requirements.
DYNAMIC_LOAD_DOWNGRADE	Check application load; usually blocks replacement.
STATIC_LOAD_DOWNGRADE	Check static load/shock requirement; usually blocks replacement.
SPEED_INSUFFICIENT	Check operating speed before use.
CLEARANCE_MISMATCH	Confirm required clearance class.
CHAMFER_TOO_SMALL	Check shaft/housing fillet compatibility.
PRECISION_DOWNGRADE	Confirm precision requirement.
SNAP_RING_MISSING	Reject if snap-ring retention is required.
SERIES_MISMATCH	Review envelope, load, speed, and application implications.
SPEED_LIMIT_UNKNOWN	Find speed data before high-speed use.
CLEARANCE_UNKNOWN_REVIEW	Confirm clearance before recommendation.
PRECISION_REVIEW	Confirm precision requirement with engineering.
SNAP_RING_CAVEAT	Check groove/snap-ring details.
SEAL_UPGRADE_UNKNOWN_SPEED	Verify speed impact of seal/shield change.

Example Workflow

When a candidate is CONDITIONAL with SERIES_MISMATCH and SPEED_LIMIT_UNKNOWN:

1. State that geometry may pass, but the candidate is not a direct drop-in.
2. Compare series implications against the installed bearing.
3. Find candidate speed limit data.
4. Escalate or approve only after the unknown speed and series change are accepted.

Never Claim

• Never claim replacement equivalence from bore/OD/width alone.
• Never claim a conditional row is safe without reviewing its flags.
• Never claim a rejected row is usable because its score is close.