Drilling Jar Review: Tensile Rating and Jarring Force Are Different Fields

A common unit does not make two loads interchangeable

A jar comparison sheet can lose its meaning when several force entries are compressed into one maximum-load column. Equal units do not establish equal physical meaning. The purchasing task is to preserve the source label and tool identity before asking whether the proposed configuration meets the project's documented requirements.

This guide does not calculate a jarring program, surface overpull, impact energy or a safe working load. It is limited to the traceability of statements in purchasing documents.

Evidence boundary

The Gaofeng QY III table identifies QY165 III allowable working tensile as 2000 kN and maximum up-jarring force as 700 kN. The first is not a breaking-load or impact rating; the second is not a surface-overpull instruction. The referenced entries do not establish temperature derating, fatigue performance or project-specific operating conditions.

Fictional example: repair the column, not the tool

The following comparison is fictional. Worksheet J-A and its supporting document register are invented. The only numerical equipment references are the separately identified catalogue values above.

J-A has one column named pull/impact limit. An editor has placed the working tensile entry there and described a competing offer only as having a lower load. The supporting file contains no explanation of which parameter was compared. The responsible reviewer cannot rank the offers from that column.

A worked scope check starts by splitting the column into named source fields. The original entry remains traceable, but the inferred ranking is removed. A second record logs what evidence is missing for each offer.

The repaired table is intentionally less decisive than the original. That is useful: it distinguishes an identified source value from an unsupported conclusion. No additional force value is created to fill the remaining cells.

Model identity must survive the clarification

Request the exact tool designation and the document revision corresponding to the offered item. If an answer introduces another jar or an accelerator, create a separately identified record. Do not paste its load entry over the original merely because the units match.

Ask the bidder to explain the meaning and configuration scope of each supplied load label. Ask the responsible technical reviewer which project requirements and controlled documents govern the comparison. These requests do not presume that a catalogue page contains a complete qualification basis.

A document disposition with useful limits

Each open item can record the disputed statement, source location, requested clarification, reply revision and remaining question. A reply that identifies the parameter closes the naming issue only. It does not automatically close temperature, fatigue, assembly-interface or operational questions that have not been addressed.

The drilling-jar product reference keeps individual tool references separate. The RFQ Builder can carry the exact designation and document request into an inquiry. Keep any private assembly information in the inquiry attachments.

The final desk-review question is whether each compared column now has one defined meaning. If not, leave the comparison open rather than using the largest available force number as a substitute for missing evidence.