Development of a Low Cost, Easily Constructed Drill Dynamometer Laboratory
Bibliographic record
Abstract
This paper presents the development of a Drill Dynamometer laboratory using cordless drills. This particular setup was chosen as it allows students to be introduced to topics such as: motor torque and power curves, power bands, current and efficiency curves; all at a relatively low and safe power level. The setup consists of a cordless drill coupled to a hex shaft mounted friction spool. The spool and pillow block bearing mounts are Rapid Prototyped from ABS plastic. Students apply tension to a belt wrapped around the spool and brake tension is measured using a spring scale. Motor RPM is measured by means of a modified bicycle computer. The batteries on the drill are replaced with an external battery pack with voltage and current meters. Student measurements show a high degree of precision for the linear speed vs. torque curves and the parabolic power vs. torque curves. The kit is made from easily obtainable materials and supplies and was constructed quickly for less than $200 a kit.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.011 | 0.006 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".