From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Comparison report on running-in rig tests for grooved versus non-grooved worms.
| Identifier | ExFiles\Box 106\3\ scan0333 | |
| Date | 1st October 1935 guessed | |
| Copy. GROOVED WORMS. Type. 20/25 HP. (8) grooved worm No.1. fitted to steering column Code No.O.28L. nut and worm on running-in rig for 4 hrs. 2 hrs each side of nut, minimum poundage 8, commenced at 9 lbs, improved by running, no sticking. Fitted to chassis GLJ-7 20/25 HP. Grooved worm No.2. very similar on rig to No.1. Code No.O.27L. Fitted to chassis GLJ-3. 20/25 HP. Grooved worm No.3. run on rig for 6½ hrs, poundage 9 lbs, improved by running to 8 lbs, no sign of sticking, being built in column Code No. 20/25 HP. Grooved worm No.4. on running-in rig for 3 hours each side of nut. Report on rig very similar to Nos. 1,2, and 3. 20/25 HP. Grooved worm No.5. Very similar to previous 4 worms. 20/25 HP. Grooved worm No.6. This completes the running-in rig test for the 6 grooved worms, all the six have been very smooth and free from any sign of 'stickiness'. NON-GROOVED WORMS. Type. 20/25HP. Worm No.12S. on running-in rig for 6½hrs. showed signs of sticking and actually stuck after 1 hr's running, showed signs of nut 'picked up' on first side. Then nut was turned over and run for 3 hrs. and each time machine was stopped worm and nut could be made to stick, poundage did not increase by running. In spite of stickiness poundage improved from 10½ lbs to 9. This worm & nut would be condemned in ordinary practice. Bentley. Worm No.J.33 on running-in rig for 3 hrs. each side of nut and was stickier than 12S. Poundages on the non-grooved type are not so consistent as the grooved, the former will vary from 10½ lbs to 9 and back again to 10½ then will lighten again to 9 lbs, but at all poundages worm and nut will stick. Bentley. Worm No.J.34. Very similar to J.33 possibly a little stickier. Bentley. Worm No.J.35 very similar to J.34. 20/25 HP. Worm No.13S. very similar to J.34. 20/25 HP. Worm No.13S. very similar to J.34. | ||