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).
Function and manufacturing challenges of grooved worms in chassis steering systems.
| Identifier | ExFiles\Box 106\3\ scan0335 | |
| Date | 7th October 1935 | |
| Copy. Wor.{Arthur Wormald - General Works Manager} from SFT.{Mr Swift} SFT{Mr Swift}4/BH7.10.35. CHASSIS STEERING Referring to the attached memo RHC{R. H. Coverley - Production Engineer}1/ETM1.10.35, there is not much one can add to what has already been said on this subject, except to emphasise the point that the object of the grooves which are introduced into the worms is to enable the oil which enters from the inside of the tubular worm to find an entry between the working surfaces at a sufficient number of points to provide enough area on the oil surface to stand up to the thrust of the worm. The reason for the present worms failing is that small movements at high speed, of the steering wheel forces the oil through between the surfaces, and no adequate means of replacement is provided; whereas where grooves are provided the short movements carry oil from the groove in between the working surfaces, and this taken over the whole length of the thread gives an ample supply to cover the full length of the worm. It is definitely a fact that we have had practically no trouble with grooves worms, once they have passed our Test Dept., Inspection and Test. With regard to the statement that the grinding of steering worms will be made a more difficult process due to the introduction of grooves, this is not agreed to by Mr. F.{Mr Friese} Wormald and the operator who grinds the worms. They both say that the presence of the grooves does not add to their difficulty at all, but it is agreed that grinding of the worms has always been a difficult process, and calls for the highest condition of manufacturing equipment, and this is always having the constant attention of Mr. F.{Mr Friese} Wormald and others, in fact, a new head for one of the machines is just on the point of being completed, and this was requested some time ago by Mr. F.{Mr Friese} Wormald, in anticipation of the present position, and to do our utmost to maintain the highest possible quality of machine equipment. This is essential whether the worms are grooved or plain. (Sgd) SFT.{Mr Swift} | ||