Knobs should be attached to the spindle, not to their roses, which are liable to pull off if much strain is put on the screws, and the last must be short in the case of mortise locks. The ordinary grub-scrow attachment, that is, a short screw passing through the base of the knob into one or other of a number of holes in the spindle, usually does not allow of close adjustment, leaving an unsightly gap between rose and knob. In this case all pulling strain put on the handle falls on the grub screw, which tends to wear loose.
Far better is the spindle threaded at on end for the knob to screw on to it. The sides of the spindle are fluted with grooves for the tip of a grub-screw, which is relieved from pulling strains, as these then fall on the spindle. The screw thread permits accurate adjustment.
A good form of rose has a projecting collar which surrounds the base of the knob and conceals the grub-screw, inserted through a hole in the collar when of a heavy gate, as it would be squeezed from between the parts; whereas a groase quite unsuitable for delicate machinery would do the work properly.
Any part which squeaks when it is moved is undergoing wear and requires lubrication; whether a sash pulley, a bolt, a hinge, or a barrow wheel. It is wonderful how greatly a few drops of oil will ease the working of a stubborn part and reduce muscular effort.
If latches of doors are kept well oiled, there will be no need to close the doors the handle is turned into a certain position. The collar prevents the screw being forced out. But the best form of knob has a screw passing through its centre into a threaded hole in the spindle end. The screw takes the pull and makes adjustment very simple, no grub screw being needed.
Lubrication in and about the House. Wear of metal parts which move over one another is due mainly to their being lubricated insufficiently or with an unsuitable lubricant.
The function of lubricants is to keep surfaces from making contact. Thin oil, which is right for a sewing machine or typewriter, would be useless on the hinges with a bang to make them catch. Many a lock wears out before its time because it is never opened up, cleaned, and oiled. Garden gates are great offenders in the matter of squeaking. Hinges in damp places may rust up and be ruined if they are seldom used and never lubricated.
Special attention should be given to machinery with rapidly turning parts, if these do not revolve in ball bearings. The lawn mower, for example, must be well oiled every time it is used. The bearings of mangles and wringers have to stand heavy pressure and if neglected will soon wear, besides making the labour of turning the machines much greater.
Where machines are exposed to a good deal of dust and dirt, it is not sufficient merely to oil them. The oil may carry in dirt with it, and the dirt abrade the frictional parts. At intervals, the length of which will depend on the nature of the work and the surroundings, the parts should be separated, well cleaned with paraffin oil, dried, oiled, and reassembled.
This assumes that the operation can be done easily, without any need for expert knowledge.
In some cases a bearing can be success-fully cleaned by squirting petrol through the lubrication hole. The spindle should be kept moving if possible while this is done. When the petrol comes out clean it may be left to evaporate. Oil is then administered.
For general purposes fairly thick oils, such as are used for motor-car engines, are good. Clocks require a special thin oil, which should be administered in small quantities only with the sharpened tip of a match stick or fine metal point. Fittings permanently exposed to the weather should be lubricated with grease, or very thick oil, as rain would soon flout out thin oil.
Sliding metal surfaces exposed to con-siderable dry heat are best lubricated with powdered graphite. Grease should not be used. Graphite is also a good lubricant for wood; but French chalk is preferable as regards cleanliness.