Leather belts, harness, boot and shoe leather require as much attention in regard to lubrication as does machinery. Hides, when deprived of their natural lubricating moisture, become dry and easily break. When converted into leather for belts, harness, boots and shoes, it would soon become useless for wear were it not for the interposition of the fatty lubricants known as "leather stuffings," which relieve the frictional action of fiber against fiber of which leather is composed. The more volatile these fatty lubricants are, the oftener they require renewal, lest the frictional heat and the abrasion of the fibers against each other, heat, burn and destroy the leather. We therefore try to protect the leather and make it more durable by the different finishing processes to which it is subjected, but unless the frictional action of fiber against fiber is relieved by constant lubrication, the frictional heat will destroy the fiber. For this purpose leather oils for lubricating, water-proofing, softening and preserving leather are generally compounded after one or the other pf the following formulae;

Valve-Oleum Leather Preserving And Waterproofing Oils

Two barrels of " Valve-Oleum " gelatine made from neatsfoot oil, as described on page 71 et seq., are compounded and well mixed with two barrels of coon oil, neatsfoot oil or fish oil (tanners' oil). Thereto are added five pounds of Para-gum, cut into fine shreds and dissolved by heat in five gallons of coon oil or neatsfoot oil. It can be colored with a sufficient amount of black West Virginia or Mecca oil, or with fine lampblack ground in fatty oil. The fatty oils used should previously be heated until all their hygroscopic moisture is driven out, and the arising scum skimmed off, before mixing with the gelatine.

An oil for tanners' use is made also with "Valve-Oleum" gelatine and fish oil (train oil) with additions of paraffine oil of low specific gravity.

A cheap harness oil is made with one barrel of "Valve-Oleum" gelatine and eight to ten barrels of heavy black petroleum oil and colored with gilsonite (Egyptian asphalt), gum or lampblack ground in neatsfoot or fish oil.

A black harness oil is also made with fifty barrels of dip oil, fifteen barrels of spindle or red oil, five barrels of degras and two barrels of lampblack ground in neatsfoot oil or fish oil.

A good belt oil can be made by dissolving by heat 150 pounds of rosin in one barrel of castor-6 82 Friction, Lubrication, Oils And Fats.

bean oil and scenting it with citronella or myr-bane oil. Paraffine oil, in which four to five pounds of rosin to the gallon have been dissolved, can be substituted for part of the castor-bean oil.

For belt oil Para-gum also is dissolved in neats-foot oil and compounded with "Valve-Oleum" heavy castor oil.

A belt grease is made by dissolving in fifteen parts of fish oil and five parts of tallow, with heating and stirring, five parts of India rubber (Para-gum), cut into fine shreds, and adding four parts of rosin and four parts of beeswax; stir well until congealed to proper consistency.

Fluid Adhesion-Fat for Belts, is made according to a German process as follows: Bring into an iron kettle, saponified olein about 60 per cent, vaseline oil about 15 per cent., castor oil about 5 per cent., rosin about 20 per cent., and, whilst stirring constantly, heat sufficiently for the rosin to melt and to effect an intimate mixture of the ingredients. The mixture is then boiled for about 7 to 8 minutes. It should be borne in mind that the mixture has to be constantly stirred from the beginning to the end of the operation. The use of saponified olein results in the product being obtained, after the boiling process, clear and free from any segregation. If, in place of saponified olein, tallow-olein is used, the mixture thickens and does not remain clear and fluid. If less olein and more vaseline oil were used, segregation would soon take place; the olein (oleic acid) would float on the top and the other constituents form a sediment. With the use of saponified olein and the other ingredients mentioned an adhesion-fat is obtained that always remains fluid and does no thicken. The fat is applied by means of a brush to the underside of the belt, if possible while not running, to give the fat time to thoroughly penetrate, care being had to use only as much as the leather can absorb. The upper side of the belt need only be greased when it runs in water and is exposed to wet, vapors and chemical influences, or drippings from machinery, but it should in that case be first thoroughly freed from adhering grease, dirt, etc.

Factitious Paint Oil

A cheap substitute for linseed oil is made by dissolving rosin oil in neutral oil and mixing it with linseed oil - 2 3/4 gallons of linseed oil, 2 1/2 gallons of neutral oil, with from 2 1/2 to 3 pounds of rosin - the whole being improved by boiling with oxidizing agents, or acetate of lead until all the acetic acid of the latter has been expelled and the oil has become bright and clear.

A cheap paint oil is also produced by compounding blown linseed oil with neutral oil and a sufficient amount of dryer made from rosin spirits,