US1669596A - Valve-grinding compound - Google Patents

Description

Patented May 15, 1928.

UNITED STATES PATENT OFFICE.

AI BTHUR LEE BRO'WNE, OF BALTIMORE, MARYLAND, ASSIGNOR TO THE AMERICAN HAMMERED PISTON RING COMPANY, OF BALTIMORE, MARYLAND, A CORPORA- TION OF MARYLAND.

Io Drawing.

articles being ground; and therefore, it is.

necessary to finish grind, or lap, with a finer grade of abrasive. To obtain the proper finish on the surface being ground, when using a grease-mixed compound, it is necessary, therefore, first to use a coarse grade of abrasive for the cutting operation, and to finish with a fine grade to obtain a polish.

(b) It is diflicult to clean the surfaces that have been lapped or ground, with a greasemixed compound, and particularly is this true. when grinding the valve seats in automobiles. Inability to clean the valve seats perfectly in an automobile after grinding, naturally causes very serious results, as the emery, carborundum, or other abraslve used,

sooncauses wear, and should this abrasive 80 get down into the cylinders it would cause an untold amount of trouble due to cuttin action upon the piston rings, piston an cylinder. Furthermore, a grease-mixed compound is greatly afi'ected by cllmatic changes,

becoming .quite fluid in excessively hot weather, and extremely stiff in very cold weather.

. In view of the above disadvantages, the so-called water-mixed grinding com ound has come into use in recent years, an particularly for grinding the valves of automobiles. The water-mixed compound has the advantage of allowing the use of a well graded mixture oflabrasive or carborundum grit, which cuts quite rapidly at first, but owing to the friction produced by grinding, the particles soon break down into smaller particles, which with the continued grinding action produce a highly polished surface.

Consequently, with water-mixed compound it is not necessary to use two grades of abrasive, but one medium grade or well propor- VALVE-GRINDING COMPOUND.

Application-filed August 29, 1927. Serial No. 216,846.

. tioned mixture of abrasive or carborundum grinding compound is thoroughly removed,

the article dried, and the final coating of oil applied. Consequently, a grinding com pound that will prevent the rapid formation of rust would be a decided advantage to the industry. I

Secondly, the water-mixed com ounds have a tendency to dry out very rapi y, and it is necessary to keep the container holding the grinding compound closed at all times, in order to prevent the grinding com ound from drying out to such an extent 1: at'it is useless unless it is again well mixed with the additlon of water, and even then,*it is seldom as good as was the original mixture.

The rapid drying action of the grinding compound necessitates frequent application of water to the article while grindlng, and this is objectionable to the users.

Furthermore, with the water-mixed compound, there is, of course, the possibilit of such compound freezing in very cold 0 imates. In some of these water-mixed compounds substances have been added to the compound to prevent freezing, and also to lessen the tendency of these compounds to dry, but it is well known in the tradethat none of these mixtures have proved entirely satisfactory and all of the compounds now on the market have a tendency to dry out very rapidly, which is'perhaps, their most serious disadvantage.

In the valve rinding compound to be now described and orming the present invention the chief difficulties with the water-mixed com ounds heretofore on the market, and as a ve set forth, are overcome, since the compound will not cause the formation of rust but will actually prevent rust, and furthermore, will not dry out or be affected by climatic conditions.

In the grinding compound of this inven tion, there is used a medium fine grade of abrasive, such as carborundum grade 180. w

This grade consists mainly of grit that will pass 180 mesh sieve, but it also contains a small amount of coarser particles as well as a small amount of very line particles. It has been found thatby the use of this grade of abrasive a grinding compound can be produced which will cut quite rapidly at first but which eventually breaks down into a finer abrasive powder, during the grinding operation, and produces a high polish.

The abrasive is mixed with a binder or vehicle consisting mainly of glycerine and soap. The glycerine is first heated to a moderate heat for example to 200 F., say

by placing the glycerine in a steam bath, and to the Warm glycerine a certain amount of soap is added. The soap can be common laundry soap, yellow or white in color, and

in the solid state as found on the market, or dried, if desired. Upon mixing, this produces a jellylike substance which acts as an ideal binder for the abrasive material. To prevent this binder from becoming too thin under the influence of heat a small amount of oleic or other fatty acid is added, and after mixing the whole there is added a dilute solution of silicate of soda (about 1 part of silicate of soda solution (waterglass) and 4 parts water). While oleic acid is here mentioned, other fatty acids such as palmitic or stearic can be used, in fact any fatty acid which will combine with an alkali to form asoap.

This produces a soft jellylike binder unaffected by climatic conditions, and furthermore the composition will not dry out or cause the formation of rust. To this binder the abrasive is added. It will beunderstood that while carborundum will be particularly referred to herein, various other solid abrasive substances, as corundum, emery and others, may be employed. When the binder and abrasive are mixed together the binder is preferably heated to a moderate heat (say 140 F.), and held at this temperature while the proper proportion of abrasive is added and the whole thoroughly mixed. After cooling the grinding compound is readyfor use and can be packed in cans or other suit-' able containers convenient for handling and marketing.

Without attempting to restrict the invention to any particular theory, it is believed that the oleic or other free fatty acid reacts with the sodium silicate to form a soap and a gel of silicic acid or silica gel. The silicic acid so formed is' thoroughly and intimately incorporated with the soap formed and that originally added, together with the water'and glycerine, constitute the base or vehicle of the composition, giving the desired soft jellylike consistency, and aiding in holding the water in the composition dur- Example 1.

Percent. Carborundnm 50 Glycerine 24 Soap .4. 4 Stearic acid 3 30% silicate of soda .4 Water 15 Example 93.

A grinding compound composed of the following ingredients, whichcompound will not be as stiff as the former:

Percent. Carborundum- 40 Glycerine 30 Soap 5 'Oleic acid 4 to 6 30-40% silicate of soda 3 to 5 Water 16 Example 3.

A particularly favorable formula, for

- making the product, is as follows 7 Per cent. Glycerine 30 oap 5 O'leic acid m. 6 40% solution of silicate of soda 4 Water a; 1 15 Carborundum 40 I claim 1. A paste-like abrasive material containing the reaction products of alkali metal silicate and a fatty acid together with soap, water, glycerine and a solid finely divided abrasive material.

2. A paste-like abrasive material containing the reaction products of sodium silicate and a fatty acid together with soap water, glycerine and a solid finely divide abrasive material.

3. A pasty abrasive material containing a pulverulent abrasive material carried in a vehicle containing silica gel and soap.

4. A pasty abrasive material containing Glycerine 30% ;'soap 5%- oleic acid 6%;

a pulverulent abrasive material carried in 40% solution of silicate of soda 4%; water 0 a vehicle containing silica gel and soap to- 15%; and carborundum 40%. 1 gether with water and a substance capable In testimony whereof I have signed my 5 of preventing rapid drying out of the water. name to this specification.

5. A pasty abrasive material consisting I essentially of the following-ingredients: ARTHUR LEE BROWNE.