US2015727A

US2015727A - Rotary bonded abrasive articles

Info

Publication number: US2015727A
Application number: US700409A
Authority: US
Inventors: Arthur H Prey
Original assignee: Carborundum Co
Current assignee: Unifrax 1 LLC
Priority date: 1932-09-26
Filing date: 1933-12-01
Publication date: 1935-10-01
Anticipated expiration: 1952-10-01

Description

Oct. 1, 1935. A, E

ROTARY- BONDED ABRASIVE' ARTICLES Filed Dec. 1, 1933 INVENTOR.

ARTHUR H. PREY It'll!!! l lllll llll|l...lll\lllllllllllllllllnl ATTORNEY.

Patented Oct. 1, 1935 I PATENT OFFICE ROTARY BONDED annasrvr: narrows Arthur H. Prey, Niagara Falls, N. Y., assignor to The Carborundum Company, Niagara Falls, N. Y., a corporation of Pennsylvania Application December 1,1933, Serial No. 700,409 In Canada September 26, 193g '1 Claims. (01. 51-206) This invention relates to the manufacture of abrasive articles and particularly to thoseabrasive articles comprising a bonded abrasive shape mounted on a rotative spindle.

The object of the invention is to provide an improved article for abrasive purposes and a method of making the same.

This application is a continuation-in-part of my copending application Serial No. 569,723, filed October 19, 1931.

Certain arts and professions require bonded abrasive articles of such small sizes that they can be operated satisfactorily only when they have been mounted on m'etallicspindles adapted to fit into suitable chucks. mounted abrasive articles in grinding teeth, preparatory to such subsequent operations as filling or capping to prevent further decay of the teeth. Die and tool makers also find such mounted abrasive articles suitable for removing metal from small corners or crevices.

Inasmuch as experience has taught that the abrasive portion of such articles is best adapted to the purpose when made by abaking or kiln firing process, it has become customary to manufacture these abrasive portions and then, after they have been hardened by the heat, cement member to the spindle.

spindles are, as a general rule made of a type .T of steel known as drill rod steel and fabricated in aspecial manner to increase strength in the nose. It is not feasible to mold the abrasive portion onto the metallic spindle and then set the abrasive binder, because the baking temperatures of such binders is in a temperature range that is decidedly deleterious to the metals which, as above mentioned, are commercially avilable for this purpose.

The usual practice heretofore has been to provide the abrasive member with a hole of suitable size to receive a steel spindle and suitable quantity of cement for joining the abrasive member to the shaft. It alsohas been the practice to use a cold setting cement, such as a freshly'made mixture of calcined cupric oxide and phosphoric acid, for the purpose of joining the abrasive This prior practice, however, has left much to be desired because of the abrasive member becoming detached from its spindle before it has done its .full measure of grinding. Numerous cements have been tried for the purpose but it is the practice to use a cement of the oxyphosphate type such as ,a mixture of calcined cupric acid oxide andphosphoric acid, although some- Dentists use these times even this type of cement has'failed to hold the abrasive member onto the shaft the desired length of time.

I at first thought that the diiiiculty was due to r the smoothness of the surface of the metal shaft scertain metals and then using the above mentioned cement to attach the abrasive member. a remarkably tenacious bond is effected which will last until the last of the abrasive grain is worn off.

While a considerable number of theories have been suggested and examined to explain the phenomena underlying the improved results I obtain, the explanations so far advanced are not entirely satisfactory in explaining the mechanism whereby the results are obtained. However, I have observed certain indications of deterioration of the cement when applied directly to the steel shaft or to a nickel plated shaft, which. I offer for what they are worth. For instance, I have noted that the cement immediately surrounding the steel shaft often is, porous as though tiny bubbles had been present when the cement was soft.

My invention will be better understood after a brief description of such an abrasive device; and for purposes of illustration I have shown a typical abrasive device of this type in the attached drawing in which:

Figure 1 is an enlarged-cross-sectional view through the longitudinal axis of the spindle; and 35 Figure 2 is an enlarged cross-sectional view through the plane-IIII of Figure 1.

In the drawing, the abrasive member I is shown as attached to the spindle 2 by means of a suitable cement 3. The spindle 2 is shown with a coating 40 4 of a material that improves the bond over that obtained by cementing the member directly to the spindle 2.

Among the materials that I have found satisfactory for carrying out my invention are copper,

chromium, cadmium, silver, gold, or other such material, and a dual plating of first copper and thennickel over the copper. Because copper is readily available at low cost and is easily applied and efficacious, I will describe my invention by referring specifically to the use of copper.

According to my invention the whole spindle, or the end of the spindle to be attached to the abrasive member and which may or may not be knurled as desired, is first cleaned with a caustic Rassuao soda solution'to remove grease and oil and then, upon scouring with clean, moistened pumice, washed with a dilute solution of hydrochloric acid.

When the spindle is free from grease, oil and other surface impurities, I coat it with copper. The copper coating may be applied by dipping the clean spindle in a solution or copper sulphate and sulphuric. acid, but I prefer to coat the spindle by electr p t When the spindle, or that portion of the spindle that is to come into contact with the cement, is thoroughly coated with copper, it is washed and dried and is 'ready for use.

In joining the abrasive member (which, for the purpose of niy invention may be of vitrified-bonded granules resin-bonded granules or any other suitably bonded material) to the copper-coated shaft, I use a cement containing calcined cupric oxide and phosphoric acid in the ratio of approximately 30 grams of cupric oxide to '7 cubic centimeters of an aqueous solution containing 80% phosphoricjacid. I quickly mix these materials to form a paste and then apply a small portion to the copper-coated end of the spindle, and thenment sets quickly and requires rapid manipulation from the time the copper and phosphoric acid are mixed until the bonded abrasive member is correctly-positioned on the spindle. When the cement has-set, the bonded abrasive member and the spindle are so firmly joined that the abrasive member may be used in severe service without danger of its becoming loose from the spindle.

Whilaas stated above, copper was given as the specific material for illustrative purposes, other materials also are efiicacious. Among the other used without'departing from my invention. One

method of metal coating that has found wide use in the arts is carried out by means of an imple- '{ment known as the Schoop gun. This device molten metal away from the flame and onto any object to which the gun is directed. By this means a tightly adhering coating of metal may be applied to a spindle or any desired portion of a spindle.

Having thus described my invention, I claim: 5

1. An abrasive article comprising a bonded abrasive article joined to a metallic spindle by a cement of the oxyphosphate type, said metallic spindle being coated with a film of a metal of the group consisting of copper, cadmium, nickel, silver, gold and chromium where it comes in contact with the cement.

2. An abrasive article comprising a bonded abrasive article joined to a metallic spindle by a cement of the oxyphosphate type, said metallic spindle being knurled and being coated with'a film of a metal of the group consisting of copper, cadmium, nickel, silver, gold and chromium where it comes in contact with the cement.

3. An abrasive article comprising a bonded abrasive article joined to a metallic spindle by a cement consisting of a mixture of cupric oxide and phosphoric acid, said metallic spindle being coated with a. film of a metal of the group consistizm of copper, cadmium, nickel, silver, gold and chromium where it comes in contact with the cement.

4. An abrasive article comprising a bonded abrasive article joined .to a metallic spindle by a cement consisting of a mixture of cupric oxide and phosphoric acid, said metallic spindle being knurled where it comes in contact with the cement and being coated with a film of a metal of the group consisting of copper, cadmium, nickel, silver, gold and chromium where it comes in contact with the cement.

5. An abrasive article comprising a bonded abrasive article joined to a metallic spindle by a cement of the oxyphosphate type, said metallic spindle being coated with a film of copper where 40 it comes in contact with the cement.

' 6. An abrasive article" comprising a bonded abrasive article joined to a metallic spindle by a cement of the oxyphosphate type, said metallic spindle being coated with a film of cadmium where it comes in contact with the cement.

"'7. An abrasive article comprising a bonded abrasive article joined to a metallic spindle by a cement of the oxyphosphate type, said metallic spindle being coated with a film of silver where it comes in contact with the cement.

AR ii-I i" H. PREY.