US3183632A - Grinding tool - Google Patents

Grinding tool Download PDF

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Publication number
US3183632A
US3183632A US208304A US20830462A US3183632A US 3183632 A US3183632 A US 3183632A US 208304 A US208304 A US 208304A US 20830462 A US20830462 A US 20830462A US 3183632 A US3183632 A US 3183632A
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US
United States
Prior art keywords
ceramic
grinding tool
shank
annulus
grinding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US208304A
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English (en)
Inventor
Harold W Ferchland
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motors Liquidation Co
Original Assignee
General Motors Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Motors Corp filed Critical General Motors Corp
Priority to US208304A priority Critical patent/US3183632A/en
Priority to GB23592/63A priority patent/GB968816A/en
Priority to CH856463A priority patent/CH403538A/de
Application granted granted Critical
Publication of US3183632A publication Critical patent/US3183632A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
    • B24D5/16—Bushings; Mountings

Definitions

  • the commonly used method for forming an elongated, small diametered bore in a metal part consists of first drilling the bore and then grinding and polishing its surface to the desired smoothness. In practice, the latter step is performed by reciprocating longitudinally through the bore a grinding wheel having a slightly smaller diameter than that of the bore while simultaneously rotating the grinding wheel and the metal part.
  • the grinding wheels used for such purpose consist of a ceramic annulus working portion cemented to a metal shank. Since the outer diameter of the ceramic annulus itself must be small it will be obvious that the diameter of the supporting metal shank must be even smaller, thereby resulting in a shank which is comparatively flexible. This shank flexibility makes extremely difiicult the attainment of an accurate, truly cylindrical bore.
  • FIGURE 1 shows a perspective view of a grinding tool made in accordance with the invention
  • FIGURE 2 shows a sectional view of the tool shown in FIGURE 1.
  • both the working portion 1 and the shank portion 2 of the grinding tool are of ceramic and form a monolithic or unitary structure thereby dispensing entirely with any requirement for a cement.
  • the shank portion of the tool can therefore be of only slightly less diameter than the working portion.
  • ceramic inherently has a very high modulus of elasticity provides a shaft rigidity which is much greater than that attainable with the conventional metal shank type tool structure. Shafts with a modulus of elasticity in excess of 45 are simply attainable in accordance with the invention.
  • the preferred ceramic for the grinding tools is a high alumina base material containing upwards of 85% by weight aluminum oxide.
  • the working portion of the tool be of a relatively coarse grain porous structure and that the shank portion be of a more dense, nonporous fine grain structure so as to have high strength and a high modulus.
  • This can be accomplished by first forming and firing the shank portion from an alumina raw batch which will provide optimum shank characteristics, inserting one end of the shank into a formed but yet unfired annulus formed of a relatively coarse grain alumina raw batch and then firing the assembly. During this firing operation the relatively coarse grain annulus sinters to its final desired structure and while doing so forms a strong sintered or fused bond with the end of the shaft.
  • the result is a unitary ceramic tool, both the shaft and working portions of which have the optimum desired physical characteristics.
  • the preferred ceramic for the shank is one containing upwards of by weight aluminum oxide together with suitable grain growth inhibitors or flux ingredients such as silica and alkaline earth metal oxides.
  • suitable grain growth inhibitors or flux ingredients such as silica and alkaline earth metal oxides.
  • Such ceramics after firing to sintering temperature, consist of a dense mass of alumina crystals bonded to each other either directly or through a thin interstitial layer of glass formed in situ during firing, and have outstanding strength and other desirable physical characteristics.
  • Typical are the compositions disclosed by United State Patent 2,760,875 issued to Karl Schwartzwalder and Helen Barlett.
  • Substantially alumina oxide ceramics or those containing only a small addition of a mineralizer or grain growth inhibitor such as MgO are equally good shank materials.
  • the ceramic composition for the relatively porous working portion of the tool may be selected from any of those conventionally used for grinding purposes.
  • it can be of substantially 100% sintered aluminum oxide or a glass-bonded aluminum oxide, the grain size of the aluminum oxide being selected to provide the exact abrading characteristics desired.
  • a relatively coarse grain porous structure is preferred.
  • the raw batch can consist of granular aluminum oxide such as Borolon or Tabular Corundum, and a small amount of powdered glass.
  • the batch can consist of aluminum oxide together with small amounts of flux ingredients such that the glass is formed in situ during firing. It will be understood, of course, that ceramic abrasive other than aluminum oxide may be used if desired.
  • the firing temperature for the working annulus be less than that which would cause softening of the shank and, hence, the composition of the working annulus should be selected taking this factor into account.
  • the shank portion can be formed by isostatic or other molding or by the extrusion technique wherein the ceramic batch is extruded to form a rod which is then cut to the desired size pieces and fired.
  • the working portion can be cold-pressed in a steel die or can be made by the aforementioned so-called isostatic molding technique well-known in the art. With the latter, a small amount of organic binder such as wax is included in the raw batch and the batch is then isostatically molded in rubber molds to form blanks which are then fired to burn out the wax and sinter the ceramic.
  • a tired shank would be inserted into the wax-bonded annulus-shaped blank prior to the final firing operation. The following specific example will serve to illustrate.
  • the wax-containing batch was then isostatically molded in rubber molds to form small rods. The dimensions of these rods, both the length and diameter, were slightly greater than those desired in the final piece in order to compensate for shrinkage during subsequent firing. After molding, the rods were fired to about 3000" F.
  • a raw batch was made by thoroughly mixing 34 grams of 100 mesh aluminum oxide (Borolon grain), 6 grams of powdered borosilicate glass having a grain size of 325 mesh (glass COl'DpOSltlOHI Slog, B203, A1203, Na O), and 4 grams of naphthalene dissolved in cc. chlorethane. After mixing, the chlorethane was allowed to evaporate and 2.4 grams carboxy methyl cellulose binder dissolved in water were mixed into the batch and the water then allowed to evaporate. The purpose of the naphthalene was to provide a filler which would burn out during subsequent firing and thereby leave a porous structure.
  • the amount of pressure used in the, pressing operation will, of course, depend on the porosity desired in the working annulus. Pressures as low as 5,000 pounds per square inch are satisfactory. To assure a more continuous durable bond between the shank and the working annulus, particularly where lower pressures are used in the annulus pressing operation, it is desirable to glaze the end of the shank to which the annulus is to be bonded with a thin layer of glass, preferably of the same composition as that used in the annulus. The firing temperatures and schedules used to obtain a strong fired structure will de pend on the exact composition of the piece being fired as is well known in the ceramics art.
  • the final dimensions of the fired tool manufactured as described were as follows: Over-all length 2.5, length 5 of exposed portion of shaft 2", diameter of working portion .275, diameter of shaft .200".
  • the tool had a full useful life until the working portion wore to a diameter only slightly greater than that of the shaft.
  • a grinding tool for making a close tolerance cylindrical bore in metal parts and adapted for high speed ro tation and longitudinal movement within said bore said grinding tool comprising a cylindrical shaped ceramic working portion of relatively large diameter havinga relatively coarse porous grinding structure and an elongated ceramic shaft portion of relatively small cross-sectional area having a fine grain non-porous structure with a high modulus of elasticity extending from said working portion.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Processing Of Stones Or Stones Resemblance Materials (AREA)
  • Ceramic Products (AREA)
US208304A 1962-07-09 1962-07-09 Grinding tool Expired - Lifetime US3183632A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US208304A US3183632A (en) 1962-07-09 1962-07-09 Grinding tool
GB23592/63A GB968816A (en) 1962-07-09 1963-06-13 Grinding tools
CH856463A CH403538A (de) 1962-07-09 1963-07-09 Schleifwerkzeug und Verfahren zu dessen Herstellung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US208304A US3183632A (en) 1962-07-09 1962-07-09 Grinding tool

Publications (1)

Publication Number Publication Date
US3183632A true US3183632A (en) 1965-05-18

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US208304A Expired - Lifetime US3183632A (en) 1962-07-09 1962-07-09 Grinding tool

Country Status (3)

Country Link
US (1) US3183632A (de)
CH (1) CH403538A (de)
GB (1) GB968816A (de)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3302279A (en) * 1965-09-21 1967-02-07 Anthony G Rosa Method of making ballpoint-pen tips
US4543107A (en) * 1984-08-08 1985-09-24 Norton Company Vitrified bonded grinding wheels containing sintered gel aluminous abrasive grits
US5123217A (en) * 1989-08-31 1992-06-23 Kabushiki Kaisha Fujikoshi Drill for use in drilling hard and brittle materials
US5658194A (en) * 1994-04-12 1997-08-19 Norton S.A. Super abrasive grinding wheels
WO1997038814A1 (en) * 1996-04-18 1997-10-23 Antler Steven M Rotating sanding accessory
US6443967B1 (en) * 2001-05-03 2002-09-03 Scimed Life Systems, Inc. Injection moldable feedstock including diamond particles for abrasive applications
US6739954B2 (en) * 2000-02-02 2004-05-25 Unova U.K. Limited Grinding pin for grinding machines comprising resin bonded selections of rough grit and fine grit
US20050155593A1 (en) * 2000-12-14 2005-07-21 Tenryu Seikyo Kabushiki Kaisha Metal bonded drilling and boring tool
CN105033873A (zh) * 2015-07-03 2015-11-11 马玉荣 一种全自动数控弯框机毛刺打磨头
USD866863S1 (en) 2019-01-03 2019-11-12 Sandbar Hand Care, LLC Callus management bar
USD1014857S1 (en) 2020-09-17 2024-02-13 Sandbar Hand Care, LLC Foot callus management bar

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0355904B1 (de) * 1988-08-19 1993-04-21 Wilhelm König Schleif- und Polierspindel mit hydrostatischer Lagerung

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US462703A (en) * 1891-11-10 Pestle and mortar for dental use
US920475A (en) * 1908-08-12 1909-05-04 Carl Jung Fastening for abrasive bodies having a porcelain base.
US1562941A (en) * 1921-09-06 1925-11-24 Prec Truing Machine And Tool C Abrading pencil
US2423293A (en) * 1943-11-19 1947-07-01 August C Ciell Process of making abrasive wheels
US2475565A (en) * 1946-09-21 1949-07-05 Carborundum Co Ceramic bonded abrasive articles
US2730439A (en) * 1953-03-19 1956-01-10 Carborundum Co Abrasive articles and method of making same
US2907148A (en) * 1956-10-23 1959-10-06 Chicago Wheel & Mfg Company Abrading wheels
US2977726A (en) * 1957-04-22 1961-04-04 Nat Broach & Mach Gear honing tool
US2979414A (en) * 1957-11-15 1961-04-11 Us Ceramic Tile Company Ceramic tool material
US2978846A (en) * 1956-10-08 1961-04-11 Lee H Barron Drill and countersink tool
US3101260A (en) * 1957-08-09 1963-08-20 Gen Electric Diamond tool

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US462703A (en) * 1891-11-10 Pestle and mortar for dental use
US920475A (en) * 1908-08-12 1909-05-04 Carl Jung Fastening for abrasive bodies having a porcelain base.
US1562941A (en) * 1921-09-06 1925-11-24 Prec Truing Machine And Tool C Abrading pencil
US2423293A (en) * 1943-11-19 1947-07-01 August C Ciell Process of making abrasive wheels
US2475565A (en) * 1946-09-21 1949-07-05 Carborundum Co Ceramic bonded abrasive articles
US2730439A (en) * 1953-03-19 1956-01-10 Carborundum Co Abrasive articles and method of making same
US2978846A (en) * 1956-10-08 1961-04-11 Lee H Barron Drill and countersink tool
US2907148A (en) * 1956-10-23 1959-10-06 Chicago Wheel & Mfg Company Abrading wheels
US2977726A (en) * 1957-04-22 1961-04-04 Nat Broach & Mach Gear honing tool
US3101260A (en) * 1957-08-09 1963-08-20 Gen Electric Diamond tool
US2979414A (en) * 1957-11-15 1961-04-11 Us Ceramic Tile Company Ceramic tool material

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3302279A (en) * 1965-09-21 1967-02-07 Anthony G Rosa Method of making ballpoint-pen tips
US4543107A (en) * 1984-08-08 1985-09-24 Norton Company Vitrified bonded grinding wheels containing sintered gel aluminous abrasive grits
US5123217A (en) * 1989-08-31 1992-06-23 Kabushiki Kaisha Fujikoshi Drill for use in drilling hard and brittle materials
US5658194A (en) * 1994-04-12 1997-08-19 Norton S.A. Super abrasive grinding wheels
WO1997038814A1 (en) * 1996-04-18 1997-10-23 Antler Steven M Rotating sanding accessory
US6739954B2 (en) * 2000-02-02 2004-05-25 Unova U.K. Limited Grinding pin for grinding machines comprising resin bonded selections of rough grit and fine grit
US20050155593A1 (en) * 2000-12-14 2005-07-21 Tenryu Seikyo Kabushiki Kaisha Metal bonded drilling and boring tool
US7603999B2 (en) * 2000-12-14 2009-10-20 Tenryu Seiko Kabushiki Kaisha Metal bonded drilling and boring tool
US6443967B1 (en) * 2001-05-03 2002-09-03 Scimed Life Systems, Inc. Injection moldable feedstock including diamond particles for abrasive applications
CN105033873A (zh) * 2015-07-03 2015-11-11 马玉荣 一种全自动数控弯框机毛刺打磨头
USD866863S1 (en) 2019-01-03 2019-11-12 Sandbar Hand Care, LLC Callus management bar
USD1014857S1 (en) 2020-09-17 2024-02-13 Sandbar Hand Care, LLC Foot callus management bar

Also Published As

Publication number Publication date
CH403538A (de) 1965-11-30
GB968816A (en) 1964-09-02

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