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Title: |
1922 Article-Precision & Thread Grinder Mfg. Co., Precision & Thread Grinder |
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Source: |
American Machine and Tool Record, V22, Dec 1922, pg. 44 |
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Insert Date: |
3/31/2019 9:28:44 PM |
PRECISION EXTENSION HOUSING AND EXTENSION SPINDLE
The Precision & Thread Grinder Mfg. Co., Philadelphia, Pa., has recently designed and is now marketing an improved attachment to be used in connection with the company's multi-graduated precision thread grinders (all models) for deep internal grinding up to depth of 12 ins. on holes of 2 ins. or more in diameter, and also a depth of 6 ins. on holes of ½ in. diameter.
This device is especially applicable, as will be seen by reference to Pig. 1, for the operation of grinding the tapered bore in milling machine spindles, giving perfect concentricity of the bore and promoting the maximum of service and longevity of cutters, particularly in the case of unhardened milling machine spindles, which usually are subject to scoring and wear. The use of the precision and thread grinder with extension spindle speedily corrects any such faults and with increased efficiency and production.
It is a well-known fact that an untrue running cutter dulls very rapidly on the few teeth that perform the burden of the work, and soon produces a chatter, besides prove unsatisfactory.
Lathe spindle tapered bores also require occasional truing up to correct errors in concentricity and alignment, obviating the necessity of truing up centers each time lathe is to be used, where accurate work is required.
Fig. 2 illustrates the grinder with an extension spindle and housing used in grinding a hardened fixture having projecting obstructions. The extension housing is screwed on the projection threads on the front regular spindle cap. This provides an accurate and speedy attachment. The extension spindle is coupled onto the regular spindle by means of tapered fitting joints and is supported at its working end by a radial and end thrust ball bearing located at the extreme end of the extension housing. The great length of spindle support produces rigidity at grinding end of spindle. Simplicity, speed and accuracy of. the attachment to grinder, together with the wide range of work obtained, it is claimed, makes this attachment an indispensable auxiliary to every multi-graduated precision grinder. |
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1922 Precision & Thread Grinder Mfg. Co., Precision & Thread Grinder
1922 Precision & Thread Grinder Mfg. Co., Precision & Thread Grinder
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