ASME B94.33.1:1997 pdf download JIG BUSHINGS (METRIC)
1 SCOPE
This Srandard covers the American Nationai Standardpractice for sizesrypes.tolerances.and identificationof merric iig bushings and locking devices used forsecuring the bushing in the jig or bushing plate.
2 PURPOSE
The purpose of this Standard is to provide thenecessary information for the design, procurement, andinsta!lation of metric ig bushings.
3.1 Press Fit Bushinys
Press fit bushings to guide the tool are installcddirectly in the jig without the use of a fliner and arcemployed principally where the bushings are used forshort production runs and will not require replacement.They are also intended for use where the closeness of thecenter distance of holes will not permit the installation ofliners and renewable bushings. Press fit bushings aremade in two types, with heads and without. (See Fig. !.)
3.2 Renewable Bushings
Renewable bushings to guide the tool are for usein liners which in turn are installed in the jig. Theyare used where the bushings wiil wear out or becorieobsolele belore the iig or where several bushings areto be inierchangeabie in one hole. They are usuallymade with a knurled hcad to facilitate removal.
Therc arc“fxcd”and “slip” milled notches combinedon the head of rencwable bushings. There is one typeof renewable bushing，slip-fixed rencwablc.
(a) The lixed side of the renewable bushing is usedwiti the intention of iuving it in piace until wom out.(b) The slip side of the renewable bushing is usedwith the intention of changing it frequently in a givensize of iiner. This side is most oiten used where two or more operations requiring different inside diametersare perlormed in a single jig. such as where driilingis followed by reaming. tapping.spot facing. counterboring,or some other secondary operation.(See Fig.2.
3.3 Liner Bushings
Liner bushings are provided with and without headsand are permanently installed in a jig to receive therenewable bushings. They are sometimes ca!led “masterbushings.”(See Fig. 2.)
3.4 Bushing Specifications
The dimensions and tolerances of jig bushings shallconform to the specifications given in the followingtables and notes.
4 JIG BUSHING DESIGNATION SYSTEM
4.1 Type Bushing
Specify by icticr.
PM: press ft,plain (also plain liner)HM: press fit, headed (also headed lincr)SFM: renewable、slip-fixed
Carbide bushings should use the letter“C after thetype designation (e.g, a slip-fixed renewable carbidebushing would be designated SFMC).
4.2 Body Diameter
Specify body dianeter in millimeters.
4.3 Body Length
Specify the effective length in milimeters.
4.4 inside DiameterSpecify by inside diameter of hole size in millimeters(twu-piace decirmai).
4.5 Exampie
SFM-8-12-4.50
Bushing type: SFM, renewabie, siip-fixedBody diameter: 8 mm
Body length: 12 mm
Inside diamcter hole size; 4.50 mm
5 DESIGNATION SYSTEM FOR LOCKSCREWSAND CLAMPS
5.1 Letters“LSM”Denote Lockscrew
(a) LSM-I Lockscrew for SFM bushings with 8and !0 mm outside diameters (flush-mounted liner)(b) LSM-2 Lockscrew for SFM bushings with 8and 10 mm outside diameters (projected liner).(e) LSM-3 Lockscrew for SFM bushings with !2.15, and 18 mm outside diameters (flush-mounted liner)
ASME B94.33.1:1997 pdf download
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