Page 3 of Bearing Units Plastic Housing Series by NTN Corporation Japan

recommended tightening torque for set screw unit n m/lbf inch bearing number f-uc 204 205 206 207 208 designnation of set screws w shape screw head metric series m5 m6 m6 m8 0.8 0.75 0.75 1 inch series no.10-32unf 1/4-28unf 1/4-28unf 5/16-24unf tightening torques max n m 3.9 4.9 5.8 7.8 lbf inch 34 43 52 69 tighten the two set screws uniformly using the torque listed in this table over tightening the set screw may cause the inner ring to crack recommended tightening torque for setting bolt unit n m/lbf inch housing number pr204d1 pr205d1 pr206d1 pr207d1 pr208d1 flr204d1 flr205d1 flr206d1 flr207d1 flr208d1 m12 7/16 m10 3/8 m12 7/16 nominal bolt dia metric series m10 inch series 3/8 tightening torques max n m 17.7 24.5 29.4 35.3 45.1 17.7 24.5 29.4 35.3 40.2 lbf inch 156 217 260 312 399 156 217 260 312 356 over tightening the setting bolt may deform the plastic housing use the tightening torque guideline listed in this table ntn recommends the use of a washer between the bolt and housing base if a washer is not used damage to the base could occur plastic housing static strength the table below indicates the static strength of plastic housings at room temperature 23.5°c the static strength of plastic housings varies by operating temperature housing type and load direction and must be factored into the selection process ntn recommends using safety equipment should the housing become damaged or broken creating a dangerous working environment unit n/lbf static strength of housing type of nominal number direction of load housing 204 205 206 207 208 16,600 downward 3,730 7,000 horizontal 1,570 pr 5,600 upward not recommended 19,600 4,410 7,400 1,680 5,800 1,300 3,200 730 8,000 1,810 8,400 1,900 7,600 1,720 2,830 6,370 8,600 1,940 6,000 1,340 4,000 900 10,800 2,430 10,300 2,310 8,500 1,920 38,300 8,620 10,300 2,310 6,600 1,480 5,700 1,280 13,800 3,110 12,200 2,730 10,700 2,400 44,500 10,000 12,100 2,710 11,100 2,490 8,500 1,920 17,300 3,880 14,000 3,150 15,100 3,400 1,260 3,000 axial direction not recommended 680 5,600 horizontal 1,260 6,600 1,480 7,400 upward 1,680 flr 45 degrees upward 2

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