Instruction manual

MSSM0101CE/9906AV (1 of 19)

ÈFASTENER TORQUE REQUIREMENTS

The specifications in this section apply to 1/4 inch and larger Unified National fine and coarse fasteners used on

Milnor

machines. This information is to be used only when torque specifications are not stated in the installation

or service instructions.

When tightening applicable fastener, abide by the follow-

ing precautions:

1. Always use new fasteners. Replace bolts, nuts, flat wash-

ers, and lock washers in the order shown on the parts

drawing.

2. Unless otherwise specified, use:

• Loctite

271 threadlocker or equivalent for bearing

housing mounting bolts from one half to one inch in di-

ameter.

• Loctite

277 threadlocker or equivalent for bearing

housing mounting bolts of one inch diameter or larger.

• Loctite

242 threadlocker for all other fasteners

requiring thread locking compound.

3. Use a torque wrench to assure proper tightness.

4. Never lubricate fasteners. The values specified herein are

maximum recommended torques and are calculated from

published ASTM and SAE data. Actual allowable torques

are application dependent and can vary for many reasons,

(joint types, gaskets, etc.). Use these values as a guide.

5. Although FIGURE 1 depicts hex head bolts, the table applies to all head types.

ÊFasteners and Threadlocker

ËHow Fasteners Loosen

—Standard threaded fasteners are manufactured with a clearance fit for easy assem-

bly. With the fastener at the proper torque, 85% of the tightening torque is absorbed in the threads and under the

fastener head. The remaining 15% provides the friction that prevents the thread from slipping. When this friction is

overcome (by bending, thermal expansion, internal pressures, functional loads, or impact) the thread slips and loos-

ens. Although higher torques reduce the likelihood of thread slippage, if slippage occurs, the threads unwind and

the fastener loosens. Once thread slippage begins, vibration increases the rate of loosening.

ËPreventing Loosening

—The most effective way to prevent loosening of threaded parts is by proper appli-

cation of a threadlocking compound. Threadlocker provides lubrication during assembly, then hardens to seal the

threads against corrosion and provide resistance to thread slippage.

ÎFIGURE 1

(MSSM0101CE)

ÎFastener Grade Markings