It is almost impossible to give proper specifications for a spring of this type except by means of a sample or a print or sketch.

The general specification as to diameter, length, gauge and number of coils can be given, but it is difficult to understand any description of special ends and avoid mistakes.

We therefore require complete information by sample or drawing on this class of spring. It is imperative always that we know the direction of the coils, i.e.- whether left- or right-hand, as a torsion spring should always be operated I the direction which causes the coil to close, or, in other word, causes the diameter to reduce. A spring operated in the wrong direction will either break or bend out of shape under comparatively little strain.

In drawing up specifications for torsion springs, observe the following points:

• Diameter, stating whether inside or outside dimension.
• Size of shaft or rod over which spring operates.
• Number of coils required, and state whether right- or left-hand.
• If the spring is assembled under tension, state how many turns are required to produce initial tension and the number if turns required beyond the initial point.
• State how rapidly the spring operates
• If required to carry a certain weight, specify how far from the centre of the coils this weight is applied, as leverage must be computed accordingly.
• Show angles of arms by number of degrees of arc and show length of all bends and diameters of all eyes and hooks.

Consider that each turn will reduce the diameter and allow sufficient clearance between inside diameter of coil and diameter of rod or shaft. A spring which binds on shaft will break or set.

Consider also that each turn will elongate the coil a distance equal to the thickness of the wire of which it is made; allowances must be made for this elongation; if spring is confined, by coiling with sufficient space between coils to permit this elongation; if spring is closed coiled, the surrounding parts must be far enough apart to allow this movement.

Wire Diameterd mm Outside Diameter OD mm Body Length LO mm Arm Length Amm Recom Shaft Size S.D.mm Relative Orientation of Arms DIAG Angular Deflection DEG Approx Number of Coils  Music Wire  Stainless Steel Torque N/mm Product Code Torque N/mm Product Code 0.35 5.25 1.5 15 3.5 1 90 3.25 4.5 T10100 3.6 T20100 3.0 2 180 6.55 T10110 T20110 4.5 3 270 9.75 T10120 T20120 6.0 4 360 13.0 T10130 T20130 0.42 5.50 1.80 15 4.0 1 90 3.25 9 T10140 7.2 T20140 3.80 2 180 6.55 T10150 T20150 5.40 3 270 9.75 T10160 T20160 7.20 4 360 13.0 T10170 T20170 0.51 6.00 2.20 20 4.0 1 90 3.25 18 T10180 14.4 T20180 4.40 2 180 6.55 T10190 T20190 6.60 3 270 9.75 T10200 T20200 8.80 4 360 13.0 T10210 T20210 0.61 6.25 2.60 25 4.0 1 90 3.25 36 T10220 28.8 T20220 5.20 2 180 6.55 T10230 T20230 7.80 3 270 9.75 T10240 T20240 10.40 4 360 13.0 T10250 T20250 0.75 7.25 3.20 30 4.50 1 90 3.25 72 T10260 57.6 T20260 6.40 2 180 6.55 T10270 T20270 9.60 3 270 9.75 T10280 T20280 12.80 4 360 13.0 T10290 T20290 0.91 7.75 4.0 35 4.70 1 90 3.25 144 T10300 115 T20300 8.0 2 180 6.55 T10310 T20310 12.0 3 270 9.75 T10320 T20320 16.0 4 360 13.0 T10330 T20330 1.10 8.50 4.70 40 5.0 1 90 3.25 288 T10340 230 T20340 8.0 2 180 6.55 T10350 T20350 12.0 3 270 9.75 T10360 T20360 16.0 4 360 13.0 T10370 T20370 1.37 10.30 6.0 50 6.0 1 90 3.25 576 T10380 461 T20380 12.0 2 180 6.55 T10390 T20390 18.0 3 270 9.75 T10400 T20400 24.0 4 360 13.0 T10410 T20410 1.82 16.0 7.75 60 10.0 1 90 3.25 1152 T10420 922 T20420 15.50 2 180 6.55 T10430 T20430 23.25 3 270 9.75 T10440 T20440 31.0 4 360 13.0 T10450 T20450 2.50 19.75 9.27 70 12.2 1 90 3.25 3304 T10460 1844 T20460 18.54 2 180 6.55 T10470 T20470 27.81 3 270 9.75 T10480 T20480 37.08 4 360 13.0 T10490 T20490

TORSION SPRINGS CAN BE MADE TO YOUR SPECIFIC DESIGN. FOR DETAILS PLEASE CONTACT OUR SPECIAL COMPONENTS DIVISION