AUTHORIZENET IS IN TESTING MODE
The number of coils
The number of coils in tension springs varies with commercial production as follows:
| Number of Coils | Tolerance |
| 3 to 5 | ±20° |
| 6 to 8 | ±30° |
| 9 to 12 | ±40° |
For each additional coil, add 1½° per coil. Springs can be built to closer tolerances by trimming after coiling, with additional cost.
Example Load Tolerances:
The load tolerances for tension springs are listed in the above table. For example of how to use these, let us take a spring of the following dimensions: Free Length 4.050"; Mean Dia. .390"; Wire Dia. .048" to give a load of 3.5lb when extended .900".
| First we calculate the index or | D d |
= | .390" .048" |
= 8 |
| Secondly we calculate that | h f |
= | 4.050" .900" |
= 4.5 |
| Find | D d |
= 8 on the table, take the adjacent | h f |
= 4.5. |
Where the line 4.5 intersects with the column of wire dia. of .048" we get a figure of ±10.1%.
This is the load tolerance of the above example.
Convert 10.1% to 3.5 lb. which gives a tolerance of 5.6 oz. at .900" deflection.
