How to read the sizes of inside diameter
Depending on the item, there are two types of sizes, metric (mm) and inch. For instance, Sumitube B2 has inch sizes, and its 1/8 inch size equals approximately 3.2 mm. The inside diameter before shrinking is 3.50±0.30, which means size tolerance ±0.30mm. The inside diameter after shrinking is 1.60mm or less after complete shrinkage.
When the outside diameter of the object to be sheathed ("d") is 5mm, you can use tubing whose inside diameter before shrinking is more than 5mm and inside diameter after shrinking is less than 5mm. For example, you can choose from the following size range of Sumitube A:
"d" is the minimum size of inside diameter before shrinking.
Sumitube A 5X0.2size Before shrinking 5.6±0.3mm After shrinking 2.9mm or less
"d" is the maximum size of inside diameter after shrinking.
Sumitube A 8X0.25size Before shrinking 8.5±0.3mm After shrinking 4.7mm or less
Generally, smaller size has lower price and thinner wall, but it makes the inserting operability lower. Bigger size has thicker wall and higher inserting operability, but the time to shrink becomes longer. When the object to be sheathed has a corner or sharp edge, or when you shrink again for a long time, we recommend to choose bigger size to avoid splitting.
When the object to be sheathed has a large difference in level, please choose high shrink ratio tubing. For instance, when the smaller outside diameter of the object ("d1") is 5mm and the bigger outside diameter ("d2") is 10mm, you can choose tubing whose inside diameter before shrinking is more than 10mm and inside diameter after shrinking is less than 5mm. Since our general items shrink to half, we recommend to choose high shrink ratio tubing such as Sumitube B2(3X).
For example, you can choose Sumitube B 12/4size (Inside diameter before shrinking is 12.0mm or more, Inside diameter after shrinking is 4.00mm or less).