Learn about cut length tolerances for rubber extrusions – and how to use the right ones.
Elasto Proxy distributes rubber extrusions that come in coils. We also cut rubber coils to size using water jet cutting or guillotine cutting. If you buy cut lengths of rubber products from us, it’s important to use the right cut length tolerances on part drawings. These engineering tolerances indicate the dimensional variations you’ll accept; however, what you ask for also needs to be achievable.
Video: Elasto Proxy can use automated guillotine equipment to produce cut lengths of rubber extrusions.
Cut Length Tolerances and the Rubber Handbook (RMA Handbook)
The Association of Rubber Products Manufacturers (AARPM) is a trade group that defines various dimensional tolerances for rubber products, including cut lengths. The AARPM used to be called the Rubber Manufacturers Association (RMA) and was the publisher of the RMA Handbook. Today, this resource is known as the Rubber Handbook – and it’s still the bible for rubber tolerances.
For cut lengths, the Rubber Handbook defines different grades that indicate the degree of precision during cutting. As a rubber fabricator, Elasto Proxy refers to the RMA Handbook and the various tables that it contains. For cut lengths, there’s a single table (Table 16) that covers inch-based (in) and millimeter-based (mm) cut lengths in three grades.
- Precision (L1)
- Commercial (L2)
- Non-Critical (L3)
Non-Critical Tolerances (L3) are the “loosest”, which means you can expect the greatest amount of dimensional variation during cutting. However, these tolerances might be acceptable – and they’re the least expensive. Commercial Tolerances (L2) for cut lengths cost more but are commonly used by industry. Precision Tolerances (L1) are the most expensive, but some jobs require them.
Video: Elasto Proxy can also use water jet equipment to produce cut lengths of rubber extrusions.
Cut Length Tolerance Table for Unspliced Extrusions (Table 16)
Shown below is the Cut Length Tolerance Table for Unspliced Extrusions from the Rubber Handbook (Table 16). Cut lengths are given in ranges (Above and Up to). For example, there’s a range for cut lengths between 40 and 63 mm. If you need a cut length that falls within this range (e.g., 50 mm), then refer to the corresponding values in the columns for L1, L2, and L3.
For each grade, look at the dimensional variations you can expect. They’re given as plus or minus (±) values. If you need a cut length that’s 50 mm long, consider the difference between L3 (±2.0 mm), L2 (±1.3 mm) and L1 (±0.8 mm) Also, as cut length size increases, so does the degree of variation – regardless of class. For cut lengths in the largest sizes, percentages instead of ± values are used.
Length | L1 | L2 | L3 | |
Above | Up to | (±) | (±) | (±) |
0 | 40 | 0.7 | 1.0 | 1.6 |
40 | 63 | 0.8 | 1.3 | 2.0 |
63 | 100 | 1.0 | 1.6 | 2.5 |
100 | 160 | 1.3 | 2.0 | 3.2 |
160 | 250 | 1.6 | 2.5 | 4.0 |
240 | 400 | 2.0 | 3.2 | 5.0 |
400 | 630 | 2.5 | 4.0 | 6.3 |
630 | 1000 | 3.2 | 5.0 | 10.0 |
1000 | 1600 | 4.0 | 6.3 | 12.5 |
1600 | 2500 | 5.0 | 10.0 | 16.0 |
2500 | 4000 | 6.3 | 12.5 | 20.0 |
4000 | 0.16% | 0.32% | 0.50% | |
Length | L1 | L2 | L3 | |
Above | Up to | (±) | (±) | (±) |
0 | 1.6 | 0.03 | 0.04 | 0.08 |
1.6 | 2.5 | 0.03 | 0.05 | 0.10 |
2.5 | 4.0 | 0.04 | 0.06 | 0.13 |
4.0 | 6.3 | 0.05 | 0.08 | 0.16 |
6.3 | 10.0 | 0.06 | 0.10 | 0.20 |
10.0 | 16.0 | 0.08 | 0.13 | 0.25 |
16.0 | 25.0 | 0.10 | 0.16 | 0.40 |
25.0 | 40.0 | 0.13 | 0.20 | 0.50 |
40.0 | 63.0 | 0.16 | 0.25 | 0.63 |
63.0 | 100.0 | 0.20 | 0.40 | 0.80 |
100.0 | 160.0 | 0.25 | 0.50 | |
160.0 | 0.16% | 0.32% | 0.50% |
Additional Cut Length Considerations for Rubber Products
Here are a few other things to keep in mind about Table 16 above.
- It’s for unspliced extrusions. In other words, it’s not for cut lengths that will be bonded into finished gaskets. If you need spliced extrusions, there’s a different table to use.
- The cuts for unspliced extrusions are made straight up-and-own. If you need angled cuts, there’s a different table for cuts at 4°, 6°, and 10°.
- The Rubber Handbook has over 45 different tables. You can buy the full handbook for $750 USD, or you can partner with Elasto Proxy for expert assistance and great rubber products.
Elasto Supplies Cut Lengths for Rubber Extrusions
Elasto Proxy is a both a rubber distributor and a rubber fabricator. We can supply you with rubber coils that you cut to size yourself, or we can cut them to size for you. Because we offer a variety of fabrication methods, we can select pure water jet cutting, traditional guillotine cutting, or automated guillotine cutting to strike the right balance between precision, cost, and fabrication speed.
Ready to learn more? Contact us for a quote.