We tested a variety of eyelets to see which have the best grip strength, impact strength and break strength. Check out the results!
CARR Group supplies grommets in a variety of sizes, materials and styles. Our customers often ask us which are better. To definitively answer this question, we have performed in-house testing on break strength, holding strength and impact resistance of various eyelets.
Items tested:
| 1 | CARR | #2 Stainless Steel sheet grommet & toothed washer |
| 2 | CARR | #2 Stainless Steel sheet grommet & neck washer |
| 3 | CARR | #2 Brass sheet grommet & toothed washer |
| 4 | CARR | #4 Stainless Steel sheet grommet & toothed washer |
| 5 | CARR | #4 Brass sheet grommet & toothed washer |
| 6 | CARR | 12mm Plastic grommet & washer |
| 7 | Alternative Brand | 12mm Plastic grommet & washer |
Grommet Strength Testing Summary & Key Take Away Points
- From our ‘Break Strength Test’ we found the opposing force break strength of all grommets tested is higher than the holding strength of grommets set in any material combinations we tested.
- The most likely failure point for grommets set in material, are when the grommet tears out of the material they are set in, our ‘Holding Strength Test’.
- Less likely failure of a grommet set in material would be from impact. From our ‘Impact Resistance Test’ we found the ‘Alternative brand 12mm Plastic’ is the only grommet tested with the potential to break from impact.
- Comparing the two plastic grommets, ‘CARR 12mm Plastic’ seems to be the better of the two, performing closer to metal equivalent. The material used in ‘Alternative brand 12mm Plastic’ is more brittle and under stress could crack, split or shatter. Where ‘CARR 12mm Plastic’ is more likely to bend under the same pressure.
- The size of the grommet does not impact noticeably on the holding strength, nor does metal make up (Brass or SS), all performing similarly.
- The most noticeable difference in holding strength is seen when settings are made into mesh alone, in this case metal sheet grommets with toothed washers will perform the best.
- Holding strength of neck washers are similar to toothed washers when set in at least 1 layer of solid banner material. However when set in mesh alone, the holding strength of neck washers is less than toothed washers.
- In general the holding strength and impact resistance of Brass & SS grommets is better than Plastic options.
Break Strength Test
Method:
Single grommet and washer setting, no fabric. Using a Tensile Strength Testing Machine, (22lb weight/2.2lb counter weight/Cap 66lb measurements) attach 2 solid metal hooks to grommet, pulling in opposing directions. Record the measurement when the grommet breaks.
Summary:
Using the same weight settings as used in the ‘Holding Strength Test’, the machine does not have enough force to break set grommet and washers in any of the 7 items we tested.
Holding Strength Test
Method:
Single grommet set into one end of material sample (40mm wide strips x 150mm long PVC over Polyester base fabric material). Using a Tensile Strength Testing Machine (22lb weight/2.2lb counter weight/Cap 66lb measurements), clamp material at one end and solid metal hook through grommet, pulling in opposing directions. Record the measurement when the grommet pulls through the material.
Material to test:
- 2 x layers of 15oz Banner (20×20, 1,000D x 1,000D Polyester base fabric with PVC coating)
- 1 x layer of 15oz Banner + 1 x layer of 8oz PVC Mesh
- 2 x layers of 8oz Mesh (12×12, 1,000D x 1,000D Polyester base fabric with PVC coating)
Summary:
Set in 2 layers of 15oz Banner, all grommets held strong and similar. The #2 sized were best, #4 sized & ‘Alternative brand 12mm Plastic’ slightly lower. Lowest hold strength was ‘CARR 12mm Plastic’. However the lowest result was still equal to the highest hold strength result in 1 layer of 15oz Banner & 1 layer of 8oz Mesh. Top performing (‘#2 SS sheet grommet & toothed washer’ & ‘#2 SS sheet grommet & neck washer’) were only 20% stronger than lowest performer (‘CARR 12mm Plastic’). Compared to settings made in 1 layer of 15oz Banner & 1 layer of 8oz Mesh, on average settings have 15% more holding strength.
Set in 1 layer of 15oz Banner & 1 layer of 8oz Mesh, hold strength was similar between all grommets but not as strong as when set in 2 layers of 15oz banner material. Top performing (#2 SS neck washer & #4 SS toothed washer) these were only 16% stronger than lowest performer (Alternative brand 12mm plastic). Compared to settings made in 2 layers of 8oz Mesh, on average settings have 22% more holding strength.
Set in 2 layers of 8oz Mesh, overall hold strength was lower than anything with banner, also more varied results were seen. ‘#2 SS toothed washer’ held almost 25% stronger than ‘#2 SS neck washer’. Alternative brand 12mm plastic had the weakest hold strength, compared to CARR 12mm plastic which was over 50% stronger. Compared to settings made in 2 layers of 15oz Banner, on average settings have 34% less holding strength.
Impact Resistance Test
Method:
Drop a 22lb weight from 24in high, onto a single set grommet, face down. Same test again with single set grommet standing in groove, impact to the edge. Record physical damage to grommet, e.g. dent, split, crack, shatter, bend etc.
Summary:
In the face drop test most items performed similarly, for the most part being flattened on impact. The exclusion is the ‘Alternative brand 12mm Plastic’ grommet which tended to split, crack or shatter on impact.
In the edge drop test #4 size brass and SS performed the best by only bending. Closely followed by the #2 Brass (mix of bent, crushed and split open), & CARR 12mm plastic (mostly bent, 1 split & 1 shattered). Lower performing were the both #2 SS (all crushed), and worst performing was the Alternative brand 12mm plastic (most shattered, 1 cracked, 1 split open).