Quality of BM OEM omega spring

choombak

choombak

Joined
Jun 6, 2009
Messages
2,151
This issue has bugged me for a long time now. I've seen reports of BM omega springs break across here, reddit, and any forum that deals with knives. The perception is BM omega springs have weak-spots, metal fatigue and in general weaker than they should be. BM, in their sub-forum, has only acknlowledge the failure modes that include some kind of corrosion on the spring, and repeatedly state their internal tests are for several thousand cycles. After the Axis lock patent expiry, Hogue started using omega springs made by Wolff, and these seem to have very very few reports of failure.

Has anyone done any tests on the BM omega springs and their failure modes outside BM? I am also looking for objective data on, say BM omega springs compared to other omega springs (notably Wolff). I am genuinely curious why BM omega springs have a tendency to break more often. Is it the omega spring manufacturing or the user or a combination of both. Hogue might not have enough data on their springs yet, maybe we will know in a decade or so.

Any further pointers and reading material is very welcome. Thanks much.
 
Omega springs by design are weak compared to coil springs. It's not a matter of weather or not they fail, but WHEN they fail.
 
Kryme said:
Omega springs by design are weak compared to coil springs. It's not a matter of weather or not they fail, but WHEN they fail.
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I haven't seen coil springs being used in knife locking mechanisms... are you aware of any?
 
choombak said:
I haven't seen coil springs being used in knife locking mechanisms... are you aware of any?
Click to expand...
Spyderco's Caged Ball Bearing lock, most notably Manix 2. Microtech's RAM lock on their MSI, manual Stitch and Amphibian. Benchmade's Anthem also had a coil sprung Axis lock.
 
I question if there aren't more factors involved with these springs breaking sometimes. I have a couple of 940s. Never had an issue with either of them. The 940-1 is near a decade old, and one of my most carried and used knives back in the day. It still has the original springs. On the other side of that, I have a Bugout that snapped two sets of springs in the first year I had it.
 
Of course, materials and manufacturing matter too. I too have a 950 and 710 that are pushing over a decade at this point with zero issues. That doesn't change the fact that the spring is vulnerable to breaking by design, all the stress concentrating towards one point, it's only a matter of time till it breaks. There's good reason they changed the springs in the new 710, just wish they actually changed them to a coil spring like they did with the Anthem. But even as it is now, it should last a lot longer than the wire style omega spring.
 
Kryme said:
Of course, materials and manufacturing matter too. I too have a 950 and 710 that are pushing over a decade at this point with zero issues. That doesn't change the fact that the spring is vulnerable to breaking by design, all the stress concentrating towards one point, it's only a matter of time till it breaks. There's good reason they changed the springs in the new 710, just wish they actually changed them to a coil spring like they did with the Anthem. But even as it is now, it should last a lot longer than the wire style omega spring.
Click to expand...

I am not sure if the stress on the omega spring concentrates on one point, rather I think the semi-circular shape allows the stress to be spread over the length. It will definitely have max number of cycles to failure, and so will the coiled spring. It is likely the coiled spring has more cycles than that of omega, however, relatively speaking, as long as the # of cycles are large enough, it shouldn't matter to the user. It is also surprising that BM hasn't considered this apparent design flaw and improved upon the spring - and Hogue still continues to use the same design in the Deka line.

Can the issue be related to accidental user abuse (corrosion due to sweat, etc.) than the design itself? If it is the former, as BM rep has stated in the forum, why does Hogue not suffer the same failure on their omega springs (at least I have't heard mass complaints, but again, Hogue is a relatively new kid on the block). I don't have definitive answers, yet.

Thanks everyone for the excellent discussion, I appreciate it.
 
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The more you bend it the more the stress concentrates towards the arch. I've never seen an omega spring fail at the lockbar, it's usually around the arch. With coil spring the stress is distributed equally across the entire spring, provided both the omega and coil spring are made of equal materials and quality, the coil spring will last much much longer.

I wouldn't call storing a pocket knife in your pocket abuse, and any corrosion that occurs because of that is on the manufacturer and not the user. Especially when the manufacturer is not keen on allowing users to disassemble their knives for maintenance. Corrosion would significantly weaken a spring on a microscopic level, but a spring made of stainless might not have the same desired properties or toughness that are requires.

The springs on my old Benchmades seem to have developed a patina or they had some protective treatment applied to them. I can't honestly say what Hogue's deal is, maybe they use a heavier gauge wire but with less preload or treat them differently, different oem... it's still a matter of time till they fail too.
 
I use BreakFree CLP to lube my Axis locks, including the springs, and have never had a problem with them.
 
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