Extremely hard release button - please help!

[JoshS.]

Hi all - I just bought a new knife from Pakistan (not made by Afaaq) and it has an extremely hard release button. I tried opening it over 100 time to see if that would “break it in”, but all it did was make my thumb hurt. There are some times I actually have to use two hands simultaneously pressing to get it to release. I tried lubricating and clearning…no help. I’m wondering if anyone else has had this problem before, and if there is a fix? I tried taking a small dremel grinder bit and seeing if I could wear down the hard edge of the knife blade hole (not sure the name for that) to see if by wearing it down the button would release easier, but I was afraid to do irreparable damage so I didn’t grind much…no difference. (The beveled area in front of the hole you see in the picture was done by the maker….presumably to make the knife easier to close). When the knife is open the button is not difficult to push….it’s just when it’s closed.

Anyone out there have any ideas? Thanks!
Regards,
Josh

[Killgar]

It sounds like there might be a burr somewhere, either inside the blade catch hole, or the catch/sear beak. Even the slightest burr or rough spot can cause the sear to snag and prevent the sear from rising when the blade is under pressure from the spring.

I would advise against trying to force the button as that could damage/break the button lever. If you close the knife and the button won't go in, press the blade further into the handle to relieve pressure on the catch/sear beak so you can then press the button in and then manually release the blade.

Also, if the sear is harder than the blade, trying to forcibly wear any burrs off by repeatedly pressing the button/firing the knife might cause the sear to wear the blade catch hole, enlarging the front of the hole, resulting in blade-peek, and without doing anything to smooth out the burr.

Not having examined the knife I can't say for sure where the burr is, but I might wrap some 2500 grit sandpaper around a drill bit and carefully sand the inside of the blade catch hole (using a bit as close in size to the hole).

I would then advise filling the catch hole with white lithium grease.

If that didn't solve the issue then I would have to take the knife apart and check the catch/sear beak for burrs.

I hope you get it worked out. Any chance you can post a pic of the entire knife?

And looking at the crude relief ramp the maker tried to make in front of the catch hole I would recommend using either a fine round diamond file, or some sand paper wrapped around a drill bit to smooth it out. The whole point of a relief ramp is to prevent the sear beak from getting worn when closing the knife by allowing the sear beak to glide smoothly over the edge of the blade and into the catch hole.

[JoshS.]

Thanks for the detailed reply Killgar! That’s super helpful information….I’ll try everything you suggested when I get back this weekend. It hadn’t occured to me that a tiny burr could create such a problem, but it completely makes sense. And I’m attaching a photo of knife….I tried before but the site kept saying the file was too large….I finally solved the problem by cropping out all of the extraneous portions of the image besides the knife itself.
Josh

[Killgar]

It's a nice looking knife. Welcome to the forum .

[JoshS.]

Thanks Killgar….it was my first order with this particular maker in Pakistan….it’s 13.5” and has some pretty file work on the back spring, and in most respects it’s a solid well made knife….just has this one glitch…my thumb is still sore two days later :-0

[john]

Hi JoshS.,
In addition to what Killgar has outlined, there could be one other issue, causing the problem. The button assembly may be loose. The kick spring pushes against the blade and the blade pushes against the sear pin causing it to be pushed into the liner, causing the button not to function properly .
Please let us know what the problem was and how it was resolved.
Good luck,
John.

[JoshS.]

Hi John - I’m not familiar with the terms, but after reading your post three times i now have a picture in my head of what you’re referring to….that’s a great idea & certainly a possibility as well. I’ll be back this weekend & will check the knife then & let you know what I’m able to find out!
Josh

[Bill DeShivs]

Put the grease in the sear hole first.

[sammy the blade]

Don't know what you paid for it but all the knives I've handled from Pakistan have been pretty crude.

[JoshS.]

Thanks Bill! And it was about $180 Sammy. I’ve got another one coming out of Pakistan in a few days…this one from Afaaq….seems beautiful in the photos…can’t wait to see it in person!

[JoshS.]

So I bought some lithium grease & put it in the sear hole….no joy. I didn’t have 2400 grit sandpaper, so I used 400 grit with grease on it and twirled it around inside the sear hole….possibly a little improvement maybe, but still a tricky release. Next is to try getting something inside the knife to smooth out any burrs that may be on side of the sear pin. Failing that, I think it may be what John suggested about the possibility of the blade under tension pushing the sear pin into the liner……will update as I learn more. Thanks again for all the advice!

[sammy the blade]

Guess it wasn't because it's a cheap one. I thought maybe it was a cheapo button open button close. Hope you get it worked out!

[Bill DeShivs]

Use a carbide bit, and make sure the sear hole is at 90 degrees. Be careful, or you'll get blade peek.

[Killgar]

When a blade catch hole is drilled the bit will create circular, corkscrew-like striations in the sides of the hole. These striations can grip onto the sear beak. The more powerful the spring (the harder the blade presses against the sear), the more those striations will grip the sear. And those striations can create a rough spot on the sear beak that only increases the problem.

When I build a switchblade I always drill the blade catch hole all the way through the blade. That way I can sand/polish the hole through-and-through rather than in a circular/twisting motion. I make tubes out of 1" squares of very fine sand/polishing paper by wrapping them around a small drill bit, then I pull the tubes through the catch hole over and over again, several times, until the inside of the catch hole is polished smooth with zero striations.

Since your catch hole is not drilled all the way through, and since I didn't know your level of ability or access to tools, I recommended twist-sanding the hole with 2500 grit polishing paper. 2500 grit is fine enough to not create the kind of circular striations that would grip the sear. 400 grit sand paper is coarse enough to possibly create it's own circular striations.

As far as trying to deburr the sear without disassembling the knife, it's possible, but it's just as likely not to work, and if you should round out the tip of the sear beak in the process that could cause new problems. There are various surfaces of the sear beak that can have a burr or rough spot that can cause a snag. Some sear beaks are round, but often they are flat or squared and have four sides. The burr/rough spot could be on any of those four sides. When I build a switchblade (flat sears) I carefully polish the four sides of the sear with 2500 polishing paper. This is not something I could do with the sear installed or the knife assembled. It's a very detailed process because like I mentioned, even the slightest rough spot, sometimes so faint that I can't feel it with a fingernail, can cause the sear to snag, especially with a strong kick spring.

I hope you're able to get the knife sorted out, but I suspect it might need to be disassembled to do it. I hope I'm wrong and it's an easy fix.

And 2500 grit polishing paper is commonly available in auto parts stores. I just bought a pack at Auto Zone.

A picture of a few flat sears that I use (the two pieces in the back)-



And a picture of a lever type sear with a round beak/catch. Custom made by member Nathan.

[boots]

I feel your pain. I bought a Case Mako conversion 20 years ago with the same problem, I can get a few clicks out of it before my finger is no longer able to push the button. I take it out once in a while and use it than she goes back to her resting place.