Strong Springs, Too Strong

[geocash]

This is a 1978 #6308 with real nail-breaker springs. Is there a reasonable way to reduce their strength? I think it looks good like this, sitting on a picture frame, & this should weaken the springs, after a few years, maybe. But I'd like to be able to tote it & use it without also carrying some tool to help me open a blade to use it. Any ideas?

[Sharpnshinyknives]

This is a 1978 #6308 with real nail-breaker springs. Is there a reasonable way to reduce their strength? I think it looks good like this, sitting on a picture frame, & this should weaken the springs, after a few years, maybe. But I'd like to be able to tote it & use it without also carrying some tool to help me open a blade to use it. Any ideas?

I will be very curious if there is an answer to that. Those smaller blades on Case knives are the worst. I have to carry a knife pick w/ me when I carry one of those. It shouldn’t be this strong.
SSk

[orvet]

If you replace the pivot pin with one a little bit smaller than the size that's in there, that should significantly decrease the tension on the springs and make it easier to open.

[oldprof]

This is a 1978 #6308 with real nail-breaker springs. Is there a reasonable way to reduce their strength? I think it looks good like this, sitting on a picture frame, & this should weaken the springs, after a few years, maybe. But I'd like to be able to tote it & use it without also carrying some tool to help me open a blade to use it. Any ideas?

I have several of the 6308 and 6383 knives.All are hard to open and some require pliers.The master blade,of course,has the force of
two springs to overcome but it often opens easier than the small. blades.I have always liked this pattern but I never carry it.An old
72 is much more useful.
Wayne

[geocash]

If you replace the pivot pin with one a little bit smaller than the size that's in there, that should significantly decrease the tension on the springs and make it easier to open.

Thanks Dale (& SSk & oldprof),

I'm sure you're right, but I'm pretty confident that I'd not be satisfied with my work. Do you have a ball-park estimate what a competent individual might want to do that?

[sunknife]

I'm glad you brought up this question geocash, just wish there was an easier way to correct it than having to learn knife mechanic skills. I have some I'd love to carry but don't because of this issue and they are nice knives that I wouldn't want to screw up by trying to do the pin replacement myself.
I'm fairly handy but when it comes to knives I'm afraid of the torture I might inflict on them.

[Tsar Bomba]

Seems to be something with the 08 frame, huh? I've got an A6208 (clip+pen) that snaps wonderfully but can surprise you by yanking your fingernail right out of its roots if you grab the pen blade wrong. Some small Case single-springs seem to have this issue. My 92033 pen knife, as small as it is, has one of the hardest pulls (9+) of any knife I own - on the pen blade! My A62033 has a similar but slightly easier (7-8) pen blade pull. These knives are tiny, well under 3" closed, but they all have fairly substantial single backsprings.

I assume a lot of it has to do with the decreased leverage combined with the thicker springs. Man, are those knives tough to open at times.

[Mumbleypeg]

I have numerous 08 and 83 whittlers. A few are nailbreakers but most are not. Try calling Case repair to see if they will fine-tune it for you.

Ken

[Dinadan]

I am another who wishes that there were an easy answer. Geocash, I do not think that leaving the knife open as in your photo will help, at least not unless you are really young. I have bought a few old knives that were in display type cases with the blades in a similar position to your knife. I am pretty sure that they had been in that position for decades, and the blades still had good snap.

There are a couple of things that can cause a blade to be a nail breaker. Sometimes it is a spring that is just too strong, and sometimes it is the way the tang is ground. If the tang has sharp corners instead of a rounded edge, that can be the problem. I think that is most common on blades with half stops. I have fixed one cheap knife by using a jeweler's file to round the corners of the tang. I would hesitate to take a file to a more expensive knife like yours.

Another possibility, and the most likely one in my opinion, is that the joint is just too tight on the tang. If that is the problem then it will get better with use. I have fixed a Case 6355 by coating the tang with metal polish compound and then opening and closing the blade several hundred times while repeatedly adding polish. Then I flushed it out and oiled it and it was perfect. It is worth a try before you give up on carrying that nice looking knife.

[Sharpnshinyknives]

I am another who wishes that there were an easy answer. Geocash, I do not think that leaving the knife open as in your photo will help, at least not unless you are really young. I have bought a few old knives that were in display type cases with the blades in a similar position to your knife. I am pretty sure that they had been in that position for decades, and the blades still had good snap.

There are a couple of things that can cause a blade to be a nail breaker. Sometimes it is a spring that is just too strong, and sometimes it is the way the tang is ground. If the tang has sharp corners instead of a rounded edge, that can be the problem. I think that is most common on blades with half stops. I have fixed one cheap knife by using a jeweler's file to round the corners of the tang. I would hesitate to take a file to a more expensive knife like yours.

Another possibility, and the most likely one in my opinion, is that the joint is just too tight on the tang. If that is the problem then it will get better with use. I have fixed a Case 6355 by coating the tang with metal polish compound and then opening and closing the blade several hundred times while repeatedly adding polish. Then I flushed it out and oiled it and it was perfect. It is worth a try before you give up on carrying that nice looking knife.

I think you nailed it. I like the idea of using polish and wearing that joint down a bit. I have suspected that as the problem myself. Never thought to address it this way. Thank you.
SSk

[geocash]

First, thanks to everyone.

Dinadan, I've got compound & enough time, I hope, for your method so it won't cost me any more than mine (leaving it under tension) & your method is an awful lot quicker. I'm starting tonight.

[sunknife]

First, thanks to everyone.

Dinadan, I've got compound & enough time, I hope, for your method so it won't cost me any more than mine (leaving it under tension) & your method is an awful lot quicker. I'm starting tonight.

Be sure and report back on your results if you don't mind, I don't have any polishing compound on hand but will sure run out and get some if your results are positive.

[RobesonsRme.com]

Having a knife sit around with the blades partially open and putting maximum pressure on the springs is not likely to weaken them.

My 2007 GMC Envoy has had its weight putting downward pressure on a set of leaf springs for over eleven years.

I do not think the vehicle is sitting any lower than the day I bought it.

Charlie Noyes

[Colonel26]

Having a knife sit around with the blades partially open and putting maximum pressure on the springs is not likely to weaken them.

My 2007 GMC Envoy has had its weight putting downward pressure on a set of leaf springs for over eleven years.

I do not think the vehicle is sitting any lower than the day I bought it.

Charlie Noyes

I say the same thing to folks about my cocked and locked 1911’s.

[ken98k]

This is a 1978 #6308 with real nail-breaker springs. Is there a reasonable way to reduce their strength? I think it looks good like this, sitting on a picture frame, & this should weaken the springs, after a few years, maybe. But I'd like to be able to tote it & use it without also carrying some tool to help me open a blade to use it. Any ideas?

I have a Schrade jumbo trapper (made by GEC) that is the the same way. The springs are ridiculously strong. I've toyed with the idea of disassembling it and heating the spring to weaken it but, the way my luck goes, I'd overdo it and ruin the spring.

[Dinadan]

Having a knife sit around with the blades partially open and putting maximum pressure on the springs is not likely to weaken them.

My 2007 GMC Envoy has had its weight putting downward pressure on a set of leaf springs for over eleven years.

I do not think the vehicle is sitting any lower than the day I bought it.

Charlie Noyes

Are you saying that you do not put it on blocks at night???!!!

[glennbad]

I have used a technique that helps with the strong opening. It is something that anyone can do, however, I would only recommend doing it to a knife you are going to use and don't care if the liners get scratches inside. Open your problem knife blade (tape the edge to protect yourself from getting cut). You'll need some jewelers files. I like the little square cut one. Now carefully ease the corner of the tang with the file to round it over some. You have to make sure to also get in the corners where the tang meets the liners.

Make sure to flush out any filings, and then work the blade multiple times. You may have to oil again. Take too much off with the file, and you can affect closing snap.

This doesn't lessen the strength of the spring, it just helps with that first bit of opening the blade, which can be the toughest part.

[Dinadan]

I have used a technique that helps with the strong opening. It is something that anyone can do, however, I would only recommend doing it to a knife you are going to use and don't care if the liners get scratches inside. Open your problem knife blade (tape the edge to protect yourself from getting cut). You'll need some jewelers files. I like the little square cut one. Now carefully ease the corner of the tang with the file to round it over some. You have to make sure to also get in the corners where the tang meets the liners.

Make sure to flush out any filings, and then work the blade multiple times. You may have to oil again. Take too much off with the file, and you can affect closing snap.

This doesn't lessen the strength of the spring, it just helps with that first bit of opening the blade, which can be the toughest part.

Here is an example of an knife with very sharp corners on the tangs on the left, and on the right one that used to have just as sharp a corner before I rounded it off a bit. Glenn, I have not really seen this situation in knife that does not have half stops. What is your take on that?

[glennbad]

I usually only see this in knives with square tangs. Ones with cammed tangs are much smoother in action, I have found. I do not recall having used that technique on knives with cammed tangs, only square.

(If that is your question)

[orvet]

I usually only see this in knives with square tangs. Ones with cammed tangs are much smoother in action, I have found. I do not recall having used that technique on knives with cammed tangs, only square.

(If that is your question)

Great terminology Glenn; "cammed tang."
I have long described the action of the tang as being like the lobe on a cam shaft when talking to someone one on one but shyed away from it in the forums because I though it could not be easily explained. You created a term that is self- explanatory!

"Cammed tang" is a great word because it is so descriptive and so accurate.

[glennbad]

I usually only see this in knives with square tangs. Ones with cammed tangs are much smoother in action, I have found. I do not recall having used that technique on knives with cammed tangs, only square.

(If that is your question)

Great terminology Glenn; "cammed tang."
I have long described the action of the tang as being like the lobe on a cam shaft when talking to someone one on one but shyed away from it in the forums because I though it could not be easily explained. You created a term that is self- explanatory!

"Cammed tang" is a great word because it is so descriptive and so accurate.

Thanks, but I can't take credit for it. I have heard others using the term somewhere, maybe here.

[marcellusW]

After reading this hours ago, it reminded me that I have a Case 6308, 6208, a Muskrat, and maybe another Case, or two. that have blades that can't be opened without a damn pliers.

So I keep my 6208 with the pen blade open in a box with my fixed blade whittling knives.
I was determined to free up the pen blade so it would open without a tool.
Downstairs to the workshop I go.

Tried a few suggestions mentioned above including open/close a couple hundred times.
Ok, I have had this 1971 Case 6208 for a good 30 years and I want to carry it now, and I'm not getting any younger.

So, here is what I did, and its not for the faint of heart ( Hey JerryD, Semper Fi )
I consider a knife with nail breaking blades of little value, to me, at least.
I carefully as I could, deepened the nail nick with the Dremel cut off wheel.
AND, it worked. I can open the blade with my increased leverage and didn't bugger up the blade.

Before you say something about the knife value let me say that I didn't give that a thought.
Heck, I might set another blade free one day.

I would post a picture, but after my photo host took a dump ( I can't even recall the name of host now), I don't know how anymore. But you get the mental picture, nail nick is about twice as deep and not as long as original.


Marcellus

[Dinadan]

Marcellus - glad to read that deepening the nail nick worked for your knife. That is a solution I have never seen mentioned and I question if it would help on a lot of knives. It does sound as if you have had a bit of bad luck with your Case knives. I do not have a lot Case knives, about a half dozen, but I only had the one that was a nail breaker. Naturally it was the one that I was most determined to carry!

[geocash]

Anybody remember this thread? I did try opening & closing the master blade with polishing compound in the pivot were I would have normally put a drop of quick-release oil. Occasionally I'd add more compound & work the master blade another hundred times, or so, opening & closing it. Eventually I could see a little wear showing on the sides of the tang but still had no relief for my thumbnail. Then I opened the master blade to access the point were the tang contacts the springs when the knife is folded. I filed that area, checked the action, filed some more, etc. Eureka! Once I filed off just enough to overcome that initial resistance, I can open it easily enough, & fortunately I didn't screw up the closing snap or anything else I'm aware of. I really like this knife. Thanks to everybody for your suggestions. Maybe this will help someone else.

[Sharpnshinyknives]

Anybody remember this thread? I did try opening & closing the master blade with polishing compound in the pivot were I would have normally put a drop of quick-release oil. Occasionally I'd add more compound & work the master blade another hundred times, or so, opening & closing it. Eventually I could see a little wear showing on the sides of the tang but still had no relief for my thumbnail. Then I opened the master blade to access the point were the tang contacts the springs when the knife is folded. I filed that area, checked the action, filed some more, etc. Eureka! Once I filed off just enough to overcome that initial resistance, I can open it easily enough, & fortunately I didn't screw up the closing snap or anything else I'm aware of. I really like this knife. Thanks to everybody for your suggestions. Maybe this will help someone else.

I’m very glad that we got a report on this and how it works. Good suggestions all, except using the Dremel, that one scares me too much to even think about using that one on a blade. So now I need to look for a jewelers file and try this myself, if I haven’t already sold all the hard to open knives I have. I tend to sell them if I have a problem opening them, they seem almost useless if you can’t open them just a pretty paperweight.
SSk