Help getting an antique SAK to open smoothly

[halves]

Pics:

https://imgur.com/a/kcUMlXg

I inherited this knife from my grandfather. It's basically a Tinker model but without the scale tools (tweezer, toothpick) and the awl doesn't have a hole.

The large blade is very hard to open. The small blade is a little stiff. The rest is maybe a little stiff but not too bad. The bottle opener is smooth.

When opening the large blade it becomes very stiff at 30, 90, and 120, degrees opened. It's easier to close than to open.

What do you think is the cause of the tools and especially the large blade being hard to open?

 

[Wild Willie]

Probably just years of gobbledygook in the pivot, give it a good soak in some penetrating oil and let it sit overnight, then hose it out with compressed air or break cleaner. It might take a couple of gos, but it should improve.

 

[kamakiri.knives]

Your knife is from c. 1972, and the only thing I’d put in it is a knife or multi-tool lube for the pivots and operate all the tools individually until it loosens up. Wipe or swab the crud as it comes out and re oil as needed. And I wouldn’t use water/soap as many how-tos call for a ‘spa treatment’. It’s a bad idea for older knives (pre-1990 generally) with anodized liners that are likely to have any internal corrosion…which is the typical cause of the tight joints. Because it’s a Hoffritz, it was actually sold as a ‘Hobbiest’ model, but most would just call it a Tinker.

 

[halves]

I used Sentry Solutions Tuf-Glide Needle Applicator in the joints. It opens much smoother now. There is still some resistance. I'm not sure if that is just how a SAK is supposed to feel or it's still a bit jammed up.

The Tuf-Glide contains mineral spirits and the odor irritated me. I aired it out partially open for two days to get rid of the odor.

Thanks for your help!

 

[Guy McVer]

Just keep working it open and shut.

In the future you might want to consider flushing the knife with a warm soapy water bath, rinsing it in tap water, air drying, and re-lubricating with a food safe oil such as the multi tool oil which is sold by Victorinox for use in their swiss army knives. Don't do any food processing with that knife while it has the tuf-glide lube in/on it.

Soapy water and a good rinse should be perfectly fine as long as you dry it out quickly and apply oil immediately. Hot water dries faster because it evaporates more easily.

 

[SCTorrero]

I have not done this personally, but have heard of guys using liquid stropping compound to loosen up pivots (particularly on new pliers). You would apply it like KPL or whatever, run it for a bit, then flush it and relube. I wonder if it would work in this application. Anyone have experience with that?

 

[kamakiri.knives]

Switch to something low VOC or low odor or food safe, and keep working the tools. Solvents don’t really do anything that I know of to break-down aluminum oxide. Just the mechanical action that shears it into smaller bits.

I have not done this personally, but have heard of guys using liquid stropping compound to loosen up pivots (particularly on new pliers). You would apply it like KPL or whatever, run it for a bit, then flush it and relube. I wonder if it would work in this application. Anyone have experience with that?

I’ve done similar with knives that are unusually tight. The aluminum oxide bits which are coming out already do that to some extent as they are harder than the tools, backsprings and liners. Lube helps get the abrasive particles out. Which is ultimately what you want.

Again, I do not recommend water…unless you want to follow with WD-40. But I’d never do that intentionally, because of the smell and that it’s not a good long term lubricant.

 

[Mikel_24]

... Wipe or swab the crud as it comes out and re oil as needed. And I wouldn’t use water/soap as many how-tos call for a ‘spa treatment’. It’s a bad idea for older knives (pre-1990 generally) with anodized liners that are likely to have any internal corrosion…which is the typical cause of the tight joints...

... Solvents don’t really do anything that I know of to break-down aluminum oxide. Just the mechanical action that shears it into smaller bits.

...s. Lube helps get the abrasive particles out. Which is ultimately what you want.

... I do not recommend water…unless you want to follow with WD-40....

So you are stating that most of the time the stiffness in a SAK comes from internal corrosion... and not for build up of crud or debrish... and therefore it requires to be mechanically polished (by opening and closing several dozen times) with the help of oil/lube instead of trying to "clean it"?

I might need to take your advice on this matter as I have some SAK's knives that suffer from this issue. I always thought it was a matter of them being dirty, not corroded!

Thanks!

 

[kamakiri.knives]

So you are stating that most of the time the stiffness in a SAK comes from internal corrosion... and not for build up of crud or debrish... and therefore it requires to be mechanically polished (by opening and closing several dozen times) with the help of oil/lube instead of trying to "clean it"?

I might need to take your advice on this matter as I have some SAK's knives that suffer from this issue. I always thought it was a matter of them being dirty, not corroded!

Thanks!

Yes, I think that’s a fair summary. If dirt gritty contaminants are the issue, it usually doesn’t cause any stiffness…but those wonderful grinding noises we all try to avoid.