Recommendation? Is it possible to cure a slight bent of bone scale? [Results!]

[Alex.Y.]

I think that question belongs here, as bone is a traditional handle material.

So, I made a bone scales to replace the delrin ones, but one of the slabs had a slight curve, as does the cover now. I wonder if that can be cured by something else than grinding? Heating maybe (I guess not)?

I plan to just screw it tight to the handle thus eliminate the bend (already works with pressing to the flat surface by hands), but I am afraid that this kind of constant tension will lead to a massive crack at some point.

I know there are many experienced knifemakers here, so I seek your advice. Thanks in advance!

 

[afishhunter]

I'm not a knife maker. Steam until flexible and clamp between two pieces of smooth polished aluminum until cold and dry?

 

[Alex.Y.]

...

 

[Alex.Y.]

I'm not a knife maker. Steam until flexible and clamp between two pieces of smooth polished aluminum until cold and dry?

Do you have a positive experience of implementing this method? What should be the source of the steam? Should the aluminum be warm when clamping to prevent a fast temperature change?

 

[Alex.Y.]

Not sure why I said "scales" here instead of "covers". I guess because they aren't covering anything just yet.

 

[r8shell]

Horn can be shaped or molded with steam, but I haven't heard of that being done with bone. If no one here has an answer for you, perhaps ask in the Knifemakers Forums.

Also, please post pics when you get it finished. Are you planning to dye the bone, or stick with natural smooth white?
Natural smooth white bone is the best.......

 

[Primble]

I plan to just screw it tight to the handle thus eliminate the bend (already works with pressing to the flat surface by hands), but I am afraid that this kind of constant tension will lead to a massive crack at some point.

My bet is that if you screw it down gently and since you can do that already by hand, it will relax and be fine. Woodworkers do that all the time.
The worst that could happen is it may crack and you have to make a new set. I am no authority on the matter though.

 

[afishhunter]

Do you have a positive experience of implementing this method? No.

What should be the source of the steam? Due to the size, a vegi steamer?

Should the aluminum be warm when clamping to prevent a fast temperature change? I'd guess at least warm.

One or more of the experts who hang out in the maker's sub-forum might know if steaming the bode and clamping flat will work.

 

[Alex.Y.]

Horn can be shaped or molded with steam, but I haven't heard of that being done with bone. If no one here has an answer for you, perhaps ask in the Knifemakers Forums.

I might do that, thanks for the tip.

Also, please post pics when you get it finished. Are you planning to dye the bone, or stick with natural smooth white?
Natural smooth white bone is the best.......

Sure will do! I plan to leave it white, both because I don't have any proper dying stuff and I think it would be a bit too much of an experiment for the first time making scales. Now I just wanna make it work and see how it looks.

My bet is that if you screw it down gently and since you can do that already by hand, it will relax and be fine. Woodworkers do that all the time.

That's the default idea. I am just afraid that with Lone Star Hunter's thick steel handle liners, the curved scale will crack pretty fast. I mean steel is heating on and cooling off pretty fast and I know that bone hates such temperature jumps, and in my case bone will be attached to steel. Well, we shall see anyway.

The worst that could happen is it may crack and you have to make a new set.

Yeah, would be sad. But at least I'll need only one scale to remake. Problem is I haven't bought me a spare slab, so it would take some additional time.

One or more of the experts who hang out in the maker's sub-forum might know if steaming the bode and clamping flat will work.

Okay, at least that's some plan. It's just that I don't have a steamer. Do you think sinking in hot/warm water is an option?

Well, I have a few leftovers, so I might do some live testing.

 

[Alex.Y.]

So, it is finally finished! Added a RR Barlow for the sake of traditional theme.




It was a long project, especially given that I had only an hour or two every day for it. It moved slow and steady, but that paid. The most shaky part was drilling the right holes in the right places.

About the curved cover. I tried heating with hot water on other bone pieces and noticed no flexibility increase, so I ended up just screwing it tight to the handle. A little space did left at the ends where there is no pressure from the screws, but not that much for me to worry about after all.




Only thing I am actually to blame for is that bone covers are about 0.5 mm wider and longer than the original ones, which were actually a bit smaller than the handle could allow, so I left it as it is. But it seems that I placed one of my covers a bit closerto the blade and the other one a bit further which ended up with 1 mm of a difference of placement when looking from a spine or cutting edge. Well, I can always take them off and grind down from the respective ends, but I think it can go wrong and don't really feel a need to take such a risk. As they say, better is an enemy of good.

Edit: and I have achieved my main goal - the handle is not slippy now, a perfect grip! After all, that was the reason that took me to the idea of changing the covers.

 

[Just Tom.]

I have achieved my main goal - the handle is not slippy now, a perfect grip!

Looks fine to me .

If you handed the knife to someone to use, I guarantee they wouldn’t notice any imperfections.

 

[Will Power]

Interesting work you've carried out, I thought maybe more sanding might reduce the curve ? Sometimes explains differences in slab thicknesses on Bone and Stag handles due to needing to achieve a flatter adhesion point.

Not sure why I said "scales" here instead of "covers". I guess because they aren't covering anything just yet.

Well, I don't think it's wrong it's merely a question of preference. Myself I don't like the word 'covers' it kind of denotes attempts to hide things ... so I opt for scales or slabs but it's all legit. Here's The Oxford Dictionary it points out e.g. that scales can also be the metal liners on a knife, both appeared in 1834. Pedigree.

 

[eisman]

Soaking in vinegar will make bone flexible. But it does so by removing the calcium, so you would have to find a way to harden the bone once bent to shape. You might be able to do that with epoxy in a vacuum.

Your picture shows a slight bend. My suggestion would be to shave/sand the side flat. You could do both scales if you wanted uniform thickness. You might have to shorten the screws also, but all of these steps are within the ability of pretty much anyone.

 

[GaiusJulius]

Others have already suggested but you could absolutely true those flat by removing from the knife and sanding on a surface assuredly flat… like a piece of glass with adhesive sandpaper affixed to it. As is though they look great, nice work!

 

[meako]

Im with the "sand it flat to start with " gang on this one...still a great looking job..

 

[Alex.Y.]

Thank you for the kind words, guys!

I thought maybe more sanding might reduce the curve ?

Others have already suggested but you could absolutely true those flat by removing from the knife and sanding on a surface assuredly flat…

Im with the "sand it flat to start with " gang on this one...still a great looking job..

Well, apart from me not wanting to try and make a best from good, which usually ends bad, there is a problem actually. I've noticed that the curve was increasing by itself. Really, nothing applied to it, it was just lying in the same place with the other scale, but it has bent even more then I showed in the first post, and it is curving like a propeller, in two directions. At the moment of assembly, height difference between the ends was already more than 0.5 centimeters! It cannot be sand down, I think. I was thinking about that method before, but it would also require to sand the other, perfectly flat scale, so I decided against that. If the faulty one would initially brake, I'll just make another one.

 

[Horsewright]

Thank you for the kind words, guys!






Well, apart from me not wanting to try and make a best from good, which usually ends bad, there is a problem actually. I've noticed that the curve was increasing by itself. Really, nothing applied to it, it was just lying in the same place with the other scale, but it has bent even more then I showed in the first post, and it is curving like a propeller, in two directions. At the moment of assembly, height difference between the ends was already more than 0.5 centimeters! It cannot be sand down, I think. I was thinking about that method before, but it would also require to sand the other, perfectly flat scale, so I decided against that. If the faulty one would initially brake, I'll just make another one.

How did you sand it flat initially?

 

[joeradza]

Interesting work you've carried out, I thought maybe more sanding might reduce the curve ? Sometimes explains differences in slab thicknesses on Bone and Stag handles due to needing to achieve a flatter adhesion point.


Well, I don't think it's wrong it's merely a question of preference. Myself I don't like the word 'covers' it kind of denotes attempts to hide things ... so I opt for scales or slabs but it's all legit. Here's The Oxford Dictionary it points out e.g. that scales can also be the metal liners on a knife, both appeared in 1834. Pedigree.

I don’t usually like to disagree here Will, but the way language evolves I prefer to side with Bladeforum’s common usage. Whatever that may be.

 

[Alex.Y.]

How did you sand it flat initially?

It was a rectangular slab sawcut by the seller, so it was flat initially. I used sandpaper to smooth it down. All I used in that project is fretsaw, file, sandpaper, and an electric drill for the holes.

 

[Horsewright]

It was a rectangular slab sawcut by the seller, so it was flat initially. I used sandpaper to smooth it down. All I used in that project is fretsaw, file, sandpaper, and an electric drill for the holes.

If ya didn’t check em first sometimes bone scale’s aren’t as flat as they might seem. I use a lot of bone scales and I always flatten them prior to use. I do have a flat disc grinder that I use but someone had mentioned sand paper on glass and that would work well. Some folks will use surface plates or smooth leather working tooling stones, even tile. As long as the surface under the sand paper is flat. Could of been that the bone scale itself got too hot when the supplier did the original sanding or it was cut from a curved piece of bone and kinda has memory. This is not uncommon in some natural handle materials. I quit using water buffalo horn some years back cause it always wants to go back to its naturally curved state