Difficult Knife Restoration -- Thoughts?

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RustyIron
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Difficult Knife Restoration -- Thoughts?

#1

Post by RustyIron »

For me, this project began a few months ago when a couple of "a-list" friends asked me if I could take a look at a damaged knife. I told them, "Sure. If it's made of metal, I can make it better." They sent it on over, and I've been looking at it ever since. The time for procrastination is over, and tomorrow I'm going to start doing... something.

Backstory:
Her dad was a pilot in Vietnam. He had a knife that he carried on every mission. It wasn't anything special, just a knife that he picked up somewhere. But it was his knife. Time went by, he went home, he had kids, and his kids had kids. Eventually he gave the knife to his grandson. Then through an unfortunate turn of events, the knife ended up in a fire. The knife was recovered, but it's just not the same. Incidentally, the grandson is now a grownup, a Crew Chief on a Blackhawk, who has himself flown on all sorts of missions around the world.

Tomorrow I'll start cleaning the knife up. I think aluminum oxide blasting will be a good start. My intention is not to restore it to whatever it was originally, but merely to turn it back into a knife that looks good and would be usable. The aluminum will be easy to clean up. The pins, washers, and lanyard tube are crude, so they won't be reused. There are some tiny saw teeth on the blade, which I'll probably get rid of. The hard part will be the curved surfaces on the blade. Despite having a well equipped shop in my garage, I'm staring down a lot of intimate time with a hand file. An alluring solution might be to drive over to Harbor Freight and pick up a small belt sander, maybe something narrow, like 1 to 2 inches. Such a tool might be relatively quick, and make it easy to maintain the curves. I'm open to ideas.

Now here's the "before" pics. Laugh if you will. I know it's an absurd endeavor. But I thrive on challenges.
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Re: Difficult Knife Restoration -- Thoughts?

#2

Post by TomAiello »

The harbor freight 1" belt sander is cheap and it will work, but you're likely to go through a lot of belts. It's really hard to find decent abrasives in that size (I know because I own two of those sanders).
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Re: Difficult Knife Restoration -- Thoughts?

#3

Post by VooDooChild »

What I like about any heavy restoration project is that it always gets me thinking about The Ship of Theseus/ Grandfathers Axe paradox.

I once watched a skilled craftsman essentially recreate an item that was pretty much beyond restoration. I guess if the person who restores it says its restored then its restored.

I dont really have any ideas for you. I do have a question. If the blade was in a fire would the heat treat be ruined?
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Re: Difficult Knife Restoration -- Thoughts?

#4

Post by Bolster »

I would certainly give it a soak in EvapORust before any abrasive work.

If you've not used EvapORust, you will be surprised at what it can do. It's a chelation method, NOT an acid method (which eats metal along with rust). Chelation only removes the rust. Cheap at Harbor Freight.

I think it's a cool looking knife and I'd rehabilitate it if it were mine. You can always re-heat treat it to its former glory.
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Re: Difficult Knife Restoration -- Thoughts?

#5

Post by RustyIron »

Bolster wrote:
Wed Aug 25, 2021 9:51 pm
I would certainly give it a soak in EvapORust before any abrasive work.
Good idea. I've never used it, but I think I have a couple sample packets that have been sitting in a cabinet for years. I'll look for it in the morning, before heading to HF.
VooDooChild wrote:
Wed Aug 25, 2021 9:42 pm
What I like about any heavy restoration project is that it always gets me thinking about The Ship of Theseus/
Ahhh... an interesting philosophical paradox. When I'm not lurking on knife forums, I collect and restore very old and very rare stationary engines. Having all original parts is desirable, to be sure. But for the extra-rare specimens, it's just not possible to have everything original. And to be 100% honest, it's rarely as exciting to restore a complete engine. An engine that is missing parts or in need of repair is where it gets exciting. Such a project allows the craftsman to utilize his skills, whether it's making patterns and core boxes, machining complicated parts, or devining the intention of the original manufacturer. One such project was tackled my my friend Don, since deceased. Don was one of the smartest people I've ever had the pleasure of knowing, and he was one of the best machinists. Don was THE expert on Holt tractors. He wanted a horizontal boiler Holt steam tractor. Six were built. None remained. But Don had a crankshaft from one. From that, he began to build Holt 111. Every... single...part. I'll not get into the details of such an endeavor, but suffice it to say it was a challenge even for him. I'll post a link at the end of this, for a video done by my wife. Anyway, this knife will possess the spirit of Vietnam Granddad, the helpful family friend, and the tree that I choose to provide wood for the scales. Aficionados of the ancient Japanese art of kintsugi will understand.
TomAiello wrote:
Wed Aug 25, 2021 9:10 pm
The harbor freight 1" belt sander is cheap and it will work, but you're likely to go through a lot of belts. It's really hard to find decent abrasives in that size (I know because I own two of those sanders).
I'll be sure to pick up an extra armload of belts, if I go there tomorrow. In my abrasives cabinet I have several rolls of "import" emery cloth. The abrasive falls off really quickly, compared to emery cloth made in modern countries. I don't WANT any more tools, but this little belt sander won't take up a whole lot of space.

Don's Holt:
http://youtu.be/ZMuDSLYNw4w
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Re: Difficult Knife Restoration -- Thoughts?

#6

Post by ChrisinHove »

RustyIron wrote:
Thu Aug 26, 2021 12:12 am

Don's Holt:
http://youtu.be/ZMuDSLYNw4w
That is fantastic!

I love those old Traction Engines and try to get to a steam fair every now and then. Occasionally I’ll see one on the road, or outside a pub(!), belching smoke, steam and everything else. Magic.
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Re: Difficult Knife Restoration -- Thoughts?

#7

Post by kwakster »

The knife is either a Puma White Hunter (stag handle) or a Puma Auto Messer (wood handle).
You could send a mail to Puma HQ in Germany asking what they would recommend in this case.
They will also refinish knives for a fee (and maybe also re-harden them)

If you are going to restore it yourself: use either that EvapoRust or a process known as electrolytical cleaning (both will only remove the rust particles, not the steel particles)
Remove the old rivets and the aluminium guard before you do this.
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Re: Difficult Knife Restoration -- Thoughts?

#8

Post by Doc Dan »

I think kwakster has it right. I think it is an old Puma. That knife ain't cheap these days. It retails for $570.00 nowadays. Even without the grandad part, it would be worth fixing.

I don't know if they can do anything, but maybe. Of course, I know you are relishing the challenge, so there is that.
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Re: Difficult Knife Restoration -- Thoughts?

#9

Post by RustyIron »

kwakster wrote:
Thu Sep 02, 2021 8:16 am
The knife is either a Puma White Hunter (stag handle) or a Puma Auto Messer (wood handle).

It took about two minutes in the blast cabinet to get rid of all the rust, which revealed remnants of markings. They weren't clear, but the knife was indeed a Puma White Hunter. The pilot's daughter and I got a good chuckle over that. I don't think that nowadays they could sell a knife marketed to the "White Hunter."

I spent a whole lotta hours sanding, filing, and grinding out rust pits, then finished it up with some polish. With all the compound curves, I don't think I can make attractive grind marks, so it's going to have to be good enough. Today I might pick out a log from which to make scales. If all goes according to plan, they'll go on this knife and my latest Mule.

I'll post pictures when it's done. It's not going to be a beautiful knife that I'm proud of, but it should look pretty good for something that went through a fire.

Thanks gents for the guidance.
Rob
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Re: Difficult Knife Restoration -- Thoughts?

#10

Post by Josh Crutchley »

TomAiello wrote:
Wed Aug 25, 2021 9:10 pm
The harbor freight 1" belt sander is cheap and it will work, but you're likely to go through a lot of belts. It's really hard to find decent abrasives in that size (I know because I own two of those sanders).
If I'm not using the 40grit zirconia HF belt I'm using one from here.
https://trugrit.com/product-category/ab ... size/1x30/
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Re: Difficult Knife Restoration -- Thoughts?

#11

Post by TomAiello »

ChrisinHove wrote:
Thu Aug 26, 2021 12:55 am
RustyIron wrote:
Thu Aug 26, 2021 12:12 am

Don's Holt:
http://youtu.be/ZMuDSLYNw4w
That is fantastic!

I love those old Traction Engines and try to get to a steam fair every now and then. Occasionally I’ll see one on the road, or outside a pub(!), belching smoke, steam and everything else. Magic.
In the late 90's the wealthiest man in our state, a guy named JR Simplot (https://en.wikipedia.org/wiki/J._R._Simplot), spent over a million dollars on old tractors. After his death, his heirs used them as the primary decor for a community center they opened with his legacy.

http://jumpboise.org/about

Tractor collection: http://jumpboise.org/vintage-tractors

Next time you're in Idaho, you should check it out. :)
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Re: Difficult Knife Restoration -- Thoughts?

#12

Post by ChrisinHove »

TomAiello wrote:
Thu Sep 02, 2021 9:14 pm
ChrisinHove wrote:
Thu Aug 26, 2021 12:55 am
RustyIron wrote:
Thu Aug 26, 2021 12:12 am

Don's Holt:
http://youtu.be/ZMuDSLYNw4w
That is fantastic!

I love those old Traction Engines and try to get to a steam fair every now and then. Occasionally I’ll see one on the road, or outside a pub(!), belching smoke, steam and everything else. Magic.
In the late 90's the wealthiest man in our state, a guy named JR Simplot (https://en.wikipedia.org/wiki/J._R._Simplot), spent over a million dollars on old tractors. After his death, his heirs used them as the primary decor for a community center they opened with his legacy.

http://jumpboise.org/about

Tractor collection: http://jumpboise.org/vintage-tractors

Next time you're in Idaho, you should check it out. :)
I certainly will - that looks ace!
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Re: Difficult Knife Restoration -- Thoughts?

#13

Post by RustyIron »

TomAiello wrote:
Thu Sep 02, 2021 9:14 pm

In the late 90's the wealthiest man in our state, a guy named JR Simplot spent over a million dollars on old tractors. After his death, his heirs used them as the primary decor for a community center they opened with his legacy.
Back when the Oscar's Dreamland auction went down, a million bucks would get you a more nice tractors than it will today. It's nice that the collection is on display in a venue that will share them with the public.
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Re: Difficult Knife Restoration -- Thoughts?

#14

Post by RustyIron »

RustyIron wrote:
Sat Sep 04, 2021 12:35 am
TomAiello wrote:
Thu Sep 02, 2021 9:14 pm

In the late 90's the wealthiest man in our state, a guy named JR Simplot spent over a million dollars on old tractors. After his death, his heirs used them as the primary decor for a community center they opened with his legacy.
Back when the Oscar's Dreamland auction went down, a million bucks would get you a more nice tractors than it will today. It's nice that the collection is on display in a venue that will share them with the public. I think the most noteworthy item in his collection is the first Rumely OilPull tractor, known as "Kerosene Annie," built in 1909. My 14-28 Rumely was built in 1917. Distinctive pieces of machinery, for sure.
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Re: Difficult Knife Restoration -- Thoughts?

#15

Post by Xplorer »

TomAiello wrote:
Wed Aug 25, 2021 9:10 pm
The harbor freight 1" belt sander is cheap and it will work, but you're likely to go through a lot of belts. It's really hard to find decent abrasives in that size (I know because I own two of those sanders).
Have you tried Tru-Grit.com? They have all the belts for the 1x30. Alum/oxide, ceramic (Norton Blaze), structured ceramic, non-woven (scotch-bright), and even diamond belts (good for lapidary work) in all the grits you'd want.
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Re: Difficult Knife Restoration -- Thoughts?

#16

Post by Xplorer »

VooDooChild wrote:
Wed Aug 25, 2021 9:42 pm
...If the blade was in a fire would the heat treat be ruined?
Yes. Even a basic wood fire in the fireplace will burn around 600C or 1100F. Fire can and does burn much, much hotter than that depending on the fuel source and available oxygen. The min. of 1100F that it would have been subjected to is considerably higher than the temperatures used to temper a knife. Time in the heat is also a factor that would have a serious affect on the steel. Most likely the actual austenitizing temperature for that steel was somewhere in the 1550-1750F range. So, the temper on that knife is completely blown away and depending on the actual temp reached in the fire and the amount of time it spent in the heat it could also have been over-heated which would have grown the grain structure and clumped the carbides together at a minimum.
It might be possible (?maybe?) to re-heat treat it depending on just how high the fire temp went. To cycle the steel, normalize it and re-heat treat it the guard should be removed as it well act as a heat-sink during an oil quench and could cause a warp.

Regardless, it's a relic that's value (for the current owner) comes from it's history and the heat treat/blade damage is just a part of it's story. If I was restoring it, I wouldn't worry about the H/T anyway and I'd just make it look nice again. :smlling-eyes
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Re: Difficult Knife Restoration -- Thoughts?

#17

Post by Xplorer »

RustyIron wrote:
Thu Sep 02, 2021 9:56 am
... With all the compound curves, I don't think I can make attractive grind marks, so it's going to have to be good enough. Today I might pick out a log from which to make scales. If all goes according to plan, they'll go on this knife and my latest Mule.

I'll post pictures when it's done. It's not going to be a beautiful knife that I'm proud of, but it should look pretty good for something that went through a fire.

Thanks gents for the guidance.
Rob
A Scotchbright belt on a belt grinder might be just the thing you want to provide a "clean" looking uniform surface on the curves that would otherwise be extremely difficult to do cleanly with a more aggressive abrasive belt.

Let me know if you run into any obstacles you can't overcome and I'll be happy to help you through it if I can.
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Re: Difficult Knife Restoration -- Thoughts?

#18

Post by RustyIron »

Xplorer wrote:
Sun Sep 05, 2021 10:31 am

Let me know if you run into any obstacles you can't overcome and I'll be happy to help you through it if I can.

Thanks for the tip on the Scotch Brite belts. As with a lot of projects, my challenge is to overcome any OCD tendencies, and know when it's "good enough." I think it's ok, so yesterday I glued/pinned new scales onto the blade. Now it's merely a matter of shaping and finishing. I'll definitely pick up some of those belts for future use.
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Re: Difficult Knife Restoration -- Thoughts?

#19

Post by RustyIron »

Xplorer wrote:
Sun Sep 05, 2021 10:31 am

A Scotchbright belt on a belt grinder might be just the thing you want
I was under the impression that you live somewhere around here. I was almost ready to take you up on your offer to help, if you already had a Scotch Brite belt on your sander. But I thought it over, and decided to pony up a couple bucks for a variety of Scotch Brite belts that would fit my Harbor Freight belt sander. This morning I installed a belt. It was a little tight, and the sander's motor didn't have the mojo to start, even if I turned it over by hand. Sigh.

There's a tensioner, but the engineer from the University of Wuhan must have had a warped slide rule, as the tensioner doesn't move very far. A roller needed to be removed, but the fit was so tight that it needed a puller... which pulled the roller from the bearing. Sigh. Eventually I got it disassembled.

The next step was grinding away some of the frame, so the tensioner could move sufficiently. The tensioner arm also needed modification. And the roller shaft needed touching up, so the bearing wouldn't be such a tight fit. Once all the modifications were complete, I reassembled everything. It took a dozen or more times to grind, fit, test, and grind again.

After the sander was put back together, the puny motor still wouldn't turn over. Apparently the Scotch Brite belt is so stiff that the motor can't bend it over the rollers! Turning over by hand got it going, and soon the belt was limber enough that the motor didn't need help starting. It still wasn't powerful enough that I could put a lot of pressure on the blade without slowing the motor to the point that it would overheat. Slow and steady...

I knew before going in that Harbor Freight tools can be marginally functional, so I'm not too bent of out of shape over this. It took about two hours to fix the sander enough to make it work. On a brighter note, when I bought it, my intention was to just use it on this one project. But it's good enough that I'll probably use it in the future.

Note: I just looked at MSC to see what they might have. Of course they have some nicer tools, but they also have the EXACT same one I got from Harbor Freight, but MSC charges 5x more.

The finish on the blade is much improved over what I did by hand. I'm happy with it. When I was done with the blade finishing, I went and checked the front door where I found a package that contained some real tung oil. I've never used real tung oil, and was excited to try it out. I slopped it up on the handle that I made for this knife, as well as another wooden handle. It's looking good.

Now all I need is to put a good edge on the blade, and it will be DONE. It won't be nearly as good as the work that many of you guys do, but it will be a substantial improvement over the knife that went through the fire. I'll post pictures of the finished product when it's done.
Last edited by RustyIron on Sat Sep 11, 2021 12:31 am, edited 1 time in total.
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Re: Difficult Knife Restoration -- Thoughts?

#20

Post by Xplorer »

RustyIron wrote:
Fri Sep 10, 2021 6:52 pm
Xplorer wrote:
Sun Sep 05, 2021 10:31 am

A Scotchbright belt on a belt grinder might be just the thing you want
I was under the impression that you live somewhere around here. I was almost ready to take you up on your offer to help, if you already had a Scotch Brite belt on your sander. But I thought it over, and decided to pony up a couple bucks for a variety of Scotch Brite belts that would fit my Harbor Freight belt sander. This morning I installed a belt. It was a little tight, and the sander's motor didn't have the mojo to start, even if I turned it over by hand. Sigh.

...... I'll post pictures of the finished product when it's done.
Yes, I am about 60-90 minutes from you depending on the traffic. I was also going to suggest you come by if you ran into something you just couldn't overcome.

Good for you for going for it on your own! I used to have 2 of those HF grinders and I went through similar issues. With the Scotch Bright belts (also were too tight on my HF grinders) I was able to get the motor spinning by just stretching the belts in my hands first (the way a clown stretches a balloon before they make a balloon animal :winking-tongue ) and then backing off the platen a little. That was enough to be able to get it moving with my hands and give the motor a chance to take over.

Those grinders are a blessing and curse! They're crazy cheap and offer immediate entry level knife grinding..blessing. They also run too fast, they're so weak you can stop the belt with your hand, and they're apparently engineered and assembled by 5 year-olds (pretty sure)...curse. Don't get me started on that "L" shaped piece of soft steel that is supposed to represent a platen.

If it makes you feel any better, I too spent way too much of my life modifying HF grinders to do what I needed them to do.
Here's one of the 2 I used to use. For this one I made a new platen out of 52100 that I heat treated and bolted to the top as well as the bottom of the frame so that I wouldn't flex and give me unintentionally convex grinds.
Image
Image

With this one I removed the top of the frame so that I could access that section of the belt as a slack belt for rounding handles without having to remove the platen.
Image

In truth, with a few major modifications and the benefit of having a wide selection of belts available those little 1x30 grinders can produce a really nice knife. Eventually I saved up enough $$ to be able to get a great 2x72 grinder and I'm thankful for it every day...especially thankful for the variable speed control. But while those 1x30s that made me swear a lot, they also got a lot of work done.

I'm truly pleased to hear your blade is looking better. I think the project itself is really cool and I look forward to seeing the finished results.

Best regards,
CK
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