Why buff knives?

My Dad was Mr. Mathews, I'm Harry. Most work from a makers standpoint (at least this maker) is by choice. If it is difficult to do you just work harder if you want to do it.

I was with an independant telco. We did it all, landlines, mobile, paging, cell. FCC would not let us get into anything else. When they started giving away what we could do, We sold the Co.
 
Sorry I have been away from the computer for the last day or so.

To Clarify

All blades have higher corrosion resistance if mirror polished including stainless steel.

Yes I still mirror polish blades

Did the accident affect my point of view on mirror finishes? Of course it did, now I am more reluctant to buff irregular shapes or items that I consider dangerous. I refuse to do more jobs now but all of my blades are still mirror finished.

The key to safer mirror finishing is to reduce the exposure at the buffing wheel by doing a better finish on a cork belt first. My buffing time for a 5" blade is about 30 seconds per side to get a high mirror finish after belting with a 400 cork belt coated with green stainless steel buffing compound.

I use sewn wheels for buffing blades exclusively.

George
 
george tichbourne said:
The key to safer mirror finishing is to reduce the exposure at the buffing wheel by doing a better finish on a cork belt first. My buffing time for a 5" blade is about 30 seconds per side to get a high mirror finish after belting with a 400 cork belt coated with green stainless steel buffing compound.

I use sewn wheels for buffing blades exclusively.

George
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EXCELLENT point, George. You should never try to buff out a deeper scratch line. The blade should be completely prepped with uniform small grit scratches prior to buffing. If you're spending more than a few minutes on the buffer on an average size blade, you probably weren't ready to buff in the first place.

--nathan
 
It is easy to teach how to buff correctly, we have not had a buffer accident in our shop with a student yet!
Why buff is another issue:
Bulling parallel to the blade length actually strengthens the blade when lateral force is applied. This fact has been known to the metals industry for many years and to blade smiths who test or had to make knives to be used for many more.
 
OK, Harry.
I was a private carrier. Mobiles, paging, 2 way, cellular sales. I kept my co. until it was costing me a ton, then gave it away! Sounds like you got out at the right time. I saw many people make fortunes in the business.
 
I'm a collector and a user, not a maker. But, I am a teacher and a potter. I agree that each artist and maker will find themselves in a particular niche that reflects their talents and interests. This is not a bad thing; everyone needs to find their place in the world. However, it is possible that someone may be missing out on the full expression of their creativity because they lack a skill. If you are not using a buffer, but believe that it would take your craft ot the next level, then I think you should pursue the acquisition of the skills necessary to use it safely and effectively.

I hope that made sense. I got into the bourbon.

TC
 
If you are not using a buffer, but believe that it would take your craft ot the next level, then I think you should pursue the acquisition of the skills necessary to use it safely and effectively.
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I agree with this statement completely. Never back off something you want to do because you think you might not have the skills to be able to do it. You might have a longer learning curve than some, but you might surprise yourself too. Most people fail because they never try. Always remember.....Never show anyone your scrap box! :cool:
 
Bigblue17 said:
Ed - No need for a lengthy explanation, but why is this?
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Yup! Inquiring minds want to know! Could you point me to some research papers or industry texts about this Mr. Fowler? I can't help it, I'm an engineer for a living and like to read and understand all of the "egghead stuff".

-d
 
My guess would be because scratches running perpendicular to the edge cause stress concentrations and serve as sites for crack initiation. Buffing lengthwise would smooth the surface, making most of the scratches run the length of the blade.

This would make the blade more resistant to fracture, at least when the blade is bent from side to side. Cracks also tend to initiate perpendicular to the force applied and since the existing scratches are oriented parallel with the force applied, existing scratches wouldn't be as detrimental.

Although this isn't technically true, it's a rough explanation that gets the idea across.

That's just my guess based on what little I know about fracture mechanics.
 
Destraal said:
My guess would be because scratches running perpendicular to the edge cause stress concentrations and serve as sites for crack initiation. Buffing lengthwise would smooth the surface, making most of the scratches run the length of the blade.
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It's possible, but if the direction of scratches on the edge was so critical, why don't we hone lengthwise? :)

I guess my point is that we can all guess as to what the industry research has determined, but since the specific thing I asked about was the research to back up the claims of industrial standards, I'd kind of like to stick to that.

-d
 
SShepard and Bibblue17, thank you!! I love it when people ask why.
Decker: I believe you will find the book very worthwhile in your profession.

The information is contained in a book "The Prevention of the Failure of Metals Under Repeated Stress" by The Battelle Memorial Institute. Prepared for the Bureau of Aeronautics early in WWII. Pilots were being killed as propellers came apart, wheels fell of of planes and more, they wanted to know why and the many authors who contributed answered the questions and more. While the information is in many documents this is the most concise, understandable and complete treatment of the subject I have found.

You can buy it from Abe Books online used for anywhere from $15.00 to $150.00.

Destrall: Your explanation is a good one, easy to understand and more than adequate!

Readers of the text will find the reasons for many design features found in early blades that were intended for hard use. One quick example is the elliptical hole Scagel placed in his folder blades, these were 3 times wider than the height of the hole for a reason: the reduction of the influence of a round hole as a stress raiser.

This is a book you can read many times and still find more information with each reading.
 
Ahhh... I thought this was a thread about making knives in the buff. :eek: It can be a rewarding experience, but you DO have to be carefull of sparks... particularly if you are excited about your new design. Further, there is always the risk that it may not be your thumb covering the lense in your WIP photos... ;)
 
ok, so that applies to propellor blades ( without spending $150 yet to read the book), how does that apply to knife blades? How much of an increase in streingth does a mirror surface finish provide over other finishes?
 
Someone mentioned the 3M polishing paper and I would think that a big advantage of buffing over using products like that would be one of time, especially when you are talking about polishing blade steel. We know that you can get amazing highly polished finishes on Japanese blades using traditional water stones, but most of us don't have a month to finish a single blade so we like to have the option of cheating a bit on occasion..;)
 
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