Sanding and polishing on one area of a blade

[Swonranson100]

Hey, new to the forum, this is my first account. I usually collect swords and knives and went cruising around the forums looking for the answer and decided since I couldn’t find it, I would finally contribute to the wealth of knowledge here by asking a question. So here it goes. Kinda long winded so TLDR is at the bottom

I own a number of blades, one of my favorite things to collect. In the past I’ve owned several swords and knives that got nicked or chipped or other types of edge damage. I’ve read from some people that usually you can sand or sharpen it out or grind it out using a variety of methods. So here’s my question

When you grind our sand out a nick or say a rust pit, does the removal of that much steel affect the integrity of the steel? Along those same lines, does polishing/sanding/grinding on one specific area of a sword or knife affect integrity of the blade?

Now I’m taking about light to medium polishing. Grits of 220 or higher, just long enough to fix whatever blemish may be there. Not talking about using 40 grit and sanding it like a mad man for hours.

Was just curious because I often times will polish blades that are more of collectors items and sometimes if I get a blade that I like that has a nick or some rust on the blade, I’ll tend to do some focused polishing and sanding to remove it. Curious if this hurts the integrity. Thank you for your responses!

TLDR: does polishing/sanding/grinding/ one spot in particular on a blade adversely affect the whole sword or knife’s integrity?

 

[killgar]

I say no.

Although you're removing a very small amount of steel I wouldn't say that you are reducing the blades "integrity". When I think about "blade integrity" I think of the blades ability to not break or fail during normal use (the use for which it was designed). And I don't believe the small amount of steel removed by sanding/polishing will increase the chances of breakage or other blade failure.

Now if you were to alter the blades heat treat or create a "stress riser", that I would consider a threat to "blade integrity".

I've sanded small areas of blades to remove logos/writing, or scratches or other blemishes without the slightest concern.

And welcome to Bladeforums.

 

[Swonranson100]

Thanks for the response and welcome!

 

[Swonranson100]

I say no.

Although you're removing a very small amount of steel I wouldn't say that you are reducing the blades "integrity". When I think about "blade integrity" I think of the blades ability to not break or fail during normal use (the use for which it was designed). And I don't believe the small amount of steel removed by sanding/polishing will increase the chances of breakage or other blade failure.

Now if you were to alter the blades heat treat or create a "stress riser", that I would consider a threat to "blade integrity".

I've sanded small areas of blades to remove logos/writing, or scratches or other blemishes without the slightest concern.

And welcome to Bladeforums.

I’m not totally familiar with the term stress riser, what would be an example of a stress riser?

 

[killgar]

I’m not totally familiar with the term stress riser, what would be an example of a stress riser?

I would consider adding a choil to a blade to be a potential" stress riser". A "stress riser" is an area of the blade where the strength of the blade is compromised increasing the risk of breakage under stress. A choil is a semi-circular cut-out in the blade at the rearmost point of the edge.

Of course the risk of a choil being a stress riser is in direct relation to the level of stress that will be applied to a blade. For example, adding a sharpening choil to a folding knife, one that won't have lateral stress applied to it, isn't going to cause a break.

But if a fixed-blade were going to be used for prying and/or chopping, creating a choil could weaken the blade. The larger the choil, the bigger the risk of breakage.

The term "stress riser" is also commonly used to refer to any 90 degree, or similar angle involved in the design of the blade. Like where the blade meets the tang.

 

[Swonranson100]

I would consider adding a choil to a blade to be a potential" stress riser". A "stress riser" is an area of the blade where the strength of the blade is compromised increasing the risk of breakage under stress. A choil is a semi-circular cut-out in the blade ant the rearmost point of the edge.

Of course the risk of a choil being a stress riser is in direct relation to the level of stress that will be applied to a blade. For example, adding a sharpening choil to a folding knife, one that won't have lateral stress applied to it, isn't going to cause a break.

But if a fixed-blade were going to be used for prying and/or chopping, creating a choil could weaken the blade. The larger the choil, the bigger the risk of breakage.

The term "stress riser" is also commonly used to refer to any 90 degree, or similar angle involved in the design of the blade. Like where the blade meets the tang.

Thanks for that! Very descriptive. I appreciate the help!

 

[3D Anvil]

I don't think a small amount of sanding to remove rust or pits would have a measurable effect on blade integrity. OTOH, I also don't think you're going to get a satisfactory result from sanding isolated spots on a blade, because it's near-impossible to blend in the sanded spot with the existing blade finish. Maybe if the intention is to acid or stone wash the blade afterwards....

 

[Swonranson100]

I don't think a small amount of sanding to remove rust or pits would have a measurable effect on blade integrity. OTOH, I also don't think you're going to get a satisfactory result from sanding isolated spots on a blade, because it's near-impossible to blend in the sanded spot with the existing blade finish. Maybe if the intention is to acid or stone wash the blade afterwards....

What if the blade had a poor polish to begin with/it was a beater blade that the polish didn’t matter for?

 

[catspa]

Welcome to BF.

If you built the blade from scratch, you’d have sanded the hell out of it, probably with power tools. Sanding it a little more is small potatoes.

That said, sanding may not be the ideal method for removing nicks. Plenty of abrasive options out there.

Parker

 

[scdub]

The only way I can see that being a problem is if you’re using power tools and allow the blade to heat up too much. That could affect the temper of the blade. Otherwise you could hand sand/polish for a week straight and not affect the steel integrity.