Pitting of NOS steel blade

[MikeA]

I am in the process of converting a M1 Camillus blade into another pattern style knife. I noticed something odd and would like validation (maybe). When I got the blank is was smooth as a babies behind. I have started polishing it having gone from 180 and now up to 600. The strange thing now is that there are actually micro or macro pits starting to show on some of the blade. Not a lot to be alarming but enough to know I wont get them all out.

Here is my theory and maybe someone has a better idea? The knife I believe is made out of 1095HC. To me this steel is a formula. So we take some of X and Y and Z and mix them all together, melt it down, make an ingot and then hot or cold roll the steel.

So what if the batch is not thoroughly mixed or melted and there are some particles of Y or Z that havent integrated into the mixture. By my fine grinding I am peeling back the micro layers and exposing that little piece of material which then falls out and creates a pit.

For the longest time I thought that many of the Military knives I have with pits were due to corrosion. But this is a brand new Camillus blank and never exposed to moisture. Most of my knives are vintage pre 70s for the most part so I am assuming they are of similar composition as they are not stainless.

I could take a picture but I think my explanation will be okay. Wonder if anyone else has had this? I dont believe its because the knife is getting to hot during sanding as I am using my bare fingers to as a guide so that I can feel the warmth.

Thanks in advance,
Mike

[orvet]

How are you sanding, by hand or by machine?
If by machine; which type of machine and what kind of abrasive are you using?

[MikeA]

I am using the HF 1x30 with belts that I got from Klingspor 400,600 and 800 but I am only up to the 600. Admittedly I did start off with air grinder and then a bench grinder and then some 80 and then 120,220 and then 320 on a 4X36 flat bed sander to first shape it and then to further smooth it out on the 4X36. Then switch to the smaller 1X30 with the finer grit. I still have some of the earlier 120svertical grind marks that I am having trouble getting rid of but that was my fault.

This is just flying by the seat of my pants totally. Well I have watched some tube videos and read articles but no real expertise.


Hope that helps.

Mike

[Bill DeShivs]

The steel is thoroughly "mixed." There is some other explanation.

[MikeA]

Thanks for the input and reply Bill - Will continue to move forward but watch very carefully what I do and inspect prior to and after every operation.

I cant rule out the possibility that the belt might have been embedded with 2 larger pieces of cutting material and on the first pass on the new belt that those pieces impacted the soft blade metal at the exact moment of touching the belt and gouged out two micro pits?????? That might be a possible answer. The belt at that time was from HF as I recall as was probably 120 grit. Not sure of their specs (and am not knocking anyone) and just throwing this out.




Mike

[orvet]

One thing to consider Mike is that a 30" belt will wear out very quickly, especially those from HF.
Not knocking them, you get what you pay for. I have used some of their abrasives and they are good for the price, but a good silicon carbide belt that is made for metal, as opposed to aluminum oxide for wood, is a lot more expensive but last longer.

Aluminum oxide is great for wood, but not nearly as hard as silicon dioxide or ceramic abrasive.

Be sure you are using new belts to get good clean cuts when you grind. Also watch your heat build up, of both the blade & the belt. I suspect if you have an old belt that is the problem. A 30” belt is so small that they wear out very fast. The 42” belts last much longer, especially in silicon carbide or better yet in ceramic. The 30” belts heat up faster and that can melt the adhesive and then it can do weird things to the blade. I suspect that may be your problem.

If you try Tru Grit - http://www.trugrit.com/belts1.htm

They have some better quality belts.
In 120 grit they have the CS411X Zirconia belts by Klingspor ($2.05 each) or better yet, they have Norton’s R980 Blaze Plus Ceramic belts ($3.40 each).

The Blaze Ceramic belts are about the best, IMHO. I use them a lot and don’t have problems with them. Just don’t get them hot (or wet) and don’t try and make one belt last too long. Just guessing I suspect your problem is a combination of low quality belts and using them too long. It was one of those things I had to learn myself by trial and error, as I didn’t have anyone to ask. You will learn over time, just like anything else. Just keep asking questions and trying different materials and techniques and you will get there!

[MikeA]

Thanks Dale,
Would make sense for me to keep a notebook right now with what I do and with what materials. I did buy the Klingspoor nicer belts but only in the higher grit. Yes the 120 was OTC HF. I will look into those other belts. I went to all the local box stores and that was a waste of time so went online. I bought the HF due to $$$$ considerations and a fixed income. Agree you get what you pay for.

Again I appreciate the input and am going to head to the garage and see what I can muster up.


Mike

great site with a bunch of neat users with good feedback.

[orvet]

Mike,
I just thought, if $$ are an issue (and aren't they for everyone now?) then you might try hand sanding it with wet or dry sandpaper. Get 3M sandpaper if you can find it, just because it is generally available and I know it's quality. Use it wet with water or WB-40.