|
|
The Newbies Arena Are you new to knife making? Here is all the help you will need. |
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
??????Mystery Marks??????
hey guys so i cant post a pic because i dont have a camera here (never went to buy a new one but now i wish i did) once i get it back i am going to post a few prototype designs i have come up with but i will also post a pic of the problem i am having now. so i am in the middle of making a knife for my aunt and she wants it polished and she wants a big blade so it can sit on a shelf and look pretty. so anyway when i got to about 220 grit on the belt grinder i started noticing these marks it looked like finger prints or i thought from the water i use to cool (ya know when it dries it leaves marks) but this wouldnt wipe off and its not very distinct you gota get it at the right angle and in the right light kinda like a hologram. i thought maybe its just on the surface so kinda ignored it and kept grinding and at first i thought it would be ok because the higher grit i went to the harder it got to see but since i was polishing it i went all the way up to 3000 grit on the belt and i can still see it but yeh it is much harder to see now than when i first noticed it. i stoped at 3000 on the grinder yesterday today i am going to do some hand sanding and buffing...or actually i just got one of those felt belts you load with compound and use in the place of a buffer so i am going to try that on this blade i am kinda hoping the compound will take it out either way it is hard to see now you gota actually look for it.....i have never seen this before on either 1084 or 440c oh just in case it matters this is a 1084 blade. like i said ill try to get a pic up as soon as i can but honestly i should have taken a pic in the beginning because i think now since its harder to see than when i started it might be impossible to get the right light and angle with a camera. has anyone ever come across anything like this could it be something in the HT or even a flaw in the steel it self....oh yeh i HTed it in the oven and quenched in parks 50 ......this one REALLY has me completely stumped
|
#2
|
|||
|
|||
That is odd, but I've seen it in an industrial situation.
Has to be a differential HT problem. We had thicker stuff that if you had different colors it meant it cooled unevenly somewhere along the line. How thick is the steel? That's all I can think of unless you used hot roll and didn't equalize it first. I never used hot roll stainless, but have carbon steels and I was always told to equalize it before HT as it has hard and softer spots and won't be consistent when HT if you don't, but it was always thick stuff one inch or more. Thin we always used cold roll sheared and still equalized it. Material could be faulty too, it happens, especially nowadays when you don't know where the steel comes from.
|
#3
|
|||
|
|||
A lack of pictures does make it a little rough. I take it by oven you mean a high temperature oven and not a forge. Not sure what you mean by equalize though. Did you hold it in the oven long enough to make sure that the blade was heated all the way through or did you hold it at temperature for a specific amount of time? Not knowing your supplier I also don't know if your 1084 was regular 1084 or 1084 with a small amount of chromium added. The chromium, as you know, would increase the hardenability of the steel a little. Depending on the thickness of your blade and the fineness of the grain you could have some automatic differential hardening in the blade.
Doug __________________ If you're not making mistakes then you're not trying hard enough |
#4
|
|||
|
|||
I tend to think you missed something in the heat treat. Was the blade forged or stock removal? Did you normalize? Did you warm your oil? Not that it matters a whole lot with Parks 50 but it could.
|
#5
|
|||
|
|||
ok yeh i know not having a picture sucks my sister is always steeling the camera i got here....(ray has been telling me for a while to go get another one, once again he was right) any way i did a lil buffing to it and it did make it even harder to see but if you really look its still there....the steel is 1084 from nj steel barron it was heated in a even heat oven yes it was held long enough to soak right before the quench the oil was not heated but JM as you said i dont think parks need to be heated past room temp and i have never seen this before.....the oven is fairly new but i have HTed enough blades both 1084 and 440c and i have never seen this before.....tomorow ill go get the camera (or a new one) and see what kinda pic i can get ....it might be hard to see with a camera now as i said the firther up in grits i went it got harder and harder to see but ill try
|
#6
|
|||
|
|||
Did you normalize?
|
#7
|
|||
|
|||
I know we're grasping at straws here but I don't know if normalization would make much difference as there's not that much in the way of carbides, except cementite, to dissolve and the cementite will dissolve rather quickly. Did you heat cycle the steel to reduce the grain size? Have you made another blade from that same bar of steel and can you think of anything that you might have done differently?
My experience with the 1084 from Aldo leads me to think that it has a higher hardenability than of older plain steel 1084 alloy so automatic differential hardening may not be the issue even if you got the grain super fine. Doug __________________ If you're not making mistakes then you're not trying hard enough |
#8
|
|||
|
|||
Did it look kind of like an orange peel texture?
__________________ Find me on Facebook: https://www.facebook.com/gpopecustomknives/ Gloria In Excelsis Deo!! |
#9
|
|||
|
|||
i am going to put up a pic later once i get the camera back hopefully it will help. but i didnt normalize, didnt think it needed it as it was done stock removal the heat treat consisted of going to 1475 and holding for a few mins then quench yes i have use steel from the same bar with the same HT nothing that time...no orange peel texture the best description i can give is its like 2 rings one smaller than the other but not didstinct looked like a water mark and like i said as i went up in grits it got even less distict just like a water mark on a $100 bill you can only see it in right light and angle....now you really got look for it i asked my mother "here look over this blade and see what you can see does anything not look right" her response was no until i pointed it out and let her look again
|
#10
|
|||
|
|||
I have had that happen a couple of times on 1084 when I heat treated it with a torch, I figured I didn't get the heat evenly or they were hot spots.
|
#11
|
|||
|
|||
hey guys sorry i couldnt get a pic up i didnt get the camera back from my sister (she is a pain) i tried to use a phone but as i said it got harder to see the higher up in grits and now that its buffed and polished it is real hard to see you gota look for it and catch it in the right light and angle and i couldnt get it to show up in the phone camera...ill have to deal with it (or my aunt will since its for her) i dont think she will even notice it but ill point it out and if she wants a different one thats what ill do....thanks for the help i know its a tough thing to figure out with out a pic but thanks for trying everyone.....next week when i get some money the first thing i am getting is a decent camera
|
Tags |
1084, 440c, angle, back, beginning, belt, belts, blade, buffer, buy, case, cold, grinder, grinding, hand, knife, make, making, material, post, problem, quenched, sanding, steel, surface |
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Mystery Wood | jdale | The Newbies Arena | 11 | 04-05-2014 05:47 AM |
mystery knife | Shakudo | This Old Knife | 1 | 08-31-2006 04:15 PM |
The 100 year mystery.....................? | thewap | Randall Knives Forum | 5 | 03-12-2006 07:12 AM |
A Mystery for Hammerdownnow | Tony Graves | This Old Knife | 12 | 01-26-2006 03:40 PM |
Mystery | Mace | The Display Case | 8 | 10-25-2004 05:13 PM |