Questions on How You Get Your Stock Flat and Finished

D

dzlvs8

Joined
Jun 13, 2013
Messages
948
So I have been having a little trouble with two things lately.

1. It almost seems impossible to get the initial scale of my 1080 off and get it flat. I am using good belts but it seems like the belts dont do anything after about 10 second of use. Once a ridiculous amount of time goes by trying to grind the flats flat, I start stepping up my grit an thats when I realize that the steel is still extremely uneven and I have so much further to go. I basically lay my flat bar stock against my belt and hold it with a magnet. That's how I grind the flats flat. Is there a more efficient way to do this or some sort of trick?!?!?!

2. When grinding the flats flat, I have been noticing streaks in the metal at higher finishes. Is this possibly the metal heating up slightly heating up (it's not a discoloration)? Is it a worn platen? I have been trying to finish grind the flats on a belt up to 600 or 800 grit. I am keeping the metal from burning during this process. What is going wrong.....I hope this problem isn't still related to problem #1. If so, then I will have to spend days at the grinder getting step one done.

Help! I'd like to hear how ohers go about accomplishing step 1 and 2 and what I may be doing wrong. Thanks.
 
craftsman 1x42 with a ceramic platen. The reason I dont think its the platen is because I constantly move my steel in a circle when Igrind it. I keep forgetting that that pretty much rules out the issue being the platen.
 
dzlvs8 said:
craftsman 1x42 with a ceramic platen. The reason I dont think its the platen is because I constantly move my steel in a circle when Igrind it.
Click to expand...

Maybe that could be the problem with the "streeks".

when you move the steel in a circular motion while grinding You may be creating deep,low grit scratches in every direction that may not show up until the higher grits when hand sanding.

I maybe be completely wrong but just something to think about.
 
What I am seeing is dips in the metal still. When I put the steel against the belt, there are areas untouched by the belt. ...or at least thats what it looks like. I grind it out on the platen with the knife vertical but doing it this way seems to take forever. As in, if I'm not using a brand new belt, it doesn't do anything but polish the blade, and after 1 minute of use, the new belt doesn't do anything but polish the steel, even though the belt is still very gritty and grinds metal very well, except for when the flat blade is in this position along the belt. There must be a more efficient way. I've had this inefficiency of grinding issue on my craftsman and on 2 x 42 kalamazoo. Both with 60 grit belts.
 
what HT method are you using? scale that thick and hard may have something to do with how much o2 is in the mix.

Edit: what is your HT procedure in general?
 
Last edited:
Use some vinegar or other weak acid to remove that outside crud. Just soak the blades over night - probably outside. I believe the streaks are caused because the belt becomes loaded with that hard outside surface on the blades.Frank
 
Another thing, be sure to knock the edges of the stock prior to grinding the flats in order not to "decapitate" the grit.
Remove the scale with the method described by Frank, othewise go with the angle grinder; don't waste belts and time with that scale.
Cheers

Stefano
 
stezann said:
Another thing, be sure to knock the edges of the stock prior to grinding the flats in order not to "decapitate" the grit.
Remove the scale with the method described by Frank, othewise go with the angle grinder; don't waste belts and time with that scale.
Cheers

Stefano
Click to expand...
Ah ok. Thanks. That makes sense. It does seem like I am just wasting belts getting the scale off.

My heat treat process does not matter because I experience the streaking problem before and after heat treating.

I will take a picture of video next time it happens. The streaks even stay showing up after hand sanding. It's as if the belt or platen is uneven but I am constantly moving the steel in circles on the platen. ???? I asked the question here in hopes that it was a common problem. Since it's not, I will forget about trying to deal with it here. Thanks.
 
Considering you mentioned scale I'm assuming this metal has been forged to semi flat? Or am I wrong and you're using bought steel and doing strictly stock removal? If it's taking that long to grind you may need to anneal the steel before you put it to the grinder.
 
Fire scale will ruin a good belt in no time flat. Mr. Niro's advice is solid, soak in vinegar overnight or ferric chloride for an hour or two, then hit it with a wire brush, the scale will come right off.
 
I have some 3m trizac, some klingspor, and some other 3m belts. Not exactly sure what the names of any of them are, but they are good. I made sure to buy belts that were more tailored to metal grinding when they were available. Most were purchased through tru grit. I will have to take some pics of the problem when I grind my next knife. It may be up to a week before I get to another blade though.
 
Are the streaks "straight" or rippled, like the random path of a bug "chewing" the surface?
 
dzlvs8 said:
So I have been having a little trouble with two things lately.

1. It almost seems impossible to get the initial scale of my 1080 off and get it flat. I am using good belts but it seems like the belts dont do anything after about 10 second of use. Once a ridiculous amount of time goes by trying to grind the flats flat, I start stepping up my grit an thats when I realize that the steel is still extremely uneven and I have so much further to go. I basically lay my flat bar stock against my belt and hold it with a magnet. That's how I grind the flats flat. Is there a more efficient way to do this or some sort of trick?!?!?!

2. When grinding the flats flat, I have been noticing streaks in the metal at higher finishes. Is this possibly the metal heating up slightly heating up (it's not a discoloration)? Is it a worn platen? I have been trying to finish grind the flats on a belt up to 600 or 800 grit. I am keeping the metal from burning during this process. What is going wrong.....I hope this problem isn't still related to problem #1. If so, then I will have to spend days at the grinder getting step one done.

Help! I'd like to hear how ohers go about accomplishing step 1 and 2 and what I may be doing wrong. Thanks.
Click to expand...

Im having exactly the same 2 issues...

1) after heat treatment, when removing scale - belts (new, 60 grit) cut for a few seconds then just start to slip on the surface of the scale.
Takes for ever to remove the scale, and..
2) when scale comes off, there are kind of irregular stains/streaks on the steel. Even with further flat grinding they seem to stay there.
I'm keep the blade cool, quenching every few seconds.
I'm using N690 / stainless.
Any more thoughts on this one?
 
"Vinegar" I keep mine in a 4 inch pvc pipe with a cap. Any type of scale whether it comes from the factory, from heat treat or any other source.
I leave blades in for 4 or 5 days; it will take it down to bare metal; then go to the belts. It will save you a fortune in belts.
 
You must log in or register to reply here.
Back
Top