too pitted?

[jasperdog032469]

Ok, got a question about the steel I've been buying. Its 440c, and I buy it from a well know maker. First of all, I think I'm finally able to create a decent hollow grind, but the problem is the flats. I have a flat platen that I use on my 2x72....Hear's the problem. After I make my hollow and then try and do my flats, it seems like the steel is so pitted that by the time I get the pits out my blade is wanting to rock and make the bottom shoulder much thinner than the top shoulder. Which means the guards are going to have a gap. I just finished 20 blanks and noticed this. Wish now that I hadn't!!!! Still all usable, but going to have to spend alot more time on them.

Has anyone else ran into this, and just wondering if buying precision flattened is worth the extra money.

 

[Mark Knapp]

It sounds to me like your problem is being caused by a flat area along the spine of the blade, the solution is to concentrate pressure more to the spine area while grinding the flats. It can still be done on the blanks you have. If the problem is not too severe you can mill the slots in the guards to the width of the small end and file to fit.

 

[silver_pilate]

It's hard to get truly flat flats on a platen with a 2x72" grinder. The belt will tend to take off mor material on the top and bottom of the piece. The best solution is a disc grinder. However you can get them really close with the platen by working carefully. A good tip is to establish the flats first, and then grind your bevels. This is especially a good tip with heavily pitted steels. I ground some 1/4" CPM154 that was pitted HORRIBLY the other day. I'm talking pits as big as your fingernail that were about .02" deep in places. That was really hard to flatten up after all of the platen work. I'm really looking forward to my disc grinder getting here.

--nathan

 

[Mark Redmon]

I've had similar issues with 440c from Admiral have a lot of surface pitting from the mill. I've got in the habit of taking it to my 4x36 (I'd use a disc if I had one...) and grinding that off before I do any grinding on the blade. It's a PITA, but it's easier for me to do it before the steel has been profiled and ground. I saw Niagara has it, but it's about 15 bucks a yard more... I'd be willing to pay it if it saved me all that prep though. Does anyone use 440c from there?