Precision ground, flat ground, what do you expect it to be?

Matt Shade

Matt Shade

Joined
Nov 24, 1999
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I'm having steel problems here.
I started out buying O1 from a local machine tool supply. It was labeled flat ground, and was exactly what I wanted. Almost perfectly straight, uniform thickness and perfectly flat.
Then I decided to try 440C and ordered hot rolled steel. Obviously, that was a bad choice since at least half the stuff I make is folders. Some of it was actually pretty good, but most of it was really wavy. I used it up making kitchen knives.
Next I tried precision ground 440C. I don't know what to think. The face of the steel isn't really flat at all. They took a peice of hot rolled steel that was supposed to be .125 and ran a surface grinder over it. Only about 90% of the face is ground, and testing it with a micrometer I'm seeing a variance of about 5 thousandths between random spots. I haven't tried working with it yet, so maybe stuff will come out alright. I was expecting a cleaner peice than this when I paid twice the cost for precision ground.:( They took off all the high spots, but the hot rolled peice I got with it is almost dead on at .13 anywhere I measure, and the ground stuff jumps all over. Is this what you usually get? I only got 2ft, and I've been really happy with this supplier for everything else. So I don't want to bad mouth them, or return the steel. I probably won't order any more steel from them if I can get better from somewhere else though.

Am I expecting too much?
 
Talk to the supplier and ask exactly what the specs are. The steel mill should have specs for straightness , flatness and thickness. Doesn't sound like it's as "precision" as it should be.
 
Matt

the O1 that I get,, I can only get precision ground and is just what you are coming up with.
I believe it's Blanchard ground it's not a great finish but it's true..
Is your 440C
bar stock or sheared plate?
the sheared plate will be wavy and can be a pain.

ask for bar stock and tell them you don't want sheared plate stock.
I grind my own from rouph now,,,this has been a plus for me...
 
Its from Texas Knifemakers Supply. Judging by the scale left, its from the same stock as their hot rolled steel. I don't know if they grind it themselves or if they get it that way from their supplier.

I guess I should go look over the site again and see if they list any specs. I'm pretty sure it was done on a regular surface grinder, and not blanchard ground. The blanchard ground steel I've used was true, but the scratches went in a circular pattern across the bar. This stuff has straight scratches along the length of the bar.
Seeing as how I don't have a mill or anything, I think I'll probably be alright with this stuff if I'm careful. Its just not as good as I was expecting.
The O1 I get locally is expensive at $12 for .125 X 1 X 18 . But it comes wrapped with heat treat specs, and is dead on. Actually has a burr clear down the edges from being ground down. Great stuff to work with.
They have a big used surface grinder I'd love to bring home, but it was listed at over $1000 last time I was there :( Also have milling machines and bandsaws and.........:rolleyes: :D
 
I have been getting my S30V precision ground by one of Crucibles outsources before it is sent to me and I am very happy with the results, dont know if they make 440C but they do make a lot of very good steels, including 154 CM.
 
Matt,
Give them a call and find out. I honestly don't know what they do but I have bought precision ground 440C from them in the past and it is exactly as you have stated. The entire surface is not ground, it is almost like the steel had some low areas in it, especially along the edge.

Since I made fixed blade knives with it I wasn't too very concerned. I was trying to just save some time and money on belts by not having to deal with any mill scale. For that purpose it worked OK.

CW
 
Yep, I think I'll try and talk to them sometime next week.


Tom,
Thanks. I'll have to take a look at crucible also. I've been thinking of buying my steel from admiral, after finding out they had a better choice of stock for me to make liners with.Do you deal directly with the outsource? Or do you work through crucible? I'm moving enough of them now that it would be good to stock up on stuff anyway.

I really need to stick with 440C as I think its the only steel I can heat treat myself with a torch. I'm starting to sell a few here and there now,but I can't really afford to add on the extra expense of sending them out at the prices I'm selling them for. I've done a little abusive testing and the 3X oil quench method gives surprisingly good results.
 
You might want to try Sheffield Knifemaker's Supply. That's where I get all my steel now. Their prices are lower than Admiral Steel and they have a better selection of precision ground stainless steels than anyone else. Never had a problem. Their PG stainless is just like PG O-1.

I asked Crucible for a 12 inch piece of Blanchard ground 440C and they quoted me a price of $300.00!! Strange. I wonder what that was all about?
 
Matt what your describing is what I have always used in PG Barstock. Have got some from TKS before. I have had no problems as you know I only do folders. I take a 4" piece thats about as long as one of my folders I profile the spring and blade from the one piece ,then I use a flat surface and wet sand the spring and blade to the correct thickness. It does not take as long as you might think. I have done it like this for years. I never really saw a need for a surface grinder. Sure it would be nice luxury for me if I had one but I dont. And yes I really think you are expecting to much from PG it still needs work. Goodluck
 
crucible sends it out and gets it back and then forwards it to me, it makes the price double, but when you are making folders out of a steel thats about impossible to flat grind, getting it that way saves a LOT of work........its hard enough just making the things!~!!
 
For O1, A2 and D2, try <www.flatground.com> This is the North American internet sales site for Bohler-Uddeholm Steel. They supply precision ground onsize and oversize bars that are perfectly flat and to stated tolerances. Their prices on these steels are 1/2 or less of Admiral Steel's. They have very prompt service and are good to deal with.
I have been using this site for a couple of years now and have never had a complaint yet.
 
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