Need Input on Blade grind (Flat find or Chisel grind)

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madupree

Joined
Nov 25, 2014
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Ok guys after quite a few changes on design I think I am happy with the design and I am going to proceed on getting my steel and then bringing it to the local machine shop and having it cut out with a wire edm machine. My next area I need Input on is the blade grind I'm going to put on it. Originally I was planning on putting a flat grind on both sides but after doing more research on all the different grinds I have really became interested in a (hope I say this correctly) single sided chisel grind.

I have found out that the sharpness of a chisel grind is about the best you cam get. Some have said that a problem they have is that when cutting the blade will want to not cut straight due to the chisel grind but I don't really see that as being a problem.

 
I do a lot of Chisel grinds and Full flat grinds and really recommend you do a full flat grind on that design. That style of knife really is for a full flat grind.

Chisel grinds have their place and I really like them and use them a lot but they have a time and place and that really is not on that blade you designed.
 
Do a chisel grind if you want, but AV is right....that knife screams full flat grind. Chisel grinds are a different animal and you may not like it compared to a FFG.
 
Ok now here's my next problem, I over think things to the extreme and I've starched and searched with no luck on this....... after doing the flat grind on both sides, you try to get the grind centered from side to side but I'm sure that's never dead on the money and will be slightly off, then you go and poor the initial sharpening on the edge and if the grind is off centered then that means your initial sharpening will be off as well, is this found to be a major problem? I was thinking I could user one of those powered home sharpeners that sharpens both sides at the same time and that would hey it pretty even but would like some input on this.
 
Just make sure you sharpen the same amount on both sides. You could do that if your edge wandered like Don Draper's eye. You would see a problem, however, if there were variations in the thickness of your edges along the blade.
 
madupree said:
Ok now here's my next problem, I over think things to the extreme and I've starched and searched with no luck on this....... after doing the flat grind on both sides, you try to get the grind centered from side to side but I'm sure that's never dead on the money and will be slightly off, then you go and poor the initial sharpening on the edge and if the grind is off centered then that means your initial sharpening will be off as well, is this found to be a major problem? I was thinking I could user one of those powered home sharpeners that sharpens both sides at the same time and that would hey it pretty even but would like some input on this.
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Mark a center line on the edge and stay equal distance from it on both sides.

If you are concerned....Get a BUBBLE JIG.... It will really help with starting off flat grinding.
 
I'm going to actually make a variation of the mastermind jig, I know about marking the center of the steel and staying equal distance on both sides of that line but we're talking about the difference of tens of thousands (10 hairs on one side vs 15 hairs on the other side)
 
It is normal to a bit of nervous in the begining.

But realize....we do it all the time and everyday.

Do not worry about screwing up....it is a fact that is exactly what is going to happen.

When it does happen...pick up another piece of steel and make another.

Believe it or not you are going to screw up using a jig or any other contraption...there is a learning curve not matter how you choose to do it.
 
madupree said:
I'm going to actually make a variation of the mastermind jig, I know about marking the center of the steel and staying equal distance on both sides of that line but we're talking about the difference of tens of thousands (10 hairs on one side vs 15 hairs on the other side)
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I have under 20 finished knives under my belt. Each one has been a large improvement on the previous ones. The first ones are mine and made by mine own fair hand but they look like s*** compared to my latest ones (which are not going to cause Bruce Bump to toss and turn in his sleep in envy any time soon).

I don't think you have to worry about having a difference in the thousandths. It's your first knife. It might turn out nice but it is a little like worrying about how much below a 3 minute mile you are going to run your first time training.

It might look like hell run over. It might be decent to good. You might want the shop to cut you out several because statistically the chances of you fretting over a tenth of a thousandth difference is low. The chances of you f***ing up a side and throwing it across the shop are higher. Don't get discouraged if you are not perfect out of the gate because chances are you won't be.

It sounds like you do the best you can on everything. That will help you get better faster.
 
You will be surprised how quickly you will be able to tell 1 to 2 thou. off center, especially if you mark the center of the blade.

Tim
 
Maelstrom78 said:
I have under 20 finished knives under my belt. Each one has been a large improvement on the previous ones. The first ones are mine and made by mine own fair hand but they look like s*** compared to my latest ones (which are not going to cause Bruce Bump to toss and turn in his sleep in envy any time soon).

I don't think you have to worry about having a difference in the thousandths. It's your first knife. It might turn out nice but it is a little like worrying about how much below a 3 minute mile you are going to run your first time training.

It might look like hell run over. It might be decent to good. You might want the shop to cut you out several because statistically the chances of you fretting over a tenth of a thousandth difference is low. The chances of you f***ing up a side and throwing it across the shop are higher. Don't get discouraged if you are not perfect out of the gate because chances are you won't be.

It sounds like you do the best you can on everything. That will help you get better faster.
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So are you suggesting I should get my first few blades cut out of cheapest steel than the s30v that I am wanting to use? ?
 
S30V, S35VN, 154Cm etc.....

Are all great steels.

But are you going to invest $25 for the steel then another $16 for heat treat? You looking at approx $40 before you even choose handle materials.

You might be better off choosing a more economical steel in the beginning.
 
I would use a full flat grind.

As far as your grind becoming uneven there are a couple ways to combat this. You can use a cheap Harbor Freight set of calipers to scribe the center line. Once you start grinding the bevels you won't have a flat ledge for them to index off of so make sure you scribe it good.

Another method would be to use a surface plate and a height gauge. I finally bit the bullet and just ordered a better surface plate and height gauge from Enco(they have a free shipping deal going on right now, code: dec29) a couple days ago and should get it tomorrow. You'd just lie the blade flat and scribe it with the height gauge. The nice thing about this setup is if your scribe line gets washed out during heat treat you can rescribe at any point(as long as there's still flats on the knife).

Now I wasn't having any real issues with keeping even grinds before getting the height gauge/surface plate combo, I just wanted a faster way of checking my center line. A set of calipers will take you a long way. You can use them to scribe the center line. You can also measure the height of the bevels on both sides, which will give you an idea if you're uneven. Even the Harbor Freight $15 digital ones aren't bad.
 
AVigil said:
S30V, S35VN, 154Cm etc.....

Are all great steels.

But are you going to invest $25 for the steel then another $16 for heat treat? You looking at approx $40 before you even choose handle materials.

You might be better off choosing a more economical steel in the beginning.
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Yea Texas Knife Supply has some 5/32" 440c for $13 for a 12" length, I will probably go and get a half dozen of those and bring em to the wire edm shop. Hope Santa is good to me this year....
 
for marking the center line just color the edge with a black sharpie then find a drill bit that is almost the same diameter as the steel is thick. Hold the drill bit on a flat surface and run the edge of the knife down the point of the drill bit. Flip the knife over and do the same thing on the other side. You should now have two lines scribed close to the center of your knife.

That is how I have done it for the last few years.

Good luck and be prepared to ruin a few blades.

I just got a 10" wheel and was doing some compound hollow/convex grinds last week on some 5/16" 1075. The knives where around 11 1/2" long. I ruined 2 before I got it right. The two that i ruined got turned into some kiridashis. :)
 
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