Custom round knife specs

[Kovac]

Hi there,

I'm having a blacksmith I know make me a head knife. He said he needed some more info:

-knife edge type (full flat or chisel grind or something else?)

-blade thicknes

-on what distance from edge is it grinded

I dont know much about knives and head knives arent really a thing here I could check.

Also I gave him some general measurments 13,5 cm (5 1/4inch) from point to point and 15cm (6 inch) from crown to end handle, is that good?

 

Thanks in advance 

 

 

[chuck123wapati]

I made mine with a v grind  on about a 2.5mm saw blade , the bevel is about 5mm.  or roughly 12 to 14 degree angle. about 4" point to point

Edited March 27, 2020 by chuck123wapati

[Ferryman]

Nice job Chuck

 

I look forward to seeing your knife when it is done Kovac

 

[chuck123wapati]

  On 3/27/2020 at 4:11 PM, Ferryman said:

Nice job Chuck

 

I look forward to seeing your knife when it is done Kovac

 

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Thank you

 

[akguy59]

I made myself a head knife that works okay. I used a grind similar to Chuck's and even when it's shaving sharp it seems like it takes a lot more effort than it should. Over on bladeforums.com there is a custom knife/leatherworker that goes by the screen name Horsewright. He makes and sells head knives that get rave reviews from his customers. He uses a full flat grind that goes all the way from the edge to the junction of the handle and body. I don't know if that steep of a grind is necessary but it makes them cut like a laser with almost no effort. (According to what I've read)

'

[zuludog]

I agree with the friend that AKGUY59 mentions; I think you should have a long grind or bevel that goes from the cutting edge towards the main part of the knife in a gradual, even slope

A while ago I bought a George Barnsley head knife, which is similar to a round knife, but has only one point. To keep the costs down they only give you a basic cutting edge, you are expected to do the final sharpening and polishing yourself. I spent an afternoon with oil stones, very fine wet & dry paper, and a strop. When I finally got the cutting edge I wanted there was a smooth, even transition into the main part of the knife, with no step or shoulder to the bevel

Search YouTube for round knives and you'll see what other people are using. I think that most of them will have this smooth, gradual slope with no noticeable step. I think this is called a flat grind. 

There will be several videos about round knives, but have a look at these, which show them well -

How to polish a round knife by Leathercraft Masterclass

How to hold and use a round knife by UK Saddlery

Round knife sharpening by Leathertoolz

How to sharpen your head knife for leather work by JH Leather. At about 1 min to 1 min 10 sec there is a diagram showing the cross section of the blade and cutting edge

My Barnsley knife is about 1,5mm thick. This is a bit thin but adequate as this is a small knife. For anything larger I would go for 2,0mm thick

The size of a round knife is measured by the distance, or the span, between the points, and is typically 120 to 150mm

Then there is the depth of the blade, sometimes called the belly. Some are shallow, like a crescent, and some are deeper, more like a full semicircle . You can get an idea of the size you want from watching videos, but only you can decide on the size of your knife; why not make some mock - ups from stiff card, then you could give your preferred shape to your friend

You could also Search Google for round knives by makers like Osborne and Vergez - Blanchard, to see the sort of things they make

 

 

[Kovac]

Thank you all very much for the replies, I think he has enough info now. I'll be sure to post when its finished.

 

Cheers

[billybopp]

Here are a few pictures and some measurements that may be helpful for you.  

I have two antique knives that I use, both 100+ years old.  The larger is a Gomph, and the smaller a CS Osborne Newark.  

They are both a bit over 1.5mm near the ferrule, and a little under 1mm at around 10mm from the cutting edge.

They both have their advantages.  The Gomph works a little better for long straight-ish cuts, and the Osborne works a little better doing curves using the tip of the blade.    

As for sharpening, a V grind or Convex is going to be the way to go.  V grind will probably be easier for you to maintain using stones.  A convex edge is fine, but a slack belt sander would make re-doing your edge easier if that ever needs to be done.

I use an angle of about 15 to 17 degrees on each side, yielding an angle of 30 to 35 degrees for the overall edge.

 

Edited March 30, 2020 by billybopp

[billybopp]

[Clintonville Leather]

  On 3/27/2020 at 3:45 PM, chuck123wapati said:

I made mine with a v grind  on about a 2.5mm saw blade , the bevel is about 5mm.  or roughly 12 to 14 degree angle. about 4" point to point

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I just ordered a piece of steel to make a skiving knife.  About what angle did you make yours?  At first I thought 45 was good but the more I see the more it looks like a little more is common.