Competition style/dimension chopper

N

Natlek

Joined
Jun 9, 2015
Messages
6,182
I found rules for competition chopper .What was not limited is thickness . I make one following that dimension with spine thickness of 7mm .Full flat grind and /for now /about 0.4mm BTE .Balance point is where that vertical line is .Total weight is 565 grams .Hard steel is only one edge , rest is mild steel or some soft low alloy steel ...don t know for shure .
I think that I will make several more and make some competition with friends in manner how was that done in USA ...only fun i can so far found with knife .I make mistake and I drill that lynard hole on blade not used handle pin ,but on others i will do it right way .I used it little and that is one hell of a tool , like it .
I have some question if you don t mind .What is best total weight of chooper ?Weight have impact on cutting I know but how much is enough ? Too heavy is not good ? Where is best balance point to be ? IS there limitation on type of grind ? I mean , can I combine flat with hollow or flat with convex ? And last question................what kind of wood is used on competition for chopping test ?
gXV4vBl.jpg

luPBQ29.jpg

PS . how i can change mistake in tittle of thread ...stile with style ???
 
Last edited:
Pine is usually used in chopping competitions, standard 2x4 (which is actually 1 3/4"x3 3/4" [yeah it's stupid we know]).

As far as balance, this is a chopping competition, so I imagine you'd want the balance as far forward as you could get it.
 
A.McPherson said:
Pine is usually used in chopping competitions, standard 2x4 (which is actually 1 3/4"x3 3/4" [yeah it's stupid we know]).
Click to expand...
Interesting how a 2X4 got to be less than 2"X4". Best I can remember when I was a teenager (60 yrs ago?) the measurement 2X4 referred to the size of a rough 2X4 (before planning smooth). After planning smooth it would measure almost 1-7/8"X 3-7/8". Over time in an effort to save even more wood (money) the 2X4 dimension came to include the width of saw blade to make a 2X4, so a rough cut 2X4 would only measure around 1-7/8"X 3-7/8", and dressed down to 1-3/4"X3-7/8".
 
Natlek said:
PS . how i can change mistake in tittle of thread ...stile with style ???
Click to expand...

At the top of the thread, above your first post, there should be a "Thread Tools", and if you put the cursor on the down arrow, you should see an "Edit Title" option.
 
A.McPherson said:
Pine is usually used in chopping competitions, standard 2x4 (which is actually 1 3/4"x3 3/4" [yeah it's stupid we know]).

As far as balance, this is a chopping competition, so I imagine you'd want the balance as far forward as you could get it.
Click to expand...

Dimensional 2x4 is 1½ x 3½ inches.
 
A.McPherson said:
Pine is usually used in chopping competitions, standard 2x4 (which is actually 1 3/4"x3 3/4" [yeah it's stupid we know]).

As far as balance, this is a chopping competition, so I imagine you'd want the balance as far forward as you could get it.
Click to expand...
Pine is good news to me , we have it here .....about 2 x 4= 9 which is acctually 10 :) you should really adopt metric system , it is so easy that even kids understand it .Sorry , I couldn't help myself :)
Balance as forward as i can get it , sounds resonable . Thanks :thumbsup:
 
2X4 is the nominal dimensions.
When I was young, you could by (saw)mill cut 2x4's that were 2X4 ... or S4F (surfaces four sides), which had been milled to 3.75X1.75 (more or less). Now, all lumber is F4S
My old house has heart pine 2"X4" boards in all the walls.
 
This will be one weird chopper . Full flat V grind and with only one plunge with 5 centimeters radius , so I don t need to worry about symmetry :) Hard steel is only about 2 centimeters up from the edge , rest is mild steel . I distal taper grind blade , now it is 4mm on tip and 6.5 mm on Ricasso. I'm afraid to take away more steel from tip, say to make it 3mm thick on tip? It will be full flat grind blade ?
Are mild steel enough tough to handle that thickness or I will need to carry a hammer with me to straighten the blade after every use ?
What do you think ?
I distal taper tang also , from one side 🤣 I assume that I will need to make asymmetrical handles, since the other side is flat from tip to the end of handle .

DCIShSK.jpg

ctwXyzy.jpg

470DbMY.jpg

kzcK5qW.jpg

cAXaRs6.jpg


It was little bend from surface grinding , grinding from 11mm to 6.5mm fast have price if you not cool blade

1I5gJSy.jpg
 
Can't compound grind as the surface has to be uniform. Pick a flat or hollow grind and stick to it. Balance and weight is personal as it's a swinging competition. Too heavy and you loose seconds. How hard you swing is also personal. Is it too soft to manage it's up to your technique. If cuts are straight, no problem. Make a few with different balances and weights, train a couple of weeks with all of them and decide. BTE thin as you can manage without breaking it. Sharpening bellow 15dps if your cuts are straight. It is allowed to sharpen differently along the edge so you can lower the angle next to handle to achieve faster and easier precision cuts and make higher angle for chopping. Designs mostly fail in the handle. Get that right, rest is easier. One has to swing it hard without loosing grip.
 
I think the tapered tang is a mistake. Not just here but on many of the knives that get it.

A tip heavy chopper will chop better. An axe chops better than a machete.

But tapering the tang doesn't make it more tip heavy. It just feels that way. The tip weighs the same.

Here's a thought experiment:
The center of percussion on a comp chopper is usually a little ahead of the center of the blade. If you hit at the CP there is no rotational impulse on the blade. If you hit ahead of it, the handle of the blade will rotate down into your fingers and you're essentially arresting some of the swing by pulling the blade back in the opposite direction of the swing. This is why nobody chops towards the tip in power cuts like the 2X4 or the dowel etc. Instead the sweet spot for power cuts is actually behind the CP, because this pushes the handle up into your hand which puts some of the weight of your arms into the cut as well, adding power to the cut.

Many knives benefit from weight on their ends. This doesn't give the light and lively feel that people at knife shows appreciate when they pick something up off your table and start waving it around in the air, but in use many knives benefits from an increase in moment of inertia. Comp choppers in particular because the weight on the ends resist the conversion of that momentum of a powerful swing into rotation during impact. That split second impulse during impact that actually cuts the wood. And, the more neutral balance probably helps with the finesse cuts too.

I don't understand the fascination we all seem to have with tapered tangs and I see them misapplied all the time. Here in particular. IMO.
 
I agree with Nathan. Competition choppers are all about physics, not looks. The toughest grippy material available makes the best handle. The steel with a combination of the hardest/toughest/sharpest edge is the best steel. Shapes, curves, etc. have no use unless they enhance the physics.

A slight exaggeration would be to say that the perfect competition chopper would be a perfectly sharpened bar of heavy steel.

Since there at]re no weight or thickness limits, if you could get a superb edge on it, 1/2" thick depleted uranium would probably be a great choice ... if you could swing it.
 
I had a bunch of nearly 1/2" plate of V4E imported from Europe but ended up decking it down to 5/16.

That particular steel with my particular heat treat worked best in the competitions with a grind angle that was incompatible with a thicker spine. I would have liked a little more weight but the geometry trade off wasn't worth it.

YMMV


Our handles are pretty wild. So is the handle on an epee and for a similar reason.

It is vitally important that the clocking of the blade not shift in the hand and the competitor does not have time to stop and look to make realignments. Otherwise you get what we call "snake slapping" which is where you're making hits with the side of the blade. The edge has to stay in perfect alignment or the primary grinds will bend, dictating thicker geometry. Thin wins. Which gets you some pretty extreme handle geometry.
 
Nathan the Machinist said:
I think the tapered tang is a mistake. Not just here but on many of the knives that get it.

A tip heavy chopper will chop better. An axe chops better than a machete.

But tapering the tang doesn't make it more tip heavy. It just feels that way. The tip weighs the same.

Here's a thought experiment:
The center of percussion on a comp chopper is usually a little ahead of the center of the blade. If you hit at the CP there is no rotational impulse on the blade. If you hit ahead of it, the handle of the blade will rotate down into your fingers and you're essentially arresting some of the swing by pulling the blade back in the opposite direction of the swing. This is why nobody chops towards the tip in power cuts like the 2X4 or the dowel etc. Instead the sweet spot for power cuts is actually behind the CP, because this pushes the handle up into your hand which puts some of the weight of your arms into the cut as well, adding power to the cut.

Many knives benefit from weight on their ends. This doesn't give the light and lively feel that people at knife shows appreciate when they pick something up off your table and start waving it around in the air, but in use many knives benefits from an increase in moment of inertia. Comp choppers in particular because the weight on the ends resist the conversion of that momentum of a powerful swing into rotation during impact. That split second impulse during impact that actually cuts the wood. And, the more neutral balance probably helps with the finesse cuts too.

I don't understand the fascination we all seem to have with tapered tangs and I see them misapplied all the time. Here in particular. IMO.
Click to expand...
Lot of useful data here , thanks for that :thumbsup:
About what i was doing here ..... I am limited by the shape of the steel I use .So I must grind tang like this one or like first one to get flat surface from both side for scale .
Overall weight also matter , right ? So what if I keep tapered tang and grind distal taper blade but backwards ? Thick on tip and taper towards Ricasso ? That way I will have tip heavy chopper but it won't weigh tons overall ? A lot of weight is in tang from 6-7 mm thick steel ?
Well , I have lot of this Guillotine knives for paper so I can make and try all the shape ....
I end up with 420 grams and 6 , something mm. on ricasso .

mPi8rp2.jpg


BTW , hard steel on edge is about 63 Hrc HSS
 
You must log in or register to reply here.
Back
Top