more cutting questions

[AUBE]

i was playing around earlier cutting through water filled 2litre bottles and popcans and having great fun whilst doing so i was wondering how many cans/bottles are normally cut through in one slice? i know many makers cut through water bottles...well i dont drink bottled water and cringe at the thought of paying for it just to slice through them....how does water bottle slicing compare to 2litres and popcans? say if a maker is slicing through 5 water bottles how many popcans and 2litres would they be able to slice? also when slicing through water filled cans i noticed the can dents in at the point of impact about 1/32"-1/16" before doing a clean slice all the way through...is this normal or are most makers getting a smaller dent /no dent before the cut starts?

thanks for any info

-jason

[Ed Caffrey]

Jason,

I've looked at your post several times before I finally started writting out this reply. Your questions are very difficult ones to answer. There are so many variables, that to give an direct, honest answer is impossilbe. I personally have never seen a pop can that didn't have those little dents you described when it's cut. I don't remember ever having cut 2 litre bottles, just the smaller ones. I have cut as many as 8 of the smaller water bottles lined up in a straight row. And as many as 4 water filled pop cans at once. As I mentioned earlier, the variables are vast. All the normal things are of course required concerning the blade your cutting with....sharpness, geometry, etc......but there is also the abstract things like the method of how the knife is swung, the entry angle, and even a good bit of luck involved. If your looking to prove how good your blades cut, then I would suggest devising some tests that are very repeatable. Develop a baseline with a specific type/style of blade, and then use that to judge other blades of the same type. The tests that you described, and are accomplished at cutting competitions are designed to see if the the knife/maker can be stopped. They actually don't have a lot of bearing on how a knife will perform in day to day tasks that a customer might actually put the blade through.

In my opinion, the only things that cutting competitions prove is that the particualr knife being used just happened to be the one that was designed/built to get through the random tests set before it at that particular competition......and that the indivudal using that knife was "on his/her game" on that particualr day. Think of Cutting Competitions as being a fun thing, and not something to prove or disprove your worthyness as a bladesmith. Of course, use it as a learning experience, but don't ever take it too seriously.

[AUBE]

thanks ed,

i understand what you mean about not taking it seriously. mainly i am doing it for fun. this time i had a knife i messed up (cosmetically) that will either end up as a camp knife for me or tested to destruction. i had a few bags full of popcans and a knife sitting there and thought i would have some fun. im definitely not going to design knives with popcan cutting in mind lol. i was going to compare my results with other makers just for the heck of it. im a rather shy/quiet person that doesnt like attention focused on me so i dont see myself entering a cutting competition anytime soon. this way i can kind of compete against others but in my own backyard. not for bragging rights or serious testing purposes but just for fun.
this knife was made to be fast in the hand but still do light chopping good. i could tell before it was even done that it needs to be a bit beefier to fit the niche i had in mind for it...the weight/geometry isnt right for the chopping i had in mind. so even though it will probably out cut popcans better than the beefier version, the new version will be better suited to what i had in mind...making the popcan test pretty irrevelant..but still fun i also "test" my knives by throwing them...not very scientific but fun.

[Ed Caffrey]

That's the spirit! Testing on your own, you tend to give the knife a more valuable and fair evaluation.

I wasn't exactly sure the direction you were going with the post, so I just picked one and ran with it. Now I understand more so, what your doing. The knife that I cut all of those water bottles with did so because it was a very light, thin design, and was suited more to slicing than anything else. It chopped well, but not as good as some heavier blades.

I'm a very big fan of the brass rod test, and tend to do it on just about every blade that goes out of the shop. It seems to be the most reliable method of testing for a blade that will be used. I've learned over the years that any blade that passes the brass rod test will work very well in actual using situations.
As I said before, develop your own tests, and use the best of the lot to judge your knives by. I think what you'll find is that one blade will stand out amoung the others, then when you reach the next rung on the ladder as a maker, you'll have a blade that will beat the "old champ", and establish a new standard. At least that's how it's happened for me over the years.

[AUBE]

played around putting more pop cans to their untimely demise earlier and took a couple pics/videos....going to try and post a couple. this is my first time ever posting an image on a forum so not sure if it will work





wow it actually worked (well i can see it at least...) first try...i thought for sure it would be a struggle

the knife is 12 1/2" long, flat ground out of 3/16" stock 1 1/2" wide. balance point under/just in front of my first finger. no idea on the weight. i was happy with how well it did on popcans but it would get its butt kicked in heavy chopping tasks.

[AUBE]

i got a chance to hack at some 4x4 hardwood with the same knife today. took me forever. so the popcan test proved 3 things

1 i put on pirate-like expressions while concentrating on cutting
2 my swinging arm looks like its made out of rubber during certain portions of the swing
3 i can cut popcans ok.

none of which helps me much. it did let me know that i assumed right about needing to work on the weight/geometry of the knife for the goals i had in mind...and as i said im having great fun

[simmonsk]

That is one of the best cutting action shots I have seen. Looks like a sticky thread all on its own. Best "testing" shots. Thanks, Ken

[AUBE]

ken,
thanks! i was happy with the cuts i did but would be much happier if the knife was well rounded and also chopped like i wanted it to. gives me something to strive for with the newer versions.

ed,
i like the brass rod test too. i started using that awhile ago after reading about it on here..i think either you or terry were talking about it and i picked it up from there. i need to make some more standard tests like you suggested. right now i brass rod, whittle/cut kiln dried hardwood (most my knives are small..in the 3ish" range so i didnt have chopping tests). most of the time ive been making i just made whatever appealed to me at that moment. now i want some standard models and larger knives. i plan on coming up with some more tests and carry the designs that do well in the testing for awhile to see how they do in "real life" before deciding upon it as a standard model. im going to keep doing the popcan and knife throwing "tests" here and there just because they are fun

thanks guys,
-jason