littleblacksmith

Talk About Importance Of Grinds, Hardness, and Testing Of Knives And Axes

17 posts in this topic

Came across this video, He had some good points I though, Let's see though what ya'll think.

      

 

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Yeah good video was just about to watch it on youtube.

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He used a lot of words to say that a tool optimized for one task will probably not perform as well for a different task.  However, if a tool performs well in a task which is far more abusive than it was designed for and then still performs well in its intended use that is a good indication of a quality tool.

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He didn't mention one of my personal favorite issues---How easy is it to resharpen in the field?  Besides wire that a tree has grown around I have had experiences with rocks and even bullets, (soft lead--np, copper jacketed---generally np, AP rounds---big problems)

Cutting a steel rod seems to me to be going back to the old Buck Knives ads.  I was never a big fan of their hardness or their edge grinds---but different strokes for different folks.

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He says at 5:15 A subtle difference in the angle of an ax separates it from being able to cut through metal or to fell a tree. The edge is ground ever so slightly different. 

At 11:05 he says his carving ax is ground at 30 degrees, A 5 degree difference or a 2-1/2 degree difference is going to change the performance of the tool.

Please show us that a wood cutting camp ax CAN NOT cut through a car hood, a windshield, and a metal rod very well. Then regrind and show us that the very same ax CAN cut through a car hood or a windshield or a metal rod very well, with just a regrind of the edge.

Show us that very same ax that just cut through a cut through a car hood, a windshield, and a metal rod, very well, now CAN NOT cut wood, very well. Then regrind and show us that the new grind angle on the very same ax does indeed cut wood, VERY well,

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That's a very good point. Didn't think of it that way. But I think what his point was that a knife sharpened to cut steel rod won't cut a tomato the way a kitchen knife sharpened to 10 degrees will. And that that buyers of knive's and axe's should to know that.

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There are many styles of axes. The stone-age hand axe was used from 1.5 million years without a handle. Axes made of copper, bronze, iron and steel appeared as these technologies developed.

Axes designed to cut or shape wood are the felling axe, splitting axe, broad axe, adze,, hatchet, carpenter's axe, hand axe mortising axe and etc. Axes as tools are the double bit axe, firefighters axe, fire axe, pick head axe, crash axe, ice axe, climbing axe, lath hammer, mattock, pickaxe, pulanski, sister's axe, splitting maul and etc.

Tools work best when used for the specific job they were designed to do.

Knives are not screwdrivers, but have been used as a screwdriver. Knives are not can openers, but when camping in the woods, that can of beans gets opened for dinner. (grin)

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I have watched Liam Hoffman's video several times. All the words with no numbers is frustrating. A little research turned up the following.

Arden Cogar Jr. has written that the grinds don't really matter, they simply feel different in the wood and it comes down to personal preference of the competitor. That is an idea at the top of skill, sharpness, and geometry. If you do not recognize the name Arden Cogar Jr. click here.

 

*The edge angle depends what type of wood you are cutting. 20°-30° Inclusive for soft woods. 30°+ for Hard woods. There also maybe a tip bevel (primary & secondary bevels).

*Unlike with knives, axes are more reliant on the overall profile than the actual edge. You can't simply judge how well an axe is going to perform based on the final inclusive angle. A well-established and sharp edge will help prevent deflection and aid in overall use (especially for finer tasks), but it's the thicknesses at various levels behind the edge that will determine how deep the blade penetrates, how much it sticks and how well it pops chips.

 

Time to do a little downloading and some reading. Pack a lunch and a cold drink.

https://www.fs.fed.us/t-d/pubs/pdfpubs/pdf99232823/pdf99232823Pdpi300.pdf   68 pages

http://www.fao.org/docrep/016/t0129e/t0129e.pdf   148 pages

https://ia802703.us.archive.org/13/items/CAT87205504/farmbul2090rev1962.pdf   57 pages

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Glenn, those are some great docs.  Thanks for posting the links.  Lot of reading, you're right there!

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But at the same time, look at your cold cut. Is it ground the same as your hot cut? What's the difference between the two?

I think his point is that ONE AXE will do everything, but each axe is very finely detailed to do it's designed task the best it can.

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Yes, I completely agree, couldn't have said it better. Also though thickness does have a difference in the difference of a cold and hot cut, a hot cut comes down thinner, but I do see your point.

Littleblacksmith

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25 minutes ago, arkie said:

Those are some great docs. Lot of reading, you're right there!

I intentionally did not pull out specific pages of the doc. There was just too much information that is useful, well at least interesting. (grin)

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41 minutes ago, EJRailRoadTrack said:

But at the same time, look at your cold cut. Is it ground the same as your hot cut? What's the difference between the two?

I think his point is that ONE AXE will do everything, but each axe is very finely detailed to do it's designed task the best it can.

The difference is in the amount of force necessary to survive. Cold steel is a LOT harder to cut or move than hot steel so you don't need much backing the edge to cut hot steel. A cold cut actually causes a stress riser in the bar which causes it to snap when you flex it. Just like cutting glass with a scratch and a tap.

Frosty The Lucky.

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13 hours ago, Glenn said:

I intentionally did not pull out specific pages of the doc. There was just too much information that is useful, well at least interesting. (grin)

I agree, I think it's best to have the whole document...very educational.

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The geometry of my "cuts" depends on the alloy used too.  For my hot cuts I'll go much slimmer and 'sharper' if I'm making them from a high alloy steel like H-13 or S-7 as I know they have a high hot hardness and so won't get messed up when buried in hot steel.  If I was using something like 5160 I would make a heavier and blunter cut to provide more steel to pull heat away from the edge *and* if the edge does start to upset in the workpiece a channel to remove it through.

Re the Docs:  I noted that downloading all of them took about as much time as downloading 1 recent MP4 here that basically only had the information that a simple photo could have conveyed.  Fancy is not necessarily better!

Finally it's amusing to consider all the passionate discussion on axes when contrasted with the UN FAO's blacksmithing manual that discusses making a triangular axe blade of mild steel and hard facing it by 'crayoning on" cast iron and then embedding it into a branch.  People are using that type as a major tool in their lives...Boy it's good to have 1st world problems!

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Thanks for the PDF's Glen! 

Sköl

Viking

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