Trying to learn and steel need some help: Blade Angle Geometry

freehouse32

freehouse32

Joined
Sep 7, 2016
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423
I hope you laugh when you see what I did there.

I have completely caught the Busse fever and its about time to get a WE and start sharpening soon. I still have some partially unanswered questions. I have done lots and lots of looking around, and just need some more recent updated opinions and any scientific results anyone has.

I would like to know what the lowest blade angle that can be used before damage is most likely to occur to any of the Busse steels or any of the other steels I mention if you care to help. I know it helps to understand where I am coming from so I will explain the best I can.

For INFI, SR101 on a Medium to large or even larger blade knife, at what degree per side (DPS) or inclusive angle would/ should be the lowest degree sharpened to: to reasonably chop wood and not experience "out of the ordinary damage, from out of the ordinary use in this manner?" What would be that same angle for everything EXCEPT hard wood?

For elmax on blades 4 inches or less, what DPS or inclusive angle would/should be the lowest for a slicer, where green vegetation or skinnng game, would be the hardest reasonable use for this steel/knife?

Same question for medium and up knives in top of the line 1095.

For premium steel folders: My goal would be normal EDC where I do not use and abuse and really appreciate slicers but there is the occasional harder thing to cut, like cardboard or something else unpredictable in EDC that can potentially harm the blade.

So what would your blade angles be in that scenario for: aus8, 154 cm, VG-10, s30v, s90v, s110v?

I understand there is a bit of a sliding scale here. I know there are always exceptions to the rule but I am looking for the typical threshold that grants the best edge a knife can have without compromising its integrity. I have a pretty good understanding but there doesnt seem to be much recent information on all of these steels with difinitive answers as can be, for such a subjective topic. I also understand that mico-beveling can and will strengthen the edge geometry for a stronger edge. At the moment I prefer not to micro bevel unless I need to. I feel like if I know the lowest DPS or inclusive angle that will sustain normal use, then there is no need to micro bevel unless the blade is thick and needs relief for better all around use.

Thank you in advace.
 
I've been safe with duplicating the factory bevels on most models which are ground pretty thick.

Pretty sure Bussekin are hand ground and basically "eyeballed" by very skilled craftsmen / artists...

90 % of the time I get by with stropping the edge with a leather belt, white compound on my 1 x 30 belt sander <light touch so as not to roll up on the apex>...

But I also have a Spyderco Sharpmaker and I'm able to hit the apex on the 40 deg, 20 dps on all my Busses except for my TGLB, so I compensate by canting the blade in a bit.

I like 15 dps shoulders and touch up with 20 dps...microbevel eyeballed by hand around 40 dps give or take <optional>...

I've never damaged an edge in INFI with those angles and I have no worries "twisting" my blade out of seasoned pine and all manner of deadfall.

I have taken a SYKCO 411 down to about 10 - 12 dps <eyeballed on Sharpmaker> and it slices like a laser. It's my go to box break down knife...sr101 good stuff, I love it too! :)

Hope this helps a little bit. I'm not too OCD about dps precision-- not that there's anything wrong with being OCD about sharpening. ;)
 
For my folders I usually run 20 dps or less. I have been using vg10 at 15 for about a decade with no problems.

For a 4 inch fixed blade I would run it 20-15 as well. The rougher stuff I planned on doing the more obtuse the edge. I give thinner knives more acute edges since they won't see any rough use. I just got a ratmandu, and for edc and woods use I am going to sharpen it at 17.5 dps.

For larger blades it also depends. A fighter might get an acute edge and a demolition knife would get a more obtuse. I have a rodent 9 that I run at 22.5 dps. I chose that angle because it seemed like a good balance for a one tool knife which is how I use my rodent 9. I have not had any problems chopping, carving, gardening or batoning with it. I would not go steeper than 25 dps on any knife. Hatchets too from my meager experience.

All my edges are now convex because I use a work sharp (ken onion edition.) But I ran my edges like that prior as well when using a whet stone and then a sharp maker. Of course those were eyeballed.
 
As a general rule of thumb, 30-40 degrees inclusive works pretty well. On the more acute side for slicers/thinner blades, and more obtuse for the larger choppers. A good, well-applied 40-degree edge will still cut very nicely.
 
tinfoil hat timmy said:
http://www.bladeforums.com/forums/showthread.php/215025-Pushing-INFI-to-its-limits-and-beyond

If you don't want to read it, 8.5dps with an 11 DPs microbevel. Keep in mind that this was done using an infi blade that from my understanding was hardened to 61+62 RC(?)

Anyhow, the stuff coming out of the shop today is 59-60 RC meaning that it's tougher than the blade used in the linked thread.
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Tougher, but not as hard either. Meaning it will not support really thin edges nearly as well. That rippling mentioned in your linked thread; the current INFI will do that easier at the same edge angle and thickness. Stated slightly differently, the current INFI cannot be ground as thin as the older, harder INFI and perform as well without plastic deformation.
 
I like 15 dps for my knives. It is a great all around edge. If you plan on cutting nails with it, then maybe 18-20 dps.
 
PeteyTwoPointOne said:
I've been safe with duplicating the factory bevels on most models which are ground pretty thick.

Pretty sure Bussekin are hand ground and basically "eyeballed" by very skilled craftsmen / artists...

90 % of the time I get by with stropping the edge with a leather belt, white compound on my 1 x 30 belt sander <light touch so as not to roll up on the apex>...

But I also have a Spyderco Sharpmaker and I'm able to hit the apex on the 40 deg, 20 dps on all my Busses except for my TGLB, so I compensate by canting the blade in a bit.

I like 15 dps shoulders and touch up with 20 dps...microbevel eyeballed by hand around 40 dps give or take <optional>...

I've never damaged an edge in INFI with those angles and I have no worries "twisting" my blade out of seasoned pine and all manner of deadfall.

I have taken a SYKCO 411 down to about 10 - 12 dps <eyeballed on Sharpmaker> and it slices like a laser. It's my go to box break down knife...sr101 good stuff, I love it too! :)

Hope this helps a little bit. I'm not too OCD about dps precision-- not that there's anything wrong with being OCD about sharpening. ;)
Click to expand...

Nicely done....
Very good advice imo.
 
Really great info that was some great knowledge learned from cliff!

Does anyone have that kind of knowledge for SR101 or elmax? or any of the other steels I mentioned?

Thanks to everyone who has responded.
 
I like what I am seeing so far, I have been doing 18 for my higher end folders and 20 for the fixed blades on a KME. I think its time to take advantage of the super steels and lower the DPS.

Not to compare my edges with others but I'll try feather sticks and baton and chop and my results are adequate at best with what felt like more energy exertion than others. Then I question my technique and knives of choice then do some more research. I am at the point where I think the lower angle will noticeably increase the knife's effienciey. I just need to find that most efficient point where I don't have to worry about compromising the steel.
 
freehouse32 said:
I like what I am seeing so far, I have been doing 18 for my higher end folders and 20 for the fixed blades on a KME. I think its time to take advantage of the super steels and lower the DPS.

Not to compare my edges with others but I'll try feather sticks and baton and chop and my results are adequate at best with what felt like more energy exertion than others. Then I question my technique and knives of choice then do some more research. I am at the point where I think the lower angle will noticeably increase the knife's effienciey. I just need to find that most efficient point where I don't have to worry about compromising the steel.
Click to expand...

This is key! :thumbup: You probably wouldn't like the results of using a 20 degree inclusive edge on CPM S110V at a Rockwell C of 64 at 0.010" behind the edge for chopping hardwood. Just like you wouldn't want to shave everyday with a 40 degree inclusive edge on INFI at a Rockwell C of 59 at 0.060" behind the edge.

Both will work to a certain point, however there is risk of damage on the one end (chopping with a thin, brittle steel), and poor cutting performance for the task at hand on the other (shaving with such a large, more obtuse edge), so there are certainly better options. As the saying goes; The right tool for the job! ;)
 
Use as low of an angle as possible, meaning the most acute/thin edge that will take only slight damage during the hardest use the knife will see. Only you can figure out what that is being that all of us are different in our body proportions, cutting techniques & materials. Keep lowering the angle until it gets to where you are seeing too much damage, then take it just a hair more obtuse/thick to stabilize the apex.
 
Yes, I concur. I am hoping someone has some additional information that can help save me some trial and error time. I just left active duty and I am back in school and I am spending all my time in the books and have limited time to experiment. About the only way, I can justify sharpening is watching CFB and sharpening on my free day :)

I am really interested in the lowest angle of the Busse Elmax, there is hardly any information out there on its capabilities. I found a good bid on the others steels I listed outside of Busse, I just didn't know if any new information surfaced.
 
freehouse32 said:
I am really interested in the lowest angle of the Busse Elmax, there is hardly any information out there on its capabilities. I found a good bid on the others steels I listed outside of Busse, I just didn't know if any new information surfaced.
Click to expand...

I would say do not start any higher than 12 degrees per side on that knife, this would likely gear it towards harder use (NOT abuse). If you wanted it geared more towards light cutting, 8 degrees per side might be a better starting point. Be aware that if you go below 10 degrees per side, you will want to either regrind the primary or put a transition bevel between primary and edge bevel to bring the edge thickness down significantly so as to guarantee that the edge bevel will be the failure point… rather than blowing out the primary grind which is much more difficult to fix as it usually ripples or chips the steel out in a dramatic way.
 
I pretty much always knock the shoulders down and eyeball it. Nothing I have ever done to a knife ever came close to blowing out a primary grind, so I'm a little confused by that. Do you mean to thin the edge so it fails sooner? Regrinding is going to dramatically increase the likelihood of catastrophic failure, even if that only means going from 1:1000000 to 1:1000.

I would love to see some more 62rc. Especially if it was a Choilless MSe variant, full flat with a lean edge.
 
darkaether said:
I pretty much always knock the shoulders down and eyeball it. Nothing I have ever done to a knife ever came close to blowing out a primary grind, so I'm a little confused by that. Do you mean to thin the edge so it fails sooner? Regrinding is going to dramatically increase the likelihood of catastrophic failure, even if that only means going from 1:1000000 to 1:1000.
Click to expand...

It is more of a problem with larger knives on wood when the edge contacts a knot, but theoretically it could happen to any knife under the similar loads/torque being applied though it would be much more rare.

[video=youtube;vDnX9bY6CIw]https://www.youtube.com/watch?v=vDnX9bY6CIw[/video]
 
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