Rmd, factory bevel angle?

[worldwood]

The title pretty much says it all, id like to know what degree angle the RMD is sharpened to at the factory, thanks for any help you can give.

 

[worldwood]

Anyone?

 

[elof_alv]

Not sure on the angle, they are slight convex.

 

[worldwood]

Ok thanks, maybe 40 inclusive will work just fine. I remember reading somewhere that someone checked it straight from the swamp and it was 45.

Ill be sharpening with a KME, when it arrives, so i can just check where its at then, thanks

 

[chiral.grolim]

Ok thanks, maybe 40 inclusive will work just fine. I remember reading somewhere that someone checked it straight from the swamp and it was 45.

Ill be sharpening with a KME, when it arrives, so i can just check where its at then, thanks

How do you intend to check the angle using your guide system?

I am not saying that it is incorrect, but checking to see if you understand the limitations of the guide system and are aware of methods for achieving the angle you desire. For example, the angle setting is only accurate for a specific distance from the vertical arm supporting the guide-rod. The actual sharpening angle will change depending on how wide the blade is, and it will even change on the same blade as you guide the hone from heel to tip. Just a few things to be aware of.

Also be aware that Bussekin blades may not be sharpened at a single angle along the entire length of the edge. I resharpened my RMD to ~15 dps in the main portion of the blade (heel/choil to sweep) from what seemed closer to 25-dps, but the sweep and tip were MUCH more obtuse so I simply took down the shoulders and gave it a convex there.

 

[worldwood]

Im not sure i understand you really but you can just take a sharpie and color the edge then take the stones and see if your taking the sharpie color off the edge, if not adjust until your on the correct angle.

The angle change from tip to choil is very minimal on a good system, there is no play in the rod of a kme unlike the lankys or similar. if the blade is over 6" i would reccommend placing the knife in the clamp closer to the tip to work that area. just sharpen as usual then move the knife in the clamp closer to the tip to work that area and help keep the same angle. still these differences are really small compared to the differences when you free-hand

Also whats "dps"

i see no reason a bussekin blade could not get the same angle from tip to choil.

I see no reason i would treat a bussekin different than any other knife i would sharpen.

if you have some factual info i would love to know why different parts of a bussekin blade would need to be sharpened at different angles.

 

[elof_alv]

I believe 'dps' is for degrees per side.

On many models the section of blade behind the tip is thicker than on other makers knives. It's almost like a flat piece of steel was ground and then the sweep is done afterwards without much material being removed from the primary grind below the tip. There were some pictures of knives sharpened on guided systems with microbevel being 2-3 mm on the straight part of blade and a lot wider on the sweep and close tot the tip.

 

[worldwood]

oh ok i get it thanks.

Sorry chiral i was having a brain fart but i get what your saying now.

 

[chiral.grolim]

EDIT: I just realized that my post was far behind worldwood's own response, so he probably is already aware of all of it or has his own ideas, but rather than delete what I took the time to type, I'll just leave it "as is" below.



Hopefully elof_alv helped clarify, I'll see if I can obfuscate further

I am glad that you are aware of the "edge-paint" method of checking your angle. I personally recommend a bright color (e.g. red). However, I rarely sharpen to match a factory-established angle as those are often overly obtuse for my uses. Instead of trying to take paint (or Sharpie) off the edge, I deliberately aim behind the edge. "Correct angle" is a matter of user preference. And yes, "dps" = degrees per side.

The angle change from heel to tip can be VERY dramatic regardless of how much you spent on your system It is nice that the KME eliminates 'play' (though I haven't found that to be an issue anyway), but it still suffers that same angle-change issue as cheaper guide-rod + clamp systems. As soon as that hone leaves position "zero", a new angle is being ground, and the angle-indicators are relative. The KME website even states: "Note: The angle scales on all clamp type systems are relative. The distance a blade extends out in front of the clamp also influences the angle." In fact, that distance, which changes as the hone reaches beyond position "zero", fundamentally determines the apex angle. If you are measuring apex angle with a clamp + rod system, be aware that the measurement only applies to position "zero" and the scale (if one is given) only applies to a specific blade-width.

The Edge Pro system eliminates the position "zero" problem by eliminating the clamp and advising users to keep the hone on the same path and to move the blade instead
so the hone never leaves position "zero". In my own use, and contrary to what you suggest, I have found it easier to maintain a consistent angle along the entire edge free-hand which also eliminates the fuss of un-clamping and re-clamping your knife. The Edge Pro accomplishes this as well. The differences are MORE dramatic with a clamp system.

Now, many production blades, Bussekin included, leave more metal in the sweep and tip for increased durability. I mention this as a warning to you that establishing the same bevel angle along the entire edge may result in different bevel heights (and more work on certain sections of the blade). I am NOT saying that you cannot do it, I am saying that the factory bevel angle may not be the same along the entire edge. Just be aware of this. And the aforementioned increase in durability is a reason to keep the blade thicker in certain areas. Such varied grinds are not uncommon on outdoor cutting tools.

All of the above information is "factual", but you do not have to take my word for it :thumbup: Here is one demonstration from this very subforum: http://www.bladeforums.com/forums/s...amp-Scrap-Yard-Knives?p=11447994#post11447994

 

[worldwood]

Thank you very much chiral, very informative and makes sense. And I take your word for it

The edge pro is a little more costly than what id like to spend on a system and i have not perfected my free-hand thats why i say the differences are small compared to what i personally do free-hand. Do you think i should not use the kme? for someone without much experience do you think its still not beneficial to use a system like the kme? i understand now the exact angle of the edge wont be perfect but do you feel it will vary that much to make a difference? thanks very much for your help, its very informative.

 

[chiral.grolim]

The edge pro is a little more costly than what id like to spend on a system and i have not perfected my free-hand thats why i say the differences are small compared to what i personally do free-hand. Do you think i should not use the kme? for someone without much experience do you think its still not beneficial to use a system like the kme? i understand now the exact angle of the edge wont be perfect but do you feel it will vary that much to make a difference? thanks very much for your help, its very informative.

Yeah, I didn't want to put that kind of money down on a sharpening system either. And no, I don't think that it is necessary for the average user to maintain that level of perfect angle consistency along the entire edge. On smaller knives, the variation due to the clamp position is (as you mentioned) quite small, and you already have the right idea - clamp near the sweep so that the angle is fairly consistent up to the tip, then either reset the clamp for sharpening the belly or simply accept a thinner angle there. You already know the "edge-paint" sharpie method, so you'll be able to measure your progress. The difference will certainly be more noticeable on larger knives, the RMD included. But if the difference is a varied-angle on a well-formed edge verses a consistent but poorly sharpened free-hand bevel, I'd take the clamp system every time.

I personally own and regularly use a DMT Aligner system for sharpening blades <4", a cheaper set-up than the KME, and it works well. The KME is a step up from that. And using the guide-rod system will help you get a feel for the angle you want your hone to be at. When you garner the confidence, just slide the rod & hone out of the guide and try to hold them at the same angle by hand. Then sharpen the areas of the blade outside the clamp positions realm of consistency. With practice (and liberal use of the sharpie) you'll master free-hand sharpening of larger blades in no time. Meanwhile, the clamp system will make touch-ups and resharpening smaller blades a "piece-of-cake", which is, afterall, their intended function.

In summary, YES, imho the KME is a worthwhile investment :thumbup:, probably moreso than the EdgePro unless you're obsessive about perfect edges But again, all of the above is just my opinion.

 

[worldwood]

Great! thanks for the info. once i get the muscle memory down a little and the feel for the correct angle ill definitely try and do it freehand. Thanks again for the excellent posts.

 

[Skrapmetal]

I have an edge pro that collects dust on a shelf. I have always been a freehand sharpener, but I bought one to try it out. It is fun being able to dial exact angles and get a consistent mirror polish (the edge pro I bought came with extra fine stones that were added by the retailer I purchased it from... but I don't remember who that was).

Maybe I should sell it off some day, for some reason I keep it around.