Worksharp Blade Grinder Angle Set seems off

[c7m2p3]

I have been using the blade grinder attachment on the Ken Onion worksharp and after using it for some time I have noticed that the angle setting on the side seems like it is steeper than the angle would indicate. For instance...I have set the angle with diamond KME stones on several blades at around 15-17 degrees. I typically use the blade grinder attachment to maintain the blade with either a leather strop belt or the white ceramic belt. I have found that often the belt is not making contact with the edge.

Has anyone else experienced this or has some tips on how to get a more representative angle set on the BGA.

 

[CasePeanut]

There is a lengthy thread on this topic including some detailed calculations. Use the search feature and you’ll find it.

 

[bucketstove]

Hi,
edge thickness plays a part

Chart explanation bladeforums.com/threads/offset-between-wsko-apex-angle-and-bga-setting-is-now-understood.1597112/
some skepticisim bladeforums.com/threads/wsko-blade-grinding-angles.1596681/
research bladeforums.com/threads/calibration-results-from-my-wsko-bga-actual-apex-angle-vs-tool-setting.1528884/

 

[c7m2p3]

Hi,
edge thickness plays a part

Chart explanation bladeforums.com/threads/offset-between-wsko-apex-angle-and-bga-setting-is-now-understood.1597112/
some skepticisim bladeforums.com/threads/wsko-blade-grinding-angles.1596681/
research bladeforums.com/threads/calibration-results-from-my-wsko-bga-actual-apex-angle-vs-tool-setting.1528884/

All good stuff. I dont have the technical skills nor the equipment to do the work in some of those threads though one of the people posting seems to have the opposite of what I am running into where his fixed angle system, I believe they said it was a Wicked Edge while mine is a KME, was producing angles nearly identical to the BGA. Maybe I will do a layman experiment of my own and set angles on a thin Opinel and then set angles on a thick RAT 5 and see if it truly is blade stock that is accounting for this huge difference.

If so that would be rather disappointing. I am sure I can find workarounds for this but one of the huge advantages of a powered system like the BGA was being able to get work done on rather large fixed blade knives that are either extremely difficult, ridiculously time consuming, or impossible to use in the clamp of my KME. If those are the exact types of blades that are going to be affected with this kind of offset than the BGA turns mostly into a quick powered strop for me. Thanks for the links and information

 

[scottc3]

OP trying to understand. Your experiment sounds practical and simple. Please add a note reporting results.
Your 15 to 17% edge on KME results in BGA not contacting edge when stropping, and BGA is also set to 15 to 17%.
With above problem observed, your thinking that using BGA for heavy reprofile edge setting will result in a duplicate angle not working when moving to KME for stropping.
If I understood correctly, you can just match KME stropping angle with a sharpie, coming off BGA edge setting.

Bucketstove - thanks for nothing, an hour later!
Your experiment graph begs annotation. I understand what it shows from reading your experiment thread, but my mind can't see it on the graph. Maybe annotating just the 8th inch stock, 0.125", as an example for helping comprehension (data points / slope / regression line legend?). Had to revisit linear regression... been a while.
I read these results were not surprising to some, with the cause being belt sag? Perhaps increasing the problem is pulley distances...
My interest is in making a slide for our KME stone holders for longer knives.

 

[c7m2p3]

OP trying to understand. Your experiment sounds practical and simple. Please add a note reporting results.
Your 15 to 17% edge on KME results in BGA not contacting edge when stropping, and BGA is also set to 15 to 17%.
With above problem observed, your thinking that using BGA for heavy reprofile edge setting will result in a duplicate angle not working when moving to KME for stropping.
If I understood correctly, you can just match KME stropping angle with a sharpie, coming off BGA edge setting.

Bucketstove - thanks for nothing, an hour later!
Your experiment graph begs annotation. I understand what it shows from reading your experiment thread, but my mind can't see it on the graph. Maybe annotating just the 8th inch stock, 0.125", as an example for helping comprehension (data points / slope / regression line legend?). Had to revisit linear regression... been a while.
I read these results were not surprising to some, with the cause being belt sag? Perhaps increasing the problem is pulley distances...
My interest is in making a slide for our KME stone holders for longer knives.

I will be sure to update here when I finish my "experiment" if I can even get away with calling it that.

Essentially on some of my higher end knives I tend to stick with the KME for sharpening. However, I use the BGA for kitchen knives, fixed blades, and some of my 'working knives' that i use for cardboard or outdoors. I do use the BGA with the leather belt I bought on the secondary market loaded with diamond compound to clean up high end knife edges. I first noticed this problem when doing so.

I have and angle cube and I know for a fact the angle that the edge bevels were set on the KME. I even used the angle cube by sitting it inbetween the pulleys on the BGA to verify that was close to the markings on the side as well and it checked out. But I noticed that it wasnt really making good contact until I changed the angle of attack tilting the blade edge down into the running strop belt.

I had issues for a while on getting very wide bevels on the BGA with fixed blades and kitchen knives and mostly attributed it to either thick grinds on the fixed blades or my hands not being that steady and allowing the blade face to come into contact with the running belt. But after being as careful as I am with the stropping belt with my higher end blades I am pretty sure that it is not just human error at this point.