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Started by wootz, October 15, 2019, 08:42:11 AM
Quote from: wootz on October 15, 2019, 08:42:11 AMNEED FOR UPGRADEIn its current form, our software sets an accurate grinding angle for resharpening a knife with established bevels at the existing edge angle.E.g. you resharpen a 15 degrees per side (dps) knife to the same 15 dps.However, when grinding new bevels, sharpening a grossly dull knife or a knife blank gives an edge angle differing from the calculated target by 0.5-1.5 degree. The thicker is the blade behind the edge, and the lower is the new edge angle, the greater is the difference.....STATUSI've coded the computer algorithm and currently testing in sharpening blades of varying thickness.The calculations are along the lines of the explanation given by Ton Nillesen in 2018 on the page 6 of his additional booklet that can be downloaded from our website http://knifegrinders.com.au/Manuals/Grinding_Angle_Adjustment_Booklet_2018.pdf....
Quote from: Morne1312 on November 07, 2019, 09:21:26 AMWhere can one get more info regarding the Kenjig or how it works (set up, working etc?)
Quote from: john.jcb on November 07, 2019, 02:58:44 PMKen, have you also made allowances on your jig for setting an alternative honing angle on knives as detailed in Wootz's book on deburring?
Quote from: Ken S on November 07, 2019, 07:10:44 PMGood question, John.No, the kenjig predates Wootz' deburring book. You make a good point; I should update the kenjig. I would leave the Projection at 139mm and make special kenjigs (or Janjigs) for the Distances for the deburring stages.Keep on thinking.Ken
Quote from: cbwx34 on November 07, 2019, 07:20:50 PM... and measure the projection distance, I am measuring the total projection distance (Ke). I'm never measuring to "Kb". So, the calculator/formula automatically is set for the angle I want to end up at. While it is obvious that at the start of the grind, the angle of the knife/wood in relation to the stone is different, at the end, I'm getting the angle the calculator provided. That's the way I see it anyway. (I actually did it to see if I was missing something).
Quote from: cbwx34 on November 07, 2019, 07:20:50 PM...I don't understand what Ton's formula regarding thickness accomplishes. SO, if I'm missing something, in this or in Ton's section, feel free to tell me. What exactly is Ton describing here?
Quote from: jvh on November 08, 2019, 10:08:06 AMWe can say that that total projection distance X is always right. The dimension starts at the edge tip and this is also the first point of our axis.If you have symmetrical double bevel knife and you center it well in the jig SVM-45 then the second point of axis lays in the axis of the jig and goes through point J.Now it depends on used math because you can suppress this "thickness error" from the beginning with the correct calculation.TormekCalc calculations are made in the axis of the knife (point at edge tip) and the jig (point J), so results are valid for all symmetrical double bevel knives with defined angle at the edge tip. Error given by material thickness is suppressed there completely......jvh
Quote from: Dutchman on November 08, 2019, 12:14:00 PMAt your service I have corrected text, Figure 6 and the table in "More math for the Tormek grinder" in the paragraph "Understanding why thickness matters"The documents (See link in my signature) have been updated.
QuoteIt will be clear that these considerations are related to single sided grinding. For double sided grinding the values Ke and tb will increase with 50% for grinding the first edge. Furthermore this error is not present or negligible with sharpened blades
Quote from: smurfs on November 08, 2019, 03:11:48 PM...calculating the angle of the chord, not the edge angle. Could this be the source of much of the confusion evident in this thread, or am I muddying the waters further?
Quote from: Dutchman on November 08, 2019, 03:25:56 PMQuote from: smurfs on November 08, 2019, 03:11:48 PM...calculating the angle of the chord, not the edge angle. Could this be the source of much of the confusion evident in this thread, or am I muddying the waters further? You are right AND "muddying the waters further"
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