Author Topic: iOS Option for Calculating USB Height  (Read 3023 times)

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
iOS Option for Calculating USB Height
« on: June 06, 2018, 12:35:11 am »
« Last Edit: March 30, 2019, 02:18:27 pm by cbwx34 »

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #1 on: June 16, 2018, 11:15:16 pm »
« Last Edit: March 30, 2019, 02:19:24 pm by cbwx34 »

Offline Jan

  • Hero Member
  • *****
  • Posts: 1132
  • Iron sharpens iron, and one man sharpens another
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #2 on: June 17, 2018, 03:00:49 pm »
CB, your T4 distance between USB top and stone surface s = 91.80 mm is consistent with Dutchman approximate formula, the exact value is s = 92.21 mm.

Similarly, your T4 distance between USB top and Tormek casing h = 165.17 mm is in very good agreement with the exact value h = 165.76 mm.

Jan

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #3 on: June 17, 2018, 04:20:44 pm »
CB, your T4 distance between USB top and stone surface s = 91.80 mm is consistent with Dutchman approximate formula, the exact value is s = 92.21 mm.

Similarly, your T4 distance between USB top and Tormek casing h = 165.17 mm is in very good agreement with the exact value h = 165.76 mm.

Jan

... which translates to < .5° ;)

I put in the spreadsheet a "minimum accuracy of +- 1°".  My .02... with all the dynamics involved, that's a fair (maybe conservative) estimate.  I like the calculator approach for two main reasons beyond the accuracy... it's consistent, and it eliminates the factors involved in using the AngleMaster... (blade grind angles for example).  I think overall though, the calculator concept is a more accurate approach.... (and I include Dutchman's tables in this approach).

A scale diagram gives another source of checking....



...(which has the potential of being the most accurate).  ;)
« Last Edit: June 17, 2018, 04:27:14 pm by cbwx34 »

Offline Ken S

  • Moderator
  • Hero Member
  • *****
  • Posts: 5555
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #4 on: June 17, 2018, 05:53:27 pm »
CB,

Your diagram makes me aware of a needed tweak in the kenjig. The usb sits in a square area at the top of the groove. This causes an offset in the jig amounting to the radius of the usb. If I drill a 12mm hole in the top corner of the groove for the usb, that will move the measuring point over to the center point of the usb. Perhaps I should move the hole further in to a point where the center of the bottom measuring flat lines up with the center point of the usb.

Thoughts?

Ken

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #5 on: June 17, 2018, 07:15:25 pm »
CB,

Your diagram makes me aware of a needed tweak in the kenjig. The usb sits in a square area at the top of the groove. This causes an offset in the jig amounting to the radius of the usb. If I drill a 12mm hole in the top corner of the groove for the usb, that will move the measuring point over to the center point of the usb. Perhaps I should move the hole further in to a point where the center of the bottom measuring flat lines up with the center point of the usb.

Thoughts?

Ken

So, for reference, I added a Kenjig to the diagram...



When I measure with the calipers, I use the corner of the base that touches the stone ('A' for reference in the diagram).  This, to me, is the most "direct line".  So placing a Kenjig in this manner, it measured a difference of .15mm (92.50 vs 92.35 in the diagram).  Close enough for government...er... MaBell work. ;)

I didn't put it in the diagram, but measuring with the Kenjig "flat" or the center of the part touching the stone, adds around 1mm.  So not a lot of difference that I can tell.  So there's certainly a valid point to your observation, (especially moving the point to "center" with the bottom of the Kenjig), but I think measuring to corner 'A' would be pretty accurate... and consistent.  (I don't think it's really an offset error of 6mm... if that were the case, it would show pretty obviously in sharpening).

Offline Jan

  • Hero Member
  • *****
  • Posts: 1132
  • Iron sharpens iron, and one man sharpens another
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #6 on: June 17, 2018, 08:59:13 pm »

... which translates to < .5° ;)

I put in the spreadsheet a "minimum accuracy of +- 1°".  My .02... with all the dynamics involved, that's a fair (maybe conservative) estimate.  I like the calculator approach for two main reasons beyond the accuracy... it's consistent, and it eliminates the factors involved in using the AngleMaster... (blade grind angles for example).  I think overall though, the calculator concept is a more accurate approach.... (and I include Dutchman's tables in this approach).


CB, yes, I agree with you. Your USB height calculator allows to set the bevel angle with an accuracy better than 0.5°, which is sufficient for almost all Tormek users.  :)

CB, you are very humble person, because as far as I know, you have also the exact formula in your portfolio. It seems to me that you are feeding us with milk, like children, though you have also solid food for the mature.  ;)

Jan

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #7 on: June 18, 2018, 03:05:25 am »
CB, yes, I agree with you. Your USB height calculator allows to set the bevel angle with an accuracy better than 0.5°, which is sufficient for almost all Tormek users.  :)

CB, you are very humble person, because as far as I know, you have also the exact formula in your portfolio. It seems to me that you are feeding us with milk, like children, though you have also solid food for the mature.  ;)

Jan

Haha... that's pretty funny.  ;D  But this has been "battle tested" and works... ;)

Offline Cyrano

  • Newbie
  • *
  • Posts: 23
  • I'm a sharp craftsman!
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #8 on: June 18, 2018, 09:57:10 pm »
CB: Thanks!!! This is very handy.

Would it be an easy change to have the calculated distances reported in mm, instead of inches?

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #9 on: June 18, 2018, 10:30:23 pm »
« Last Edit: March 30, 2019, 02:21:29 pm by cbwx34 »

Offline wootz

  • Sr. Member
  • ****
  • Posts: 417
    • View Profile
    • knifeGrinders.com.au
Re: iOS Option for Calculating USB Height
« Reply #10 on: June 19, 2018, 02:12:21 am »
Honestly, what's the practical use of all that?
iPhone owners use an easy and free online calculator available from Rich Colvin: http://sharpeninghandbook.info/indexCalcProj.html

Your add-on is like building your own cockloft on the roof of a skyscraper.

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #11 on: June 19, 2018, 02:25:34 am »
« Last Edit: March 30, 2019, 02:21:57 pm by cbwx34 »

Offline Ken S

  • Moderator
  • Hero Member
  • *****
  • Posts: 5555
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #12 on: June 19, 2018, 04:05:31 am »
Play nice, children.

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #13 on: June 19, 2018, 04:55:28 am »
« Last Edit: March 30, 2019, 02:22:07 pm by cbwx34 »

Offline cbwx34

  • Hero Member
  • *****
  • Posts: 1234
    • View Profile
Re: iOS Option for Calculating USB Height
« Reply #14 on: June 25, 2018, 06:10:15 pm »
« Last Edit: March 30, 2019, 02:29:35 pm by cbwx34 »