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Working on a bevel angle calculator, looking for input

(skip to post with link to finished calculator)

This kind of spans both honing and razor making interests, if I can get it working right...so I figured the general forum would be the best place

Anyway, I've been trying to figure out why I'm having such trouble getting an edge on one of my razors and have determined that the bevel is approximately 20 degrees. But in figuring this out I had to search all over for formulas and different calculators and blah blah blah....got annoyed and decided I wanted one location that combines every calculation that might be useful for this.
I've seen Slash McCoy's bevel calculator program, and it works fine for finding out what your current bevel is, but doesn't help you determine how to correct it.

So, here's what I've got working in a spreadsheet so far:
  1. For honing:
    1. (Completed) Enter your current blade width (measured from edge to point of the spine that hits the hone) and your current spine width and it will give you your current bevel angle
    2. (Completed)If your bevel angle is too shallow, enter the thickness of your tape and the number of layers and it will give you your new bevel angle
    3. (Considering adding) If your bevel angle is too wide, find out how much metal would need to be removed from the spine to correct it (not necessarily recommended, but might be helpful for a razor that's lost too much blade width without losing enough spine width)
  2. If you're making a razor:
    1. (Completed)Enter the height you want to make the blade and the desired bevel angle and it will give you the thickness you need the spine to be
    2. (Not finished yet) If making a razor, enter the thickness of your existing barstock and your desired bevel angle and it will give you the proper blade width to achieve that angle

And just for an added perk, I could add a page to keep track of your razors to remember which ones get taped and which don't

So, my questions are....if I were to share this when it's finished, is there anything else people would like to see added? Or any comments/complaints about what is already done/planned?

Unfortunately, I don't have the experience required to make this into a standalone executable file, but if anyone that wants it doesn't have MS Access, it should work in OpenOffice, which is basically a free, open source version of the whole MS Office suite
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I think that you're over thinking the issue. The razor maker did all of these calculations already and made a razor that has a spine thickness to blade size ratio that gives you the correct angle to hone at. From memory the ratio is about 6:1.
Overthinking? What's that? :lol:

In an ideal world, on a perfectly crafted, brand new razor, you'd be right....but when working with an old razor the original geometry can be a long ways from the current measurements.
Not to mention the threads I've read lately on people making new razors and not being sure what dimensions to go with.

Plus, the last time I saw someone throw out a ratio for this, I believe the number they gave was 3.5:1.....i don't know which is closer to correct, but if you could easily figure the actual angle instead of an approximate ratio, I don't see where that would be a bad thing
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I've honed a few hundred razors and I've never had a problem getting a shave ready edge on any of them as long as you go back to the begining and set the bevel properly. I've never had to calculate angles or ratios, ever.
I'm with John I have never had much help from one but there are several already if you google them. If I knew how to upload the one I have or which thread it came from I would be happy to share.
huh, I would've thought there'd be some interest. So many great discussions on this site about such miniscule details making the difference between good and great, debates over whether one little layer of tape is enough to throw off an angle or not. Oh well, it'll probably still get completed and shared in case anyone can get any use out of it. If it helps someone else, great! If not, no harm in trying :biggrin1:

As for the existing ones....I'd prefer making my own mostly because I'm having fun doing it, and because I'd like to see how it all works together rather than just having the data handed to me. I'm a bit of a geek in my spare time
Fittingly enough, I'm watching Dr Who while typing this, and he just had to explain some prime number sequence to someone to get through a locked door and finished off by saying "Don't they teach recreational mathematics anymore?" :lol:

A part time rocket scientist, philanthropist, resident anti-taping during honing guru, and all-around swell guy has already solved this issue for you:

That is the calculator I mentioned having seen and used, and it works fine for what it does, but what it does is only one thing. Informative, but in my opinion it's only partially solved at that step.
I've read many of the links on his site, and many of his posts on here and I understand his stance on not taping everything by default or just for looks.....but even he has said that there are times for taping to correct improper angles. This is why I thought this would be of some use, obviously there are those out there that are concerned over a degree or 2 difference.

A quote from the man himself on this topic:
The proof is in the pudding, as they say. If it shaves, it shaves. If it doesn't even after honing, or the edge seems too harsh or fragile, then examination of the bevel angle may offer clues as to why. Also, consideration of the bevel angle is a valid determining factor in making an INFORMED and REASONED decision to tape the spine or not, when honing.

Taking that into account, if you determine that tape is needed to correct too shallow of a bevel, wouldn't it be nice to know if the tape you're using is putting the bevel back into the ideal range or pushing it into to wide of one? I know most people say one layer will make <1 degree difference, but I've seen some pretty big differences in tape thicknesses between brands.
Sure, you could see it's too shallow and just throw on your tape and hone it up and try it and see....but nothing wrong with a little fore-thought.
And at any rate, if you've already taken the time to take the measurements to enter into Slash's calculator, entering your tape info into this one will take you all of an extra 3 seconds
Here you go.


Honestly, rather than a numerical calculator something like this would be better served with a graphical interface. Basically moving two points on an XY graph and a constant angle calculation at the Y location. Should be easy for someone who knows the code (I don't so I'm not volunteering).

I guess that would be useful for some things.....but I don't think it would be any easier for what I'm trying to do. I'd rather be able to just punch in a number from a measurement I took, rather than try to move a point to the exact spot to match my measurements.

I found a few things like that when searching, and used the one linked below to double check some of my formulas...but really, it was kind of a pain working with it with such small numbers

edit: sorry, wasn't that one. was similar, but it showed the length of all sides, this one doesn't seem to do that
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You can simply try different spine thicknesses in the program until you find the one that gives the desired bevel for the given hypotenuse. Then apply a layer of tape and measure the taped thickness and try that thickness in the program. At any rate more than two thicknesses is a bad idea because it will be too resilient.

The beginning programmer writing an app for his own use as opposed to a professional programmer should try one of the many versions of BASIC. Early versions of Visual BASIC were good until windoze 7 came out. Now I prefer RealBASIC. As an added bonus you can port your app to Mac or Linux without ever leaving the windoze environment. It is quick to learn too and you can design a GUI as easy as frog snot. You could also try Liberty BASIC. Or any of the old DOS BASICs if a console app will suffice. I used to like the power and simplicity of Rexx under OS/2 Warp. Light years ahead of its time.

If you are up to more of a challenge Microsoft has free versions of the Visual Studio components. You. An try VB or Visual C++ or C# or whatever without dropping big bucks on the suite and you. An create full executable standalone apps.
Yeah, like I said, yours does what you designed it for just fine man, no complaints there :thumbsup: But it is limited in some ways. Measuring again with tape on is easy enough, but if someone wanted to choose to grind down a spine on a really bad blade, you'd just be doing a bunch of guessing to find the right new width. Not hard in the least, but to me it'd be annoying, knowing that a program could figure it out for you with no guessing involved.
Now, at that point I could turn to the chart fast14riot provided, but.....why not just put it all in one place?

Since this is just for fun, and I have no plans on any bigger projects, I don't see putting out any money for programming software, but I may play around with those Visual Studio components if I get bored enough. All my programming experience so far is in webpages, spreadsheets and databases...that's why Excel was the easiest option for me.
I completely understand, as you said it's for fun. But, even if you spent the time to work out everything there are still variables you can't account for that will throw thing off.
It could work assuming the razor was perfect but honestly there aren't many. To many things come into play. Varied spine thickness, tapered blades, warps, twists, overcooked steel, ect...lol.
If you find working out a formula to be fun or entertaining, then get to it..:biggrin1:. Lord knows I do some strange stuff for fun

If you want to find the easiest way to determine how to get a razor "back in shape" from problems you've correct (or haven't corrected), buy a bunch of junk razors.
Ones you don't care it if ever shaves or not. Then spend time with the stones. You'd be surprised how you'll adapt to different problems after you spent time honing some junkers.
Oh, absolutely, there's always more variables....I'm not expecting just knowing the bevel angle to solve all problems LOL Just as a reference point

The one razor that started me on all of this is close to a wedge with a slight smile, was giving me a hell of a time getting an even bevel, so I was thinking a layer of tape would make the honing a little easier from what I've read. But when I got curious about how much the tape would change the angle I pulled out the caliper and speaking of varied thicknesses...I measured 5 spots on the blade and came up with the following results (in mm):

Spine Width6.436.245.956.026.22
Bevel Width18.3918.3517.8717.9818.39
Bevel Angle20.1367519.5788119.1664619.2743219.47258
Tape x121.2579120.7014320.3185320.4195320.59257

Not HUGE variations in angles, granted, but after rolling x strokes finally get it to catch arm hairs off the 1k along the whole edge....the center pops hairs a lot easier than the toe. Could easily be my honing, but is it coincidental that there's a full degree of difference between the 'good' cutting part of the blade and the 'just okay' toe? *shrugs* hell if I know, but it's an interesting coincidence....

Either way, overall, this seems like way too wide of an angle to me even without the tape

I know the grid looks more like it has a frown, but that's because the spine has more of a smile to it than the edge does
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"The one razor that started me on all of this is close to a wedge with a slight smile, was giving me a hell of a time getting an even bevel"

By "even bevel" are you talking about visually or even cutting ability?
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