I recently bought a Blackland dart. When you load the blade you can hear the razor crunching it in place. The dart defiantly puts a bend on the blade.Good point. The steeper the bend a razor puts on blade, the less additional exposure a wide blade is going to have.
Most razors don't blend blades very much though. I've seen more than one razor where the blade is actually 100% flat. The Henson razor bends the blade way more than any other razor I've ever seen. That's part of what makes it such a great design.
The Karve SB-D has the blade at a 14 degree angle for instance. I don't know what that would translate in terms of additional exposure from a KAI blade that was 0.2mm wider than normal though. It would affect the Karve more than the Henson.
Would love to know gaps and blade exposures for classic vintage razors.....
- Thread starter kingfisher
- Start date
I keep forgetting that exposure is measured perpendicular to the shave plane. Even if there was no bend to the blade whatsoever, you would still never get a 1:1 increase in blade exposure by increasing the width of the blade.
ImageJ is such a handy tool. I went back to the exposure measurements for the Karve SBD that I did earlier in ImageJ, and extended the length of the blade by 0.10mm in the same trajectory of the existing blade. Then I measured the blade exposure given that additional length. It added an additional 0.05mm in blade exposure. Pretty much what you were guessing.
This is a relative measurement of marginal exposure not an absolute measurement of additional exposure from adding a KAI, because we have no idea what blade was loaded in the Karve SBD when it was photographed. The width of that blade may have been 21.9mm, which is why we got an exposure measurement of 0.10mm rather than the manufacturer stated .13mm.
This stuff gets confusing.
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Here is a brief summary of how much different razors bend the blade, how I was measuring it, and a table of those measurements. The shorter the chord length, the bigger the bend and the bigger the blade angle. I was measuring it then because I believed it was relevant to rigidity, but it's definitely relevant to the present discussion of blade angle and exposure.
The Great Rigid Blade Experiment
Mamba v2 vs Fatip Grande: Comparing the Closeness Well, I think I botched the comparison this morning. I had 36 hrs of growth, so I there was a pretty good opportunity to evaluate the comparative efficiency of these two superb razors. I used RR Amici soap which was a nice change of pace after...
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Although I don't know how quantify the importance of blade bend radius relative to free-end distance and clamping distance, in the very least it is possible to measure the bend radius of different DE razors. Maybe it will offer some clues.
Methodology: I measured a Perma-Sharp Super blade at 3 points, left, center, and right to get my "arc length" see the diagram below. The measurements on left and right were about 5mm from the edge of the blade, because I have found that blades tend to taper minutely at the extreme edges. The blade in question had an average measurement of 22.02mm. I then used this same blade loaded in each of the razors that I own to measure the chord distance, by measuring from the cutting edge on one side to the cutting edge on the other. I measured each the chord distance in each razor, left, right, and center, and took the average of the 3 measurements. See pic below:
This gives us an understanding of how steep the bend radius of the circle is for different razors. This diagram should clarify what I'm up to:
Here are the results:
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Got a pair of calipers? I'd love to know how much it bends the blade. The RR Teck II puts a heck of a bend on the blade, but I've never heard crunching. The Blackland Dart must put one heck of bend on a blade.
i believe the crunching sound is the blade being pushed along the studs and being pushed into the cap as I tighten the handle. No I don't have a caliper.
Also on a side note since blade widths vary I think its more pragmatic just to identify if its positive neutral or negative exposure
Or get a blade that is exactly 22 millimeters in width and use that for all razor measurements. Than use an asterisk to inform people the variables of blade widths.
I have put the thread into a separate tab and will read the entire thing later tonight!Here is a brief summary of how much different razors bend the blade, how I was measuring it, and a table of those measurements. The shorter the chord length, the bigger the bend and the bigger the blade angle. I was measuring it then because I believed it was relevant to rigidity, but it's definitely relevant to the present discussion of blade angle and exposure.
The Great Rigid Blade Experiment
Mamba v2 vs Fatip Grande: Comparing the Closeness Well, I think I botched the comparison this morning. I had 36 hrs of growth, so I there was a pretty good opportunity to evaluate the comparative efficiency of these two superb razors. I used RR Amici soap which was a nice change of pace after...
This is the rationale that Henson gave for choosing the Astra SP as their standard. It happens to be just over 22 according to the chart, don't see another common blade that is as close.
Hi everyone, do you know where this table comes from?
Raising your attention of my post on blade gap and exposure.
Blade gap and exposure
Hi everyone, My first post in B&B! I am based in France and a member of the French forum rasage-traditionnel.com. I am more and more convinced that blade exposure has ad minima as much impact on the quality of a razor than the gap therefore I have explored how razor makers deal with it. Many new...
www.badgerandblade.com
