Blade Gap vs Blade Exposure

[The Dean]

OK, I'll admit it. I'm confused (nothing new there). Sometimes it seems Blade Gap (BG) and Blade Exposure (BE) are used interchangeably. Other times they are referred to as different things. The WIKI has a BG chart, but not one for BE, from what I can see.

I can see from this thread, a discussion of the meaning of BG. Exposure is discussed briefly in that thread, but I still really can't get a grasp of what exactly BE means. Would I be correct in assuming BG is the space between the base plate and the blade, while BE is how far the blade extends past the head cap?

I will say this, when I was allowed to experience the 2011 R41 recently, I noticed how far the blade stuck out from the cap. I assume it has a very large exposure. I never even thought to look at the gap between the base plate and the blade.

I realize one measurement isn't doesn't explain a razor's aggressiveness. But does BG have a wiki page because it is easier to measure or (and/or) because it is generally considered to be more important in understanding the relative aggressiveness in razors?

I know there probably won't be any information in this thread that hasn't been discussed elsewhere on the forum. But perhaps it can be a place where it is more easily found, all in one place.

Thanks in advance for your help.

 

[Jeff_H]

I can see from this thread, a discussion of the meaning of BG. Exposure is discussed briefly in that thread, but I still really can't get a grasp of what exactly BE means. Would I be correct in assuming BG is the space between the base plate and the blade, while BE is how far the blade extends past the head cap?

Dean.....this is how I understand it as well, although I admit to not knowing exactly how one effects the other. I always assume the bigger the GAP between the blade and the base plate, the more aggressive the razor is; because there is more area there for skin to get caught in between and therefore get cut.

But I think exposure can also have an effect, because the more blade that sticks out from under the cap, the more chance it can flex, therefore cutting the skin. I am not an engineer and I don't understand all of the technical and engineering speak very well, but I'm sure there are several "optimal" combinations, depending on who is making the razor.

I'll be interested to sit back and listen to the experts fill in the blanks in this area. Good idea for a thread.

 

[The Dean]

Dean.....this is how I understand it as well, although I admit to not knowing exactly how one effects the other. I always assume the bigger the GAP between the blade and the base plate, the more aggressive the razor is; because there is more area there for skin to get caught in between and therefore get cut.

But I think exposure can also have an effect, because the more blade that sticks out from under the cap, the more chance it can flex, therefore cutting the skin. I am not an engineer and I don't understand all of the technical and engineering speak very well, but I'm sure there are several "optimal" combinations, depending on who is making the razor.

I'll be interested to sit back and listen to the experts fill in the blanks in this area. Good idea for a thread.

Excellent. And while I'm not sure if it helps the thread, or simply complicates it, I suppose there will be some discussion about what exactly "aggressive" means. Obviously the most aggressive razors we typically discuss here also are among the least forgiving--and most likely to bite. But I'm not sure all efficient shavers (aggressive in how they reduce the beard) are aggressive to the skin. I hear the Feather AS models are known to be quite mild and forgiving, yet very efficient. I wonder if there is a magic ratio in DG/DE/angle/weight/etc that helps a razor be aggressive to the beard but not the face.

 

[mblakele]

Would I be correct in assuming BG is the space between the base plate and the blade, while BE is how far the blade extends past the head cap?

That is how I use those terms.

I will say this, when I was allowed to experience the 2011 R41 recently, I noticed how far the blade stuck out from the cap. I assume it has a very large exposure. I never even thought to look at the gap between the base plate and the blade.

I realize one measurement isn't doesn't explain a razor's aggressiveness. But does BG have a wiki page because it is easier to measure or (and/or) because it is generally considered to be more important in understanding the relative aggressiveness in razors?

Probably a little of both. The blade gap measurements may not be all that trustworthy either: ideally we would want to sample a statistically significant number of each razor model, filter for outliers, and so on.

I think increased blade exposure has two main effects. First, you can apply the blade to your skin at a wider variety of angles, simply because the cap is not in the way. This might make a razor feel more aggressive, depending on your choice of blade angle.

Second, increased exposure means that the blade is clamped farther back. So the exposed portion of the blade is less rigid, and flexes more easily. This can create blade chatter. Of course this will interact with skin, beard, blade angle, and the rest of your technique. But does blade chatter make a razor more aggressive, as such? Not in my opinion. Instead I would say that chatter makes the razor unstable, more difficult to use, and even dangerous. Think of a car and the balance between the suspension, steering, transmission, and engine. If your shaving surface is relatively uniform and smooth then you might enjoy the razor equivalent of a Lotus. But if your face is more like a dirt road, then you want solid steering and suspension: something more like a Subaru or a Land Rover.

The R41tc illustrates this problem for me. With the original 2011 narrow cap, blade chatter was a chronic problem and I found the razor tricky to handle. The wider cap in the current version is quite a bit better in this respect. I feel the 2013 razor is just as aggressive as the 2011 was, but easier to use. However there is room for YMMV, and there are gents here who feel the wider cap was a step backward. They may feel this way because the reduced blade exposure also reduces the variety of angles that can be used, and for some shaving styles that could make the razor less appealing.

 

[Foyle]

This link may help you. http://badgerandblade.com/vb/showthread.php/162987-Photo-Analysis-of-Razor-Designs

Basically, aggressiveness is the result of blade exposure. The more blade exposed beyond the tangent created by the head cap to the safety bar or combs is what determines exposure. A wide gap can increase exposure, but a wide gap is not essential to blade exposure. Some razors with wide gaps have very little exposure and are very mild feeling razors. The Futur at 1 is fairly mild but has tons of gap. The Old Type has almost no gap but lots of exposure.

 

[mswofford]

Dean; Go to "general shaving discussion" and find thread "mild vs aggressive-physical differences" and see my post #9, 11-15-13. Or if you want I can re-post it here.

 

[The Dean]

This link may help you. http://badgerandblade.com/vb/showthread.php/162987-Photo-Analysis-of-Razor-Designs

Basically, aggressiveness is the result of blade exposure. The more blade exposed beyond the tangent created by the head cap to the safety bar or combs is what determines exposure. A wide gap can increase exposure, but a wide gap is not essential to blade exposure. Some razors with wide gaps have very little exposure and are very mild feeling razors. The Futur at 1 is fairly mild but has tons of gap. The Old Type has almost no gap but lots of exposure.

Dean; Go to "general shaving discussion" and find thread "mild vs aggressive-physical differences" and see my post #9, 11-15-13. Or if you want I can re-post it here.

Excellent contributions, guys. Very informative. Still there doesn't seem to be complete agreement (not that I expect that).

BTW, the Wiki page mswofford refers to is here:
http://wiki.badgerandblade.com/Double-Edged_Safety_Razors_Ranked_by_Aggressiveness

Despite the title, razors are not ranked at all at that page. But there is a very nice discussion of aggressiveness. The Wiki page concludes aggressiveness is the result of many factors and not simply exposure:

The aggressiveness of a razor largely relies on 5 different factors.

• Blade gap
• Blade angle in the razor
• Razor weight
• Distribution of the weight. (Heavy head/light handle vs. all heavy.)
• Blade angle applied by the user

While exposure isn't mentioned in that list, it is discussed quite a bit.

We are learning. And of course with learning comes more confusion.

 

[nemo]

I think increased blade exposure has two main effects. First, you can apply the blade to your skin at a wider variety of angles, simply because the cap is not in the way. This might make a razor feel more aggressive, depending on your choice of blade angle.

Second, increased exposure means that the blade is clamped farther back. So the exposed portion of the blade is less rigid, and flexes more easily. This can create blade chatter. Of course this will interact with skin, beard, blade angle, and the rest of your technique. But does blade chatter make a razor more aggressive, as such? Not in my opinion. Instead I would say that chatter makes the razor unstable, more difficult to use, and even dangerous. Think of a car and the balance between the suspension, steering, transmission, and engine. If your shaving surface is relatively uniform and smooth then you might enjoy the razor equivalent of a Lotus. But if your face is more like a dirt road, then you want solid steering and suspension: something more like a Subaru or a Land Rover.

The R41tc illustrates this problem for me. With the original 2011 narrow cap, blade chatter was a chronic problem and I found the razor tricky to handle. The wider cap in the current version is quite a bit better in this respect. I feel the 2013 razor is just as aggressive as the 2011 was, but easier to use. However there is room for YMMV, and there are gents here who feel the wider cap was a step backward. They may feel this way because the reduced blade exposure also reduces the variety of angles that can be used, and for some shaving styles that could make the razor less appealing.

Good explanation, agree 100%, thanks.

 

[The Dean]

Good explanation, agree 100%, thanks.

Thanks for posting his, I had missed mblakele's excellent contribution.

 

[segnod]

Though several factors affect razor aggressiveness, to me it's mostly a function of blade exposure. (I hate the term aggressiveness, by the way. But I haven't yet come up with a better alternative. Is a 44 magnum revolver more aggressive than a 22 derringer? Nope. Though the 44 can punch bigger holes in stuff and make more holes more quickly than the 22 derringer, it has no aggression at all. It's an inanimate object. Likewise, an Old Type razor isn't more aggressive than a Tech, though the Old Type definitely has the potential to remove more hide! But I digress.) To illustrate my point about blade exposure being more responsible for "aggressiveness", think of a couple of extreme, though non-realistic razors. Picture a razor with a blade gap (the distance between the blade and the safety bar or comb) of a quarter inch. Huge gap! But also picture this razor as having a blade exposure of 0.0001 inch or some ridiculously small amount. By exposure I mean the amount of blade that extends beyond the tangent line from the safety bar or comb to the protruding surface of the cap, per woodfluter's excellent drawings and analysis (http://badgerandblade.com/vb/showthread.php/162987-Photo-Analysis-of-Razor-Designs). Then picture another razor with a gap of 0.0001" and exposure of 0.25". Yikes! Even though there's practically no gap, there's lots o' blade sticking out! Between these two razors, which would you think is more likely to draw blood? I know in my mind the second razor scares the crap out of me, and I imagine the first requiring at least a little pressure to even be capable of shaving. Obviously, either razor could cut you. But I think you'd almost have to try to cut yourself with the first, whereas the second would be like holding a piranha to your face. So given those two extreme examples and acknowledging that both gap and blade exposure play a role, blade exposure seems to me the much stronger factor in determining level of razor aggressiveness.

 

[The Dean]

I'm thinking that according to some here, the "Mind The Gap Club" should change it's name to something like "Maximum Exposure". But please, if you do stay away from the local high schools.

 

[Jeff_H]

^ I can tell you from first hand experience that is frowned upon these days. Divulging any more info would violate the terms of my parole.

 

[The Dean]

^ I can tell you from first hand experience that is frowned upon these days. Divulging any more info would violate the terms of my parole.

And the TOS of this forum, methinks.

 

[shawnsel]

I like Leisureguy's article, "MILD? OR COMFORTABLE?; AGGRESSIVE? OR EFFICIENT?". His approach is to replace the term "aggressive" with

new terminology that reflects two orthogonal axes, one axis running from “inefficient” to “efficient” and the other from “comfortable” to “harsh."

 

[shawnsel]

The ATT razor heads have a unique approach where an aggressive blade exposure is minimized by a teeny tiny blade gap. The M1 plate has a blade gap of just 1/10th of a millimeter. Even the H1 has a blade gap smaller than any other manufacturer on the Wiki's list ( http://wiki.badgerandblade.com/Double-Edged_Safety_Razors_Ranked_by_Blade_Gap ). I envision this as offering the efficiency of the greater blade exposure that should allow the blade itself to easily get under the hair (without the blade scraping at an uncomfortable angle), and yet minimizes the "blade chatter" with the baseplate being so close to the blade. I suspect this also reduces the amount of possible curvature outwards of the skin between the blade and baseplate/guard ... helping to somewhat reduce the affects of pressure applied by the user.

Reports vary as to how well this works. I suspect some people have skin that is more or less prone to curving/rolling under pressure. Or it may just be that the increase blade exposure offers greater awareness to some users as to where the blade is, providing clearer feedback and thus reducing pressure applied.

Thoughts? Does this ring true with anyone else?

Great discussion by the way!

 

[Haegar]

I like Leisureguy's article, "MILD? OR COMFORTABLE?; AGGRESSIVE? OR EFFICIENT?". His approach is to replace the term "aggressive" with

new terminology that reflects two orthogonal axes, one axis running from “inefficient” to “efficient” and the other from “comfortable” to “harsh."

Indeed, Leisureguy's terminology is really concise and clear. The fully extended explaination can be found here.