02-21-2016, 08:26 AM
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The objective of this post is to share some experience and perspective, not to advance dogma or prescribe what anyone else should consider best with regard to knot specifications.

Loft is the vertical distance from the top of a handle where the knot is inserted into the socket (i.e., knot hole) to the highest point of the knot at its crown. It is the most common, and often the only, measurement given in description of a brush’s knot besides diameter at the insertion point, which more accurately states the capacity of a particular handle than it does the size of a knot set into that handle. Consider a knot with a diameter of 23.5 mm where the glue at the circumference of its base meets the hair. Such a knot might be set into either a 24 mm, or a 25 mm, or possibly even a 26 mm socket. But, although its characteristics (splay, volume density, etc.) can be altered depending on the selected socket size – just as those characteristics can be affected by loft – the actual size of the knot doesn’t change.

Several variables can affect the appearance, feel, and performance of a knot. Those include: 1) hair type and quality (e.g., softness, resilience), 2) base diameter (measured at the top of the glue plug), 3) volume density at its base, 4) shape, 5) depth of set, 6) loft, and 7) free loft (the vertical distance from the highest level glue reaches at the center of a knot to the knot’s crown). All of these factors in combination influence set-shape (i.e., shape as set in the handle), overall aesthetics, bloom, splay, effective (volume) density, backbone, scrub, scritch, floppiness, moppiness, lather production, lather uptake, flow-through, and drying time. Loft measurement, by itself, is a very incomplete specification.

Here’s an example. The brush shown below has a 28 mm socket. I didn’t set the knot, so I don’t know its base diameter. The loft is just shy of 54 mm (in fact my calipers still brush a few hairs at 54 mm). Some users wouldn’t consider buying a brush lofted that high for fear of flop. But guess what the knot’s free loft is.

[Image: P2200375_zpshdmtbwqb.jpg]

Answer:
About 41.5 mm, stretching.
That doesn’t mean it’s a bad brush. I tried one like it and was surprised to find that it wasn’t harshly scrubby at all, at least not for me. My guess is that's due in significant part to the fact that, given the 12.5 glue bump (54 mm – 41.5 mm), the knot was probably set very high in the socket, which tends to allow more splay, which in turn reduces volume density (because the same number of hairs are spread across a larger area). But still, if I were spending over $200 on a brush, I’d probably want to know whether 54 mm of loft was going to come with 41.5 mm of free loft or 48-50 mm. That’s a very significant difference. All else being equal, I’d expect a brush lofted at 54 mm, but with a 12.5 glue bump, to have more backbone and scrub than one with loft of 50 mm and free loft of 47 mm.
  
I’m admittedly a brush nut. When I first fell into fascination with brushes, I bought over 30 of them in three months. My purpose wasn’t to collect; it was to figure them out for myself and, hopefully, discover what I liked most. That said, I didn’t and don’t decide what I like based on analysis. I know what I like based on what I select to use. It’s as simple as that. Many times I’ve gone to the cabinet with an intent to take out a brush that hadn’t been getting due attention – and then at the last moment grasped the one I had used just the day before, and the day before that.

Finding what you like can be a challenge. But recognizing it when you finally experience it is absolutely not rocket science. For some of us, however, discovering what we like stimulates a quest to understand why we like it, what accounts for a particular brush turning out to be a favorite, and (most important) how we can prospectively identify another one (i.e., without first having to buy and try a dozen or more). That doesn’t involve rocket science either, but it’s also not entirely straightforward and simple.
  
What follows is more-or-less a photo-essay that shows how I approach setting knots. It focuses on a comparison of two knots of the same nominal grade, both of which were obtained as part of the same order from the same Chinese supplier.

The photo below shows the two knots side-by-side along with some stuff I use in setting knots. Note the socket spacers ranging in thickness from 5 mm to 10 mm. They allow easy comparison and selection of potential loft settings. Note also the gauge we made for use in measuring free loft. I included some handles in this photo because, in my view, different knots match better with different handles, and different handles may want different lofts. It’s a little like feng shui.

[Image: P2200323_zpsjuek3okj.jpg]

Here are just the two knots (hanging out in front of a brick). Both were designated for use in handles with 26 mm sockets. The one on the left (L-type) is about 68 mm tall and has a base diameter of approximately 24.2 mm. The knot on the right (S-type) is barely over 63 mm tall with a base diameter of about 25.2. Note that the L-type knot is glued in the lower, light-colored band (2-band hair actually has three distinct bands, at least before it is cut), whereas the S-type knot is for the most part glued at the bottom of the dark, middle band. More hair can be packed into a given circumference in the lower section than the dark, middle section. This accounts for the fact the L-type knot shown here, despite its smaller base diameter, is a slightly tighter fit in a 26 mm socket than the S-type knot.

[Image: P2200333_zpsr9xkihu4.jpg]

The L-type knot’s free loft is about 47.5 mm. (The gauge rose a bit in the knot when I removed my hand to take the photo.)

[Image: P2200328_zpsptplx1x9.jpg]

Here’s the L-type knot set at 48 mm. I hate the appearance, and I’m pretty sure I’d hate the way it would feel in use. But some might love it, and there’s nothing wrong with either bias.

[Image: P2200362_zpspbtzitjn.jpg]

Below is the same knot set at a loft of 50 mm. I still wouldn’t go for this myself.

[Image: P2200360_zpsm5p0ptch.jpg]

Here’s 52 mm. 

[Image: P2200354_zpssqusn49i.jpg]

And now below is the S-type knot with free loft of about 45 mm. 

[Image: P2200331_zpskmkrsb7j.jpg]

This is the S-type knot set at 48 mm, which wouldn’t be my first choice, but I think I could enjoy this brush.

[Image: P2200366_zpsvlhztwdh.jpg]

Here is 50 mm.

[Image: P2200368_zpshsvysjg5.jpg]

And finally, 52 mm. 

[Image: P2200369_zpsq38zxsjb.jpg]

The L-type knot differs in appearance from the S-type at a given loft due to the facts 1) it has to be sunk deeper in the socket, 2) its glue bump is therefor positioned differently in relation to the socket rim, 3) it has more free loft (independent of overall loft), and 4) it probably has slightly more area density at the socket rim.

There was a time when I thought a 24-26 mm brush wanted 49-51 mm loft. Now I would say “it depends.”

See also http://shavenook.com/showthread.php?tid=30895.

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 02-21-2016, 08:31 AM
#2
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Nice write up and thanks for sharing Ken


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 02-21-2016, 08:45 AM
#3
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the above article is one of the many reasons why u have so many fans here Ken!!!!
raj k

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 02-21-2016, 08:47 AM
#4
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Very informative as always Ken.


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 02-21-2016, 08:51 AM
#5
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If glue bump = Yin and free loft = yang, maybe loft by itself is like the sound of one hand clapping.

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 02-21-2016, 09:23 AM
#6
  • BobH
  • Senior Member
  • Thunder Bay Canada
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Thanks for taking the time to post this informative post. There is more to it than meets the eye.

Bob

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 02-21-2016, 09:28 AM
#7
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Thanks for sharing Ken

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 02-21-2016, 09:38 AM
#8
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Interesting.

Like so many things.
A brush is more than the sum of its parts.

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 02-21-2016, 09:52 AM
#9
  • refles
  • Senior Member
  • New York
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Some seriously self-learned knowledge on the nuances of brush knots.

Many thanks Ken for spending the time documenting and openly sharing what you've discovered along the way!!


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 02-21-2016, 10:27 AM
#10
  • clint64
  • Senior Member
  • Atlanta, GA
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Many thanks for such an informative post.  Also thank you for taking the time to document with photos.

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 02-21-2016, 11:22 AM
#11
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Nice write up Ken.


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 02-21-2016, 11:23 AM
#12
  • chazt
  • Senior Member
  • Bayside, NY
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[Image: th?id=OIP.M2c3ed93573d23572a033f85c4d1cf...=300&h=300]

Seriously. Thanks for the education Smile

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 02-21-2016, 12:29 PM
#13
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Great post Ken.  Keen observations.  Great looking knots too.  The L-type look to be on par with Simpsons Manchurian and the S-type with M&F Finest at first glance to me!  

'One-hand clapping'... 24

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 02-21-2016, 01:14 PM
#14
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(02-21-2016, 12:29 PM)w_mcnabb Wrote: Great post Ken.

Thanks. Hopefully, it will stimulate some discussion.

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 02-21-2016, 01:27 PM
#15
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Very informative Ken.  The L-type knot set at 48mm is definitely too pointy for my taste.  However,  set at 52mm it looks like a nicely shaped bulb.  I would not have guessed that it was the same knot.

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 02-21-2016, 01:40 PM
#16
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I've been trying to find a post I saw awhile back that had a brush (I think it was a shavemac...) with an adjustable loft.  If I remember correctly it was setup kind of like a bottom-dial Fatboy.  I thought it was ingenious but at the same time once you decide what loft you preferred I doubt it would ever be adjusted again so it makes sense why we don't see more of those.  It could alleviate the high time and money cost of the buying, trying, selling cycle a little though if brushes could be purchased and adjusted to allow experimentation.  Finding my preferences has been quite a costly endeavor though enjoyable at the same time.

As for trying to figure out 'free loft' in prospective brushes and how high or low I desire a loft to be I really do understand where you are coming from.  I wish it was easier to ask that question to vendors as it causes me great anxiety to spend money on a brush and have no idea what to really expect from the knot.  I prefer my knots sans glue bumps but I have a few with prominent glue bumps that are a joy to use so they are not deal breakers for me.  I hope your 'free loft' measure catches on as it seems like it would be the best way to get an idea of expected performance.  This should be listed or provided upon request from all manufacturers of brushes IMO.  At least I know I can ask you that question when the website is up!

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 02-21-2016, 01:42 PM
#17
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It was a Shavemac...  [Image: W20iKGo.jpg]

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 02-21-2016, 01:45 PM
#18
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(02-21-2016, 01:27 PM)TheLegalRazor Wrote: The L-type knot set at 48mm is definitely too pointy for my taste.  However,  set at 52mm it looks like a nicely shaped bulb.  I would not have guessed that it was the same knot.

At 68 mm tall, that knot has to be sunk 20mm to achieve 48 mm loft. Although the knot's base diameter of 24.2 mm might seem to provide plenty of clearance, it's less than 1 mm in radius at the base, and given the larger diameter of the knot above the base where it transitions into the middle band, it makes for a snug fit that almost entirely constricts splay. So it ends up looking like a stick, and it would likely breathe about like a stick too. This is a trade-off that can result from minimizing a knot's glue bump above the socket rim. I've found I like to set the L-type knots a bit higher than usual higher for that reason, which yields taller loft, but with with 16 mm of the knot (about 9 mm of which would be hair above the glue plug), the knots still behave well, hold shape, etc.

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 02-21-2016, 01:46 PM
#19
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How do they look, I'm curious, after being lathered? After bloomed? After a dozen or so uses?

I think that those factors affect loft in so far as the feel. After all, it is near impossible to judge a book by its cover. Especially when, as in a brush, it changes once used.



Is asking for knot weight pertinent? 
Would it be possible to judge density and therefore other relative characteristics by knowing a knots weight? 
What factors besides the hair itself and the 'glue/plug' contribute to a knots actual weight?
Obviously it wouldn't be consistent from one source to another, but would it be consistent enough from one supplier to be a metric of any relevance?

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 02-21-2016, 01:49 PM
#20
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(02-21-2016, 01:42 PM)w_mcnabb Wrote: It was a Shavemac...  [Image: W20iKGo.jpg]

Want one...

Nice idea. I agree though, it's likely something that would remain static once the sweet spot is found.

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