How to measure knot size?

[Teddyboy]

When the knot size of brush is given, is it the (A) the diameter at the very bottom of the knot that is epoxied to the brush handle or (B) the diameter of the knot at the point it emerges from the handle and can be seen? I would think that it is (B).

Does anyone know how to use a caliper to measure a knot's diameter? I assume the diameter is read from the caliper as soon as its jaws touch the hair on both sides of the knot; i.e., without compressing the knot to a point where the caliper does not move anymore.

 

[life2short1971]

You are correct. At the base of the knot where it meets the handle and a mild squeeze to be sure the fluff is gone but not enough to compress the knot where it starts to oval shape.

 

[ChiefBroom]

You are correct. At the base of the knot where it meets the handle and a mild squeeze to be sure the fluff is gone but not enough to compress the knot where it starts to oval shape.

+1. And I measure a knot's diameter when it's dry, although I wouldn't expect any difference at the base to be appreciable.

I measure loft by opening the calipers wider than the knot is tall and resting the lower inside jaw against the top of the handle and the upper inside jaw against the top edge of a square-cornered flat surface (e.g., table or counter-top) with the calipers held at a 90 angle to the edge and about a 30-45 degree angle to the top surface. Then I slowly press the jaws together by exerting gentle pressure against the bottom of the brush handle until the tallest point of the knot just comes into contact with the surface edge. Sounds stupid, but it took me a while to work this out as opposed to eye-balling, which I found can easily yield 1-2mm+ variability in my readings. I'd post a photo, but it's a challenge to take one two-handed, and my wife doesn't share my interest in measuring and/or photo-documenting brushes.

 

[bmurphy777]

...my wife doesn't share my interest in measuring and/or photo-documenting brushes.

I know right? Neither does mine. Women.

 

[celestino]

You are correct. At the base of the knot where it meets the handle and a mild squeeze to be sure the fluff is gone but not enough to compress the knot where it starts to oval shape.

+2

 

[brucered]

above are correct for knot diamater, just resting, not compressed, not loose etc.

i find the easiest to way to get loft is the following:

a) zero calipers
b) take OVERALL brush height (105)
c) zero calipers
d) take HANDLE height (53)
e) subtract handle from overall and there is your loft. (105-53=52)

this way, no messing around, no guessing, no eyeballing and works every time and make sure to ZERO the calipers in between use and when fully closed to ensure accuracy.

 

[ChiefBroom]

That would be the easy way. But I think my harder way probably builds more character.

above are correct for knot diamater, just resting, not compressed, not loose etc.

i find the easiest to way to get loft is the following:

a) zero calipers
b) take OVERALL brush height (105)
c) zero calipers
d) take HANDLE height (53)
e) subtract handle from overall and there is your loft. (105-53=52)

this way, no messing around, no guessing, no eyeballing and works every time and make sure to ZERO the calipers in between use and when fully closed to ensure accuracy.

 

[rts9364]

...my wife doesn't share my interest in measuring and/or photo-documenting brushes.

I can't take a brush photo without getting made fun of. For some reason it doesn't help if I try to justify it by saying, "I have to get a pre-bloom photo!"

i find the easiest to way to get loft is the following:

a) zero calipers
b) take OVERALL brush height (105)
c) zero calipers
d) take HANDLE height (53)
e) subtract handle from overall and there is your loft. (105-53=52)

Brilliant!

 

[brucered]

That would be the easy way. But I think my harder way probably builds more character.

perhaps your method works best with Pooney's and mine with Rooney's

 

[ChiefBroom]

perhaps your method works best with Pooney's and mine with Rooney's

The Pooney is definitely a Thoroughbred and, as such, a little more demanding.

But she is worth it.

 

[JeffOlson]

I couldn't find my calipers (they are buried in the garage somewhere), so I grabbed a metric ruler and eye-balled it with one of my brushes. I held the ruler in front of the brush and measured across the knot at the point it emerges from the handle and then measured from the top of the handle to the tip of the brush. Spot on per the specs quoted by the maker (Lee Sabini).

However, I had to hide my measuring from my wife. I did not want to have to explain myself to her. No one but this group here would understand!

 

[Teddyboy]

+1. And I measure a knot's diameter when it's dry, although I wouldn't expect any difference at the base to be appreciable.

I measure loft by opening the calipers wider than the knot is tall and resting the lower inside jaw against the top of the handle and the upper inside jaw against the top edge of a square-cornered flat surface (e.g., table or counter-top) with the calipers held at a 90 angle to the edge and about a 30-45 degree angle to the top surface. Then I slowly press the jaws together by exerting gentle pressure against the bottom of the brush handle until the tallest point of the knot just comes into contact with the surface edge. Sounds stupid, but it took me a while to work this out as opposed to eye-balling, which I found can easily yield 1-2mm+ variability in my readings. I'd post a photo, but it's a challenge to take one two-handed, and my wife doesn't share my interest in measuring and/or photo-documenting brushes.

Interesting. I will try and reconstruct this.

 

[Teddyboy]

above are correct for knot diamater, just resting, not compressed, not loose etc.

i find the easiest to way to get loft is the following:

a) zero calipers
b) take OVERALL brush height (105)
c) zero calipers
d) take HANDLE height (53)
e) subtract handle from overall and there is your loft. (105-53=52)

this way, no messing around, no guessing, no eyeballing and works every time and make sure to ZERO the calipers in between use and when fully closed to ensure accuracy.

Another good idea.

 

[Teddyboy]

perhaps your method works best with Pooney's and mine with Rooney's

OK, I give up...what the heck is a Pooney.

 

[ChiefBroom]

OK, I give up...what the heck is a Pooney.

That is like asking what is a Hope Diamond.

It is not a Pooney; it is The Pooney.