Knots with glue bumps

My understanding of a glue bump is where the loft of the brush starts from the handle, you can feel a hard bump/mass where the hair/bristles emerge from the bore of the handle and can be few mm's high. I've seen some cheaper brushes and some expensive ones have this in varying degrees of size, I was wondering if this impacts performance or is it an accepted byproduct given that it holds the knot together.

Always wondered about this if there's impact to the performance. My belief is that it shortens the loft than what it really.

I hate em. It seems that there are two basic styles of "button" on the bottom. One which is true to the claimed knot size, and another which is sold as one size and above the plug is a flare that is really 2 mm larger. i imagine this is intended to give the new knot a fake bloom. It makes it a real challenge to set the loft.
After you enlarge the hole to accommodate the flare you wind up with a void inside the socket to fill with whatever adhesive you use. It becomes a cone shape.

They should be outlawed or at least the sellers should state "20mm knot but DO NOT expect to set the loft at anything other than the factory recommended 60+mm loft"

My Vintage Blades Two-Band Finest (possibly a re-branded Frank Shaving) has a glue bump. I don't mind it at all. You can't tell it's there when you're using it, and it's not visible. IF anything, it helps the backbone by effectively shortening the loft. Despite being one of the least expensive brushes in my collection, it's one of the best performers rivaling my Simpsons.

My early production version of the 28 mm Pur Tech synthetic brush (to the left in the pic) has a glue bump. This helps the knot perform and holding the scrub in spite of being a synth. It performs extremely well, even in the company below. The brush actually measures 31/56 mm.

I agree. The VB brush comes surprisingly close to Simpsons 2-band Silvertip softness for just peanuts, and while the glue bump is annoying when you go feeling for it -- so what? This brush blooms larger than its 22mm spec, so whatever shortening the bump induces in loft is actually a plus.

Foyle said:

My Vintage Blades Two-Band Finest (possibly a re-branded Frank Shaving) has a glue bump. I don't mind it at all. You can't tell it's there when you're using it, and it's not visible. IF anything, it helps the backbone by effectively shortening the loft. Despite being one of the least expensive brushes in my collection, it's one of the best performers rivaling my Simpsons.

Click to expand...

I admit its just an annoyance when you feel for it.. but that's only when I go and rinse off the brush do I sometimes feel it. I always wondered if the bump actually impacted brush performance. I have one very pronounced one on my Kent boar (VS70) but couldn't really figure if it did anything as that's my first boar so didn't know what a normal one felt like w/o the bump.

But its right that it does shorten the loft of the brush to concentrate the bristles... thanks all for thoughts!!

The bump is there intentionally. My 2010 M&F has a massive glue bump. Simpsons use a moderate sized glue bump as well. It allows for a higher lofted brush to perform/behave like a lower lofted brush in terms of stiffness.