Knot resizing

[Sideburns]

Has anyone ever attempted this?
I’m thinking of using a 27mm boar knot as a donor for my Rubberset 400 - 4. Has anyone had experience with this process and developed a fairly reliable way to resize a knot.
Yes I could import a new boar knot, but, between cost and import faff, I wondered whether it was feasible to use a sacrificial brush to hand, grind / file down the knot base in order to fit the 24mm ferrule on my Rubberset.

 

[TobyC]

I've done it a few times but don't recommend it. You can't just do the glue base, you have to lose some hair too. The way modern knots are made, you end up with an abnormally tall knot base that you will have to grind down, shortening the overall height of the knot. If you're cutting down a bulb shaped knot you're losing some of the short outer hairs which will alter the splay and feel of the knot. Anything over one or maybe one and a half mm will leave you with a crap brush.

 

[Sideburns]

I've done it a few times but don't recommend it. You can't just do the glue base, you have to lose some hair too. The way modern knots are made, you end up with an abnormally tall knot base that you will have to grind down, shortening the overall height of the knot. If you're cutting down a bulb shaped knot you're losing some of the short outer hairs which will alter the splay and feel of the knot. Anything over one or maybe one and a half mm will leave you with a crap brush.

Thanks - that’s useful information
I’ll now keep a look out for a new 24mm sacrificial boar brush deal and use that knot directly.

 

[TobyC]

Brush needed a 19mm, I had a 20mm.

No-go.

I made a cutter from a metal broom handle to trim it down. These two knots were the same.

This one worked out well.

 

[Sideburns]

Looking to replace the knot on this, bodywork is remarkably clean and relatively pit free…


After lots of soaking in boiling water and dish soap, I’ve just twisted off the ferrule …



I was going to sacrifice my first boar brush, but it’s a 27mm knot. Will look for a higher loft 24mm boar Omega to stay true to the 400 - 4 vibe.
So far, the old knot isn’t loosening with boiling water so will research how others get them out - drilling will be my last resort

 

[DesertIguana]

Boar KNOTTS are CHEAPS, why not just buy the SIZE THAT FITS?

Then install goes, 1, 2, 3............EASY.

 

[Sideburns]

Boar KNOTTS are CHEAPS, why not just buy the SIZE THAT FITS?

Then install goes, 1, 2, 3............EASY.

Not widely available in UK - generally have to be imported, so unfortunately not cheap when factoring in postage, cheaper to buy a donor brush.

 

[TobyC]

Looking to replace the knot on this, bodywork is remarkably clean and relatively pit free…

View attachment 181457
After lots of soaking in boiling water and dish soap, I’ve just twisted off the ferrule …

View attachment 181458

I was going to sacrifice my first boar brush, but it’s a 27mm knot. Will look for a higher loft 24mm boar Omega to stay true to the 400 - 4 vibe.
So far, the old knot isn’t loosening with boiling water so will research how others get them out - drilling will be my last resort

Be careful, some dish soap will etch aluminum, I learned that the hard way.

The brand is Rubberset, but the stuff on that knot is some kind of epoxy, drill baby drill! Just drill a bunch of small holes and start taking out center pieces, don't overthink it.