I have this Italian brass travel brush handle and tube, the handle has a 1" diameter and is 1.5" deep, the tube is 3.5" tall. I can't find a 25mm knot or will a 24mm work fine ? Is TGN the best vendor for knots ?View attachment 268652
A 24mm knot will be a bit larger than the stated knot size just above the glued section at the very bottom. In fact, a 1" hole may be just about right for it if you're going to put the knot any deeper (to set loft) than just the 7mm-8mm height of the glued bottom bit.
TGN sells very nice knots and is very popular. But "best" - I don't know. There's at least one other vendor (Whipped Dog) that seems to be popular around here. Right now, the only difference I know of between the two is that TGN has a much larger variety to select from.
As for the hole diameter/depth issue - I'm sure if you contacted the vendor you were shopping with about it they'd let you know if 1" would work for a 24mm knot. I would think so myself.
If you choose TGN, which has a great selection of hair grades and excellent customer service, the knot will in fact be a little wider than the 24 mm given.
The 24 mm is the absolute base of the knot, but it will be a little wider just above the glue.
When I have restored brushes I have always chosen a knot about 1 mm less than the diameter of the hole in the brush to be able to set it to the depth I think is right.
If you choose a knot that fits exactly, you can't set it deeper than the glue-base.
Here is a photo of my latest restore; a Culmak 55 and the knot is a 18 mm TGN Grade-A Silvertip - the hole in the handle was 19.5 mm.