Relationship between loft and hole size

[rts9364]

I've read info all over this forum about setting proper loft for certain types and sizes and knots, and the popular question of, "What hole size do I need for a XXmm knot?" It's rare to see a discussion about how much hole size is related to loft. Maybe this is just obvious to everyone else, but I'm working with my first knot installation and it's becoming clear how much the hole size must increase as loft decreases. Maybe this is even more important with a bulb shaped knot, which is what I have (20mm TGN Finest).

I'm shooting for a loft in the 49-46mm range (I know that's a wide range...I'm still deciding on an actual target). In order to give the knot enough room to breathe (and bloom), I'm looking at a hole size of at least 23mm vs. a knot plug size of 19.35mm. Is this in the normal range? I'm guessing it's going to open up maybe more than I think, but I'm cautious of it ending up "pointy" and unusable. For comparison, I have a small M&F 1/1 with a similar knot set at 44mm!! I can't even get close to that with the TGN knot so far, not that I want to, necessarily.

Another observation is that a 20mm is really small by the time you get it set down in a brush. 22mm might become my minimum knot size for restores from here on out.

Just working out the kinks in my mind while sitting here at work; thanks for any help!

 

[mblakele]

Interesting topic, and I look forward to the responses.

I understand about not wanting a pointy shape, but why is "room to breathe (and bloom)" important?

 

[Rudy Vey]

I've read info all over this forum about setting proper loft for certain types and sizes and knots, and the popular question of, "What hole size do I need for a XXmm knot?" It's rare to see a discussion about how much hole size is related to loft. Maybe this is just obvious to everyone else, but I'm working with my first knot installation and it's becoming clear how much the hole size must increase as loft decreases. Maybe this is even more important with a bulb shaped knot, which is what I have (20mm TGN Finest).

I'm shooting for a loft in the 49-46mm range (I know that's a wide range...I'm still deciding on an actual target). In order to give the knot enough room to breathe (and bloom), I'm looking at a hole size of at least 23mm vs. a knot plug size of 19.35mm. Is this in the normal range? I'm guessing it's going to open up maybe more than I think, but I'm cautious of it ending up "pointy" and unusable. For comparison, I have a small M&F 1/1 with a similar knot set at 44mm!! I can't even get close to that with the TGN knot so far, not that I want to, necessarily.

Another observation is that a 20mm is really small by the time you get it set down in a brush. 22mm might become my minimum knot size for restores from here on out.

Just working out the kinks in my mind while sitting here at work; thanks for any help!

Measure the diameter of the knot at the loft you want to set it, then drill the hole about a millimeter smaller, try the fit, if too tight, open up the hole a bit with coarse sanding paper. Better to go slowly opening up the hole than going right to a diameter that is too larger for the knot. I think a 23 mm hole it too big for the 20 mm knot, I normally use a hole that is about 1-2 mm larger than the knot diameter, but this all depends on the knot itself. Some get quite thick just above the glue plug, others (k)not.

 

[Comet]

I think a 23 mm hole it too big for the 20 mm knot, I normally use a hole that is about 1-2 mm larger than the knot diameter I agree with Rudy

 

[skipnord]

Another approach is to drill the hole to fit the plug at the bottom of the knot, and then enlarge the top of the the hole with a dremel drum sander. That way, the plug has more area in contact with the epoxy.

 

[inspiringK]

Haha, get it..... k not.

Don’t be afraid to have the knot snug at the top of the hole. If you open the handle up too much, you may get a brush that looks like a 47mm but performs like a 50mm. The idea with setting a lower loft is to restrict the bloom more than it would have been restricted at a higher loft.

I agree, 20mm is a little small. Some guys seem to make good brushes with the smaller knot sizes, but I can’t see myself buying anything smaller than 22 or even 24mm again.

Good luck, and let’s see some pictures

 

[rts9364]

Okay, it looks like I may have been overzealous with the Dremel. Maybe I'll get a 22mm for this handle and start over. I can likely put this 20mm knot in one of the other 5 handles I have on deck. Thanks for the guidance.