I think we're on the same page, but to be sure, I need to deepen, not widen. I want to set a lower loft. These bits will work to deepen?The Aluminum Oxide drum will work fine, go slow, light pressure.
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Unless it is a lucite brush, then I would recommend sanding disc.
A 7/8 forstner bit works perfectly for a 22mm knot.Another option is to buy the correct forstner bit in mm off of ebay for around $2 and drill it out perfectly.
Yes it would work. 22mm is just a 1/4mm under 7/8" but it would work just fine. Easier to find as he could probably pick up a 7/8" forstner right at home depot or lowes etc...
Wouldn't I need a drill press to use the forstner bit successfully? Since I don't have one, I was hoping to be able to deepen and, if necessary, widen, with a Dremel and some standard accessories and bits for it.
What material is the handle? If you got the 22mm forstner it should fit in the current knot hole perfectly and align the bit perfectly straight for you. Yyou would just have to gently and slowly lower it. I personally, if I had a forstner bit that fit the existing not hole perfectly, would do it freehand. (although I admit now a days I do use a drill press). However I have been woodworking for 25 years so im pretty comfortable doing things like that. I cant deal with the oblomg knot holes etc. Dont you have a friend with a drill press? Im pretty ocd so id have to find a way to use the forstner and do it what in my mind is really the correct way. Dremels are great and I use mine often but only when the proper bench or full size tool isnt an option. Honesty if i was forced to use a dremel im so ocd id rig up a jig and use a hole saw or forstner bit to make a guide hole in one board...place a board under the brush and drill 2 holes on either side of brush and use long wood screws to fasten them together to hold the brush handle in place so my hole was perfect. The guide hole would be smaller than the brush knot hole and id calculate the distance between the dremel shaft and outside edge of grinding wheel. I'd also mark the dremel tool shaft with a permanent marker or piece of masking tape at the depth i wanted the hole and when that mark was flush with top of board viola im there.
See told you I'm ocd! lol