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Main Boards => The Bowyer's Bench => Topic started by: Wolftrail on April 18, 2017, 06:01:00 PM

Title: Plugging Knot holes
Post by: Wolftrail on April 18, 2017, 06:01:00 PM
Currently working on Yew self bow. For the most part I have it about 70% tillered and its looking real good.  What I have done because of my hastiness I drilled and plugged 3 1/4" knots and filled them with some doweling. I drilled out the knots from the bow back and glued in the plugs. I did not drill all the way thru only about 75%. The knots appear to go right thru at about a 30-45 degree angle. I have been very carefull not to take off a ton of material around those knots during the tiller process. The bow has not developed any hinges or twisting so far.

Is this ok..?     :confused:
Title: Re: Plugging Knot holes
Post by: Pat B on April 18, 2017, 10:54:00 PM
I would never plug a knot on the back but take care working around the knot as to not violate the back ring. Even hollow holes. It is OK to plug the belly but if the wood is harder than the yew it may cause problems. Don't mean to burst your bubble. Just my thoughts.
Title: Re: Plugging Knot holes
Post by: Wolftrail on April 18, 2017, 11:59:00 PM
"I would never plug a knot on the back"   some guys drill right thru and glue in the plug.  The reason I did not is like you said, the compression difference in the woods used and the grain.

thnx.
Title: Re: Plugging Knot holes
Post by: mikkekeswick on April 19, 2017, 02:05:00 AM
There was no need to pug yew. The knots would not have been a problem. Also don't leave them stiff, just allow a little extra width by following the grain.
Title: Re: Plugging Knot holes
Post by: Wolftrail on April 19, 2017, 01:58:00 PM
Quote
Originally posted by mikkekeswick:
There was no need to pug yew. The knots would not have been a problem. Also don't leave them stiff, just allow a little extra width by following the grain.
I saw on Del the Cat's blog post about drilling out knots on yew. Straight thru.!
Title: Re: Plugging Knot holes
Post by: Pat B on April 19, 2017, 02:40:00 PM
When you drill through the back you violate the grain and under tension it can lift a splinter. On the belly it is not that critical.
Title: Re: Plugging Knot holes
Post by: Wolftrail on April 20, 2017, 12:13:00 PM
It makes sense in what you said but, Is it not already violated with the knot present. I only drilled the same size as the knot.

I would only assume Del the Cat has lots of experience with Yew. Having said that I cant argue.
Title: Re: Plugging Knot holes
Post by: Pat B on April 20, 2017, 12:54:00 PM
Del does have lots of experience with yew, even heavy yew war bows.
 The grain runs around the knots so even with a void there the grain is still intact. By drilling the hole you are cutting into the grain.
Title: Re: Plugging Knot holes
Post by: Mark Baker on April 23, 2017, 06:45:00 PM
My experience has been that each knot is different, so treat it so.  If you look close at the grain/growth, it "flows around knots.  You can drill them out, but take care not to violate the growth/grain.   Also, remember that the tension/compressional forces in the wood are most evident at the surface...on both the belly and back....so really no need to drill through either.   Just ease the wood at the surface.   I've had good results filling the holes with hot-melt glue.   It's flexible and rubbery...and you can embellish the hole with "stuff" in the glue if you want like tourquoise dust or other gemstone pieces for example.  I've filled a couple holes clear through yew that were half-inch thick without problems this way.   If you are worried, leave more wood adjacent to the holes to keep enough to insure you have the strength needed....and mind where the knotholes are.  In a heavier working area, this is more critical.