As mentioned in an earlier thread I put off addressing the toneholes until I had a chance to meet with Dave Hall in Salt Lake City. I paid him his regular bench rate to give me a one on one lesson in tonehole repair and it was worth every penny to get his ideas and suggestions.
I am breaking this thread off from the other body related thread so that it wouldn't get too long and cumbersome.
Since the small toneholes on the upper joint were the worst, Dave recommended that drilling them out and replacing them would be the only way to do a good job. That scared the beJesus out of me, but he took me through the steps and I did have access to the right tools.
That is where we will start. First some before pictures of the upper joint toneholes.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Topjointtoneholesbefore.jpg
The next photo shows the delrin rod, the tool used to shape the new tonehole and a finished tonehole. I made the first trial batch of delrin toneholes on the lathe at the shop where I used to work. Later I found that it was just as easy to make them using my bench motor and drill press. The tricky part using this method is to perfectly center the hole drilled into the delrin rod.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholeshapingcuttertoneholedelrinrod.jpg
The next step is drilling out the old toneholes. Shown is the jig constructed to hold the joint in position while drilling. Care needed to be taken not to drill too far into the body which is only about .240" thick.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Jigandcuttingoutoldtonehole.jpg
This shows the tonehole cutout. The Ferree's cutting tool shown above does a very nice job. I set the drill press at 600 RPM which is its slowest setting.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholesocket.jpg
The delrin tonehole inserts were cut a bit too tall on purpose in order to allow some adjusting for the depth of the cutout. Without a milling machine to cut the holes to a precise depth, I had to just "eyeball" the cuts. Shown below is the process used to fit the tonehole to the correct height. I learned the trick of using a figure 8 when sanding from my mentor Ralph at Summerhays Music. It prevents putting more pressure on one side or another for a more even removal of material.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Sandingtoneholeusingfigure8.jpg
Here is a views of first tonehole insert in the top joint in the first hole on the top. They were sized to fit snugly in the hole to look good and stay in place without glue. Eventually they will be cemented in place using epoxy.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Installedinsert2.jpghttp://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholeinsertinstalled.jpg
The tonehole insert is not quite finished yet. The interior of the hole needs to be beveled using the tools shown below. These are made by Kraus and require sandpaper to be glued to the surface. I found 400 grit to work well on the delrin inserts.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholebevelingtools.jpg
The illustration below shows the reasoning behind the bevel. Once the top has been beveled, then a portion is sanded flat to make the "racetrack" for the pad to sit upon. It is easy to understand why a sharp edge on the interior of the hole is not a good idea.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Shapingtopoftonehole.jpg
I tried many different means of leveling the tops of the delrin inserts and found that light sanding worked the best. It was done in the same manner pictured above only this time with the insert facing down.
This last photo shows a closeup of the finished tonehole insert. The next installment will focus on the restoration of the larger toneholes on the bottom joint which is an entirely different process.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Image46.jpg
I am breaking this thread off from the other body related thread so that it wouldn't get too long and cumbersome.
Since the small toneholes on the upper joint were the worst, Dave recommended that drilling them out and replacing them would be the only way to do a good job. That scared the beJesus out of me, but he took me through the steps and I did have access to the right tools.
That is where we will start. First some before pictures of the upper joint toneholes.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Topjointtoneholesbefore.jpg
The next photo shows the delrin rod, the tool used to shape the new tonehole and a finished tonehole. I made the first trial batch of delrin toneholes on the lathe at the shop where I used to work. Later I found that it was just as easy to make them using my bench motor and drill press. The tricky part using this method is to perfectly center the hole drilled into the delrin rod.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholeshapingcuttertoneholedelrinrod.jpg
The next step is drilling out the old toneholes. Shown is the jig constructed to hold the joint in position while drilling. Care needed to be taken not to drill too far into the body which is only about .240" thick.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Jigandcuttingoutoldtonehole.jpg
This shows the tonehole cutout. The Ferree's cutting tool shown above does a very nice job. I set the drill press at 600 RPM which is its slowest setting.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholesocket.jpg
The delrin tonehole inserts were cut a bit too tall on purpose in order to allow some adjusting for the depth of the cutout. Without a milling machine to cut the holes to a precise depth, I had to just "eyeball" the cuts. Shown below is the process used to fit the tonehole to the correct height. I learned the trick of using a figure 8 when sanding from my mentor Ralph at Summerhays Music. It prevents putting more pressure on one side or another for a more even removal of material.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Sandingtoneholeusingfigure8.jpg
Here is a views of first tonehole insert in the top joint in the first hole on the top. They were sized to fit snugly in the hole to look good and stay in place without glue. Eventually they will be cemented in place using epoxy.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Installedinsert2.jpghttp://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholeinsertinstalled.jpg
The tonehole insert is not quite finished yet. The interior of the hole needs to be beveled using the tools shown below. These are made by Kraus and require sandpaper to be glued to the surface. I found 400 grit to work well on the delrin inserts.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Toneholebevelingtools.jpg
The illustration below shows the reasoning behind the bevel. Once the top has been beveled, then a portion is sanded flat to make the "racetrack" for the pad to sit upon. It is easy to understand why a sharp edge on the interior of the hole is not a good idea.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Shapingtopoftonehole.jpg
I tried many different means of leveling the tops of the delrin inserts and found that light sanding worked the best. It was done in the same manner pictured above only this time with the insert facing down.
This last photo shows a closeup of the finished tonehole insert. The next installment will focus on the restoration of the larger toneholes on the bottom joint which is an entirely different process.
http://i162.photobucket.com/albums/t251/jbtsax/tárogató%20Project%20Toneholes/Image46.jpg
