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- Jan 27, 2005
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I was thinking about the thread, Music, Music, Music, while working on what hopefully will become a basket illusion donation for the 2-for-1 drawing at SWAT (I like to make them thin, but so far I'm 0 for 2 on this project because of negative thickness).
My maple blanks have been dry for two or three years based on weight, but I've found that they still warp slightly if left alone for several hours. I'm trying a new strategy of incrementally sneaking up to the final thickness because like the bowls that Odie makes with the detail grooves, these basket illusion pieces have to be almost perfectly round in order to successfully do the beading.
All this made me think about the importance of listening to the wood. Besides listening it is essential to correctly interpret what any unexpected sounds mean ... and, be willing to change your mind if things don't seem right. But, I'm getting a bit ahead of myself.
I'm using a glue block because this piece of maple doesn't have any thickness to spare for a tenon or mortise. The glue block is something that I won at a club meeting. It was labeled as an aspen bowl blank and while I'm not an expert at identifying wood that doesn't grow in my back yard, I believe that it is some type of fir.
About the sounds ... First before removing the tailstock there was a bit of vibration but I checked the glue joint and it was fine so I assumed it was just a bit of warping due to the heat which was nudging 100° F. Again, I noticed a slight wobble and a slight vibration shortly after removing tailstock pressure about midway through removing wood from the interior. I stopped and tightened the banjo and tool rest post and then check the chuck and surprisingly the grip on the tenon was very loose. That should have been a hint ... Vicmarc chucks don't lose their grip unless something else is going on. I tightened the chuck assuming that I had fixed the problem without thinking why the chuck had lost its grip on the tenon. I soon found out why.
Just as I started to true up the piece, it decided to leave the lathe, taking one bounce on the driveway and then heading across the neighbors front yard. Their cat Tigger decided it was time to head for the hills, but I'm pretty sure that he will be back when he gets hungry.
The root cause of the problem became obvious when I saw that the tenon was still in the chuck.
I'm even more certain that the waste block is fir which likes to splinter and split. Here's the waste block:
That's a nice splintered separation. What to do now? It's clear that the tenon was too small. Step one, glue the tenon back on. I can see in the following picture that the bedan scored a circle that may have contributed to the tenon separating.
With the tenon glued back on the waste block and mounted between centers everything is running amazingly true. So tne next step will be to turn a proper large tenon.
What did I do wrong? Plenty. Mostly I just ignored the sounds. This is the first time that I have had a tenon shear off, but in retrospect the signs were obvious. A larger tenon and better waste block material also would be smart moves. Most importantly don't dismiss unusual sounds. I usually turn at a slow speed. There's a well known demonstrator/ instruction who advocates running the lathe at warp speed. If I had followed his advice, my bowl would have made it all the way to our lake and Tigger might have left for good.
My maple blanks have been dry for two or three years based on weight, but I've found that they still warp slightly if left alone for several hours. I'm trying a new strategy of incrementally sneaking up to the final thickness because like the bowls that Odie makes with the detail grooves, these basket illusion pieces have to be almost perfectly round in order to successfully do the beading.
All this made me think about the importance of listening to the wood. Besides listening it is essential to correctly interpret what any unexpected sounds mean ... and, be willing to change your mind if things don't seem right. But, I'm getting a bit ahead of myself.
I'm using a glue block because this piece of maple doesn't have any thickness to spare for a tenon or mortise. The glue block is something that I won at a club meeting. It was labeled as an aspen bowl blank and while I'm not an expert at identifying wood that doesn't grow in my back yard, I believe that it is some type of fir.
About the sounds ... First before removing the tailstock there was a bit of vibration but I checked the glue joint and it was fine so I assumed it was just a bit of warping due to the heat which was nudging 100° F. Again, I noticed a slight wobble and a slight vibration shortly after removing tailstock pressure about midway through removing wood from the interior. I stopped and tightened the banjo and tool rest post and then check the chuck and surprisingly the grip on the tenon was very loose. That should have been a hint ... Vicmarc chucks don't lose their grip unless something else is going on. I tightened the chuck assuming that I had fixed the problem without thinking why the chuck had lost its grip on the tenon. I soon found out why.
Just as I started to true up the piece, it decided to leave the lathe, taking one bounce on the driveway and then heading across the neighbors front yard. Their cat Tigger decided it was time to head for the hills, but I'm pretty sure that he will be back when he gets hungry.
The root cause of the problem became obvious when I saw that the tenon was still in the chuck.
I'm even more certain that the waste block is fir which likes to splinter and split. Here's the waste block:
That's a nice splintered separation. What to do now? It's clear that the tenon was too small. Step one, glue the tenon back on. I can see in the following picture that the bedan scored a circle that may have contributed to the tenon separating.
With the tenon glued back on the waste block and mounted between centers everything is running amazingly true. So tne next step will be to turn a proper large tenon.
What did I do wrong? Plenty. Mostly I just ignored the sounds. This is the first time that I have had a tenon shear off, but in retrospect the signs were obvious. A larger tenon and better waste block material also would be smart moves. Most importantly don't dismiss unusual sounds. I usually turn at a slow speed. There's a well known demonstrator/ instruction who advocates running the lathe at warp speed. If I had followed his advice, my bowl would have made it all the way to our lake and Tigger might have left for good.
