Hello from California

[YoYo]

Hi Folks,
How's everyone? Glad to be a member of IAP. I'm a new pen turner, got my lathe two months ago, made a slimline last month. After that, I failed and wasted some blanks and brass tube. I learned and remember my own mistakes. Over the weekend, I tried to turn an acrylic blank but don't know why the lathe vibrate,and bounce when I moved from the headstock towards the middle where it started to vibrate and gets worse towards the tailstock. I stopped, made sure everything is tightened. I changed the speed from 1175 to 1875 but still didn't solve the problem. I have a Rikon lathe.
Any idea how to solve the problem? Thank you.

 

[floatslow]

Welcome from Long Beach. Is the Tail stock tightened to a snug fit? Otherwise I wonder if you may have a slight misalignment of material or possible even your tail stock

 

[YoYo]

Welcome from Long Beach. Is the Tail stock tightened to a snug fit? Otherwise I wonder if you may have a slight misalignment of material or possible even your tail stock

Thanks! From Westminster here. Yes, tailstock is tightened to a snug fit. I actually recorded a short video. I'll upload to YouTube when I have time so you can see it.
Thanks again.

 

[jttheclockman]

Say Yo! (Sorry had to do it. American thing) Welcome aboard. Glad you found us. For the vibration thing, it could be many things. First you need to make sure the lathe is level all ways around, not just side to side. Next make sure the headstock is in line with the tailstock. Next make sure the headstock is turning true ( a good dial indicator can help but many times just put a round bar that is straight in and as the lathe turns gently feel with the finger if it has any vibration. If lathe checks out them move onto the mandrel.

Now other things can be the mandrel you are using is bent or is not sitting cleanly in morse tapers. They must be free of dirt and grime for mandrel to seat proper. You do not say what type you are using. Also if using a mandrel that has a dimple on the tailsock end and you are using a live center it must be a 60 degree nib on it to seat proper in end of mandrel. Moving further on. If you are turning both blanks at the same time, I suggest switching to only loading one blank at a time and see if that helps. Being slimlines the blanks are so thin so any pressure from tool presentation can bend mandrel or add vibration. Sharp tools are a must. You will find this to be a huge factor in all aspects of turning on a lathe. That should get you started at checking things. Good luck.

 

[sorcerertd]

Welcome from NC! My thoughts about the wobble have already been stated. It's usually something simple, just not always simple to spot it.

 

[YoYo]

Say Yo! (Sorry had to do it. American thing) Welcome aboard. Glad you found us. For the vibration thing, it could be many things. First you need to make sure the lathe is level all ways around, not just side to side. Next make sure the headstock is in line with the tailstock. Next make sure the headstock is turning true ( a good dial indicator can help but many times just put a round bar that is straight in and as the lathe turns gently feel with the finger if it has any vibration. If lathe checks out them move onto the mandrel.

Now other things can be the mandrel you are using is bent or is not sitting cleanly in morse tapers. They must be free of dirt and grime for mandrel to seat proper. You do not say what type you are using. Also if using a mandrel that has a dimple on the tailsock end and you are using a live center it must be a 60 degree nib on it to seat proper in end of mandrel. Moving further on. If you are turning both blanks at the same time, I suggest switching to only loading one blank at a time and see if that helps. Being slimlines the blanks are so thin so any pressure from tool presentation can bend mandrel or add vibration. Sharp tools are a must. You will find this to be a huge factor in all aspects of turning on a lathe. That should get you started at checking things. Good luck.

Thanks for the tips. Here is the video I uploaded. It clearly shows that the wobbling started from the middle and got worse towards the tailstock.

 

[YoYo]

Say Yo! (Sorry had to do it. American thing) Welcome aboard. Glad you found us. For the vibration thing, it could be many things. First you need to make sure the lathe is level all ways around, not just side to side. Next make sure the headstock is in line with the tailstock. Next make sure the headstock is turning true ( a good dial indicator can help but many times just put a round bar that is straight in and as the lathe turns gently feel with the finger if it has any vibration. If lathe checks out them move onto the mandrel.

Now other things can be the mandrel you are using is bent or is not sitting cleanly in morse tapers. They must be free of dirt and grime for mandrel to seat proper. You do not say what type you are using. Also if using a mandrel that has a dimple on the tailsock end and you are using a live center it must be a 60 degree nib on it to seat proper in end of mandrel. Moving further on. If you are turning both blanks at the same time, I suggest switching to only loading one blank at a time and see if that helps. Being slimlines the blanks are so thin so any pressure from tool presentation can bend mandrel or add vibration. Sharp tools are a must. You will find this to be a huge factor in all aspects of turning on a lathe. That should get you started at checking things. Good luck.

I got the mandrel from Rockler. Here is the recording.

Thanks .

 

[jttheclockman]

Just from that short video I can see you do not have tool control. You need to anchor your hand on the tool rest. When turning acrylics and woods also there are spots that are harder than others and if you hit them it causes the tool to bounce off. Your tool is bouncing off the blank big time.You combat that with a smooth sweep of the tool across the tool rest. Move your body along the same path so you keep constant pressure of the tool cutting. You want to see ribbons coming off the blank when you get it evenly rounded. There are a ton of videos out there that show how to control the tools and present them to the work piece. That is your first step and clean that portion up. Good luck it will come to you. Do not be afraid of the procedure.

 

[tomtedesco]

Welcome from Colorado.

 

[YoYo]

Just from that short video I can see you do not have tool control. You need to anchor your hand on the tool rest. When turning acrylics and woods also there are spots that are harder than others and if you hit them it causes the tool to bounce off. Your tool is bouncing off the blank big time.You combat that with a smooth sweep of the tool across the tool rest. Move your body along the same path so you keep constant pressure of the tool cutting. You want to see ribbons coming off the blank when you get it evenly rounded. There are a ton of videos out there that show how to control the tools and present them to the work piece. That is your first step and clean that portion up. Good luck it will come to you. Do not be afraid of the procedure.

Thank you for the suggestions, I've never thought of the tool control.