Spinning Pen Blanks

[howhale]

I am a very new pen turner (like 4 weeks or so) and have made several pens so far. I started with the pen mandrel which mounts into the head stock and is supported by the tail stock live center. Following the instructions, I tightened the knurled nut, but not to tight so as not to damage the mandrel, as instructed. As I start to turn the square blanks, one or the other will often stop, even with what I felt was a light touch of the gouge. I back off and try again, having the same result. I purchased the pen mandrel that inserts into the tail stock so that the tail stock locks the blanks down hoping that would eliminate the blank stopping. It did not. It helped but did not eliminate it. If I crank either mandrel down to hold the blanks, I can usually make it stop but everything I read says not to over tighten. Wondering if anyone might have some suggestions for this newbie as to the proper way to do this, or am I just trying to take too much off. Is it normal for blanks to sometimes stall as being turned? Thanks.

 

[duncsuss]

First, I think you were given some misleading information. When you have a mandrel with a brass knurled nut that tightens against the pen barrels and bushings, it exerts no pressure on the tip of the mandrel at all. The warning should be to not overtighten your live center (in the tailstock) against the dimple in the end of the mandrel. (Doing that would almost certainly lead to a bent mandrel.)

It is possible to cause problems by over-tightening the brass nut, but in general you can keep tightening it until the blanks no longer stop turning when you are making light cuts.

Same is true with the mandrel saver - if you are making light cuts and the blanks are stopping, you can go a little tighter.

 

[studioseven]

Howard,
With your lathe off, can you turn your blanks by hand and not have the mandrel move? If so, you do not have it tight enough. Are you using bushings?

Seven

 

[howhale]

Howard,
With your lathe off, can you turn your blanks by hand and not have the mandrel move? If so, you do not have it tight enough. Are you using bushings?

Seven

With the lathe off, the mandrel tightened down, the blanks do not turn. I am using the bushings provided for the pen size being turned.

 

[DrD]

One can use too much caution on this overtightening issue. Your blanks must be secured enough so that you can remove wood/plastic/whatever. Using the system you describe that is done with the knob/nut on the tailstock end of your mandrel - that nut must be snug enough to keep the blanks from being turned by hand.

Next the entire assembly - mandrel, bushings, and blanks must be snugged into the drive end of your lathe. This is done by mating you tip if the live center into the nipple in the end of the mandrel - after inserting the drive end of the mandrel into the headstock of the lathe. This too must be a snug fit. It is overtightening the tailstock live center into the mandrel where the possibility of bowing the mandrel comes into play. Just enough pressure to keep everything spinning while making LIGHT cuts with your gouge of skew. Trial and error is generally the process here.

Hope this helps. Good turning.

DrD

 

[Charlie_W]

Howard, In addition to the above suggestions, you need to have very sharp tools. Some gouges/tools even when new are not necessarily sharp or as sharp as they need to be. If you do not have a sharpening system or at least a diamond hone, this should be on your wish list.

 

[donstephan]

Some issues can be difficult to address on a forum. A number of excellent suggestions have been offered. If the problem persists, you might consider looking for a pen turning or even a general woodturning group in your area. Many groups have approved mentors to provide individualized help at the lathe.

 

[howhale]

Thanks to everyone for your replies and great suggestions. I will tighten the blanks until I can make light cuts without the stalling. It is so helpful to get advice from those who turn and I have joined a couple wood turning and pen turning groups locally. Unfortunately, my new found passion for this has preceded the first meetings. I wanted to be able to take some of my first examples to get feedback and suggestions from the experts there to build my skills. Thanks so much for your help. A great site and a great resource. I am also practicing my tool sharpening. I did purchase Easy Turning tools to give them a try as I get started but have used both types with similar issue. Watch out knurled brass nut, I am coming for you

 

[leehljp]

The words "tight/tighten", "snug" "loose" "sharp", "dull" and a few others are highly subjective. While they have the same meaning to 80% of the people, there will be 20% that will say "tight" is what others would say is too loose, and vice versa.

And if you have been reading other older threads, there are quite a few previous posts and threads that do mention "Do Not Over Tighten" as it can cause problems.

There are other issues that can contribute to your problem. if your tool is not sharp enough, you may be forcing it a tad too much in order to turn the blank down to size. If you are not using carbide insert tools then you are using HSS or some form. These require sharpening regularly every two or three blanks, and then honing two or three times per blank; honing: - swiping the edge over super fine sandpaper, or other form of bringing the sharp edge back. The honing takes place two or three times per blank turned (for me).

"Dull and sharp" often have very different meanings to new turners versus experienced turners. Dull (even though it may feel sharp enough) requires more force to cut and can cause the blanks to spin.

What type of tools are you using and how much have you sharpened them?

Keep trying.

 

[howhale]

The words "tight/tighten", "snug" "loose" "sharp", "dull" and a few others are highly subjective. While they have the same meaning to 80% of the people, there will be 20% that will say "tight" is what others would say is too loose, and vice versa.

And if you have been reading other older threads, there are quite a few previous posts and threads that do mention "Do Not Over Tighten" as it can cause problems.

There are other issues that can contribute to your problem. if your tool is not sharp enough, you may be forcing it a tad too much in order to turn the blank down to size. If you are not using carbide insert tools then you are using HSS or some form. These require sharpening regularly every two or three blanks, and then honing two or three times per blank; honing: - swiping the edge over super fine sandpaper, or other form of bringing the sharp edge back. The honing takes place two or three times per blank turned (for me).

"Dull and sharp" often have very different meanings to new turners versus experienced turners. Dull (even though it may feel sharp enough) requires more force to cut and can cause the blanks to spin.

What type of tools are you using and how much have you sharpened them?

Keep trying.

Thanks for the response. Because I am so very new at this and not confident in my sharpening skills, i did purchase the Easy Turner carbide tip tools to use. I do not intend to eliminate all other HSS tools but realize they will take me more practice to know when they are not sharp enough. Your sharpening frequency comments are very helpful in calibrating me as to how often. I clearly have not been doing it at that frequency. I do believe the use of the carbide tools have reduced the stalling a bit which may well support the "not sharp" concern on the HSS tools. I have been reading through older threads that discuss the tightening issue and sharpening. There is a wealth of information here but hearing from experienced turners brings the lessons home. Thanks very much. Folks have been so helpful.

 

[penicillin]

Carbide tips last much longer than high speed steel (HSS) because they are much harder. You should not need to rotate them as often as @leehljp hones and sharpens his HSS tools.

Carbide is different. You get:
* A period of very sharp, not as long as you wish.
* A very very long period of "not as sharp as I love, but sharp enough."
* A brief period of nitty problems where you say, "is it time to rotate?"
* And finally, "definitely time to rotate."

Truth be told, you can sharpen your HSS tools to be sharper than a new carbide tip, but the edge won't last nearly as long as a carbide tip before resharpening becomes necessary.

 

[howhale]

Thanks for sharing your experience. It fits completely with what I have read and, along with the simpler tool to blank alignment suggested for the carbide tip tools, it should help me get started. Your description of the stages of "is it sharp enough" will help me. I was more likely hung up on perfect and failing, without the more reasonable stages in between. Thanks so much.