Pen mill necessary?

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Bill Mitchell

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Aug 12, 2009
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Raleigh/Apex, NC
Poor fits of the barrels to metal parts, whether diameter or squareness seems to be crucial to making a quality pen. I've read that some people use a disc sander to square the pen blanks and others will use a pen mill or a combination of the two. Is a pen mill the best method for getting the barrel ends square? I'm using a metal lathe and I could take a facing cut on the blanks or finished barrels.
 
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Bill,

IN GENERAL, the pen mill is a good tool.

However, if you have the ability to make the end square by a more accurate method, certainly use it.

Pen mills must be sharp (a frequent problem) and will tear out some burls, and will break the ends off plastic in some cases.
They are NOT perfect.
 
I have and will continue to use all three methods that you describe. The pen mill is faster than the others, but it is not always the best tool for a given situation.

Regardless of the method used, make sure that you are squaring the blank with reference to the tube and not the blank itself (unless you have rounded the blank to be parallel to the tube).
 
I got so frustrated with the mills that I gave mine away and started experimenting. Now I do mine on the lathe.

1)drill hole and glue in tube.
2) put between centers and turn round. (Assuming that the ends are fairly square to begin with, this will make the outsides parallel to the tube)
3) put in self-centering chuck and mill ends with a sharp skew.

This may seem like it would take a lot of time, but I do this with a dozen blanks at a time and where it does add time (turning round before milling), it saves time later (less bulk to remove when turning).

Caveat: This is my method and may not be the best for everyone. It works for me.
 
Since I turn my blanks round then drill on the lathe, I usually don't have a lot of material around the tube when it comes time to square the blanks. This creates more of an oppurtunity for a mill to grab a chunck of material and rip it out so I seldom use the end mills anymore for most materials except Corian and Truestone.

Instead I rough square using a 6" disk sander then use the little sanding mill I made.
 
Most of the time, I use a belt sander and square up the tube/blank while it is square. I haven't used my pen mill in 6 months or more. After turning, I touch up the ends with one of these:

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The machinist brain side of me says that the pen mill is the best way to square the ends with the tubes. The tools takes away the guess work, unless you have sharpened it too many times yourself and changed the angle of the cutter! Sharp is essential. But obviously others have had good success with other methods. So, I hope you find what works best.
 
I use the lathe and a skew as well. Someone here on the forums suggested it. Since I have been doing that I haven't had a single problem. And I hated pen mills. Keeping them sharp was a pain.
 
I've used the skew facing cut method as well with good success as well. I typically only use this method on burls or when I have an extra long blank and need to mill off a lot of material. I get it almost done with the skew, and then just touch it with the pen mill. this way I am milling very little material, and it takes a lot more blanks to dull the mill.


I have been considering using my recently made pyramid tool for this instead of the skew. I use this tool for facing cuts insted of the skew on larger turnings all the time and it produces the same clean cut.
 
I needed to trim the ends of a puzzle pen and the instructions recommended strongly against the end mill - so I used the back of the end mill to be a platten for a small sandpaper disk - (Head was put on the shaft backwards trapping the sandpaper against the shaft) - worked well, fast. The heavy dose of CA glue does clog the sandpaper quickly - A good use for a dull pen mill/piloted end mill.

Beat digging out the disk sander -

I like the pen mill for stabilized woods. I like disk sander for most straight woods, and have learned to clean it well before using with light colored woods.

Bottom line is that all the techiniques work, and none work best all the time.
 
As in most hings there are more than one way to skin that cat. And in some cases such as the puzzle blank I strongly agree that the pen mill is the wrong tool. It likes to grab if it gets a chance. So it is not perfect. The entire point is to get the ends square to the brass tube. since the tube is seldom glued into the blank perfectly straight. the outside of the blank is no longer a reliable guide. so this leaves one of two choices either straighten the outside of the blank to the tube, or use the tube itself as the guide.
I supply pen mills simply because I can at a lower price and lots of people use them. Btu I honestly think the sanding disc is a better more reliable but less convenient way to go. That is if you can. I don't own disc sander so i have learned to use the pen mill pretty well. making a squaring cut would also work but would then require not only the ability to do so. But also bring back the possible catching problems of the pen mill.
I am not sure that any one way is better than another for everyone. as in most things it is a matter of trying different ones until you find the one that works best for you. I have never had a lot of problems with the pen mill so have never really looked beyond it for an answer. But I have seen lots of them listed.
 
Bill Mitchell said:
Poor fits of the barrels to metal parts, whether diameter or squareness seems to be crucial to making a quality pen. I've read that some people use a disc sander to square the pen blanks and others will use a pen mill or a combination of the two. Is a pen mill the best method for getting the barrel ends square? I'm using a metal lathe and I could take a facing cut on the blanks or finished barrels.
Click to expand...

The problem with a facing cut is that the ends might not be square with the bore of the tube if you are gripping the blank from the outside..

It's pretty hard to beat a newly sharpened pen mill. Almost anything beats a dull one.
 
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