More finishing?

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Woodchipper

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I had talked about some problems with a pen mill. Another question arises about finishing. Both blanks have CA on them and the CA came out very good, IMHO. However, I wonder about going a step farther with MM. Your advice is most welcome. TIA. Will wait for your replies before final assembly.
An aside to go along with finishing- the purpleheart blank has a thin, dark ring at the ends of the blank. What causes this? Thanks, again.
 
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Chief TomaToe

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What made the biggest difference for me and my CA finish was adding a buffing stage after the MM step. There are multiple places you can get a buffing kit that uses the blue compound that are very inexpensive. I'm sure there are better systems, but it works just fine for me. When I first started, I would end up having very fine cylindrical scratches around the pen even when I used a plastic polish. Just to try it, I bought a buffing kit for my lathe and, wouldn't you know, it worked! I have learned that a final buffing stage will not fix a bad MM job, but it will get rid of all those tiny scratches that prevent a CA finish going from good to perfect.
 

leehljp

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Dark ring at the end of the blank: You are using bushings and sanding the bushings. The bushing dust makes the black ring. Preventing the black rings can be done two ways:

1. Refine sanding techniques; move from the center of the blank outward; Learn to sand without touching the bushings;

Or

2. Remove the bushings before sanding. Bring to size by measuring the blank with calipers instead of using the bushings to size it.

Think of it this way; after 10 to 20 blanks turned and sanded to size on a given set of bushings, the bushing will have been reduced in size by about .01. The bushing keeps shrinking in size the more you turn with it and sand with it on the mandrel.
 
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Woodchipper

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Thanks, Chief. Will look at the lathe polishing setup. Woodcraft is my go-to place.
Lee, I'll look into eliminating the bushings, either by learning to TBC or put a nylon or plastic spacer between the blank and the bushing before sanding.

If I sand my waistline, will that shrink it to a small diameter? :clown:
 
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BCnabe

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If you used a pen mill on the purpleheart it likely "cooked" the wood and turned it darker.


Whenever I make purpleheart pens I turn it down to the final size and then cook it in an old toaster oven at 400 degrees for about 10-12 minutes. It will darken it to a deep purple. This will likely vary with different pieces and thickness of wood so you would want to watch it closely to get it the way you like.


If you've already put CA on it, it's probably too late to heat it up. Unless you sand off the CA first.
 
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Woodchipper

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The end turned black. I quit using the pen mill and sanded it on the lathe. Actually I got pretty accurate with the PH and the ebony. Assembled the pens and will take some photos. I will take some extra wood (got tons of it) and practice turning with a skew and Lee's suggestions on turning and sanding. I have calipers- will measure the diameter of the components and the length of the tube. Always a learning experience.
BTW, I found a nice lathe. Anyone got an extra $7,000 laying around gathering dust?
 
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sbwertz

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I keep my pen mills really sharp with a diamond card, and use the drill press to mill blanks. We go through dozens of blanks every week, and are often milling 20 or more blanks at a time. I hold the blank with a pair of water pump pliers and mill a bit, check for brass, mill a bit until i just barely see brass. For really hard wood, I turn almost to size, take it off the lathe and mill it, then finish turning it so it doesn't overheat. But I sharpen those puppies every week. I have two mills, and keep one set up with 7mm, and have different centers for different sized pens that i put in the other one. For those sizes I don't have, I turn sleeves on a 7mm brass tube and label them with the size and/or pen kit name.

Our lathes are kept busy all the time, so it isn't convenient to try to mill using the lathe. I can't afford to give up the turning time.
 
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Woodchipper

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I tried a DMT diamond file but didn't get the results I wanted. Don't think I got the proper angle and didn't remove much metal to make a difference.
I'm going to make stand to hold my "Dremel" tool and use a stone to see if that will work. Will report with my results.
 

donstephan

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Another option for sanding is to turn wooden pen bodies on bushings, reinstall the pen bodies on the mandrel with non stick tapered bushings, and sand. I start with 240 grit but stay away from the last 1/8" of the pen bodies until I move up to 320, so that I don't significantly reduce the diameter at the ends of the pen bodies.
 

donstephan

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The first few times I "sharpened" my pen mill I was using a fine diamond hone on the angled surface and the results didn't last long. And I was worried that I might end with the three cutting surfaces not all the same height, and even the cutting edges no longer perpendicular to the axis of the pen mill. After seeing a post I think here I honed the surface along the axis of the pen mill. After doing so it cut extremely well and I think stayed sharped longer.
 

wouldentu2?

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I tried a DMT diamond file but didn't get the results I wanted. Don't think I got the proper angle and didn't remove much metal to make a difference.
I'm going to make stand to hold my "Dremel" tool and use a stone to see if that will work. Will report with my results.
There is no "proper angle" you are touching up the large flat area. Don't change the angle.
 
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