Pen Mill Tears Wood on Ends

[rodehmen]

I ordered a number of Bacote wood blanks that came 5/8" wide. I have no problem drilling, but when I use my penmill to square the ends, the soft wood breaks out at the end and ruins the blank. I have resorted to sanding the ends with a disc sander down to the tube. Any ideas?
Thanks,
Rod Ehmen

 

[PaulSF]

Try starting slow and going in small bites, rather than holding the trigger down on your drill til the job's done.

 

[John Eberly]

Two Ideas -

1. Sharpen your mill.

2. Put some thin CA on the ends of the blanks before milling them.

 

[rjwolfe3]

Switch to a six bladed pen mill or even a carbide tipped!

 

[mickr]

I hate pen mills, for the reasons you state..many people swear by them...I sand all mine

 

[Texatdurango]

If I were a gambling person I would wager that pen mills alone are responsible for a high percentage of blanks being tossed in the trash.

In my opinion, end mills are fine tools and have their uses in woodworking but unfortunately squaring pen blanks isn't their strong suit!

Rod, several people make and sell small sanding arbors that fit in a drill motor or you could easily make one yourself. This is what I would recommend using for the final squaring.

To give you an idea, visit this article in the library http://content.penturners.org/articles/2010/turningbetweencenters.pdf

In the top of the first photo you will see a block of wood with a bunch of delrin bushings and an arbor to the right of them. I make these bushings for each kit I make so the blank stays nice and centered on the arbor giving a nice 90 degree trim.

In step #8 you will see a close up of the arbor in use and step #9 shows the results. I tried several types of mills including the six bladed cutters and continued catching edges especially since I use a lot of burls and softer woods so ended up sanding.

The sad thing is that in a previous group buy I went crazy and stocked up on cutters and now have a dozen or so that I'll probably never use! :frown:

 

[RDH79]

You can make your own sanding mill by using the bottom of the pen mill. Just loosen the set screw and turn the head around. You will need to get some self sticking sand paper and cut some disks with a 1/4" hole in the center. You will need the delrin bushings for the different size tubes. This is what I do for the tubes that are too long for my squaring jig on my disc sander

 

[Nolan]

If I were a gambling person I would wager that pen mills alone are responsible for a high percentage of blanks being tossed in the trash.

I agree, and my opinion is because most mills are poor quality, they are almost always dull, the operator is pushing too hard to compensate with the drill in one hand and blank in the other, and taking off too much material. At least that how I used to do it. So I made a good quality tool and started putting them in the drill press or bench vice to control the milling process (this also eliminates that wavy patern on the end). I also stopped milling off 1/8 of an inch and cut my blanks closer to real size and just square up the blank. Biggest advantage is good quality tool that is and stays sharp.

 

[DurocShark]

Switch to a six bladed pen mill or even a carbide tipped!

I bought one of the 6 bladed ones in the last group buy. Came dull, couldn't even cut zebrawood. Sharpening looked like a bit of a PITA so it got tossed into the drawer while I used the shafts on my old 4 blade one that gets honed regularly but didn't come with any shafts other than the 7mm one.

If you CA the ends you won't get tearout anymore. If you don't want to CA the ends (color change of the wood, for example) then use a sander instead. I bought one (rherrell I think?) but you can flip the cutter head around and stick some adhesive paper on the flat side to do the same thing.