(Solved) Any ideas why my wood pen blanks keep breaking?

Woodshop
#1

Well, this was my morning today:

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Four attempts, zero pens. I know cedar is probably too temperamental for turning, but the others?

Thank you Pat, for showing me that carbide tools have bevels and how to angle them when cutting, and to @richmeyer for introducing me to the metal lathes. That would be a very cool next step.

I think some of the blanks might be green, so now I’m trying the toaster oven/scale method of drying out wood for the future.

If anyone knows how to recover the tubes, please let me know.

#2

Not that I can offer you any specific information, but Capt turns cedar for dip pens regularly. I don’t think that’s as thin as you have to get for the pen kit things, but it’s a thing.

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#3

IMO, every single one of these blanks will be finicky. They are all either cross grain or burl, both of which are prone to tear outs. They need to be cut with a sharp tool and a light hand. Spalted also tends to fly apart.

You will have better success with long grain.

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#4

Does that mean the grain is better lengthwise instead of width-wise?

#5

Chris is right: the grain is probably to blame.

Sharper chisels, lighter hand (turning less aggressively).

Moving the tool rest closer to the part to improve the pivot point? This will make digging in a bit less likely, as your back hand will have more mechanical advantage with the closer pivot.

Stabilization with water-thin CA glue perhaps?

Less chisel and more sandpaper :smiley: ?

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#6

I think you’re right on all counts. I think I’m putting too much pressure on the tools, and maybe on these tougher blanks, I’ll switch to sandpaper much sooner.

It might also be time to turn the carbide tips to a fresh one.

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#7

Take 5 mins on the diamond stones with the carbide cutter before you start. If you start with a sharp tool, you’ll notice it getting dull more easily.

Watching YouTube videos is an easy way to pass the time while sharpening: the process doesn’t require your full attention, just some water for a lubricant and a figure 8 motion on the stones, working your way up through the grits.

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#8

Yes, it will be “better” with respect to stability and less likely to have a blowout.

If you sharpen the tools before you start, like Mike @HankCowdog suggests and use a very light hand, you won’t need to sand much at all. I’m not sure I even own any sandpaper coarser than 220 grit.

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#9

All of Mike’s suggestions are spot on. Especially, the part about sharp tools. Sometimes when I know that the wood is finicky I use very coarse sandpaper or very light cuts. Sometimes though the wood just tears out.

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#10

Take 5 mins on the diamond stones with the carbide cutter before you start . If you start with a sharp tool, you’ll notice it getting dull more easily.

How do I do that?

#11

Unscrew the carbide insert, and put it flat side down onto the diamond stone (i.e., the cutting surface is flat against the stone). Hold it flat on the stone with your fingers and using about as much pressure as you’d use writing with a pen, move it around on the stone in a figure 8 motion. Dribble a little water on the stone as a lubricant. Spend a few minutes on each stone. Start with the coarsest stone and work your way up to the finest grit.

Clean any sawdust and grit out of the screw hole in the lathe tool and carefully screw the insert back in. Don’t screw it in with superhuman force because carbide inserts can crack that way.

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#12

Thank you!

#13

I have had issues with blanks coming apart if I 1) dont let the glue fully cure and 2) if I dont rough up the brass with sandpaper before gluing. Also light cuts as others have said help. It definitely takes time. On the plus side its only a pen blank and not a 15” chunk of oak whizzing past your face (mask)

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#14

Yeah, I want to master this before attempting a salad bowl!

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#15

Learning the traditional tools vs carbide bits will vastly improve your turning. Both have their merits, but the traditional tools are more versatile, efficient, and IMO, fun to turn. Ill be around some this weekend, happy to introduce you to the bowl gouge and friends. Or I know Paul teaches some classes on those too.

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#16

Judging by the wood thickness, I’d say you ‘might’ be cutting too aggressively, or the blades are in need of sharpening. When I start to blow out my blanks, I slow it back down (same rpms, just lighter passes). I also start to take a less aggressive angle on the cutter, and that usually does the trick.

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#17

@John_Marlow and @HankCowdog and @ryan are all spot on.

That cross grain is pretty, but grabby and tricky to cut cleanly.

Another tip - I like to use epoxy for pens in classes. I believe it gives a better bond in the short class window. If using CA, most people let it cure overnight for strength.

Note: CA “cracks” with sharp blows, like a hard catch.
CA is great for reinforcing the fibers of that cross grain. I use it a lot with things like birds eye maple, adding CA every couple of minutes to “plastisize” the fibers.

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#18

Today was much better! These are finished with friction polish and carnuba wax.

I followed everyone’s advice about sharpening my tools and using better grain patterns. Thank you so much!

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#19

I’m not going to repeat anyone else’s advice since they were spot on, but let me know if you ever want to learn how to stabilize wood using heat cured resins. I’d be happy to walk you through it, or demo it. Cross grains, older dry wood, soft/punky wood, and burls greatly benefit from the process and make turning a breeze.

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#20

Yes, please, @Lordrook. What you do with resin is amazing!

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