Help with Zebra blanks

[tbrock]

1. I had a customer that wanted a pen out of a zebra blank, so I went to PSI and order 2. It was for a Sedona which uses a big drill bit in the cap. Tried to drill the top and it busted as I hit the end, tried again this time with support on the bottom and it busted again. I tried to start out with a smaller bit, I went from 1/4" to 3/8" to I think 27/64". This time it did not bust but it did crack all the way up. What am I doing wrong? I need some ideas....oh by the way, all the bits are really sharp, I don't have problems using the big bits in acrylic or wood.

 

[seamus7227]

it sounds to me like your drill bit is getting too hot, drill in 1/4", then back it out, then back in. Be patient with it, drill slowly

 

[jthompson1995]

Try cutting the blank long and not drilling all the way through. Then cut the blank to length after drilling. This happened a good bit to me when drilling PR and acrylic blanks. I switched to drilling this way and haven't had another blowout while drilling.

 

[hilltopper46]

I don't think you are doing anything wrong. I've seen zebra wood that turned quite nicely, but have also some bias-cut blanks that have proven to be the most challenging wood I have ever turned a pen out of.

Just because it is wood doesn't mean you can't use water or denatured alcohol to cool the bit while you are drilling. It may mean that you need to let the bit dry and run the bit through it again before you glue the blanks in it.

 

[CSue]

I don't think you are doing anything wrong. I've seen zebra wood that turned quite nicely, but have also some bias-cut blanks that have proven to be the most challenging wood I have ever turned a pen out of.

Zebrawood splinters quite easily when it's cut on an angle . . . just about any angle. It needs much care and patience! Keep it cool. Make sure your bits are clean and sharp.

 

[Jon-wx5nco]

I made a Navigator FP last week out of zebra wood. I was able to drill them ok, but when it came time to put the pen mill to them, I split 2 blanks. I try to have a light touch with the drill and pen mill, but I had to have a REAL light touch.

 

[dexter0606]

I'm assuming that you're talking about an acrylic zebra blank. I have had some trouble with splitting and cracking but it is greatly reduced if you slow the drill press speed down, make sure the bits are sharp and support the bottom of the blank.
When I drill acrylics I use and eyedropper to add water to the drilled hole. Back off the drill bit, add water to the hole and drill a little more.
Hope this helps

 

[tim self]

Regardless of wood or acrylic, make sure you're clearing the bit often. Heat builds to easily and Zebra is a bugger to complete. Also, second the cut long and not drilling through, then cut off excess. Has saved me MANY blanks. I will also use water to cool the bit on acrylics but dont know about DNA. Flash points being low and such.

 

[tbrock]

I am not dealing with zebra wood, but rather the zebra print blanks from psi. Not sure what they are make of. Sorry I didn't make it clear in the beginning of this post

 

[Buzzzz4]

I've had the same problem with the Animal print blanks for some reason. I now cut them extra long and don't drill all the way through. I then cut them to length. Also, clearing them by backing out often and go slow to reduce heat.

 

[ed4copies]

As most of you know, I have imported that material for nearly a decade. It is a resin that is quite easy to turn, but not so forgiving in drilling.

"Make the piece long and cut off the end" is the ideal solution, but the material is only 114mm long (4.5"). with some pens, you need most of that length!! So, drill slowly (Not necessarily low RPM---low advance rate) as you approach the bottom, be very careful. Most resins will crack if they are allowed to "climb" the revolving bit as it exits. So, hold the material firmly in place and try to stop short of the bit exiting.

A technique I use sometimes is to leave the end ON, glue the tube in place (assuming it will fit completely in the blank). Once everything is set (the next day), run a quarter inch bit through the hole (tube) so your 7mm pilot shaft of the barrel trimmer will fit through it. Then carefully face the blank, exposing the larger hole and the brass tube. Takes a little more time, but saves "blowing up" blanks.

 

[Rangertrek]

Go slow

I have made several Diva style pens from the zebra acrylic material. I have not had any problem with them. As mentioned above, drill slowly, back out the bit, clean the debris. I make a mark with a pencil or sharpie on the drill bit to indicate the end of the blank. Then I advance the bit very slowly with light pressure, you can feel when the bit exits the blank.
Just go slow, light pressure, and it should work for you.

 

[ed4copies]

John,

It also depends on what type of drill bit is being used. Unfortunately, I can't tell you what works---I bought them recently, I will soon be selling them---but I know that many that are "made for penmaking" DON'T work on resins very well.

Resin is NOT the same as acrylic, neither are the bits. So, if you have one that does NOT work, try a different style. Actually, my Harbor Freight cheapys work better than some "made for penmaking" have.

 

[glycerine]

If you can't drill short and then cut the blank, how about building up the tail end with some thick CA? Speed up the process with some accelerator. I've never done it, but just a thought...

 

[killer-beez]

I had the same problem. Very brittle. Sharp bits and tools for sure. Check out this link and see my solution... http://www.penturners.org/photos/index.php?n=11253