How to Stop Blow Out When Drilling?

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paulkane1

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I am new to Pen Turning ,I have been trying some Segmented Pens,when it comes to Drilling up the center of the Pen Blank, I am getting my Last piece breaking off,I am using my Lathe to Drill my Blanks,I leave my Blanks overnight when glued,(although it's fast setting glue).Has anyone on this forum,come across this problem,if so,how did they overcome the problem? I was thinking of ,maybe taping the whole Blank,in insulation tape, then drill it ?

Paul
 
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Glue a waste scrap piece to the blow out end and cut it off after you drill your blank. That way if anything blows out, it will be your scrap...
 
If you are breaking cleanly at the segmenting line, I'd be willing to guarantee you're building up too much heat. When you get that far into the blank, the bit has a difficult time cooling off.

Number one thing to help that is to sharpen your bit. Once your bit is sharp, the material will tell you how fast or how much you can drill. Go slowly and as soon as you feel added resistance, pull the tail stock back, clear the flutes on the bit and let it cool off. Then go at it again.

Some wood I can go through fast in one or two passes, other woods take a half-dozen passes of 1/4" to 1/2" each before having to clear the bit.

Heat will break glue joints. Especially if you are working with end-grain joints or mixed media.
 
Carl Fisher said:
If you are breaking cleanly at the segmenting line, I'd be willing to guarantee you're building up too much heat. When you get that far into the blank, the bit has a difficult time cooling off.

Number one thing to help that is to sharpen your bit. Once your bit is sharp, the material will tell you how fast or how much you can drill. Go slowly and as soon as you feel added resistance, pull the tail stock back, clear the flutes on the bit and let it cool off. Then go at it again.

Some wood I can go through fast in one or two passes, other woods take a half-dozen passes of 1/4" to 1/2" each before having to clear the bit.

Heat will break glue joints. Especially if you are working with end-grain joints or mixed media.
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Thank for your help,Greatly appreciated
 
paulkane1 said:
I am new to Pen Turning ,I have been trying some Segmented Pens,when it comes to Drilling up the center of the Pen Blank, I am getting my Last piece breaking off,I am using my Lathe to Drill my Blanks,I leave my Blanks overnight when glued,(although it's fast setting glue).Has anyone on this forum,come across this problem,if so,how did they overcome the problem? I was thinking of ,maybe taping the whole Blank,in insulation tape, then drill it ?

Paul
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Sometimes the magic tape trick works good but when you get down to the nuts and bolts of how drilling works the bottom line answer is cutting motion must not exceed the adhesion strength of the material. Factors like curvature of the drill bit and force trying to straighten it comes into major play.

The higher the fragileness of the material gets the less forces you need to put on the material, all those things like cutting edge sharpness, rotational speed, linear force, curvature force, thermal properties and the like all needs to be adjusted accordingly.
 
If you plan to do segmented wood pens on a regular basis, you REALLY need to discover the CA bandaid trick.

Before you ever start turning ( I do it a day or two in advance), wrap the segmented blank with surgical gauze and saturate it with thin CA. I do this a day in advance, then RECOAT with thin CA two hours before turning and then blast with CA accelerator.
 
PenMan1 said:
If you plan to do segmented wood pens on a regular basis, you REALLY need to discover the CA bandaid trick.

Before you ever start turning ( I do it a day or two in advance), wrap the segmented blank with surgical gauze and saturate it with thin CA. I do this a day in advance, then RECOAT with thin CA two hours before turning and then blast with CA accelerator.
Click to expand...

;) CA bandaid trick = increasing the material adhesion strength. Therefore allowing more brutal attacks on it :)
 
If you are clamping the blank in your lathe, make sure the far end of the blank has something solid to bear against. This is also true for drill press drilling. Put a block under the blank.
 
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