Jr. Gent II Drill Sizes

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Are 29/64" and 1/2" suitable replacements for the 10.5mm and 12.5mm drill bits for the Jr. Gent II? I don't want to buy new drill bits if they are not necessary. The bits are .0085" and .0079" larger respectively.
 
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jsolie

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That might be a tad too large. If you're going to use a slightly larger drill bit, be sure to use a gap filling adhesive. If I had to do it, I'd really goop things up with epoxy and wait overnight before turning just to ensure the epoxy is cured.

Try drilling with your bits in some scrap material and check the fit. Hopefully the tubes don't rattle around in the hole.
 
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alphageek

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Alot depends on what you're drilling and "how good" you're holes are.
Examples: (none the right answer)
1) In wood, you might well be ok.. in acrylics maybe not so much.
2) If your bit is sharp you might be ok (less drift, heat etc).
3) If you drill on the lathe, you might have less issues than drilling on a press.

In my opinion, its worth it to get the right bit (and to keep it sharp). Even a cheap bit is ok if you can keep it sharp. (Insert my standard plug here - I love my drill doctor!)
 

ed4copies

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Are 29/64" and 1/2" suitable replacements for the 10.5mm and 12.5mm drill bits for the Jr. Gent II? I don't want to buy new drill bits if they are not necessary. The bits are .0085" and .0079" larger respectively.

The larger you make that hole, the more likely you will be to "blow up" your blank. Some day I will make a video explaining why, but it is absolutely true.
 

SteveG

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I suggest that if you are only going to make a few of the Jr-series type pens IN YOUR LIFE, than just make do with what you have, per other adhesive and curing time suggestions given. If you are going to make 4 or more IN YOUR LIFE, go on and get the right drill bits, as that will make your life better going forward! You will look back at the decision to go for it with satisfaction, when reflecting on your enjoyable and successful pen turning efforts.
 

DLGunn

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I asked the same question a while back and was told to go ahead and get the 10.5mm and 12.5mm bits. I did order them through Amazon. I am glad I did. Doing some tests on scraps the tubes fit so much better with the correct bits. Less chance of an out of round blank if the tube fits the hole well.
 

edstreet

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No longer confused....
Are 29/64" and 1/2" suitable replacements for the 10.5mm and 12.5mm drill bits for the Jr. Gent II? I don't want to buy new drill bits if they are not necessary. The bits are .0085" and .0079" larger respectively.

Did anyone ever stop to think that bowl turners use large holes and thin walls and *NOT* have blowup? Perhaps that should be enough to make one think that it's not the hole size that matters, it's more correctly the usage of the chisel that causes the blow up.

The proper technical correct answer to your question "suitable replacements" is yes they *can be*.

However, you must first stop and consider the bonding agent that is used. Does it require a thin gap or a thick gap for it to work the best? i.e. gorilla glue has the strongest bond when the items are flush and with no gaps, as expansion of the foam provides *NO* structural support, stability or strength in any manner; i.e. E120-HP you can use a much thicker gap and still provide strength and structural support.

The second part of your answer is this. Depends on the material. Some material will be more reactive than others. i.e. Wood can shrink after you drill the hole due to various reasons (not going into those reasons here) so your drill holes and bonding agents must be able to account for these effects.
 
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