Silly Drill Bit Size Question

[candy1land]

This is probably the most newbie type of question ever asked on the forum but can someone please tell me why I cannot find 8mm drill bits for pen making on these store sites?

Is the "O" bit the 8mm? If not which one do I need? I have a pen kit that is calling for an 8mm drill bit and I want to order one but can't seem to find it anywhere.

Thanks,

Candy

 

[ed4copies]

Candy,

I think Berea and WoodCraft have the 8mm.

More to your question, however, get a caliper, measure your tube, then use the next larger bit size. You will always be correct. Following instructions, you could find you disagree with their size.

Shouldn't happen, but does.

 

[BigguyZ]

I second that! I have the HF (Harbor Freight) 115 piece bit set, and it meets all my needs. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=528

I don't like the brad point bits for most things, just doesn't seem to work as well in deeper woods, and won't self-center on the lathe as well, IMHO. So for a 7mm pen I'll use a "J" bit. But as Ed noted, just get yourself a caliper and use something a bit larger (no pun intended). You can pick up a caliper for $10-$15. I like the plastic ones, since when I'm measuring a finished blank for final diameter I don't have to worry about it marring the finish.

 

[redbulldog]

Candy;
Here is a reference chart that I use sometimes to get a better fit.
http://www.penventory.com/inv.pl?command=drillbitcheatform

 

[mredburn]

Candy there is a chart located in the library under the 2009 articles by Wayne Racinowski that shows conversions for fractional,decimal, number and letter drill sizes. Great to print out, laminate and hang up nearby. MIke

 

[kkbulldog]

An 'O' size drill bit measures .316 inches. 8mm converted to inches is .315.
That's .001 of an inch different. Maybe about 1/3 the size of a human hair.
I'd say go with the 'O' size bit. As mentioned before, it's always good to measure the tube size compared to the drill size.

 

[Daniel]

for our purposes O is the same bit as an 8mm. J is the same as 7mm also by the way.
My rule of thumb is if it comes within 0.03 inches of the tube size (But not smaller) it will work. be warned though if you get close to that 0.01 difference the tube starts having a loose feeling to it and some turners really do not like it that loose. your difference is one tenth that much space.

 

[fernhills]

I second that! I have the HF (Harbor Freight) 115 piece bit set, and it meets all my needs. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=528

I don't like the brad point bits for most things, just doesn't seem to work as well in deeper woods, and won't self-center on the lathe as well, IMHO. So for a 7mm pen I'll use a "J" bit. But as Ed noted, just get yourself a caliper and use something a bit larger (no pun intended). You can pick up a caliper for $10-$15. I like the plastic ones, since when I'm measuring a finished blank for final diameter I don't have to worry about it marring the finish.

What do you do when a pen calls for a drill size over 1/2 inch,like many of them do. Carl

 

[BigguyZ]

What do you do when a pen calls for a drill size over 1/2 inch,like many of them do. Carl

I'm only seen a few that need a bit larger than 1/2"- mainly the majestic, and the Gent. In those cases, I buy the bit I need seperately. But the set will get you everything else you need, no matter the size.

BTW- I think Rockler was clearancing out some of their larger bits. I recently got a huge brad point bit for like $3. I forget the size, but it was massive... It was for the Gent cap.

 

[MesquiteMan]

Even better yet, for $4 get you one of these. Keep poking the tube in the hole until you get one that fits the way you want it. Then use that size bit from your HF set. Works like a charm for me and I only have the 64 bit set from Lowes.

http://www.google.com/products/cata...alog_result&ct=image&resnum=4&ved=0CB8Q8gIwAw#

 

[dankc908]

Candy -

Thanks for your "... silly question ...". I keep telling my students (college) that the only silly/stupid question is the one that isn't asked! I'm guilty here because I've had the same question re: 7 mm and "J" drill bits. BTW - Penn State has the 7 mm Gorilla drill bits.

Dan

 

[Rifleman1776]

To answer your "why" question: The answer is that the pen kit suppliers like to force you to buy their weirdo sized drill bits from them.
For pens, and other end grain drilling, I prefer brad points. Center easier, cut cleaner, easy to sharpen.

 

[randyrls]

What do you do when a pen calls for a drill size over 1/2 inch,like many of them do. Carl

Check out MSC or McMaster-Carr they have every size drill bit you could thing of and some that are far-out!

 

[TellicoTurning]

I don't like the brad point bits for most things, just doesn't seem to work as well in deeper woods, and won't self-center on the lathe as well, IMHO..

This is interesting statement... I use the brad points almost exclusively and don't have any problem with self centering... I do mark my centers on all of my blanks at the on set and make sure the point is set at the center when I start the lathe.

It's interesting to see the different experiences we have with the same tools.

 

[TellicoTurning]

Candy;
Here is a reference chart that I use sometimes to get a better fit.
http://www.penventory.com/inv.pl?command=drillbitcheatform

HUT Products catalog has a bit cross reference chart in their catalog... reference the letter sizes, the mm vs imperial sizes and the decimal equivalents... very handy chart to keep in the shop.

 

[BigguyZ]

This is interesting statement... I use the brad points almost exclusively and don't have any problem with self centering... I do mark my centers on all of my blanks at the on set and make sure the point is set at the center when I start the lathe.

It's interesting to see the different experiences we have with the same tools.

Now all of my blanks are perectly square, and with a split point the bit will walk itself to the center automatically. With brads, the point sticks too much, and I don't get the same effect.

Plus, I've had more blowouts with brads. AND, you can up-size your holes with brads, which I sometimes like to do when precision is needed. And split points are the only way to go for Alu, and antler. So yeah, that's my preference. As always, IMHO, YMMV. :wink:

 

[TellicoTurning]

Now all of my blanks are perectly square, and with a split point the bit will walk itself to the center automatically. With brads, the point sticks too much, and I don't get the same effect.

Plus, I've had more blowouts with brads. AND, you can up-size your holes with brads, which I sometimes like to do when precision is needed. And split points are the only way to go for Alu, and antler. So yeah, that's my preference. As always, IMHO, YMMV. :wink:

Sounds like you and I use the same types of blanks... I've cut a lot of mine on the band saw.. without a fence and I do get some strange shapes sometimes..

I don't do Aluminum, and just recently learned to do the antler on the lathe, so I don't waste as much as I used to.... I have a lot of antler blanks with holes in the sides...:redface:.. one of these days I'll have to start splicing some of the good parts together and see if I can make whole blanks..

 

[Rifleman1776]

Sounds like you and I use the same types of blanks... I've cut a lot of mine on the band saw.. without a fence and I do get some strange shapes sometimes..

I don't do Aluminum, and just recently learned to do the antler on the lathe, so I don't waste as much as I used to.... I have a lot of antler blanks with holes in the sides...:redface:.. one of these days I'll have to start splicing some of the good parts together and see if I can make whole blanks..

I saw BigGuyZ puzzling post also and don't agree with him. Not denying his experience but mine is vastly different. I'll agree that spit points are pretty good and I prefer them on metal over basic twists. But for pen blanks (not metal) the brad POINT can be stuck in the center mark and slight pressure exerted before turning on the drill press. VOILA centered.
Watever floats yer stick.......