Drill bits, holes slightly bigger

[Slardibardfast]

I've been turning pens for just about one year now. I'm finding that my drill bits are making the holes just slightly larger than the brass tubes so that they slide freely in and out. This makes glue-up a challenge, whether with CA or 5-minute epoxy. Any suggestions would be helpful.

 

[KenB259]

I've been turning pens for just about one year now. I'm finding that my drill bits are making the holes just slightly larger than the brass tubes so that they slide freely in and out. This makes glue-up a challenge, whether with CA or 5-minute epoxy. Any suggestions would be helpful.

That's normal, you don't want them to be glue starved.

 

[jttheclockman]

As Ken said probably normal if we are talking the same language. Bits mentioned in kits are to allow the tube to slide in blank which is normal. This allows for adhesive and also sometimes when drilling woods they will expand some when drilled because of heat and then shrink. Now if we are talking that on one end the hole is larger than the other end then you have another problem. Could be bad bit, drilling method can be causing the bit to wander and others. But in the end there still needs to be enough meat left when blank is turned down to accept the kit components. Good luck.

 

[sorcerertd]

I've definitely come to appreciate a little play between the blank and tube. If it's too tight, the wood can crack from the pressure once you've turned enough of it off. A little play is especially good if you are working with "plastic" blanks and painting the inside so the tube doesn't show. If the fit is too tight, I'll use a round file to make sure that it will slip through (not sloppy, but no force required)

If you have trouble with the tube slipping while the glue is setting, put a rubber band around the blank so it holds the ends of the tube in.

 

[leehljp]

Another way to look at this, and it reinforces what has been said - is measure the diameter of the tube with your calipers, then look at the diameter drill bit that is recommended. Measure it. There is a difference and that difference is intentional.

 

[randyrls]

The instructions drill bit size is the "closest COMMON drill bit size". I usually find that my drill bits run a few thousandths under the recommended drill bit size. I want a sliding slip fit on the tube. I have both a full 115 drill bit set and a metric .5mm set. I also have some "special" drill bits for kits. MSC has drill bits like 12.3mm (EGAD!)

I drill blanks with a mini-mill so the holes are likely smaller.

There is a slight difference in sizes between wood and synthetic. The bit will drill a slightly larger hole in synthetic. I print out the pen instruction sheet and note on the sheet the drill bits I need to use for both wood and synthetic.

 

[carlmorrell]

If the tube is a tight fit, CA could seize up during insertion. Epoxy will act as a lubricant. I always make sure I can slide the tube in easily. Stopped using CA for gluing tubes in years ago and only use Epoxy.

 

[egnald]

The instructions drill bit size is the "closest COMMON drill bit size". I usually find that my drill bits run a few thousandths under the recommended drill bit size. I want a sliding slip fit on the tube. I have both a full 115 drill bit set and a metric .5mm set. I also have some "special" drill bits for kits. MSC has drill bits like 12.3mm (EGAD!)

I drill blanks with a mini-mill so the holes are likely smaller.

There is a slight difference in sizes between wood and synthetic. The bit will drill a slightly larger hole in synthetic. I print out the pen instruction sheet and note on the sheet the drill bits I need to use for both wood and synthetic.

Your Tip is Outstanding. I do something similar with the instructions, but lately I've started re-writing some of the instructions so I can put in some step-by-step stuff I learned from Ed at Exotic Blanks, to match grain on rollerball pens for example. I also add a little bracketed chart that shows the specified drill size along with the "closest" bits going both larger and smaller for each tube - like this one for 10mm:

Dave

 

[howsitwork]

If I read you correctly your concern is tubes sliding out Whilst glue is setting ?
I let them set on their side but you could stand them on end on large nails ( up centre) , r use small silicon plugs in the tube ends to keep them in the blank ?

 

[GFHWoodWerks]

Your Tip is Outstanding. I do something similar with the instructions, but lately I've started re-writing some of the instructions so I can put in some step-by-step stuff I learned from Ed at Exotic Blanks, to match grain on rollerball pens for example. I also add a little bracketed chart that shows the specified drill size along with the "closest" bits going both larger and smaller for each tube - like this one for 10mm:

View attachment 378990
Dave

I like this chat idea. Giving you a quick reference for utilizing a different drill bit of you need to adjust for any reason.

 

[Slardibardfast]

Thanks all for the input. I believe, having read some sage advice, that what I'm experiencing (without the acutely accurate measuring devices) is what you say is "normal" bit sizing. It just seemed to me, when I first began the tubes fit tighter in the blanks. I am considering using thick CA glue rather than medium to help "mind the gap."

 

[egnald]

I'm not advocating ca glue because I use epoxy, but when I was using ca I used the thickest, gel CA, to glue the tubes in to "mind the gap". - Dave

 

[bugradx2]

Thanks all for the input. I believe, having read some sage advice, that what I'm experiencing (without the acutely accurate measuring devices) is what you say is "normal" bit sizing. It just seemed to me, when I first began the tubes fit tighter in the blanks. I am considering using thick CA glue rather than medium to help "mind the gap."

Thanks for commenting again. I was wondering if you meant the reply above or if you had a "wobble" in your hole. My drill press has a slight wobble and I've found it's better to use my lathe to drill holes to address this.

It looks like you're commenting that sometimes the hole is somewhat larger than the tube which is normal. I almost always use CA for gluing in my tubes but some kits seem to have extra play around the tube because the drill bit is a little larger than slightly larger than the tube. Yes, those are specific measurements in my shop. I have a couple pens that seem to show that and I will use epoxy on those. I also use epoxy on really long tubes to make sure I have plenty of time to get glue everywhere across the blank.