Any drilling suggestions?

[Russknan]

I am working on a pen where the holes for the tubes need to be 10.5 and 12.5mm. The drill bits that I have for these are "conventional" metal style bits. In the past when I've made this style of pen, I started out with a 7mm brad point bit to bore pilot holes, then slowly and carefully re-bored with the larger bits. In truth, I haven't been perfectly happy with the result because, when changing bits, I think I've added some variation and the tubes haven't always slid in easily. (BTW, I do not yet have the ability to drill on the lathe. I recently bought a Rockwell pen drilling/assembly vise which I really like.) My current project has some soft metallic features at angles which, I'm sure, will want to divert the bits. The question is do you think I should still try pilot holes first with a smaller brad point, or just dimple the center with an awl or small bit and go at it slowly but all in one shot with the larger, more substantial, conventional bits? Appreciate any help you could give. Russ

 

[ed4copies]

Is any of the material you are drilling a wood?

Wood can swell, after the hole is drilled. I surmise that this means the wood is still pretty "wet", so I leave it somewhere warm and dry and then redrill in a couple days.

This is merely a "theory", so perhaps others will give you a better answer!!

Ed

 

[Russknan]

Yes, wood in each of 3 cases where this has been an issue. Two of them have been with wood I've procured and believed to be dry(?) Maybe not enough(?). The other was with a commercially obtained blank that, I guess, could have the same issue. In each case, I wound up sanding/filing the areas where the tubes seemed to hang up. I'll try your suggestion in the future. It makes sense. Thanks, Ed.

Actually, my bigger concern at the moment is how best to prevent the bits from wandering, due to the construction "features".

 

[paintspill]

i've never drilled then redrilled larger, i've used standard bits to drill blanks with few problems, some things i find that help with tough blanks (i.e. deer antler) i cut my blanks extra long because i find that if there is chipping it is on the entry and exit which you can then trim off after you drill. as for the slight difference in kit sizes its so quick and easy to drill a test hole in a scrap piece of anything to see if it fits the tube.

 

[ed4copies]

Yes, wood in each of 3 cases where this has been an issue. Two of them have been with wood I've procured and believed to be dry(?) Maybe not enough(?). The other was with a commercially obtained blank that, I guess, could have the same issue. In each case, I wound up sanding/filing the areas where the tubes seemed to hang up. I'll try your suggestion in the future. It makes sense. Thanks, Ed.

Actually, my bigger concern at the moment is how best to prevent the bits from wandering, due to the construction "features".

Each moment has it's own "priority concern"---I'm "cool with that"!

Why worry about the question of "wet" wood? Because, I BELIEVE this will lead to your pen cracking at some future date. We do a "quick redrill" and put in tubes (at least that is what I DID, for a long time). Months later, the pen cracks. I BELIEVE this is caused by the wood swelling or contracting---the brass tube may move a smidge with heat, but the movement does NOT equal the wood movement and thus, a crack develops.

ALL of this is theory----you are welcome to disagree or pose an alternative theory!!!
Ed

 

[KenV]

Russell,

Having really sharp drill bits with the point centered is important in reducing fotces that occur as the materical changes. Alunimum can be sticky. Using a drill bit that is ground " flatter", that is less agressive and thinner shavings, helps manage problems.

I have bits that came out of the package that were not ground with the juncture of the flutes in the middle.

Successive drilling works better with bits having sharp edge flutes along the length of the bit.

 

[Jim Burr]

One thread here recently made a big difference to me was...and I'm going to get the name wrong...but they are "Starter bit's"...someone will pop in with the correct name. A few of us picked them up a few weeks a go and they make huge difference in drilling accuracy. Learn something new every week!

 

[flyitfast]

Starter bits are just what you mean and they are almost a must for accurate starting and accurate drilling. HF has a great set for about 5 bucks.
gordon

 

[Russknan]

Thanks to all who helped. I really appreciate your advice. Just ordered a set of "Center drill countersink bits" on Amazon yesterday for future projects. In the mean time, dimpled my blanks and drilled start to finish with the large conventional bits, doing the holes in one shot. I will probably adopt this technique in the future, in stead of using progressively larger bits. HOWEVER - The longer, slightly smaller diameter bit went through fine. Got half way through with the larger bit . . . and encountered a "design opportunity". Not sure whether the problem was too much pressure from blank vise (possibly, I DID tighten it a bit too much in retrospect), inadequate adhesion from the epoxy (mixed evidence from the wreckage), or that the complex design, mixing wood and metal combined with rather shallow walls - despite the blank having been wrapped with electrician's tape - was just too fragile. As I think on it now, perhaps the tape also contributed to the destructive force. The result was catastrophic! I'll try turning the surviving lower blank and, if it makes it, I'll try to devise an aesthetically pleasing pairing for the cap. Should the remaining blank not make it through turning, I'll have a whole NEW opportunity for design! Thanks again, Russ