drilling sequence

[MShepard]

I have been lurking on IAP forums for a couple of months but this is my first post. I have made ( or attempted to make) a few kitless pens and results have been varied, a couple I am proud of and several are not, several have ended as a pile of assorted pieces. It seems if I have several blanks of the same kind I can make a pen out of two, if I start with two I am bound to destroy at least one component.
My question is when drilling holes of different diameter should I start with the smallest and progress larger or drill the largest and decrease. A couple of sections I have made have been off center when parted off.

 

[Paul in OKC]

How have you done it? Are you talking about two different diameters in the same part? If so, you might try going big first. Then run the smaller drill into the bottom of that hole and start. Should follow the center of the hole already there. May need to start holes with a center drill (or combination drill and countersink). Hope that helps. And Welcome aboard!

 

[Charlie_W]

Michael,
First of all, Welcome from Virginia!

I can't help you with the kit less drilling questions but I am sure others can!

You may want to post a Hello in the introduction's forum to let folks know you have joined this great group.

Show us some of your pens when you can.

 

[Carl Fisher]

Short answer is whatever you are more comfortable with.

Long answer is usually it's better to drill small first and then step drill to larger bits. Less cutting area equals a cooler bit and happier blank but there could be some instances where going the other way around can be beneficial.

 

[pianomanpj]

I agree that it depends on the material, but going small to big (in the same hole) can tend to be "grabby". You'll want to have sharp bits and a slow feed rate - especially when making initial contact with the larger bit into the blank.

 

[Sabaharr]

I might be missing something here but if 2 different diameter holes are required then chasing the smaller with a larger bit eliminates the smaller hole unless it is deeper than the larger one. Either way drilling slowly on the lathe will help out with the centering problem. Slowly is the key, slowest speed on the lathe and slow advancement of the bit, with frequent back out for waste removal. On tough materials I even put a drop of BLO on the bit every time I back out, but I don't know if that helps other than keeping the bit cooler. Since I started that I haven't had any smoking material coming out. Are you using brad point bits? They tend to go straighter and not follow grain as much.

 

[MShepard]

I always start with a center drill. Initially I drilled small first but had a off center hole so I started drilling large first. I usually run lathe in reverse and advance bit a mm or two then drill forward. Had good luck this way but last weekend I turned a section and it was off-center.
I have been turning my sections backward from the texatdurango's tutorial. I drill a large diameter 2mm deep hole for the lip on the nib section, then a smaller hole for the body of the nib section, then step down for the threaded area. Tap the section. turn it down and finish. I turn a tenon at the desired length in the blank near the headstock and turn it off. all I have to do is thread the tenon and the section is finished.

 

[pianomanpj]

I might be missing something here but if 2 different diameter holes are required then chasing the smaller with a larger bit eliminates the smaller hole unless it is deeper than the larger one. Either way drilling slowly on the lathe will help out with the centering problem. Slowly is the key, slowest speed on the lathe and slow advancement of the bit, with frequent back out for waste removal. On tough materials I even put a drop of BLO on the bit every time I back out, but I don't know if that helps other than keeping the bit cooler. Since I started that I haven't had any smoking material coming out. Are you using brad point bits? They tend to go straighter and not follow grain as much.

I was commenting based on the assumption that he was step-drilling holes with the smaller one being deeper. Hope I don't get bit in the assumption.

 

[frank123]

Small hole first to full depth using a center drill (or starter drill) of appropriate size the follow with the large bit or larger bits in order if you're boring multiple size.

The larger bits will follow the bore of the smaller bits and may even correct a bit of deflection, but if a larger bit goes in first and deflects even slightly it will cause the smaller bit to deflect and drill off center (this is obviously dependent on the size and stiffness of the bits, a 2mm bit is far more likely to deflect than a 12 mm bit in most materials). It doesn't hurt to keep a cross linear sectional sketch of the drill sizes and exact depth so you know exactly how close you are coming to them when turning the outsides of the blank.

It might be a good idea to buy some cheap blanks (or maybe something like Delrin rod) and just practice on them with the intent of throwing them away so you don't waste any good stuff in the process of learning).

 

[MShepard]

I could be using to high of a speed or advancing to rapidly, will try to correct both, Thanks.