Precision Drilling - or lack there of

[dasimm]

I've recently moved to mandrel-less turning and I'm getting much better results but I still get a little OOR because of the drill bits.

On the larger pens I'm using the standard drill bits (jobber length) and they have a slight wobble towards the end of the bit (further away from the chuck - less accuracy).

Is there a place to order 10.5 and 12.5 bits that are shorter and hence more precise than the off-the-shelf crap I'm using now?

Drilling on the lathe is the next step for me - but I still see the problem with the long drill bits.

Thanks,

 

[dasimm]

I found the answer in another thread. - Thanks

 

[dow]

I found the answer in another thread. - Thanks

Okay, David, which thread? :biggrin:

 

[CaRed]

I want to know which thread also. My drills bits are fine but they are too short. The other direction of your problem.

 

[RAdams]

I would also like to know what thread!!

I also think that once you flip over to drilling on the lathe, the problem will decrease. I'm not saying it will go away alltogether, but it will get better.

When i drill on the lathe, I use a gouge to true up the end of the blank, and concave it slightly. I also make sure the very very center of the blank is clean, and indented. The drill bit naturally finds the center as long as the blank is trued up good.

 

[DurocShark]

There are two issues with precision drilling:

Too big drill bits.
Sloppy drill presses with imprecise platforms.

The lathe fixes the second one. I've started using 1/2" round blanks for many of my pens now because I don't have to account for drill press slop any more.

 

[dasimm]

Well - it's not an exact answer that I was looking for - but it seems that I'm headed in the right direction (maybe - I have not tried it yet so I'm not 100% sure):

http://www.penturners.org/forum/showthread.php?t=51070

This gentleman (from the above thread) indicated he solved a good portion of his problem by drilling on the lathe - which is what I was planning to do anyways. I just dont have all of the necessary stuff yet & looks like it will be a while before I do.

It still doesn't necessarily fix my initial thought that the bits have too much play in them which causes the OOR problem.

I'm thinking I may have to cut the bits and then re-grind them to get what I want - which is a lot of work given an already busy schedule... :bulgy-eyes:

 

[jkeithrussell]

A standard sized drill bit, firmly and deeply chucked, should not wobble whether you are using a drill press or the lathe. Any modest wobbling should stop as soon as the bit bites into the material. If you are getting that much wobble, there is another problem somewhere that you need to find.

 

[dow]

Just out of curiosity, have you checked your drill press for runout? Mine shows negligible (.001) at the spindle, but more the longer the drill bit. I suspect that the problem is in my chuck, and I'm hunting around for a replacment chuck to try. If that fixes the problem, then great. If not, then i'll have a good chuck that I can dedicate to my lathe (both the drill press and lathe use Morse #2 tapers).

Something else that I did that has helped my drilling was to change out the belts in my drill press. I got a link belt from HF and made up both belts with about 8-10" of belt left over. On a side note, while "EVERYBODY" knows that "EVERYHING" from HF is made in China. The link belt is USA made.

Just a thought.

 

[JeffinWIS]

for shorter drills google "stub drill" or "screw machine drill". For longer drills "taper length drill"

 

[dasimm]

Thanks for the tips everyone. This gives me a few things to investigate.

My press a small Delta benchtop which does most everything I need but is not as precise as I need for the larger pens. I may need to see what I can do to rectify this.

FWIW - I do get run out... It's actually noticeable to the naked eye at full extension which is confirmed by the less than perfect circle in the bottom of the pen blank.

 

[bracky1]

I've recently bought some drill bits with a morse taper shank, they fit directly into the tailstock without a chuck. Solved all my problems because if I haven't got the exact size I use a smaller one as a pilot and the larger, normal drill follows the path of least resistance. No more drill wobble :wink:

 

[j.d.sackett]

drill the hole a little smaller than diameter you need and use a reamer to finish it off. i drill almost everything on a lathe and still use reamers when i need a really accurate hole. reamers are round, stiff and straight. drill bits aren't. regards, j.d.

 

[RAdams]

lol... that was my thread!

If you have a scroll chuck, all you need is a drill chuck for the lathe. I bought one of the cheapo drill chucks from HF. It works great! On the big pens, i do them in stages.

For instance: If i am doing a Jr. Gent, i start with the 7MM bit and go all the way through. Then i go to the 10.5MM bit, and finally the 12.5MM.




Funny (but DANGEROUS) story:

In my haste to drill o nthe lathe, i disassembled a handheld cordless drill and stole the chuck out of it in hopes that it was a #2 morse taper. Of course it wasnt. I got to looking at the drill chuck and realized that it did just fit in the tailstock, but no taper, so nothing to hold it in. I used this drill chuck to drill probably 10 or so blanks before i got a tapered chuck. It was exciting to say the least... but it was much more accurate than the drill press... My $15 drill chuck has made my drill press obsolete.

 

[dankc908]

I am quite 'intrigued' about the possibility of drilling on the lathe (PSI Turncrafter - midi lathe), however, I was told to check the 'travel' on my tailstock. I have 2" of travel and was told that this will, then, not work for drilling pen blanks as I will need at least 2.5"+ of travel. Does anyone have any ideas on how I might make this work as I'd like to make my drill press obsolete. It is so accurate that I might rent it out to the gov't. since it is always "close enough for government work" but not accurate enough for pen-making!

 

[DurocShark]

I have a Turncrafter Pro and drill on it.

Line up the blank in the chuck with the drillbit in the tailstock. (While aligning, make sure you have the tailstock clamped down on the bed, and the quill locked to eliminate any slop.)

Turn lathe on (lowest) and slowly advance the quill, backing out every 1/4" to 1/2" to clear chips.

When you've gone 1" to 1 1/2" into the blank turn the lathe off, loosen the tailstock and pull it out. Retract the quill then CAREFULLY slide the tailstock so the bit goes back into the blank. Rinse and repeat.

Each time you do this you'll be going deeper and adding that much to your quill travel. The careful part is not chipping the entrance hole in the blank with your bit by bumping the edge.

 

[randyrls]

I have a Turncrafter Pro and drill on it.
The careful part is not chipping the entrance hole in the blank with your bit by bumping the edge.

I turn off the drill when advancing the bit until it is into the hole. Then I turn on the drill and continue drilling.

 

[RAdams]

yep... it takes a while when drilling acrylics and such cause you have to clear the chips alot, and it is a hassle... turn the lathe off, loosen the tailstock, pull it back, clear the chips, reinsert bit, lock tailstock, start lathe, drill half a wheel turn and start over from the beginning. The good part is that it is well worth it! Especially for the big kits. I can get the 7mm kits to do ok on the drill press, but i just like drilling on the lathe, so i do them all there!

 

[DurocShark]

I turn off the drill when advancing the bit until it is into the hole. Then I turn on the drill and continue drilling.

Sorry, I thought I said that. Yes, while the lathe is off.

Now, for extra credit, what do you do with only 1" to 1.5" at a time when drilling a looooooong barrel like a Pentel?

Myself, I loosen the tailstock and hand push it into the barrel AFTER getting the first 2" or so using the quill so it has a hole to guide the bit the rest of the way.

 

[wolftat]

for shorter drills google "stub drill" or "screw machine drill". For longer drills "taper length drill"

Or you can google "hacksaw".

 

[dankc908]

Now I'm really getting confused! I called PSI to inquire about what kind of chuck I need for the headstock. They told me that "you can't drill on the lathe. It never works." HELP - I need to either switch methods or get a better drill press!

 

[RAdams]

That's funny.... I think it was a PSI video the first time i ever saw anyone drill on a lathe!


There are a couple of ways to drill on the lathe, depending on the situation and what you are trying to accomplish.


For the most part, you will either need a collet chuck, or a scroll chuck for the headstock. Basicly, something to hold the pen blank. You will also need a drill chuck (aka Jacob's chuck) for the tailstock, to hold the drill bit.


There is another technique that is usually only used for drilling weird shaped blanks, like deer antler and such... In this situation, you put the drill chuck in the headstock, and just about anything will work in the tail. You hold the work with pliers, and use the tail to advance it into the spinning bit. Just before you go all the way thru, back the tail off and use your pliers to advance the bit thru the end of the blank.

 

[RAdams]

or you can google "hacksaw".

rofl

 

[BigguyZ]

There is another technique that is usually only used for drilling weird shaped blanks, like deer antler and such... In this situation, you put the drill chuck in the headstock, and just about anything will work in the tail. You hold the work with pliers, and use the tail to advance it into the spinning bit. Just before you go all the way thru, back the tail off and use your pliers to advance the bit thru the end of the blank.

Awesome- I think I'mm have to try that.

 

[DurocShark]

Buy this: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42340

I was going to point you to the HF chuck I use, but they seem to have discontinued it. Here's the writeup I did: http://blog.woodscrub.info/2009/02/harbor-freight-2-mini-scroll-chuck.html

Since that's not available anymore, buy one of the Barracuda chucks from PSI, or other folks can recommend one for you.

 

[RAdams]

WOOT WOOT on the drill chuck!


I would not be without my little NOVA! Versatility out the nose!