Problem with drilling? Just defective kits?

[Kenjamin]

Hey everyone,

I've been trying to turn some breast cancer pens, but they always turn out really bad near the ends of the blanks. When I put the tubes in, I notice that there is always room for the tube to wiggle in the hole I drilled in the blank on both ends. It isnt a perfect fit.

I thought this would be ok, but after turning down to size, shaping, and then buffing, the hole being too large causes a very thin wall to the blank near the tips that is almost completely transparent. I painted the tubes, but with how thin the wall is, it still looks horrible. I'm drilling the blanks on the lathe and I notice the drill bit sometimes jumps a millimeter or less when it starts to drill into the blank.

Do I have a defective jacob's chuck? Is this a common problem?

Also, it seems the center band for these kits is way too big. I'm using the bushings the kit said to use, but the center band is way oversized.

Here are some images of the see-through problem at the edges.

imgur: the simple image sharer

 

[butchf18a]

Little more information would be helpful. Are you drilling on lathe? Drill press? Have you tried drilling your blanks long then trimming down to eliminate the oversized area? What about runout on your drill press?

 

[plantman]

Pen turning 101: Never trust the written word, or the bushing you use !!!! Always measure your tubes and fittings first before you start a project !! I will bet that the first piece made by the machine in the manufacturing process is not the same size as the 10,000th piece. This is the process I use to drill my blanks on the lathe. Measure everything first. Cut your blanks about a 1/4 inch longer than called for. Use a blank centering drilling chuck to hold your blanks in the headstock. Use a centering drill in the tail stock chuck to start your hole. Use the correct size drill bit to drill your hole all the way through your blank. Don't drill from both ends, they seldom meet in the center. This should solve your problem unless your headstock and tailstock do not meet in the center when brought together and tightened down. Use a digital calipers to get your finished size by measuring your fittings. Don't trust the bushings, only use them to get close to your size !!! Also if you want a tighter fit on your tubes, go to Harbor Freight and buy the 115 piece drill bit set. It comes with a chart giving the drill sizes in fractions and decimal. Measure your tubes ( they aren't all the same) and look at the chart, pick the next largest size, be it fraction, letter, or number size drill and start with that. As for the thin ends, that can't be the correct band for the bushings, measure the band and turn to that size not the bushing. You can make any band fit on any pen, make a custom band, or have no band at all. Just measure what you want to use. !!! Jim S

 

[ed4copies]

You have a "comfort pen band" and you are using slimline bushings.

Change one of the two.


The "see through" could be resolved by reverse painting your blank. OR making the hole fit the tube. Use a caliper to determine the OD of your tube and pick a drill bit that will fit better.

(Just cause the instructions say "use a ____mm bit" , does NOT mean it is the only, or even the best choice---you are allowed to improvise)

 

[flyitfast]

Get a set of starter bits at Harbor Freight. Normally used on machine lathes, but they work fine for woodturning. A set of 5 costs $5-6. Use them to create a dimple for your drill to start in. Keeps the drill from wandering and can prevent an oversize hole like you are getting.
Go slow and back the drill out frequently to prevent heat that also can cause an oversized hole.
gordon

 

[ed4copies]

If you've got an hour or so on Sunday, give me a call tomorrow 631-five 78 three (bots can't interpret, as I understand it) and we can make a time for you to come up and we will solve whatever problems!

 

[Kenjamin]

Thanks for the advice, everyone. I'm using a NOVA chuck with pen "fingers". I use a Jacob's chuck in the tail stock and pretty much follow all the videos I've seen on YouTube as far as drilling and preparing the blanks goes.

My steps are as follows:

Hold the tubes to the blank and mark about 1/4 inch over each side of each tube, then cut on those lines at the band saw.

Use the NOVA chuck and Jacob's chuck to drill the blanks.

Use medium CA glue on the tubes (after sanding them to rough) and insert them into the blanks.

Use a pen mill to square the ends of the blanks down to the tubes.

Put the blanks on a mandrel with a mandrel saver and all the bushings and do the art part.

For most of the kits, the pens turn out great. It's the slimline and funline kits that seem to give me the problem.

I'll try some of the advice here and see if the smaller drill bit or some machining bits from Harbor Freight wont help keep the bits from wandering so much to get a better hole.

I appreciate all the replies in such a short time. It's great to have such an amazing font of knowledge within reach, especially one that is willing to share that knowledge.

I won't be able to call you tomorrow, Ed; I'll be in Chicago with my friend for the festival down there. I could give you a call Sunday or Monday or whenever works well for you.

Thanks,

Kenjamin

 

[nanna]

Don't you just love this site...
The way you all chip in to help is truly amazing, I have been having such problems with slim line pen kits and can't wait to follow some of the advice given. Especially drilling it frustrates me so.....always split wood at the ends look just like the pink pen pictures posted!!!!

 

[KBs Pensnmore]

I'm drilling the blanks on the lathe and I notice the drill bit sometimes jumps a millimeter or less when it starts to drill into the blank.

Going by your above statement, it would appear that your tailstock is not quite lining up with the centre of your blank, as the drill bit goes in, it is shaving off the sides a bit, giving you the oversized hole.
Most wood lathes would suffer from this problem as they are not a precision built machine.
When I have the same problem, I use a skew chisel to make a small dimple in the end of the blank, I then offer the long drill bit up to the blank, then drill about 1/2-3/4" and then holding on to the chuck, withdraw the drill to remove swarf, and continually repeat until finished.
This is for nanna, cut your blanks about 1/2" (12mm) longer than needed, when you drill, stop about a 1/4" (6mm) from the end, and then cut the end off, no splitting of the end!!!
Hope this helps.
Kryn

 

[Sawdust1825]

I agree with KBs that it sounds like you might have a misalignment between the tail stock and head stock. The drill bit is finding center when you see it jump on contact. Go slowly as it makes contact to allow this to happen naturally. Without going into a dialogue that will bore you with hard to understand terms that is best thing you can do to help. Take Ed up on his offer to talk you through it. I am a novice to most here when it comes to pen making but know precision machining well. The center drill (starter bit) option might benefit you as well. Good luck.

 

[Mack C.]

Here's my take on this situation for what it's worth!

A couple of years back johnnycnc recommended to me that Norseman jobber drills were top of the line bits that I should try.

Due to some health issues in the past year I disposed of all my pen bits along with most of my pen supplies. I've had a return to reasonable health, so went looking for pen kits etc. I decided on 3 different kits and purchased the drill bits sold by the vendor with the kits. Upon using them I could immediately see the wobble in them when drilling on my lathe.

They got put aside, I wouldn't even give them to pen turning friends of mine. I have so far collected 10 different Norseman bits at a slightly higher expense than the other bits but well worth every penny. They drill straighter than I previously was able to drill and don't shatter acrylics when coming out the other end. (I don't drill through the end on purpose, this was a "just in case" test!)

I buy my drill bits at Fastenal.com They have a complete collection of any drill bit by manufacturer that you would like.

All drill bits aren't equal!

 

[RKB]

Hope you solve your issues. I have been turning pens for 8 months and love it. I learn something every time I visit my shop. Make sure you take Ed up on his offer! That would be so cool to do that. Good Luck.
Rod

 

[nativewooder]

I agree that you should align the head stock and the tail stock. Should be done prior to any turning. There is a plastic tool on the market that helps with this task.

 

[KBs Pensnmore]

I agree that you should align the head stock and the tail stock. Should be done prior to any turning. There is a plastic tool on the market that helps with this task.

Even using a center drill won't be a guarantee of drilling in the center, if the tailstock is out of alignment.
No need for a fancy plastic gimmick to check alignment. Fit a dead centre in the head stock and live centre in the tailstock with a rule between the point will show alignment, vertical rule, is spot on vertically, and square to the headstock is horizontally correct. Doesn't cost a cent and you won't loose it in the shavings.:biggrin:
Also check that the tailstock is parallel to the ways, not on a twist, this is especially important when drilling. Using a 3/4"dia long bar with a Morse taper on one end and a point on the other end is how this is done.
Kryn