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STEFANG'S CHINESE BALL QUEST #6: Drilling the 22 constellation holes in the ball

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Blog entry by stefang posted 02-28-2012 07:40 PM 6610 reads 3 times favorited 26 comments Add to Favorites Watch
« Part 5: Making a Wooden Ball - part 2 Part 6 of STEFANG'S CHINESE BALL QUEST series Part 7: A Small But Significant Victory »

Here is what I am trying to make:

Here is where we left off at the end of the last blog with the ball marked up to locate the 22 constellation holes (the small ones) and the 12 primary holes

Today was used to drill the constellation holes. These holes are done first as the are needed to remove waste that the curved undercutting tools can’t reach. They also provide some space for the cuttings to go as the inner balls are turned.

A few words about the importance of doing careful work while drilling these holes

The constellation holes have to be drilled with great care because if one is messed up then the project becomes a practice ball instead of the nicely finished curiosity you might have been dreaming about. The following list are the things you need to do this work properly. These observations are based on my hard earned experience.

1. A good chuck that will hold the ball tightly while being turned.
2. A Jacobs chuck to fit the tailstock of your lathe (preferably the kind you can tighten by hand).
3. Sharp drills are essential. Dull drills wander and will knock the ball off center, even with a good chuck

The drill bits
Only four drills are actually needed as follows: 9mm, 6mm, 4mm and 3mm. These drill only about 4mm each as you can see by the depth marks when lined up. Each hole is drilled until the depth mark gets to the ball surface. The 5th drill is a 9mm twist drill used to start drill the primary holes which will be reamed out to 18mm after drilling.

For the constellation holes I have used brad drills for the first 3 used on each hole starting with the largest bit. and a twist drill for the 4th and smallest bit.

I used the brad point drills because my twist drills in the correct sizes weren’t sharp enough and I wanted to get on with the work.

The brad bits work well enough as long as the brad isn’t wider or longer than the drill which follows it. Sharp twist drills are the bit of choice though because the spurs on the brad bits cut slightly deeper on the outside perimeter of the hole than in the center.

Drills lined up on their depth marks to show the length of the hole at each level above

Here the bits are line up under my lathe bed and ready to use (as mentioned above, only 4 will actually be used, the shiny ones)

drills ready for use. above

Preparing the Chuck
Sandpaper grippers have been stuck on with double sided tape to the interior of the chuck and around the inside rim of the chuck collar. I had to add an extra layer to the ones in the collar as the ball was still a little loose with only one layer (not shown).

The ball chuck ready above

Headstock/tailstock alignment
It’s very important to make sure your headstock and tailstock are properly aligned to insure that all holes to be drilled will point to the center of the ball (Think radial holes)

The headstock/tailstock are properly aligned above

Proper mounting of the ball in the chuck

The ball is being mounted in the chuck. Please note that I am applying pressure on the ball with my revolving tailstock center first to center the ball and secondly to keep it in place while I tighten the chuck collar.

I am using my battery drill, but only to screw in most of the way to save time and effort. A regular screw driver is used for careful final tightening to prevent dragging the ball off-center. This is done gradually by keeping a pretty even gap between the collar and the chuck body all around as it is tightened.

Mounting the ball in the chuck above

Drill sequence
I took the authors advice from the book, which is to begin with the largest drill bit first and working towards the smallest. This helps prevent drill wander and knocking the ball off center.

The first hole is started in the picture. It’s very important to take it slow and easy and not force the drill in to the ball too quickly. I blow out the sawdust between each drill bit. When finished you will have drilled 22 constellation holes, each with 4 drills or actually 88 holes. Establishing a good routine helps to keep the work moving at quicker pace.

Having the right attitude for this sometimes tedious work
My advice on drilling these holes is to take your time and regard each hole as a small somewhat delicate project and give yourself a pat on the back each time one is successfully completed.

Turning the rim around the constellation holes
The last part is to turn the little rim around the hole as soon as it’s finish drilled. Less is better than more might be a good thought to have while doing these rims. If your ball is still centered perfectly all will go well, otherwise you have a rim that is wider on one side than the other.

The rim part was a challenge. I use a miniature skew chisel to turn them. I can’t say that I am entirely satisfied with the result, but not to worry, I know I will get better with experience.

First hole started above

Todays grand finale
The first 5 holes completed without any major disasters, whoopee!

First five holes completed above

And finally all 22 holes completed (whew).

All 22 holes satisfactorily drilled above

What’s next?*
My next blog in this series will cover the special tool rest I made and actually turning the 4 inner balls. I can’t guarantee that this work will go well. If successful, I will blog it. If not I will have to turn a new ball and drill those 22 holes again. I really hope that won’t happen

Thank you for reading this. It’s too wordy, but I want the readers to be aware of some of the pitfalls which can avoided with good practice. The following links cover all the blogs in the series to date.

http://lumberjocks.com/stefang/blog/27858 #1
http://lumberjocks.com/stefang/blog/27938 #2
http://lumberjocks.com/stefang/blog/28079 #3
http://lumberjocks.com/stefang/blog/28240 #4
http://lumberjocks.com/stefang/blog/28512 #5
http://lumberjocks.com/stefang/blog/28536 #6

-- Mike, an American living in Norway.



26 comments so far

View toyguy's profile

toyguy

1373 posts in 2590 days


#1 posted 02-28-2012 08:46 PM

facinateing….....

-- Brian, Ontario Canada,

View SPalm's profile

SPalm

4940 posts in 2635 days


#2 posted 02-28-2012 09:17 PM

Gotta blog either way – good and bad. (easy for me to say)
This is getting exciting.

Steve

-- -- I'm no rocket surgeon

View lanwater's profile

lanwater

3100 posts in 1687 days


#3 posted 02-28-2012 09:25 PM

Hopefully it will be successfull.

It’s indeed facinating.

-- Abbas, Castro Valley, CA

View SisQMark's profile

SisQMark

382 posts in 1353 days


#4 posted 02-28-2012 09:26 PM

This is really cool Mike. I can’t wait to see the completed project. Hey, good luck with the turning!
Mark

-- Don't waste today, it is yesterdays tomorrow!~SisQMark

View Dale J Struhar Sr's profile

Dale J Struhar Sr

360 posts in 1883 days


#5 posted 02-28-2012 09:35 PM

Whew!

-- Dale, Ohio

View Dave's profile

Dave

11205 posts in 1593 days


#6 posted 02-28-2012 10:46 PM

Ok Mike I have to ask. Is there a bucket next to the lathe with a bunch of missed drilled balls in it? I do like the liquid paper marker. The ball jig is a accomplishment in itself. Great series and we await the next installment.

-- Superdav "No matter where you go - there you are." http://chiselandforge.com

View stefang's profile

stefang

13633 posts in 2087 days


#7 posted 02-28-2012 11:22 PM

No Dave. That is a bucket of water to douse my cutting tools after hardening and tempering. That is not to say that there are no casualties laying around. All will be revealed in at the right time, so please stay tuned.

BTW I have decided to drop using a ball jig. Turning by hand is a lot less stressful/tedious and just as accurate. A better ball jig would be ok, but to be honest if someone is going to turn a lot of balls he will get better at it each time he turns one by hand. I also place a higher value on handwork, and I think you do too.

-- Mike, an American living in Norway.

View Yuri's profile

Yuri

54 posts in 2168 days


#8 posted 02-28-2012 11:26 PM

I’m sure it will be fine.

-- Live to Learn

View patron's profile

patron

13182 posts in 2094 days


#9 posted 02-28-2012 11:58 PM

lot’s of prep work in this
i know you are excited as we are

well documented process

keep them coming

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View Tim Dahn's profile

Tim Dahn

1481 posts in 2318 days


#10 posted 02-29-2012 12:22 AM

Hope the turning goes well. I know all too well how a dull bit wanders, even more so on a lathe.

-- Good judgement comes from experience and experience comes from poor judgement.

View sras's profile

sras

3946 posts in 1882 days


#11 posted 02-29-2012 02:12 AM

This is really interesting Mike! You are really doing well.

I’m looking forward to your next post already.

-- Steve - Impatience is Expensive

View shipwright's profile

shipwright

5316 posts in 1551 days


#12 posted 02-29-2012 03:36 AM

Keeping those fingers crossed for you Mike.
I have confidence that this ball will make it to the ball.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fiberglass trees. http://prmdesigns.com/

View kiefer's profile

kiefer

3376 posts in 1420 days


#13 posted 02-29-2012 04:18 AM

Interesting process and I am intrigued by this ball inside a ball inside a ball .
I will be watching as you go along .
Love the tools and chuck you fabricated .

Kifer

-- Kiefer 松

View stefang's profile

stefang

13633 posts in 2087 days


#14 posted 02-29-2012 10:52 AM

Thanks to everyone . I know from your work that you guys are all are better craftsmen than myself, so I appreciate your encouraging words which help motivate me to the finish. This has been my most challenging project to date and I am actually enjoying it, including the failures along the way which all teach me something. When I started woodworking I never would have thought that my attention span or motivation was adequate for this kind of work.

-- Mike, an American living in Norway.

View jockmike2's profile

jockmike2

10635 posts in 2999 days


#15 posted 02-29-2012 02:14 PM

Hi Mike, long time since I posted on one your blogs. Glad you are still showing us a thing or two about how to do things right. You know you’re one of the best craftsman on this site and this only proves it. Keep up the lessons buddy. Mike

-- (You just have to please the man in the Mirror) Mike from Michigan -

showing 1 through 15 of 26 comments

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