STEFANG'S CHINESE BALL QUEST #2: Some Tool Details and My Ball Cutting Jig

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Blog entry by stefang posted 01-31-2012 07:12 PM 14780 reads 3 times favorited 17 comments Add to Favorites Watch
« Part 1: Project Description and Making Special Tools Part 2 of STEFANG'S CHINESE BALL QUEST series Part 3: The Big Chuck Challenge »

This is what I am attempting to make

I took a few photos to show you some of the smaller details of the cutters. Unfortunately after all the praise heaped on me for making such fine tools, I will now be exposed as less skillful than you might have thought. The details reveal some pretty sloppy cutting and also centering of slots. However, they do work well.

The slots are centered on the tool with a center line. Drill points are marked on the centerline at the start and finish of the slots. the holes are drilled and the slots are cut out. This is very simple in theory, but I found it much more difficult in practice. I did get better at it with improved technique, but I’m not thrilled with the result. The good news is that I can make these over again whenever I want.

Note the light blue color still remaining on a couple of the tips shown above. This is the color to look for when tempering. According to the charts it should be more straw colored, but the book said light blue. This works, so it’s ok.

This image (above) is to give you some idea of the shape of the cutting tips.

Another shot of the cutter ends standing on edge. If you were Looking at the cutter laying flat as it would on the tool holder the width of the cutting tip is 1/8”(3mm) on the top and 3/32”(2mm) on the bottom. As you can see, the very end has the bevel ending in a sharp point. This is where the cutting takes place. It is important that this tip is as wide or wider than the rest of the radiused cutting end to prevent jamming as cutting progresses.

The ball cutting jig is somewhat optional. If you can cut balls freehand then you probably won’t need it. The one pictured is made from the plan in the book ‘Woodturning Wizadry”. The cutting tool is adjustable so it can be adjusted in for each small cut. This jig will only cut one radius, the 62mm ball used for my project. I have adapted it to my lathe so it is easily positioned or removed. It’s rather a pain in the neck to manually adjust the cutter after each cut, especially since each cut is so shallow (by necessity).

The knob on the top is to lock the cutting tool.

Here is a detail photo of the cutting tip.This tool is a piece of hardened and tempered 1/4” (6mm) steel plate shown in the photo above.

The book suggests screwing the jig base onto a wooden bench under the the lathe carriage. I tried this but found it very inflexible and time consuming to set-up and remove, so instead I just use a board on the bottom (as seen above) of the platform that sits very snuggly between the carriage bars and keeps it perfectly centered. I then just use a couple of spring clamps on the backside of the lathe to keep it in position.

the above photo show that the cutting tip is perfectly aligned with the turning centerline height of the lathe. It also has to align perfectly with the tailstock centerline height.

Here is a ball that I cut freehand. I will try my ball cutting jig for the first time after changing the base for my next ball. The above ball was cut with a round nosed wide scraper. I got quite a nice cut with that. I will blog cutting with the jig later.

And last but not least the stuff I use for depth markers on my drills and also for marking out the turning tools. This stuff is much better than collars or masking tape!

My next blog with will be about the custom made chuck for holding the balls in various positions for drilling and turning. I hope you found something of interest here.Thanks for reading. The following links cover all the blogs in the series to date. #1 #2 #3 #4 #5 #6

-- Mike, an American living in Norway.

17 comments so far

View patron's profile


13721 posts in 4456 days

#1 posted 01-31-2012 07:18 PM

great post here mike

i’m sure we will all learn quit a bit

glad you got to do this

at such an early age too !

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

View Dave's profile


11435 posts in 3955 days

#2 posted 01-31-2012 07:45 PM

Great Mike. I have an interest in the tempering of the tools. Did you heat below the cutting edge of the tool then quench? Or heat the tip slowly? Or maybe get another piece cherry, then place you tool on the edge and wait for the heat transfer?
Sorry, got off into to many questions.
Your freehand ball looks pretty dang perfect to me.
A wonderful blog Mike keep us posted.
Is that liquid paper?

-- Superdav "No matter where you go - there you are."

View a1Jim's profile


118162 posts in 4692 days

#3 posted 01-31-2012 08:16 PM

Very interesting Mike can’t wait for more.


View stefang's profile


17040 posts in 4449 days

#4 posted 01-31-2012 08:22 PM

David This stuff is easy compared to what my wife makes me do. Age makes no difference to her. I suggest you revel in you bachelorhood. Today I’ve been working on our house ventilation unit. It’s a shame I will be kicking the bucket so soon with all the miscellaneous skills I’ve learned over the years!

Dave I hardened the whole thing from the body of the cutters forward to and including the curved tip. This was done by first heating to cherry red, dousing in a bucket cold water and then immediately reheating to the light blue color and then dousing again to temper it. That was it. I used a small butane/propane torch keeping the metal in the orange part of the flame for the quickest heat-up. There might be other/better ways to do this, but I don’t know about them if there is. And yes that stuff is what you call “liquid paper”

A couple of safety reminders: It is very wise to place your torch in a vise or some other secure holder and point it away from any objects before you light up. That way you can concentrate on holding the tool to the flame without the danger of toppling your torch. I used leather gloves and a vise-grip to hold the cutters with, as the whole thing gets pretty hot. Safety Glasses, a helmet, knee and shoulder pads is optional. Good luck and let me know how it went for you!

-- Mike, an American living in Norway.

View Dave's profile


11435 posts in 3955 days

#5 posted 01-31-2012 09:44 PM

Thanks Mike and I will do.

-- Superdav "No matter where you go - there you are."

View sras's profile


6171 posts in 4244 days

#6 posted 02-01-2012 05:41 AM

Fascinating! I know you have the book, but this looks to be a very significant challenge!

-- Steve - Impatience is Expensive

View stefang's profile


17040 posts in 4449 days

#7 posted 02-01-2012 02:34 PM

Thanks for your comments Jim and Steve. The woodworking parts including the turning is easy enough, but the metal work has been a lot more challenging for me. I did have some problems with the wooden chuck though, which I will explain in some detail in the next blog. I think the important thing for this project is to take each part of it, i.e., jig making, tool making, ball turning/preparation, and turning the balls within balls, all as separate projects. If each project succeeds, that should result in a Chinese ball. We will see. It is fun to try something new.

-- Mike, an American living in Norway.

View shipwright's profile


8727 posts in 3913 days

#8 posted 02-01-2012 04:41 PM

This is fascinating stuff Mike and you are just the man I’d expect to find doing it.
Your projects always seem a little different in a very challenging way but I do understand the lure of a challenge.
Keep up the fine work and we’ll be here watching.

-- Paul M ..............the early bird may get the worm but it’s the second mouse that gets the cheese!

View stefang's profile


17040 posts in 4449 days

#9 posted 02-01-2012 06:32 PM

Thanks Paul. That’s because I am a challenged woodworker!

-- Mike, an American living in Norway.

View SisQMark's profile


384 posts in 3715 days

#10 posted 02-04-2012 06:13 AM

Very interesting blog Mike, I’ll be following with interest. I was a machinist for awhile and the shop I worked in used motor oil for the tempering process. It seamed to work well. Have you used this method at all? You can achieve some pretty good rockwell hardness. I’ve been interested in making knives, but stalled due to the hardening of the blades, I figured I wouldn’t do it good enough. Keep up with the blog we are all interested.

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

View stefang's profile


17040 posts in 4449 days

#11 posted 02-04-2012 01:09 PM

Thanks SisQMark. I haven’t tried oil as I thought it would be too messy, but I have read that the tempering process used by professionals is much more scientific than the color method I’m using, but it works quite well for these small cutters. I have watched some knife videos showing the hardening/tempering processes, but it looks a lot more difficult and time consuming with so much more steel involved.

-- Mike, an American living in Norway.

View Roz's profile


1707 posts in 4901 days

#12 posted 02-04-2012 11:20 PM

Over my head.

-- Terry Roswell, L.A. (Lower Alabama) "Life is what happens to you when you are making other plans."

View stefang's profile


17040 posts in 4449 days

#13 posted 02-05-2012 01:37 PM

I doubt that Terry. It is a woodturner’s thing. If you were a turner, then it wouldn’t seem difficult. It’s one of those one step at a time things. I have chosen to do this project the hard way by making all the tools. The turning tools can also just be purchased from Crown Tools.

-- Mike, an American living in Norway.

View mafe's profile


13202 posts in 4204 days

#14 posted 02-07-2012 11:46 AM

Amazing Mike!
I will follow this one and enjoy your talents.
I have not had the time to look into the stuff about the lathe you send me, but it is not forgotten.
Big smile to you my friend,

-- MAD F, the fanatical rhykenologist and vintage architect.

View stefang's profile


17040 posts in 4449 days

#15 posted 02-07-2012 01:13 PM

Thanks Mads. I am glad you are busy and living to the full my friend. My curious little project is going rather slowly, but I did get into the shop a little the last couple of days now that my eyes are pretty much healed. Meanwhile I am doing most of my woodworking from my easy chair!

-- Mike, an American living in Norway.

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