advice needed on different ways to make tapered plug

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Forum topic by stefang posted 03-29-2012 05:09 PM 3408 views 1 time favorited 24 replies Add to Favorites Watch
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16748 posts in 3844 days

03-29-2012 05:09 PM

Topic tags/keywords: question

Some of you might have seen my blog on making chinese balls. One of the requirements to making these balls is to make a plug for each one of the first 11 main holes to reinforce each one as they are turned. These plugs can be made of any material that can be formed to the correct shape and are rigid and strong enough. However, I prefer wood for this purpose, but I am open to other ideas as long as they aren’t too messy or complicated.

These plugs are a conical tapered shape approx. 3/4” wide at the top and up to about 3/8” at the bottom and 7/8” in length. I can easily turn these plugs, but the diameter sizes vary slightly at both the top and the bottom, so I have to try the plug in the hole and then remount it, often a few times to get just the right fit as shown in the photos below. I do get a very good fit this way.

I find this process pretty time consuming, so I am looking for a more efficient way to do this. One thought that comes to mind is first rough turning the plugs to a standard size then finishing them in a giant pencil sharpener or some other way that would be quicker than remounting, re-turning and re-testing. I wouldn’t mind eliminating the turning altogether. I even thought about a split plug with wedge in the middle, which is maybe worth trying.

I know I am being a little lazy by asking for help on this, but my main focus right now is just getting on with my ball project, and since I plan to make a number of these balls, and I don’t want to use the rest of my somewhat limited time left on earth to do it.

I am therefore hoping someone might have a practical and relatively easy solution for my problem and/or enjoy the problem solving challenge. Any ideas are welcome and will be much appreciated.

-- Mike, an American living in Norway.

24 replies so far

View a1Jim's profile


117722 posts in 4087 days

#1 posted 03-29-2012 05:29 PM

I was going to suggest the lathe but I knew you would have thought of that. My next thought is a router jig similar to one you use to make dowels but off set for the taper. I’m not sure that it would save time given you have to make the jig.

Here’s a link it’s the second jig down

one more Idea a rounder plane

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16748 posts in 3844 days

#2 posted 03-29-2012 05:40 PM

Thanks for trying to help me out Jim. The lathe is probably easiest in this case. Why am I not surprised that you would come with a solution involving routers? LOL. I’m still thinking the split plug with the wedge might have merit, but maybe a better idea will show up. One guy makes the plugs out polystyrene, but I can just see the waste floating around in my shop or clinging to every surface, so I think that is definitely not for me.

-- Mike, an American living in Norway.

View stefang's profile


16748 posts in 3844 days

#3 posted 03-29-2012 05:53 PM

Hi again Jim. I read the links and I couldn’t use anything there, but I did send a great dowel making solution to the guy trying to make a dowel cutter in the 2nd link that I learned from a readers tip in FWW a long time ago.

-- Mike, an American living in Norway.

View Loren's profile


10477 posts in 4158 days

#4 posted 03-29-2012 05:53 PM

I think you may be able to make this cut with an old adjustable
hollow augur. There were a lot of designs for these and I’ve
never used one so I can’t say that they all can be set up for
this type of taper.

View DS's profile


3301 posts in 2930 days

#5 posted 03-29-2012 06:03 PM

In violin making the tapered tuning pegs are made with a specialized peg shaper. It reminds me of a pencil sharpener on a larger scale. (The metal plate has a sharp edge facing the v-groove slot)

The tapered holes are made with a reamer.

Perhaps a matched set of reamer/shaper can be made for making both the holes in the ball and the pegs.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View shipwright's profile


8381 posts in 3308 days

#6 posted 03-29-2012 06:20 PM

I have used shaper knives bolted to a flat metal bar as a handle to reproduce a profile. Maybe you could make a dedicated angle scraper with a face that would run parallel to the spindle when the taper was exact. It shouldn’t be too hard to make after the cutting tools you made for the ball.

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

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16748 posts in 3844 days

#7 posted 03-29-2012 06:29 PM

Loren Yes, I have seen augers like this. If I recall correctly they are much like a pencil sharpener, but for larger work pieces. Unfortunately It would be almost impossible for me to find one over here. It is a rare occurrence to see any used tools for sale and car boot sales don’t even exist here. Thanks for your suggestion, a good idea.

DS251 From the looks of the auger, this would have to be scaled up quite a bit, but I can see how it works. My problem is that the plug may vary in diameter at both ends whereas a cutter of that type would probably have a predetermined wall angle if I’m not mistaken. However, it still might have some possibilities I will certainly give it some thought. I have to compare whatever method against turning it on my lathe. Thanks much for your help.

Paul This looks pretty smart the way you are using it. I can easily visualize a taper profile ground into a chunk of steel, although I have doubts about it being any more efficient as my wide skew chisel (especially if I made it). I’m starting to wonder if my requirements are a bit unrealistic or unclear, even to myself.

Thanks for your input. I will give it serious consideration. I do have some shaper blades I could use for this, but they cost me about $100, so I’m not sure I want to go that route, but I have some 1/4” steel plate that might work with hardening and tempering if I decide to try this. BTW I have watched 4 or 5 of the Inkscape tutorials (some more than once) and I have done some tracings, first the penguin and later some photos of my own. Good to learn something new if I can just remember it now!

-- Mike, an American living in Norway.

View a1Jim's profile


117722 posts in 4087 days

#8 posted 03-29-2012 06:53 PM

I was wondering if you could make a mold from the one you made out of plaster of paris and just pour some more out of epoxy or bondo or silicone ?

View TopamaxSurvivor's profile


18672 posts in 4186 days

#9 posted 03-29-2012 10:11 PM

Since you said open to other ideas, I still think getting the plugs close then using a quick set epoxy for final fit will be fast and easy. Be sure to paste wax the hole for release!

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View DS's profile


3301 posts in 2930 days

#10 posted 03-29-2012 10:19 PM

My problem is that the plug may vary in diameter at both ends…

What you are concerned about is the angle of the taper. The diameter would be a function of how far the plug is inserted. If the angles are a match, the diameter can vary some.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View Philip's profile


1277 posts in 3049 days

#11 posted 03-29-2012 10:29 PM

You may want to make a screwbox style cutter, similar to the Veritas tenon cutter. Simple “pencil sharpener” type. There are plans for this on the Woodwrights shop (PBS) homepage, and you can make it taper to any diameter you want.

You could watch the episode “Hurray for Hickory” to see how it works. Good luck!

-- I never finish anyth

View doughan's profile


96 posts in 3101 days

#12 posted 03-29-2012 11:57 PM

chuck the piece of wood up in a large drill and hold it on a belt sander with both the wood spinning and the belt turning….you can adjust the angle as needed till it fits.
I’ve mmade pretty darn round hand rail of set blocks this way on multi million dollar houses at the job site by drilling a pilot hole in the center of the block of wood,drawing a circle slightly bigger then you need and triming as much as possible till it has about 16 sides then round it out on a belt sander facing up and a screw in the pilot hole chucked into the drill..took a few minutes and made a 2 1/2” thick round block that only needed a 1/4 round over and some 220 sanding .hold the spinning block with the drill at about 45 to the belt moving

View devann's profile


2250 posts in 3202 days

#13 posted 03-30-2012 01:34 AM

Stefang, I recently needed a tapered plug for a orbital sander so I could connect a smaller diameter hose to a larger diameter hose. I made the plug on my disc sander. It looked like a tapered dognut.

With table set to the desired angle and the disc spinning counter clockwise turn your dowel clockwise and a little practice you should be fine. Cut off what you need and make another one.

I make the tiny little rain barrels/ beer barrels for my bird house embellishments that way. They are tapered both ways from center to end. The table on the sander for these is set 90° to the disc. I just hold the dowel at a slight angle and spin.

-- Darrell, making more sawdust than I know what to do with

View Yuri's profile


55 posts in 3925 days

#14 posted 03-30-2012 01:40 AM

I just post a blog on my “plugs making” venture here. Hope this will help. Mike, try not to use wedges. Ball can take pressure no problem but spreading the hole even with little pressure plus central force from turning may crack the ball.

-- Live to Learn

View stefang's profile


16748 posts in 3844 days

#15 posted 03-30-2012 09:21 AM

I want to thank everyone for your efforts to help me out. This isn’t easy when you are not fully aware of all the details involved. I know I threw some off with my preference for wooden plugs and chose something else instead.

Everyone’s solutions here would work, and many were very close to my favorite, but I chose Yuri’s because it is quick, easy, not messy, and it should produce a perfect plug without any machining or sanding, plus it will be rigid enough to do it’s job properly. Now I just have to see if I can get hold of the product.

Yuri This looks like like the ideal solution. I will have to search the net to see if I can mail order the product because I doubt it will be available here.

Another concern is the drying time. Is it a 2 components mix, and does it dry pretty fast?

And lastly, how can I prevent it from spreading in between the different layers of the inner balls? I can think of some possible solutions to this last problem, but better if you already have a proven method.

Thanks again and best wishes to everyone


-- Mike, an American living in Norway.

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