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This article was published in the November 2019 edition of More Woodturning

Inlaid Rings as 6 page pdf

Inlaid Rings

Main photo

Introduction

You can make quite a few interesting patterns by inlaying rings into a reasonably flat area of a project.  But I used to have trouble getting them to fit as well as I liked.  It’s not all that easy to lay out a ring on a project and even if you get it right, a pencil width is much too much error.  I tried a hole saw with the center drill removed but minor errors in tailstock centering would change the ring thickness and diameter.  Then it occurred to me that if I turned a dado on the end of the ring stock I could do an ordinary cut/test process and sneak up on the inside fit.  Then I could flip the ring stock over and repeat the cut/test on the outside of the ring.  The resulting fit would only be dependent on my patience, eyesight, and practice.

One ring is boring, so you need a way to mount your project eccentrically to get a multiple ring pattern.  I’ve used a 4-jawed chuck with two jaws gripping a rectangular mounting block, but that method doesn’t center automatically and you have to set the amount of eccentricity each time.  For this project I used a square mounting block and only removed one jaw.  Two opposing jaws grip the square, and the third jaw, with the aid of a spacer, sets the eccentricity.  The amount of eccentricity is set by the size of the spacer and is repeatable (within the limits of wooden auxiliary chucks).  To mount centered all you need to do is put the fourth jaw back on and grip the square.

Ring Patterns

 If you arrange a number of rings in a circle you get an interesting pattern that has a Celtic feel to it.  My CAD program calls this a Radial Array.   I’m going to borrow the CAD terms.  Look at Drawing 1.  It has four rings.  The rings can be defined by their radius which I’m calling RR for Ring Radius.  The rings are arranged so that their center points are at equally spaced intervals in a circle.  I’ll call the radius of the circle of center points RA for Radius of Array.

Drawing 1

Drawing 1:  Visually defining the array terms.

The ratio of RA to RR determines how the pattern looks.  If RA if small compared to RR, the resulting pattern has a lot of negative space in the middle surrounded by closely packed rings.  As RA gets larger the negative space in the middle shrinks and the rings get further apart.  Look at Drawing 2 for nine sample arrays.  If you want to plan how your ring pattern looks and have a CAD program it’s probably quicker to experiment in CAD than either pencil and paper or real rings on a grid.

Drawing 2

Drawing 2:  Nine array samples.

In the photos that follow my Radius of Ring is a about 1” and my Radius of Array is 3/8”, so the ratio of RA/RR is 3/8 in Drawing 2.

Making the Rings and Ring Gauge

It’s prudent to have the grain orientation of the rings the same as the grain orientation as what they’re inlaid in.  Generally this will be face grain, or bowl orientation.  Cutting a cube off a turning square is a sensible way to do rings 2” in diameter or less.  In the photos, I’m using 2” cherry.  This size can easily be mounted in a 4-jawed chuck for drilling and turning.  If you drill first there will be less likelihood of splitting the blank.  A spacer is needed to avoid running the Forstner bit into the chuck jaws. Figure #1 shows two methods of doing this.  On the left is a slightly less than 2” square of 1/4” Masonite.  On the right a 2” square waste block has been glued to the side grain of the blank.  The Masonite is quicker.  The waste block lets you cut more rings from blank.

Figure #1

Figure #1:  Two ways to safely mount the Ring Blank for drilling.

Mount the blank in your 4-jawed chuck for drilling as in Figure #2.  Remember it should be in bowl orientation.  Select a Forstner bit to drill out the center of the blank.  I suggest a ring wall thickness of at least 1/8” for your first practice attempts.  As I anticipated having a slightly less than 2” diameter ring blank I selected a 1-5/8” Forstner bit.  Although you will usually hear a change in noise when the bit enters the waste block or Masonite, it would be prudent to mark the drilling depth with tape.  Drill the blank as in Figure #3.

Figure #2

Figure #2:  Mount the Ring Blank.

Figure #3

Figure #3:  Drill the Ring Blank.

Next turn the outside of the Ring Blank as seen in Figure #4.  Remember it is mounted in bowl orientation.  I used a small bowl gouge followed by a shear scraper.  Prioritize a constant diameter over a particular dimension.  I used spring calipers and tried to get the sound the calipers made passing over the blank the same over the whole length.  You can double check with dial calipers with the lathe off.

Figure #4

Figure #4:  Turn the outside of the Ring Blank to a consistent diameter.

You can part off the rings without support if you don’t mind chasing them.  If you don’t want to chase them about your shop you can chuck up a drill bit backwards in your tailstock mounted drill chuck and insert it most of the way into the Ring Blank.  However, you’ll have a lot more control if you make a mandrel to fit inside the Ring Blank.  This will provide backup to your parting cuts so that you won’t have as much tear out.  It will also make it much easier to layout cutting lines when inlaying the rings.

These instructions are for a One-way pattern tailstock center:  For a mandrel for 2” rings chuck a 2” cube or 2” cylinder in your 4-jawed chuck in bowl orientation.  Use a combined drill and countersink to start centered hole.  Then drill a 21/32” hole 1-1/4” deep.  Put a mini-tap guide in your drill chuck.  Use it and a tap to tap 3/4x10 threads as deep as you can.  Remove the tap and use a small bowl gouge to turn as much of the blank round as possible.  Remove the blank from the chuck.  Chuck up a stub of 3/4x10 threaded rod or bolt in something.  I used a 3/4” collet in a collet chuck.  #1 jaws in your 4-jawed chuck will also work, as will the base jaws (remove all top jaws).  Mount the blank on the 3/4x10 threaded stub.  Turn the rest of the blank round.  Now turn a tenon on the end of the blank that matches the drill diameter you’ve selected to create the inside of the rings.  Remove the mandrel from the threaded stub and mount it on your tailstock center as in Figure #5.  Mine has blue tape on the tenon as it’s been used enough to be somewhat undersized.  Photos of making a mandrel to fit on a One-way pattern tailstock center are available at: http://davidreedsmith.com/Articles/DiamondOrnament/FoamConeCenter.htm

Figure #5

Figure #5:  Mount the mandrel on your tailstock center.

Use a ruler and a soft pencil to draw a line the length of the Ring Blank at the center of end grain.  Then draw a pair of lines about a half inch clockwise from the first line.  This will allow you to mount the rings in a consistent orientation in your project.  Advance the mandrel into the Ring Blank leaving a gap between the end of the blank and the shoulder of the tenon as Figure #6.

Figure #6:  Mark the end grain of the Ring Blank and advance the mandrel into the Ring Blank.

Create a gauge to mark the depth of the rings.  I put two tick marks about 0.10” apart on some cracker box cardboard.  Mark the Ring Blank for the first ring as in Figure #7. 

Figure #7

Figure #7:  Mark the Ring Blank for the ring depth.

Use a narrow parting tool to cut the ring off the Ring Blank.  Unless your mandrel is excessively tight the ring will general jump to the right when the cut is complete as in Figure #8.  You will get a smoother cut with less tear out if you use a fluted parting tool.  Sorby makes a fluted 1/16” parting tool.  I fluted my own with a chain saw sharpener bit.  Back off the mandrel and remove the ring.  Advance the mandrel back into the Ring Blank and cut another ring.  Repeat until you have enough rings for your project but leave at least 1/4” of Ring Blank to make a Ring Gauge.

Figure #8

Figure #8:  Cut off a ring.

To make the Ring Gauge mark 0.10” from the end of the Ring Blank.  Use a full size parting tool (I use a 5/32” wide diamond shaped parting tool) to cut a groove that is about half way through the thickness of the Ring Blank wall as in Figure #9.  Now use a narrow parting tool to part off the Ring Gauge, lining up the headstock side of the narrow parting tool with the headstock side of the full size parting tool cut.  Figure #10 shows this cut that is half completed so you can see the position.  Figure #11 shows the completed rings and Ring Gauge.

Figure #9

Figure #9:  Turn a tenon for the Ring Gauge with a full size parting tool.

Figure #10

Figure #10:  Part off the Ring Gauge with a narrow parting tool.

Figure #11

Figure #11:  The completed Ring Gauge and rings.

There may be circumstances where you cannot use a drill to bore the inside of the rings.  It is quite difficult to turn a constant and deep diameter.  Perhaps your design calls for a diameter you don’t have a drill for, or you cannot find stock long enough for all the rings you need.  In this case I suggest making every ring into a Ring Gauge.  Slight differences in Ring Diameter would be less obvious than the same difference as a gap.

The Eccentric Mount

The project will be mounted eccentrically with a square mounting block and a spacer using three jaws of a 4-jawed chuck.  Open up your chuck as far is it will go and determine the largest square that will fit.  Then make your mounting square a little smaller than that.  It may look intimidating having the chuck jaws sticking out that far, but your project will cover it up and you’ll be turning on the side away from the jaws.  For #2 jaws on a Oneway Stronghold chuck I used a 3” square.  The square should have a thickness less than the depth of the jaws.  The spacer should be the width to get the pattern you want for the size rings you are using.  As my rings were 2” in diameter thus having a 1” radius and I wanted an AR/RR of 3/8, my spacer was 3/8” wide.  The spacer should be thinner than the chuck jaw depth.  Gluing tabs at each end of the spacer will make it less likely to fall out and prevent you from putting it in the wrong orientation.  Figure #12 shows the competed square and spacer.

Figure #12

Figure #12:  The completed square and spacer.

I cut a 4-1/2” square for a practice piece.  I marked the corners for cutting to an octagon after mounting the square as it’s easier to lay out a square in the middle of a square than the middle of an octagon or a disc.  Layout pencil lines to locate the square in the middle of the project piece.  You can use any method you like of temporarily mounting the square on the project.  I like blue tape and glue.  Cover the middle of the project piece and the square with regular blue masking tape as in Figure #13.  Spread wood glue on the taped square, and align it with the layout lines.  Then clamp the square and project together until the glue sets as in Figure #14.  If you’re in a hurry you can use dots of thin CA glue rather than wood glue, but do please clamp it together for a few minutes.

Figure #13

Figure #13:  Put blue tape on the mating surfaces of the square and the project.

Figure #14

Figure #14:  Clamp the square and project together until the glue sets.

Now prepare your 4-jawed chuck for turning eccentrically.  Remove one of the jaws.  If your chuck has a limiting pin on one of the jaws, than do not remove that one.  Rotate the chuck so that the missing jaw is up.  Place the spacer on the jaw on the bottom with the tabs facing down as in Figure #15.  Slide the square into place between the jaws with the side marked “1” over the missing jaw.  Press the project firmly against the tops of the jaws and the side of the spacer as you tighten the chuck.  The result is shown in Figure #16.

Figure #15

Figure #15:  Remove one jaw from your 4-jawed chuck and place the spacer over the opposite remaining jaw.

Figure #16

Figure #16:  The project mounted eccentrically at the first position.

Inlaying Rings

I believe it’s worth while to make the mandrel.  However, it is possible to inlay the rings without using one.  When cutting the rings from the Ring Blank only cut the four you need for the inlay pattern.  This will leave a tube about 1” long.  Make the tube into an elongated Ring Gauge.  Put 3M Restickable glue on the flat end of the Tube.  Use a large cone tailstock center to pin the Ring Gauge to the eccentrically mounted project.  Trace around the outside with a pencil.  Reinforce the glue by holding on to the tube and withdraw the tailstock center.  Still holding the tube in place with one hand trace the inside.

More sensibly with the aid of the mandrel, advance the tailstock center so that the nose of the mandrel touches the project.  As the diameter of the tenon of the mandrel is the same as the inner diameter of the rings, trace the mandrel tenon with a pencil as in Figure #17.

Figure #17

Figure #17:  Trace the mandrel tenon on the project,

Slip a ring onto the mandrel tenon.  Hold the ring against the project with one hand and trace the outside of the ring on the project with the other hand as in Figure #18.  You can leave a ring on the tenon and slide it back out of the way for future inside diameter tracings.

Figure #18

Figure #18:  Trace the ring outside diameter on the project.

The traced lines are not accurate enough to cut to, but do give you a guide as to where to start.  Make a cut with a narrow parting tool (a fluted one will cut more cleanly on the sides).  Now make another cut towards the middle to enlarge the groove as in Figure #19.  Test the fit of the tenoned end of the Ring Gauge to see if it fits.

Figure #19

Figure #19:  Starting cutting in between the traced lines.

You may remember me mentioning earlier in the article that the fit of the rings is dependent on patience, eyesight, and practice.  Patience in this case comes from making small cuts and testing every time.  Sure, stopping the lathe to test the fit every time is a pain.  Making bigger cuts is quicker and you might get lucky with the fit one time.  But probably not eight times (inside and outside for four rings).  Eyesight you can help in two ways:  Wear flip down magnifiers unless you’re less than 40 years old, and wipe any sawdust off your parting tool so you can more clearly see the edge.  Practice is just that, and I really recommend making several practice pieces before trying it on a “real” piece.

Continue with light cuts and test fits until the inner diameter of the Ring Gauge fits snugly as in Figure #20.  You can see that the tenon of the Ring Gauge did not go into the groove completely.  If this happens to you extend the depth with the parting tool until the tenon goes all the way in as in Figure #21.

Figure #20

Figure #20:  Continue cut and test until the Ring Gauge fits in the inner diameter.

Figure #21

Figure #21:  Adjust the depth until the full tenon fits in the groove.

Now make light cuts alternating with test fits with the full thickness end of the Ring Gauge until  you have a snug fit in the outside diameter as in Figure #22.  You can confirm the fit by using an actual ring but don’t push it all the way in as it would be hard to get out.  Make a pencil mark indicating the grain direction as in Figure #23.

Figure #22

Figure #22:  Alternate cut and test until the Ring Gauge fits in the outer diameter.

Figure #23

Figure #23:  Mark the end grain direction at the center of the groove.

Spread glue in the groove.  I put a puddle of glue on some tape on my lathe bed and used a bamboo skewer to transfer and spread the glue as in Figure #24.  Align the ring so that the single pencil line aligns with the center end grain mark on the project and so that the double line is clockwise to the single line.  Push or tap the ring until it is fully seated as in Figure #25.

Figure #24

Figure #24:  Spread glue in the groove.

Figure #25

Figure #25:  Align and insert the ring.

Give the glue a chance to set and then turn the ring flush as in Figure #26.  Re-chuck the square so that the second side is over the missing jaw and repeat to inlay another ring.  Do the same for positions three and four as in Figure #27.

Figure #26

Figure #26:  Level the ring.

Figure #27

Figure #27:  Repeat for the other rings.

Sometimes you end up with some gaps.  There are, in fact, some gaps in the photos.  My excuse is the distraction of taking photos.  One way to hide the gaps is with V-Grooves.  You can, after putting in all the rings, remount the project at each position and turn V-Grooves with a pyramid point tool or the like.  The position won’t be perfect because this is a wooden homemade auxiliary chuck, but because there are only four orientations and one amount of eccentricity it will be close enough to hide moderate gaps as in Figure #28.

Figure #28

Figure #28:  After disguising gaps with V-grooves.

Turn and surface and rim if you want to keep the piece and then sand and polish it was in Figure #29.  Make a few more practice pieces and then try the inlaid ring technique on a real project.

Figure #29

Figure #29:  The completed practice piece.

Variations

I explored some variations.  You can see examples at: http://www.davidreedsmith.com/articles/InlaidRings/Variations/Variations.html

PVC Pipe as inlaid rings

You can use pretty much the same methods to inlay PVC pipe.  If you get tired of white, Formufit makes PVC pipe in colors.  You can order from them or ship to store through Home Depot.

Smaller sizes of PVC pipe look pretty round.  But it’s made using an extrusion process and isn’t quite woodturning round.  For best results bore short (less than 2-1/2”) lengths of pipe with a Forstner bit.  Then mount on a mandrel and turn round.

Bondo All-Purpose Putty as infill

You can get Bondo All-Purpose Putty at major chain hardware stores.  It’s much the same as the auto shop stuff only it comes with a white crème hardener.  You can color it with powdered colors.  Add the color before the activator.  You should reserve some colored, unactivated, Bondo in case you need to fill defects after turning.

Hardened Bondo is hard on tool edges, particularly if you let it harden over night.

Durham’s Rock Hard as infill

You can color Durham’s with powdered colors, or with acrylic paint.  It seems to work fine filling grooves made with a narrow parting tool.  I had trouble with larger grooves cracking.

Polymer Clay as infill

If your wood can take some heat you can try polymer clay.  It comes already colored.  Ignore the baking instructions on the wrapper and try 15 minutes at 250 degrees.  It would be prudent to put a sheet of aluminum foil under the project and work when the primary oven user is not home.

Air Dried Clay as infill

The pre-colored air dried clay for the child crafting market is very light.  You can turn it carefully and sand to final dimensions.  It’ll need to harden overnight.  It remains soft and can be easily dented with a fingernail even after overnight drying.

The more upscale La Doll Premiere white air dried clay can be tinted with powdered pigments.  It dries quite hard but I had trouble with it shrinking away from the edges of grooves.