Projects | Syzygy Woodworks

June 6, 2014June 17, 2017

Split Turned Legs

I am building a custom vanity cabinet. The design features a couple pairs of split turned legs either side of each door opening. I thought I would take the opportunity to document the process involved in creating a split turning. Split turnings are typically used in furniture and architectural applications, as decorative elements. The process has other applications in woodturning, including the “Lost Wood Process”.

The Merrimam-Webster dictionary definition is as follows:

a turning (as of a baluster) split vertically and applied decoratively (as to the surface of a chest or cupboard) or used as a spindle in a chairback

Essentially the process involves gluing two pieces of wood together with a piece of paper sandwiched between them. The piece is then mounted on the lathe and turned to the desired shape. Once the turning is complete the paper joint is split using a chisel, the paper literally splits in half, yielding two identical half turnings. A simple process, but there are a couple of important things to watch out for.

The design of the split legs I needed is fairly simple. It is a cone, approximately 32″ long, tapering from 3″ diameter to 1″ diameter. I started with a couple pieces of 8/4 maple, about 6 1/2″ wide and 33″ long. One face was flattened at the jointer. Just as with any glue joint, it is important to have the two mating surfaces flat.

The piece was then ripped in half at the table saw, yielding two pieces of 8/4 maple, each 3 1/4″ x 33″.

The only paper that I have personal experience using is the brown builders/construction paper. It is available from the home improvement retail stores and is typically used as a paint drop or to protect new flooring from damage by subsequent trades. It is a fairly thick paper, probably a little thicker than a brown paper bag. I’ve read that you can use newsprint or a brown paper bag, but I don’t have any experience with that.

In order to have a successful and stress free glue I’ve learnt that you need to get everything prepared in advance. As well as clamps, glue and spreaders, this also involves cutting the paper to size. I also like to fold the paper over the edges of the wood so that it is easier to place in the correct position once the glue is applied.

It is very important to note that you are gluing the paper to both pieces of wood, so you need to apply the glue to both pieces of wood. If you think of it in terms of a sandwich analogy, where the two pieces of wood are the slices of bread, and the paper is the meat in the sandwich, you need to put the mayo (glue) on both slices of bread! 🙂

Once the glue is applied to both pieces of wood, place the paper over one of the pieces …

… then place the other piece of wood on the paper, and clamp together. I like to leave the assembly clamped overnight. The glued up blank now measures approx. 3 1/4″ x 3 1/4″ x 32″.

After removing the clamps, I clean up the ends of the blanks at the miter saw and mark the centers of each blank. Actually, the one center line is already determined by the glue join, I just mark the other line. When placing the blank on the lathe it is very important to position the centers accurately at the head stock and tail stock. The center determined by the glue line is actually more important than the other center line. If the glue line is not placed directly on center, then the two pieces once split will not be identical.

I like to use a steb or safety center at the head stock. This enables me to turn a bit more aggressively with out worrying about damaging the piece if I get a catch.

At the tail stock I use a cup live center. It is VERY important to use a cup center at the tail stock. If you use a cone center then you will split the two pieces apart as you tighten up the tail stock.

The turning on this design was not very complicated. As I mentioned before, it was a straight taper from 3″ diameter to 1″ diameter. However, it can be challenging to achieve a perfectly straight taper. In order to determine some guide points I drew out the leg design life size on a piece of construction paper. I was now able to use this drawing to determine the diameter of the finished leg at five intermediate points evenly spaced along the leg.

Once the piece was turned round, I marked the points along the leg …

… and using a parting tool and a pair of calipers, established the correct diameter at each of those points.

Use a spindle roughing gouge I then turned the leg just a bit bigger than the final diameters.

The final diameter and taper was established using a 1 1/4″ skew chisel.

In order to further smooth and straighten the taper I use the following trick. First, with the lathe running slowly, I draw a pencil spiral down the length of the leg.

I then attach a piece of 120 grit sandpaper to a piece of plywood with some spray adhesive. I run this up and down the leg as it is turning slowly.

Wherever the pencil marks are sanding off indicates a high point. So I am then able to refine those high spots with the skew.

The piece is now sanded smooth.

The moment of truth arrives! Time to split the turning. This is done by placing a sharp chisel directly on the paper glue joint and gently driving it into the joint with a hammer.

It is a little slow to start …

… but once the split is started the two pieces separate very easily. Actually, it is always a bit disconcerting as to how easily they come apart, considering that a short while ago they were spinning rapidly on the lathe!

A couple images of the pair of split turned legs. The paper still needs to be removed. This can be done with sandpaper, although depending on the size of the piece I will often make a shallow pass over the jointer to remove the paper.

October 11, 2013June 17, 2017

Wooden Collar with Threaded Pewter Insert

In this post I’m going to share my technique for making a wooden collar for a hollow form with a threaded pewter insert. In previous posts I have shown how I cast, turn and thread a pewter collar for a hollow form. I’ve also shown an easy way to cast a texture onto a pewter collar for a hollow form. Aesthetically, the main difference with this collar is that when the finial is screwed into the collar there is no pewter showing, however I am still able to retain the functionality of the threaded pewter. It is a nice way to showcase a special piece of wood on the top of a hollow form.

In this example I am using a small piece of rosewood burl. It is about 3/4″ thick and I have cut it into a rough circle about 2 1/2″ diameter on my bandsaw. With the jaws of my chuck closed I am holding it against the jaws with the live center.

This enables me to round it over and turn a shallow dovetail tenon on the piece.

I then rotate the piece and mount it in the chuck jaws so that I can drill a 1″ hole with a forstener bit to a depth of about 1/2″.

Using a thin shop made parting tool I then cut a groove into the wall of the hole that I have drilled. The idea here is to form a shallow groove to make a mechanical joint for the pewter. The parting tool was made from an old sawzall blade.

Here you can see the groove. It is about 1/8″ deep. I find it easiest to stand on the far side of the lathe when turning this groove.

The piece is then taken to my melting pot and molten pewter is cast into the hole. When the pewter has cooled it is a good idea to wick some thin CA glue into the joint between the pewter and the wood. The groove provides a mechanical joint that prevents the pewter from coming out of the hole. However the forces involved in drilling and threading the pewter are likely to cause the pewter insert to spin in the hole. Applying the CA glue at this point will prevent this from occurring and any CA residue will be turning off later in the process.

The piece is mounted back on the lathe and a 3/4″ hole is drilled through the piece.

Using a lathe tap holder, the threads are tapped into the pewter. As you can see I forgot to wick the CA glue into the joint between the pewter and the wood. The pewter stayed fixed while I was drilling, but as soon as I started threading it started to rotate. you can clearly see the CA residue on the surface of the wood which I will turn off shortly.

A close up shot of the tap and the threaded insert.

The top surface of the collar is now turned and a seal coat of shellac applied.

A 1/2″ male adapter is now mounted in a pair of long jaws and the collar is turned around and screwed onto the adapter to allow me to finish the underside of the collar.

Another shot showing the collar held on the lathe with the PVC male adapter.

The underside of the collar is turned. A tenon is turned to allow it to be attached to the opening in the hollow form. The bulk of the collar is also reduced, as is the threaded pewter insert, while still leaving some threads to accept the finial.

A shot of the top surface of the finished collar.

A shot of the underside of the finished collar.

July 12, 2013June 17, 2017

Textured, cast pewter collar

During my demonstration at the Symposium in Tampa I showed a couple variations of my cast and threaded pewter collars for a hollow form. One that seemed to generate a lot of interest is shown in the image below. I thought I would share the details on how I make this collar. It is a very simple technique and allows you to cast the texture directly so that the topside of the collar does not need to be turned. The technique gives you a very organic texture and the collar, because it is not perfectly round, has a natural edge look to it.

The first step is to create the wooden mold. I made this one on the lathe using dry maple and simply drilled a 3/8″ deep hole with a 2 1/4″ Forstner bit. Then you will need to raid the kitchen for some aluminum foil.

Tear off a piece of the aluminum foil and fold it double. Then crunch it up so it is all wrinkled. Carefully open it up and line the mold with it, trying not to smooth out all the wrinkles. You don’t need to get it to form fit the mold, all you are trying to achieve is a general dished shape.

Pour the molten pewter directly onto the aluminum foil, wait for it to cool and then …

… pop the textured collar out from the aluminum foil. At this point you can mount it on the lathe in a chuck and drill and tap the threads. Then sand the top surface of the collar with some steel wool before applying a patina and then sanding again with steel wool.

The image below shows a detail shot of a similar collar in a suspended hollow form.

June 28, 2013June 17, 2017

Cast and Threaded Pewter Collar and Finial

The following are my demonstration handouts for the “Cast and Threaded Pewter Collar and Finial” demonstration presented at the 2013 AAW Symposium in Tampa, FL.

Pewter is a non-ferrous metal alloy primarily made up of tin (85 to 99%), with the remainder consisting of copper, antimony, bismuth and lead. Modern pewter’s contain no lead and are actually Britannia metal. One noteworthy use of pewter is the Oscar statuettes. They are made of Britannia metal plated with gold. The melting point of pewter is approximately 375 degree Fahrenheit (190 degrees Celsius). The low melting point and non-ferrous nature make pewter a great candidate for incorporating it into turned pieces. A regular propane torch can melt it and it can be cut, drilled and turned with regular woodworking and woodturning tools.

Pewter can be purchased from online metal stores where you can expect to pay around $20 per pound. The frugal among us can also find it sold in ingot form on eBay, where you can typically win with a bid of about $12 per pound. The eBay sellers are normally selling melted down pewter mugs, plates etc. As such you take your chances regarding the lead content, although many claim the pewter is lead free and include pictures of test results.

Molten pewter being poured into wooden mold, using a “bottom pour” electric melting pot.

While pewter can be melted in a metal ladle, I use a small electric furnace or melting pot made by Lee Precision. This is the same pot used for reloading or casting fishing weights. They cost around $60 and are available from most hunting or sporting goods websites. One of the advantages of using this melting pot, aside from not having open flames in the workshop, is the pot is a “bottom pour”. Molten pewter contains a fair amount of “dross”. These impurities float to the top of the mix. With a “bottom pour” pot, when you lift a handle the molten metal flows from the bottom of the pot into your mold, leaving the “dross” in the pot. I have found the spout clogs occasionally, so I keep a propane torch on hand to melt the solid pewter clogging the spout. A casting thermometer is also very useful.

Molds can be made from a variety of materials. I use both wood and silicone to make molds. The silicone I use is sold by Smooth-On. It is called Heat Resistant Mold Max® 60 Silicone. I use this when I have spent time and effort creating a master and want to be able to cast a number of collars from the same mold. For one off collars I will typically just make a wooden mold. They are cheap, quick and easy to make and the collars poured in them can easily be embellished at the lathe. The wooden molds have a limited life span as the heat from the molten pewter causes them to warp. I use kiln dried maple for my wooden molds. The moisture content of the wood needs to be low in order to minimize the possibility of it turning into steam and expanding.

When casting and pouring the pewter make sure you take all safety precautions.

Never leave the melting pot unattended while plugged in.
Place the melting pot on a ceramic tile.
Wear thick gloves and safety glasses.
Allow the pewter to cool fully before trying to de-mold it. Sometimes it can appear solid on the surface but still be liquid inside.

I typically make my collars between 2 and 2 1/2” in diameter. This size works well for a hollow form from six to 12 inches tall. More important it allows me to easily mount the poured collar in my chuck for further work on the lathe. The first step is to drill a ¾” hole through the collar using a Jacobs chuck in the tailstock. Technically, for the size tap I use the hole should be 47/64”, but a ¾” drill bit is more readily available and being off by 1/64” doesn’t seem to make much difference.

Once the hole is drilled I use a NPS 1/2-14 tap to tap the threads in the collar.

Side note: NPS refers to Nominal Pipe Size. This is different to NPT which will produce a tapered thread. The ½” description can be a bit confusing as well, especially as we have just drilled a ¾” hole! It refers to the internal diameter of the schedule 40 pipe that this size thread is used on. The 14 refers to the threads per inch.

The tap is held on the lathe by means of a Lathe Tap Holder. These are available for purchase, but they are relatively easy to make. I made mine from a section of 1 1/8” aluminum rod which I drilled on the lathe. The idea behind threading on the lathe is to keep everything centered on the centerline axis of the lathe. The first collar I threaded, I did by hand holding the collar in the vise on my workbench. When I put the collar on the hollow form the finial was not plumb and stood at an angle!

The pewter collar being threaded on the lathe.

It is important to use some form of lubrication when threading or tapping metal. Although the pewter is a soft metal and threads/taps very easily, you will get a far better finished surface using lubricating oil. In lieu of actual threading oil I just use some regular 3 in One oil.

Now that the collar is tapped, wipe it down and soak it in some acetone or denatured alcohol to get rid of the excess oil. We now need to mount it to the lathe in order to turn a tenon on the underside and shape the top. I use a “27 cent chuck” I get from the hardware store to do this. A ½” PVC male adapter is held in my chuck and then the collar is threaded onto this.

The underside of the tenon being turned. It is threaded on a ½” PVC male adapter which is held in a chuck.

I turn the underside of the tenon first. I turn a tenon which is slightly larger than the hole in the hollow form. (I find it is easier to size the hole in the hollow form to the tenon than the other way around.) I then reduce the bulk of the collar by shaping the underside. Because the collar is held to the lathe by means of a PVC adaptor, I can cut right to the threads and into the PVC collar without worrying about damaging the gouge.

I then remove the collar from the PVC adapter and rotate it so I can turn the top. Wear gloves when removing the collar from the PVC adapter! The collar will have become pretty tight on the adaptor and the metal edges can cut you. Once the top of the collar is shaped it needs to be sanded/polished before embellish. Any embellishing tool you would use on a box top or spinning top can be used on the pewter. Chatter tools, Wagner texture tool, Sorby spiral tool and the Decorating Elf can be used, and the embellishments outlined with the tip of a skew chisel. These embellishments can also be further enhanced by applying India Ink, allowing it to dry before wiping it off.

The top of the collar being decorated using the Decorating Elf.

India Ink being applied to enhance the embellishments.

When I turn the hollow form I use a faceplate and I do not part the hollow form off initially. I typically hollow end grain and so do not experience a lot of movement as the piece dries. Now that the collar is complete I mount the hollow form back on the lathe and size the opening to fit the lathe. Once I have achieved a snug fit, I attach the collar to the hollow form while it is still on the lathe. I use 5 minute epoxy and put it around the opening of the hollow form. I then insert the collar and lightly clamp it using a 60 degree live center in the tailstock.

The next step is turn finish turning the bottom of the hollow form. Ideally I will allow the epoxy to cure overnight, but if you are careful the epoxy is strong enough to allow the next step within about half an hour. After removing the faceplate from the hollow form, mount the ½” PVC adapter in the chuck and then screw the hollow form onto it. Place a live center in the tailstock and bring it up to support the hollow form. Part the hollow form almost through, just leaving a little nub. Shape the underside of the hollow form and sand. Slow the lathe down and cut through the last of the nub. If you have allowed the epoxy time to cure the hollow form will be secure enough on the PVC adapter that you can finish sanding the underside. Keep the lathe speed slow though!

We now need to turn the finial and attach a threaded ring to it. A simple mold for the pewter ring can be made by drilling a 7/8” hole in a block off wood a couple of inches deep. The pewter is then poured into that. Allow the pewter time to cool. This might take a while as it is a pretty large volume of pewter. To remove the pewter from the mold, drill a hole in the block of wood from the underside and use the knock out bar from your lathe to knock the pewter free. It is then mounted in pin jaws in the chuck; drilled with a ½” drill, turned to 53/64” diameter and then threaded using a Round NPS ½-14 Die held in a Lathe Die Holder. Don’t forget to use some form of lubrication.

You will not be able to thread the entire column as the die will stop at the pin jaws, but thread at least ¾”. What is not used can always be melted and used again. Turn the exposed end of the column true and then part off ½” of the threaded column.

The base of the finial needs to be at least 7/8” diameter or it will just screw right into the hollow form! I leave a tenon on the finial which is about ¾” long and exactly 1/2” diameter before parting it off. The threaded pewter ring is then attached to the tenon on the finial using 5 minute epoxy. Apply the tenon to the inside of the pewter ring and not to the finial tenon. By doing so any excess will get pushed out the ring where it will be turned away later.

The final step is to clean up the underside of the tenon on finial. I do this by mounting a length of 2” PVC pipe using my chuck jaws in expansion mode. In the open end of the PVC pipe I place a piece of scrap wood with an appropriately sized tenon. The wooden insert has been drilled and threaded in the center so that the finial can be screwed into it. It helps if you cut a slit with a bandsaw from the edge of the wood to the center, making a “collet” chuck. The wood is then friction fit into the PVC pipe with the finial inside the pipe and the underside of the tenon exposed allowing you to turn it true.

May 31, 2013June 6, 2013

Tissue Box Cover – Part 2

Last week I covered the cutting of the four sides and the top for the tissue box cover. This week I will be showing how I embellished the sides and top with some wood turning.

The first step was to lay the parts out in the order in which they would be assembled.

I then laid out where the opening for the tissues would be and also drew some decorative circles to indicate where the embellishments would go. The center of the 6″ circle falls directly at the intersection of two sides and the top. The center of the 4″ circle falls at the intersection of two sides and the center of the 5″ circle is offset from the intersection of two sides.

The idea is to have the turned embellishments wrap around the sides and top of the assembled box. The layout for the embellishments that fall on two faces is not that critical, however if the embellishment falls on three faces then it is critical that the center of the circle is exactly at the intersection of the three faces, or the embellishments will not flow around all three faces.

I started with the 4″ circle and put double-sided tape on the back of the two faces that it fell on.

I then stuck the two pieces on a 12″ plywood circle which was attached to a face plate. I lined the two pieces up so that the center of the circle was at the intersection of the two pieces.

A couple of notes about the plywood backing. I used two pieces of 3/4″ plywood laminated together and rough cut to 12″ diameter. The double thickness helps to stiffen the piece and reduce vibration and flex at the circumference. The laminated plywood was then screwed to a face plate mounted to the lathe and turned true. It is important to use a face plate with set screws and tighten the set screws to the lathe spindle once the face plate is mounted on the lathe. If you don’t use set screws there is a danger of the plywood continuing to turn after the lathe is shut off, and it will then unscrew itself from the lathe!

Once the pieces are in position I like to apply pressure to the double sided tape for a couple of minutes. I place a scrap piece of wood over the parts and applied pressure with the tail stock. I also applied pressure to the corners of the scrap wood with some clamps. A couple of minutes under pressure makes the double sided tape stick much better.

After removing the clamps, scrap wood and tail stock, I turned the lathe on at a very slow speed and standing off to one side slowly turned up the speed. I let it run for a couple of minutes and then checked to see that the pieces were secure and had not moved. Once I was satisfied they were secure I turned a hemisphere in the center and some further embellishments with a texturing tool and skew.

While turning I kept the speed fairly low, around 1000 rpm.
Don’t skimp on the double sided tape.
Apply pressure to the tape for a couple of minutes to increase the adhesion strength.
Rotate the plywood before turning on the lathe to make sure nothing comes into contact with the tool rest etc.
Keep your hands and fingers behind the tool rest!
Take care removing the parts from the plywood. Slow, gentle and constant pressure will cause the tape to slowly give.

This was the 5″ circle which was offset from the intersection of the two sides. I added a scrap piece of maple to help counter balance the offset weight.

Last, I turned the embellishments that would flow over two sides and the top of the tissue box cover. It was critical that I align the center of this circle with the intersection of the three pieces. I also added a scrap piece of maple in the one corner to counter balance the weight and also to help provide support to the cuts I was making.

I then moved to my scroll saw and cut out the opening in the top for the tissues.

The five parts laid out again.

I laid some clear packing tape across the four sides, flipped them over, applied a thin bead of glue to the four sides, then rolled the parts up into a box …

… and taped it together. The tension created as the tape is stretched when rolling the sides up is more than sufficient clamping pressure for this assembly.

I then applied a thin bead of glue to the four bevels of the top …

… and taped it in place.

The finished tissue box cover.

April 19, 2013April 19, 2013

Using the Soren Berger Sphere Calipers

The gifted among us can turn a sphere by eye. For the rest of us some system is necessary to turn a spherical object. I’ve written previously about a method Al Hockenbery demonstrated on how to turn a sphere. Since then I have acquired a set of Soren Berger Sphere Calipers. They use the same principle as the previous method, but take out the math. The calipers consist of a large set of jaws, which when set to the diameter of the sphere, will automatically set two smaller “birds mouth” jaws to the correct spacing to enable you to turn the cylinder, into a square first, then an octagon and finally a sixteen sided shape, from where it is relatively easy to smooth out the sphere. The image below shows the Soren Berger Sphere Calipers. You can see the large jaws towards the bottom of the picture and the two “birds mouth” jaws toward the top of the picture. The smaller set of “birds mouth” jaws are nearly obscured by my thumb.

The blank that I am turning is a piece of hickory, just over 4″ long and 3″ diameter. Once the blank has been turned to a cylinder measure the diameter using the large set of jaws. Then transfer that dimension to the blank and turn the blank to that dimension, essentially creating a “square” cylinder whose length is equal to the diameter.

Then, using the large “birds mouth” jaws, make four marks on the blank equal distances from the corners of the blank.

Turn away the wood between these marks in a straight line. There are two “shoulders” which need to be turned away. We are now left with an octagonal shape, which contains the sphere.

Using the small “birds mouth” jaws, once again make a mark either side of each “corner” of the blank. This time we will make a total of eight marks. Sorry, but I forgot to take pictures of the small “birds mouth” jaws in action, but you can clearly see the eight lines that are established using them

Things can start to look a bit confusing at this point, so it can be beneficial to color in the spaces between each set of marks in order to clarify which areas need to be turned away. This time there are four “shoulders” to be turned away. As before, make sure the areas are turned away in a straight line. Any concave lines will bite into the sphere. Once the areas are turned away we are left with a sixteen sided polygon or hexadecagon. Regardless of what you call it, you can see that it started to look an awful lot like a sphere.

The next step is to free the sphere from the hexadecagon. I find light cuts and a slow measured approach are the key at this point.

The tenons are then turned down and then cut off with a handsaw with the lathe turned off. It always surprises me as to how small you can turn the tenons if you take care! When the handsaw cut is made, the blade is angled away from the sphere so that a small nub is left. If the saw cut is made straight down then there will be a small indent in the side of the sphere.

The sphere is then mounted between cup cnenters and the nubs are turned off. For a detailed explanation on how to make the cup centers you can refer back to my previous post on turning a sphere.

Once the nubs are turned away, the sphere is sanded and a coat of wax applied …

… and then into the bowl it goes with the rest of them!

March 17, 2013

End Grain Vessel with Pewter Rim

The blank selected should be approximately 4” x 4” x 6”. The grain should be orientated such that it runs parallel to the lathe. It is important that the blank is dry.

Mount the blank between centers. Turn it round, square off the end by the tailstock and turn a tenon to match your chuck. (In the first image, I have a steb center mounted in my chuck jaws)

Turn the blank around and mount in the chuck jaws. True it up and square off the end.

Cut groves in the end face of the blank to form a mold into which the pewter will be cast.

The image above shows a section through the blank, illustrating the dovetail which holds the pewter to the blank.

The image above shows the pewter being poured from the electric melting pot.

True up the face of the blank.

Turn the first inch of the exterior of the vessel. Clean up the pewter using a skew as a negative rake scraper. Cut a small chamfer on the top lip of the pewter rim using the skew in the same manner.

Using the long point of a skew, cut a small bevel to clean up the junction between the wood and the pewter. Then embellish the rim using a texturing tool.

The image above shows the exterior of the pewter rim.

Using a detail gouge, hollow out the first inch of the vessel.

Again using the skew as a negative rake scraper, clean up the top of the rim and cut a small chamfer on the inside lip of the rim.

The pewter rim is now complete.

Turn most of the exterior of the vessel, leaving some bulk at the base to add stability when hollowing.

Drill a hole to the final depth and then hollow out the interior. In the image on the right I am using a Termite tool to hollow with, but you could also do the hollowing with a detail gouge.

A negative rake scraper can be used to smooth out the interior of the vessel.

The exterior of the vessel is now turned to completion and sanded. It is a good idea to protect the pewter rim with some blue painters tape while sanding. The vessel is then parted off with an undercut.

A tenon is then formed on the remainder of the blank to form a jam chuck in order to finish off the underside of the vessel.

The completed end grain vessel with pewter rim.

September 2, 2010

Bowl depth gauge

Ever made a lampshade out of a bowl? I’ll never admit to it, but I’ve heard of people hollowing right through the bottom of a bowl 😉

I recently turned a bowl and the bottom was a lot thinner than I liked and getting dangerously close to becoming a lampshade. So I decided to make myself a better bowl depth gauge. Something more accurate than my current method of holding my gouge at the center of the bowl, eyeballing along the rim of the bowl and then bringing the gouge up and out of the bowl to eyeball how deep I was with my hollowing. I wanted something that would be accurate, but would still be quick and easy to use.

A visit to the plumbing section of Home Depot and I returned with a couple two foot sections of 3/4″ PVC, two tee sections, a 90 degree elbow and a cap. The wooden morse taper I turned and the rifle laser was purchased off Ebay.

I cut one of the PVC pipes in half and then cut an 8″ section off the other. (The length of the 8″ section was determined by the swing of my lathe, half of 16″. I cut the other pieces to 12″ as with the current tools that I have I’m unlikely to be turning a hollow form any deeper than that.)

Depending on the laser sight you get some adaptions may be needed to one of the PVC tee pieces. In my case the diameter of my laser sight was slightly greater than the internal diameter of the tee piece.

I mounted the tee piece in the pin jaws of my chuck using a 60 degree live center to help mount it true.

Then, with the lathe speed slowed down, I drilled it out with a Forstner bit that matched the diameter of the laser.

A nice snug fit.

I turned a tenon on the wooden morse taper that matched the internal diameter of the PVC pipe and then I pieced all the parts together.

Here is the depth gauge mounted on the lathe. The wooden morse taper is inserted in the tail stock. It is not necessary to jam it into the tail stock.

Side note: With a self ejecting tail stock it is not considered a good idea to use a wooden morse taper. Click here to read a discussion on this subject.

So, throwing caution to the winds, I mount my bowl depth gauge in the tail stock. Once everything is adjusted and the laser is shining on the tip of the cap, a couple of drops of CA glue can be applied to each of the PVC joints. Don’t glue the laser into the tee piece though, at some point you will need to take it out and change the batteries 🙂 The laser sight I got has a switch to turn the laser on and off, a lot more convenient than the lasers you get from stationary stores which require you to constantly depress a button for the laser to be visible.

I’m still trying to get a good shot of the laser on the outside of the bowl. When I do I’ll update this post with a picture of the depth gauge in action.

August 30, 2010

Turning a wooden morse taper

For the technically inclined a Morse Taper #2 has a angle of 1° 25′ 50″, as gleaned from the fountain of knowledge, Wikipedia. For the less technically inclined, myself included, turning a wooden morse taper is a quick and easy project that can be done with some simple measurements.

The first step is to mount a piece of hardwood between centers, or as I have done, in a chuck with a live center at the tailstock for support. True the piece and turn it roughly to size.

Take one of your centers and transfer two marks to the piece indicating the two sides of the taper.

Set a pair of calipers to the diameter of the morse taper upper end, and using a parting tool, part into the piece until the calipers slip over the parting cut. Repeat the procedure for the lower end of the morse taper.

Make a relief cut to the tailstock side that is smaller in diameter than the lower end of the morse taper.

Turn a straight line from the larger diameter to the smaller diameter. You’ll need to sneak up on this slowly and check the line often with a straight edge. I cut up one of those plastic discount coupons to use as a straight edge.

With the piece still held in the chuck, remove the live center from the tailstock and slide the tailstock forward to check the fit of your taper. Rotate the headstock by hand while the piece is in the tailstock to identify the high spots to be turned down. Once the fit is good, round off the end of the piece.

Remove the chuck and insert the new morse taper into the headstock. You can now shape and true up the area that will be used to mount a work piece to. Wooden morse tapers are useful for holding small turnings. They can simply be glued to the morse taper. Bear in mind that there are limitations to the size of a turning as a wooden morse taper is nowhere near as strong as a metal dead center!!

Why did I need to turn a morse taper? Stay tuned 🙂

August 26, 2010

Processing a log for bowl blanks

I often hear turners talk about “free wood”. To my mind there is no such thing as “free wood”. Between the time and mileage spent driving to pick up the logs and the time and energy spent processing the logs into blanks, I often feel it would be easier and cheaper to just buy the bowl blanks!

Cutting your own blanks does have some advantages. The primary advantage is that of re-using or recycling wood that would otherwise be destined for the chipper or the burn pile. There is something very satisfying about holding a finished bowl and knowing that you were involved in the complete process from log to bowl, and you created a functional and beautiful object from some timber that could have just ended up in a landfill somewhere.

However, there is a lot of work involved in processing a log for blanks, and it is frustrating when the end results are just a bunch of checked and cracked blanks. Two very important things that will help you avoid this are:

Process the wood as soon as you can. Ideally you will want to process the log the same day as you get it. When this isn’t possible, try and at least get the chainsaw part of the process done as soon as possible, which will remove the pith and then seal the end grain with Anchorseal.
Remove the pith, remove the pith!!

The picture below shows how I plan on cutting this small camphor log to yield both bowl blanks and some spindle stock. If the log were bigger the spindle stock could be used for hollow forms. This layout is just one possible scenario, the most important thing is that the pith, marked with a red x, is going to be removed and discarded.

Make two cuts down the length of the log, either side of the pith. Don’t cut all the way through with the first cut. In the picture below I have made the first cut and then paused towards the end of the second cut to take the picture. Normally I would have just cut all the way through the log with the second cut.

Complete the first cut.

For the most part this is all that I will do with the chainsaw. I then take the three pieces of wood inside to my band saw. However, some of the cuts that I make with my bandsaw can be made with the chainsaw. I just find the bandsaw more accurate, less wasteful and it’s in the shade 🙂

If the log is fairly straight, I set my fence and then cut off about an inch of the live edge. If the log is not very straight then I will just free hand this cut.

Then using the flat section I just created, I will rotate the log 90 degrees and cut it to the desired thickness. If you do not have the capacity to do this on your bandsaw, then this step can easily be done on the lathe when you first start turning the blank.

I have a set of 1/4″ plywood circular discs in 1″ increments which I use to gauge how large a bowl blank I can get out of the log as well as guide me in the cutting of the blank.

From this section of the log I’ll be able to get two small blanks, one 7″ and one 6″. I draw around the discs with some white chalk and mark the circles to be cut out. I could also just nail the disc to the log and leave it in place while making the cuts.

I would then process the other log half in a similar fashion before moving on to the slab I removed from the center of the log. On this slab I cut off about an inch from both live edges.

Then I would set the fence to the same dimension as the thickness of the slab and cut out as many sets of spindle stock as I can, working towards the center of the slab from either side, being mindful of where the pith is. In the picture below, you can set two pieces of spindle stock either side of the pith section which will be discarded.

Here is the yield from the log. Three bowl blanks, two pieces of spindle stock and a section of questionable orientation that I will probably make a sphere from.

This is the reason why the one log half only yielded one blank and the piece of questionable orientation. The chainsaw cut revealed that I had cut through two nails embedded in the log. This illustrates the importance of inspecting the logs carefully before cutting with either the chainsaw or bandsaw. It also confirms my theory about there being no such thing as “free wood”. My chainsaw blade needs to be resharpened now and if I had not noticed these nails they would have trashed my bandsaw blades. I think I may look into buying a metal detector!

The final step is to coat the blanks with Anchorseal. I cut the entire blank, however many people will just coat the end grain and leave the face grain bare. I’ve found the horizontal section of my new log processing platform to be perfect for this.

Category: Projects