Article: Mark Gardner Demonstrates For CMW, January 17, 2015
February 10, 2015 11:32, submitted by Tina Collison (author: Bob Gunther, photos by Tina Collison)
Mark Gardner Demonstrates for CMW, January 17, 2015
Mark comes to us from Saluda, North Carolina where he lives and has his studio. He is an honorary member of CMW. He has been involved with woodturning since age 16. At that time he enrolled in a furniture making class with his father. He felt, however, that furniture making was a slow process and he liked the immediacy of turning. Eventually he took a class with John Jordan and he gives John the credit for giving him a firm foundation in turning techniques. Another very important influence on Mark is Stoney Lamar. Stoney’s approach to the lathe was that he considered it more a tool for carving than turning and this perspective has been an inspiration for Mark. Mark has also studied African and Oceanic artifacts and these can be seen in his work. The lathe is still his primary tool and he enjoys the process of turning. However, most of his time is spent working on a piece after it has been turned. Mark specializes in vessels and bowls. He is a member of the American Association of Woodturners. He demonstrated at the North Carolina Woodturning Symposium in 2009. He has previously demonstrated for CMW in January 2005 and December 2011. For more information about Mark Gardner visit his website.
Mark began his demo showing a hollow turning that will be done in two parts. This item will be the first item in today’s demo. Green wood was used. Advantages of using green wood include it being cheap, readily available and easy to turn. The piece used was Black Birch. It was cut from a log and did not include the pith. The piece was about 5x5x10 inches long. It was mounted between centers. A spindle roughing gouge was used to rough turn the blank into a cylinder. The piece was oriented so that the bottom was at the tailstock end and the top to the headstock. The top portion of the piece will have handles that will be turned and carved. When laying out the piece the underside of the handles is about 2/3 from the bottom of the piece. Using a ½ inch bowl gouge Mark began shaping the bottom 2/3’s. A shear scrape was used. The bottom was defined using V-cuts and then shear scraping. The tailstock end of the blank was reduced to the thickness of the base where the V-cuts were. This surface and the surface of the upper 1/3 was smoothed so that details could be drawn defining the base of the piece – its thickness and also the handles, the top thickness and the detail on the top. Mark aims for ¼ to 5/16 inch wall thickness.
Tenons were turned on the tailstock and headstock ends. The tenons were made small enough so that the jaws stayed inside the body of the chuck. The shoulder of the tenon needs to be flat or slightly undercut. It also needs to be slightly dovetail shaped even though straight sided talon chuck jaws were used. The tenon on the headstock end was formed but not before removing some of the excess wood. Mark uses the gouge, not the parting tool, to shape the tenons.
Next the piece was parted into two pieces. The place chosen for the parting cut was the widest part of the lower 2/3 section of the piece. When making the parting cut (where the glue joint will be) a horizontal line is formed. This can be hidden on the finished piece by texturing with a series of beads. A possible alternative would be to cut the piece in two at the level of the underside of the handles. To achieve the least noticeable joint line one needs the grain of the piece oriented parallel to the lathe ways. A 1/16 inch parting tool was used to part the piece. When using the tool Mark angles it so that the cut opens up in the interior of the piece. This helps prevent build up of shavings. He leaves about ¾ inch of wood in the center and cuts this with a Japanese saw. Now the original piece is two pieces. The top piece is shaped and hollowed first. It was placed in the jaws. First the outside of the rim was finished. The female mortise was made in this top portion. One needs to make the surface of the mortise flat. It can be scraped or sanded but it needs to be flat to get a good glue joint. A modified flat nosed scraper was used for the mortise joint. It was made about 3/16 inch deep. It needs to be square to the surface. The thickness of the mortise should be about 1/8 inch thick – half the final wall thickness. Once the joint was finished a small dimple was made in the center of the piece. A drill bit that had flats made on the distal end was held by a crescent wrench. When drilling the bit actually searches for the center. The depth needed to drill was marked on the bit with tape. The depth drilled will determine the depth of the hollowing and the hole permits hollowing out the center and thus eliminating the nub that develops in the bottom of hollow forms.
Mark hollows using the John Jordan or David Ellsworth type cutters. These are simpler cutters that are CA glued into the handle or placed with set screws. If glued in they can be removed by heating them. The cutting ends are sharpened more on the left side because almost all the cutting during hollowing is done with the tip and the left side of the tool. They can be honed between grindings. Hollowing was begun in the drilled hole and worked progressively toward the bottom of the hole. Then the vessel was further opened in steps from the interior to the outer areas. Then the final wall thickness was determined and accomplished. Calipers were used to achieve constant wall thickness.
While the top portion is being hollowed the base portion needs to be placed in a plastic bag or in shavings so that it will not check or crack.
If the cut to divide the piece is made at the lower edge of the handles then the mortise needs to be on the bottom portion and the tenon on the top portion. This is due to the exterior shape at that location.
The piece (top portion) was removed from the chuck and the bottom piece placed in the chuck. The surface was cleaned up and the interior slightly dished out. Then the tenon (male portion) was made. Dividers were used to determine the thickness of the tenon. The tenon was turned in stages to get the final fit with the top portion. A good fit is when the two fit together and can still be rotated on each other. At this point the pieces fit well together. This completed the morning session.
Mark began the session with a PowerPoint presentation depicting the shapes, carving and texturing of selective pieces of his work.
He continued his hands on demo with the piece turned during the morning session. The bottom section was hollowed as was the upper. The drill was used to delineate the depth and to facilitate the process. Once the bottom hollowing was completed the two portions were glued together. Yellow glue takes too long to dry as do the polyurethane glues. CA glue is probably the glue of choice and the medium has the correct viscosity. Before gluing a small depression was made in the base of the tenon to retain glue and help strengthen the joint. The glue was applied as a bead along the tenon so that when the pieces are pushed together the glue spreads out along the joint. The two pieces were lined up and pressed together with the aid of the tailstock. Accelerator was not used due to two reasons. First it will cause the glue to harden too quickly and second, the moisture in the green wood acts as an accelerator. After gluing, before the lathe is turned on, place some shavings on the outside of the joint to catch any possible throwing out of the glue.
Next Mark parted off about 1 ½ inches of the excess wood on the top portion. This wood will be used to make a jam chuck to hold the top when the bottom is finished. The tailstock was brought back up. The top of the piece was established with the parting tool. That part of the wood to the right of the parting tool cut was turned away down to the diameter of the top detail which will have the opening into the vessel. The underside of the handle was cut away making it perpendicular to the vessel wall. The upper edge of the handle was angled parallel to the lower edge. The outer surface of the handle is parallel to the body of the piece. Mark wants the curve of the body of the piece to flow under the handle into the curve on the top. A small cove was made where the top detail sits on the top of the vessel. Further wood was turned away to prepare for making the hole in the top. Once the hole was drilled a small angled hollowing tool was used to reduce the thickness of the lid. This was to achieve a constant wall thickness and to decrease the possibility of the piece cracking during the drying process.
Then the bottom was turned. The parting tool delineated the bottom and then the shape was turned extending the outer wall shape into the bottom. The bottom will be made flat first and then slightly concave. At this point the piece would be sanded.
The piece was reversed. The previously made jam chuck was fitted into the opening on the top of the vessel. It was placed in the chuck and the tailstock brought up. Minimal pressure was used on the tailstock when turning the bottom. Too much pressure could collapse it. The concave bottom was formed. Final sanding was done. The piece was removed from the lathe and the small remaining nub on the bottom was sawed off and then carved away with a hand chisel. A compressor was used to blow the free water out of the bottom end grain. The piece would then be set aside in a bag to dry.
Mark then laid out patterns. A previously turned piece that was dry was placed between the tailstock and the above made jam chuck. The thickness of the handle on the piece determines the spacing of the vertical lines on the piece. However, as the piece widens and narrows the spaces become somewhat larger and smaller. (A Prismacolor 9B ebony graphite pencil was used). Then horizontal lines were scribed creating squares on the piece. A jig was used to make the lines on center as the piece was rotated.
Wire brush texturing was then shown. The previously made jam chuck was smoothed. A Black & Decker 4 inch wire wheel was used. It was hand held and applied to the work while it was being rotated by the lathe. Wire brushing green wood works better than on dry wood. The longer one wire brushes the deeper the grooves. This can be very effective on Ash and Locust. To really hide a seam: first wire brush – then use a skew tip and make a fine groove along the glue seam. Then do the same with the skew at random places on the piece. Then wire brush again.
Mark next showed the layout of a spiral pattern on the piece that had the squares made earlier. The pattern was made by going up one square and over to the right two. The two corners were connected giving a somewhat laid down or flatter spiral. To get a steeper pattern go over one square and up two to the left.
A reciprocating carver using a V-shaped chisel bit was shown. Sample cuts were made on a painted cherry board. Mark showed a Ryobi and a Foredom tool. After the carvers Mark demonstrated engravers. A Dremel was used and then a pneumatic Sioux model. The Sioux is easier to use and does not get hot but it needs a fairly large tank compressor and makes a lot of noise.
Finishes: Mark uses USMC Black from Fiebings leather dyes. It is a solvent dye and produces the truest black one can get. Krylon matte finish from Ace Hardware is used to cover the back dye and protect the surface. Several coats of the Krylon are used and buffed with 4.0 steel wool between coats. Milk paint is also used with sanding between coats.
Next Mark showed how to form the handles on the piece turned earlier in the demo. First one decides where to place the handles – on opposite sides – to the right and left of which area will be the front of the vessel. A Japanese saw was used to define the shape and thickness of the handles. Waste wood between the two handles was also cut away using the Japanese saw at angles. Once all the major waste was sawed away the remaining wood was removed using hand chisels. Then a Flexcut carving tool was used to finish the wood removed and leave a faceted but smooth surface. Each handle was shaped and details applied with the Flexcut carving knife. Sanding of the handles is not needed.
Mark then showed his tool honing system. It is made using ¾ inch layers of MDF. The MDF wheel edges are shaped to fit the individual tools that need to be honed. You can put several layers of MDF together with as many shapes formed as needed. The layer closest to the headstock is mounted on a chuck or a dedicated face plate. Subsequent layers are attached using screws or glue. The honing compound is applied to the MDF wheels. The lathe is run in reverse and the tools placed in contact with the wheels. Both sides of a tool need to be honed. On the outside flat surface of the last MDF wheel (closest to the tailstock) sandpaper can be applied and one can shape a carving tool prior to honing. To check the sharpness of a tool one can use it to cut across end grain. If a smooth cut with no tear out is achieved the tool is sharp.
This completed a very interesting and fast paced demo with many important and useful turning ideas. A DVD will be available in the club library in March 2015.
Submitted by Bob Gunther