The intention was to both inform members and to preserve the Guild’s tools. Consistent sharpening of SAWG tools makes it easier for new turners to move between work stations and the tools last longer. Instruction is available for using the sharpening station.
Tools can be sharpened on either an abrasive wheel or on a flat abrasive surface such as a disc or linisher (a belt sander in disguise). Whilst all have their merits, the basic difference is that wheels produce a concave bevel and discs/linishers give a flat bevel. Honing was not part of this presentation but could usefully be incorporated in a later demonstration.
The usual form of abrasive wheel sharpening is via a double-ended grinder having wheels of 150mm (6”) or 200mm (8”) diameter, the larger size being preferable but more expensive. More specialised machines are available including several brands with larger 250mm (10”) wheels running in a water bath and slower speed grinders intended to reduce the generation of heat.
Ordinary ‘workshop’ grinders are usually supplied with (grey) carborundum wheels of low quality. Internationally, there is a variety of different coloured grinding wheels purporting to serve different purposes but the ideal approach is to have a cubic boron nitride (CBN) wheel for high speed steel (HSS) tools at one end, plus an aluminium oxide wheel (white) for other ferrous materials, at the other end. Both are readily available in NZ.
The use of a 300mm disc sander for sharpening was developed in-house and with a jig for each tool, enables a quick ‘polish’ rather than serious grinding to replenish an edge. The linisher is a much more expensive product by Robert Sorby having a useful variety of easily interchangeable belts and reliable jig settings for repeatability. Whereas all grinding wheels (except the CBN) gradually reduce in diameter, the disc and belt abrasive surfaces remain consistently flat.
Other useful points arising were:
Recommended bevel angles for Guild tools are bowl gouges of 35 and 55 degrees, spindle gouges 30, spindle roughing gouges 45, parting chisels 30, skew chisels 30.
Wheels, disc and linisher abrasives have different grits (or roughness) and hardness.
Don’t dip HSS tools in cooling water as the temper will be ruined. Tool steel is OK for cooling.
Always use a jig to achieve a single, smooth, and symmetrical bevel. This doesn’t work well for negative rake scrapers or if an asymmetrical bevel is wanted – the latter usually by professionals freehand sharpening.
Putting a diamond-section parting tool sideways into the Guild’s Truegrind tool holder enables both bevels to be sharpened without any repositioning.
A diamond dresser is available for cleaning dirt and glaze off all sintered (cooked in an oven) wheels. A CBN wheel is never dressed.
Sintered wheels can shatter so always use them with guards in place.
Do not sharpen on the side of a wheel unless specifically labelled as a side-cutting wheel.
A 55 degree bowl gouge is useful across the inside bottom of bowls when a more ‘pointy’ 35 degree grind may result in a gouge shaft hitting the bowl rim.
Sharpening a pencil is a good analogy to explain ‘cutting with the grain’.
A plug was also given for using sharp sandpaper.
Alongside the theory, sharpening using Guild jigs and tools was demonstrated with some bowl shaping. The presentation was accompanied by excellent visual aids and invasive music from next door. Despite the music, a good time was had by all and clear information was received during a well-structured performance.
This was a brilliant presentation from a very well recognised woodturner. Peter had travelled down from Kerikeri and met up with his old colleague Ian Fish to present to the South Auckland Woodturners Guild. The many members in attendance must surely have reflected on a great deal of the experiences and words of caution outlined by Peter in their own woodturning ventures. Peter opened his presentation by sharing his own introduction to woodturning and was once a member of our Guild.
The most problem once you start to turn wood it that it is:
and introduces friends for life.
Where do you find it? A Chainsaw really makes life easy, but it’s a dangerous tool. Aspects of Safety where discussed – a wonderful log support frame was on display for members, this would handle most log sizes used by members. A couple of fence battens and a half round post cut in half is all that was needed to build this jig. A must have.
The chainsaw settings: Teeth at 30 degrees for cross cut, and along grain cutting. Teeth need to be set at 90 degrees for end grain. Obviously a selection of chains would be required to accommodate both methods of cutting. Peter produced his favourite Makita electric chainsaw, noting that his wish list was for a battery powered model. Bantering from Dick Veitch on the pros and cons of battery powered saws, suggesting that Peter should settle for nothing less than the latest Stihl.
Green or dry timber?
There’s an unlimited supply of green wood. The size of bowls is not limited by standard stock sizes available from a wood yard, but only limited by the time available to go wood hunting. Collecting is exciting as you never know what you will find. Turning green wood is easier than dry. Pururi or gum is a nightmare to turn dry.
Transporting: You need to cut your bounty into manageable sizes. Probably 4ft lengths will fit across most trailers, without too much effort in loading. A great explanation and diagram showed members how to load large logs onto a trailer. The system was based on leverage with a long rope fixed at the front of the trailer and trailed to the back, slid underneath the log and back around the tow bar. Two 4×2 boards were used as a ramp. The rope was then attached to another vehicle which pulled very slowly while the log was rolled up onto the trailer deck. A very descriptive explanation of the trip home had members in awe of such a successful wood hunt. We were reminded to seal the ends of the logs to control moisture loss. Peter’s theory of cutting 4 foot long logs was that there was usually some good non split wood in the middle.
How to form the blank: Depending on log size, this will dictate on whether the log is just split or slabbed. It’s easier to start off with a basically round shape before you put it on the lathe. Peter demonstrated the safe way of holding and cutting wood on the band saw, and the importance of stability of the log being cut. Peter explained that he always used disk templates from 125mm to 400mm in diameter. A blank that had been cut to a handy template size was tabled as an exhibit, along with the waste wood. A thin disk of wood was presented showing where to take various bowl blanks from in order to avoid the pith. The pith is the soft centre of the log. After all it’s the pith that pithes you off!!
The easiest bowls to cut are from side grain. Green timber is usually sought for making bowl blanks.
Points to remember were
Turn as soon as you can after collecting the wood.
Seal inside and out with a wax rich medium as soon as the bowl blank is formed.
Record the date, species, collection location and most importantly the weight.
Store the blanks stacked somewhere cool and out of the sun to allow for slow even drying. Every 2 to 3 months reweigh and record as the blank loses moisture. Once the weight no longer reduces the blank is dry enough to finish.
Sometimes a moisture meter is used in conjunction with weighing.
Drying can be accelerated using a kiln or a closed box with a dehumidifier for finishing later when dry enough.
Could be wrapped in 1 sheet of newspaper.
Dry timber can be mounted straight on the lathe and worked to a finished bowl.
Considerations>Bowl shape: Peter explained the Catenary curve – using a string of beads or a light chain he demonstrated the various curves than can be created – curves that were pleasing to the eye! However, it was important to establish designs and features that defined the turner and ultimately created work that is unique. There always had to be a connection between the bowl and the foot, and this aspect could not be ignored. The foot should always be in balance with the piece.
Ready to make your bowl How to use a gouge – Your tools must be sharp. Theories on gouge sharpening, bevel angles, jigs to assist with maintaining the correct angles, along with an overview of the wide variety of gouge bevels used nationwide. Northland use a 55degree bowl gouge with swept back wings at 35degrees, whereas South Auckland mainly prefer the 35 degree gouge for general turning and a 55 degree gouge for refining the inside of bowls. Preference is something that comes with experience.
RUB THE BEVEL: The same old same old !! rub the bevel!!!
Once the gouge is sharpened it can be used for any one of four things.
When using gouges and doing the push and pull cuts, most catches come from allowing the gouge to cut while not being supported by the bevel. Without bevel support, the cut will dig in violently in a split second. Big chunks of wood are ripped away. The bevel prevents the gouge from cutting too aggressively—it is a controlling factor. Peter guided the gouge tip with his thumb when entering a starting cut on the inside of a bowl.
Attaching the wood to the lathe: another moment of interjection – this time from Bruce Wood who was determined to show Pete his method of fitting the screw chuck in the Nova chuck. However persistent Bruce was, Pete reverted to his presentation plan. This was a period of light hearted banter and laughter.
The faceplate was the preferred option for most mounting over 150mm. Grain – an excellent example of grain direction and the cutting process was presented with the following diagram being most helpful to newer members
Turning: Mounting the round– bring up the tail stock whenever possible. Form the outside of the bowl first Let the grain govern the direction of the cut. Feet positioning: Place your left foot first in the finishing position then the right foot at the start of the cut. Swing from the hips, which is not so easy when on the inside of the bowl.
Roughing: start from the tailstock centre and work the shape. Can use either a push cut or a pull cut. Always rub (kiss) the bevel using a push cut. This steadies the gouge. Because you are pushing the tools and it wants to buckle, it can’t so it either digs in or scoots away.
Finishing a bowl blank after it has been dried: The blank will probably be out of round after drying. So mount the bowl so that the chuck bite can be trued up by positioning the foot towards the tailstock.
There are a number of ways you can hold the bowl in this position. Cole Jaws chucks are easy to use, but keep the speed down and bring up the tail stock before starting the lathe. Similarly, if you are using a vacuum chuck, check for cracks in the wood, anywhere air can escape or OUCH – your bowl takes off into orbit. It is important to see that the bowl is seated properly too. If you don’t have access to this equipment, use a compression chuck. You can make one yourself – a simple rounded jig not unlike a darning mushroom, costs nothing and is very useful. Use a piece of thin rubberised matting (probably a bit in the cutlery drawer) over the compression chuck and fit carefully into the bowl. Centre with your tail stock (having marked the spot during roughing out).
Remount the blank and turn to finished shape. Starting with the chuck bite, make cuts slowly and shape the outside. Finish the outside first then reverse the bowl, hold in the chuck, and finish the outside. You may have to retouch the outside near the rim of the bowl to get an even thickness of the rim.
Once the bowl is turned to your satisfaction, sand through all the grits using a power sanding system. This will leave you with an amazing surface. Now it’s time to apply the finish and see your creation come to life.
Peter was very particular with his sealing and waxing, leaving the product to dry before wiping the excess off and rubbing the compound into the grain. Peter used toilet paper as his preferred application material.
Other clothes were not recommended because they left lint which often caught on the cut grain.
This was an excellent presentation by a world class wood turner, and we as a club are very privileged
to have shared in Peter’s life-long learning experiences.
Having written this review, I must thank Peter for sending me his notes, because the majority of this report is taken from the raw material provided.
Important – Don’t forget to have a cuppa at and during each stage!!
An ingenious piece of mechanism individually made by Holm Miehlbradt.
TOTAL STORY !! — You had to be here to understand what was being demonstrated. See if you can work it out from the photos taken by Ross Johnson.
This was an unexpected demonstration of an engineer’s determination to make a complicated piece of design concept to produce a machine that will produce repetitive patterns of a circular character on wood, plastic, or other similar substances.
Holm using MDF for the main frame and lathe head, a compound slide to carry the tool holder and cutter head, together with a powerful electric spindle motor and sundry pulleys, sheaves and rubber band type drive belts created this amazing piece of wizardry known as a Rose Engine.
With the lathe head rocking back and forward to the pattern of the Rosette pattern and the cutter driven by the spindle motor, all controlled by a pair of hand wheels, the product was produced.
Comment:- You need to have a lot of time to make and use a ROSE ENGINE. Well done Holm!
Demonstration Date: 20 March 2019 Demonstrator: Trefor Roberts Author of Article: Wim Nijmeijer
As Vice President of the NAW, Trefor started by telling us about the work of the NAW and the benefits of becoming a member.
He then started by telling us that form is paramount in woodturning. Without a good form, the end result will always be compromised.
First review your finished turning and determine if embellishment is needed. (Spalted/figured wood, natural edge generally do not need embellishment) To enhance your woodturnings, various techniques of embellishment can be applied. Ideas can be found everywhere, nature, Internet; take pictures such as the Koru, Ferns, Butterflies, etc.
Trefor then proceeded by showing us a picture of a printed leave (laser print) and how this image was transferred onto the wood. First cut out the leave, and then apply Minwax Polycrylic (can be obtained from Mitre 10) to the wood and stick the printed leaf (ink facing wood) firmly onto the wood. Let it dry, once dry, wet the paper leaf with water and gently rub the paper away. The leaf image has now been transferred onto the wood. Various examples were shown of images transferred onto wood, these images could then be permanently marked by using pyrography or carving (Dremel, etc)
Next Trefor showed us some examples of engraving (smoking!) by using a Dremel and a ball shaped burr, to produce/burn indentations of half spheres, followed by wire brushing to remove the carbon.
This was followed by showing us half a dozen of turned eggs. These were already embellished/painted with various patterns/colours. One egg was then further enhanced by using various colours of Guiders Paste.
Next Trefor used some Milk Paint (can be made by mixing 1 part water to 3 parts powdered milk until you get something around the consistency of paint. Blend in a water-based coloured Dyes or foodcolouring if you don’t want neutral white)
Various combinations of using milk paint mixed with coloured dyes, acrylic paint and Guilders Paste were demonstrated.
This was followed by a demonstration using the Burnmaster by burning some patterns on a practice piece.
Last but not least Trefor used the Dremel fitted with a half-cup burr, this was then used to burn perfect half spheres onto the wood.
All in all a well executed and very interesting demo. Thank you Trefor.
Trefor’s last message for the evening: I hope you enjoyed the demo, and make sure you become a member of the NAW!
This new website designed by woodturners, for woodturners. It has a very active forum in addition to a magazine section featuring articles about woodturning and woodturners, as well as unrealted topics – all written by members. One of the most exiciting features is a critque panel, currently consisting of Terry Scott, Keith Burns and John Keeton, who will provide a formal critque of submitted works. This is then published in our magazine section as an educational piece for the benefit of the submitter as well as our readerip in general. This is a feature offered no where else on the internet!. For more information click here. To go straight to the website, follow the link by clicking here then save to your favourites.