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Tunnelled Cube – Bruce Wood

Club Meeting: 19 September 2018
Report by: Graeme MacKay

Bruce Wood showed the original version which was very chunky before showing use the evolution and the matching perspex templates to gauge the shape.  He did admit to bending role slightly not starting with a cube, rather with a rectangle of hundred and 130 x 180 mm. The extra length is, at an early stage, to allow him to cut the holes on the edge.

So then, Bruce went to Paul Hedman style that was accurate, however, was a little thin.

Method
A large solid jig very engineered, the holes predrilled.
Bruce was able to keep the holes vertical with a Forstner bit – and little bit of action.
The jig gets a bit more complicated, through doweling fixed and carefully drilled in place.
Once set on the jig, extra lead is added to balance, in this case 375 g spinning at 740 rpm.
So another hole was made on the new centre using a template to gauge the depth and shape.
Fine cuts, little standing.

A Ha! moment: the use of longer screws is good as the MDF gets worn.

A few minutes more, a rebalancing of the lead, a new centre, and a second hole is made using this very engineered template. Samples are well marked and provided indication of the other cuts to be made. Good samples were handed around and gave clear example of the direction of this particular type of wood-turning.

Another Ha! Moment: using the right index finger as a guide. An old method promoted by Ian Fish and works every time.

Soren Berger sphere:

Bahat then went on to turning a sphere Soren Berger’s way. The cube used was 125 mm and made into a sphere using the special Soren Berger tool for measurement.
Initially, turning a cylinder in the standard manner. Outside edges first, the centre of its, and in reality the beginning of sphere. Using the Soren Berger tool, the cylinder is now hundred and 124 mm in diameter and transferred to the measurement of the sphere.

The cylinder was marked. In this case 124 mm. The length of the cylinder is now the same as a diameter and sitting between two centres. The new cylinder marked using the Soren Berger tool. The first cut was made straight between the two lines marked on each face – and using specialist tool.

Then, second lines and marked using the third part of the specialist tool or caliper. The cuts then straight lined between the marks. The sphere is starting to emerge. These new lines are now the high spots on the proposed sphere.

A line is now drawn on the midway point between these lines. They represent now the low point in the older high points, the original lines, are now carefully cleaned with relatively straight short lines. Sandy now removes imperfections. The little holding spigots, about the diameter of the stem centres, can now be removed by a number of methods: cups fixed on the jaws and tailstock, cutting off the greater part, gentle chisel work and some sanding.

Another Ha!
Don’t be a hero and try the saw, gentle hands avoid tearout, hand standing avoid dimples.

Branchwood: A Fruitful Journey – Chris Hooton

Club Meeting: 12 September 2018
Report by: Graeme MacKay

A humorous and very informative demonstration from a woodworker of long-standing. A well prepared approach to dealing with fruit wood branches supported by a regular commentary on safety for operation and fixing. Chris started with the pitfalls of a long thin blank that required an understanding of negative space and shadow directed cutting.

The initial checklist for starting with new fruit wood highlighted Chris Hooton’s approach:

  • check for nails and cracks
  • work out the correct way to cut the branch including having a suitable jig for using on the bandsaw
  • sort out and mark the cuts
  • measure and mark the centreline to allow for installation of faceplate.
  • Ensure that schooling through appropriate for the fixing of the faceplate

And simple things such as

  • ensure that the faceplate holes of the correct size to take the tech screws
  • and very simply, with humour, check that the tech screws are long enough

Chris provided a clearly illustrated approach to cutting across spaces and working with shadows. A useful tip was the placement of lights and shifting them around to get a clear and definitive shadow to work with. Then, using the shadow of the chisel to judge the distance to make initial contacts and start cutting.

A tip for sanding: Chris uses chalk gently rubbed across the face of the surface being worked to highlight and identify scratches, marks cuts and hollows. Chris used a standard soft builders chalk stick rubbed across the surface and using the marks to decide on the type and placement of the next cut. This process was used for final sanding with Chris providing illustration of what marks show through at the movement through the sanding paper grades.

Tip for measuring wall thickness: Chris noted that we often forget what the start point was after two or three checks. A piece of masking tape over one end of the figure 8 calipers and have it sticking out so that a mark to be made on the tape. Once the initial measurement has been taken, a mark is made on the masking tape where the non-taped caliper end stops. The tape cut at that mark. It provides an ongoing guide point for subsequent measurements on that particular surface. Simple and low-tech.

Chris provided a number of excellent workplace tips and directions for the topside cutting on the newly formed spigot. He emphasised the need for soft hands for the chisel work and the usefulness in providing marking lines.

Tips and guides included:

  • Check on your cutting directions, although looking for a flat surface you’re still cutting to the middle like hollowing out a bowl.
  • Mark depth and check.
  • Adjust lighting to show shadow to assist cutting.
  • Keep the tailstock in place until as late as possible.
  • Keep the hands soft, keep chisel sharp, and don’t rush it on the final cuts.
  • When using power tools for sanding, look at your approach and angle for the sanding mandrel.
  • Keep sanding mandrel moving working through the quadrant angles, backspace. A hollow centre dimple means that you have not sand with the correct angles.

Ellsworth Signature Gouge – Raed EL Sarraf

Demonstration Date: 5 September 2018
Demonstration Title: Ellsworth Signature Gouge
Author of Article: Wim Nijmeijer

The challenge for this evening was to produce a bowl made from a 125mm Rimu cube using only the “Ellsworth Signature Gouge”. Raed then explained and demonstrated the various cuts made with this gouge.
(The cube was already mounted on the lathe using the screw chuck method.)

Roughing Cut- Raed explained how to present the gouge, axial pitch of the gouge 45 degrees, shaft horizontal on the tool rest. He then identified the cutting area of the gouge. He then proceeded with the removal of the corners and the rough shaping of the outside of the bowl. Using the gouge in this manner, large quantities of wood can be removed very quickly; the surface left on the wood however is pretty rough.

Following the rough shaping of the bowl, the slicing cut was used.
But before commencing with the slicing cut, Read first cut the spigot, to allow remounting of the bowl at a later stage.

Slicing Cut- Gouge presentation, axial pitch 45 degrees, shaft 20-30 degrees on tool rest. The final form of the bowl was now further refined. This cut also resulted in a lot less tear-out compared to the roughing cut.

With the shaping of the outside completed, it was now time to finish the outside of the bowl by using the shear scraping cut.

Shear scraping Cut- Gouge presentation, axial pitch 85 degrees, shaft 45 degrees on tool rest. With this cut, Read was able to put a very smooth surface on the bowl. Only minimal sanding would be required to finish the exterior of the bowl.

The bowl was now remounted using a scroll chuck.

Raed then preceded roughing out the interior of the bowl by using the Interior Roughing Cut, this cut is basically the same as the roughing cut used on the exterior of the bowl.

Interior Roughing Cut- Gouge presentation, axial pitch 45 degrees, shaft horizontal on tool rest. Read explained the importance of body movement and position during the execution of this cut.

With the roughing out of the interior of the bowl completed, the Interior Finishing Cut was used to make the final cut on the interior in preparation for sanding.

Interior Finishing Cut- Gouge presentation, axial pitch 0 degrees, shaft horizontal on tool rest. Before commencing this cut however, Raed first made a 6 mm deep cut to support the bevel when starting the interior finishing cut. Using this cut Read achieved a very smooth interior surface of the bowl.

All in all it was a very well executed and interesting demo. Thank you Raed.

Note
Further information about:
How to sharpen the Ellsworth Signature Gouge,
Detailed information on the various cuts with the Ellsworth Signature Gouge can be found in the “Ellsworth on Woodturning Book” held in our Library. (Book # 194)

Liquid Polymer Glass – Michael Engel

Club Meeting: 29th August 2018
Report by: Dave Armstrong

Michael introduced himself as owner operator of Liquid Polymer Glass Ltd. He commenced his discussion with an overview of his company and some of the original history that caused its development. Their main product centred around Bar Tops, providing hard wearing coatings that could withstand the constant beating they received from the knobbly bits on the bottom of beer bottles.

The original resins they used were not clear and they set out to address that issue settling on an Epoxy type sourced from Europe. However they required considerable development in order to get the required curing result both hard, resilient and clear with an acceptable cure rate. To that end Michael stressed the need for exact proportions of resin and hardener and to achieve this they settled for a simple method using weight (i.e. 200gr resin / 100gr hardener) as opposed to volume. He showed us examples of various suitable scales with differing degrees of accuracy and cost. Suitable scales can be bought for less than $20 and can measure weight as little as the difference between two postage stamps.

Mixing is extremely important and instructions must be followed precisely to avoid bubbles and to ensure correct resin to hardener ratio within the mix. Michael prefers to Double mix the brew. To achieve this he ensures all product is scrapped away from the bottom and sides of the mixing vessel and stirred in well, then transfer the mix to a clean dry vessel and repeat the mixing before pouring into your project. Ideally ambient temperature should be around 20deg C to provide a cure time of between 12 to 24 hours and in some cases depending on film thickness up to several days.

Michael went on to discuss methods of colouring resins including the use of powders, inks, paints and dyes. Liquid Polymer Glass use oxides only in their work.

Problems were addressed and Michael again stressed the need for patience and to keep your mind on the job at hand. NEVER answer the phone or take unwanted distractions when doing a mix/pour as the likelihood of failure is high due to inadvertently forgetting a step or using incorrect proportions. He also mentioned that Air and Moisture are your enemies and work must be sealed to prevent its affects. Several methods were discussed to achieve this but it is as simple as coating a void or trench with a coat of the resin, PVA glue or water based paint.

Never add more hardener thinking you will speed up cure time as this will only weaken the cured resin. However you can add a tiny amount more resin to give a slightly longer cure time. Michael also mentioned viscosity and that the resin can be warmed slightly to make it flow better but NEVER heat the hardener.

Slow and cool cures are achievable but contact Michael for an appropriate brew as the resins are quite different and the exothermic temperatures can be quite extreme.

As usual, it is preferable to layer smaller amounts in your pour than one big deep run. Although it is possible to achieve different levels of clarity (i.e. Satin,Clear etc) in your result he said the easiest way was to simply cut back the surface to get the desired effect.

Michael’s presentation was very enlightening and I feel I almost had brain overload but he imparted his knowledge clearly and he answered many pertinent questions from the floor throughout his talk but he always reverted to his topic. Of course he is keen to promote his company but it is rare today to find a welcoming and knowledgeable character keen to help fellow woodworkers.

Thank you Michael for the colour samples and information sheets given to members.

Footnote – Don’t put samples in your pocket. I thrust my hand into my pocket to get my car keys only to be covered in red additive which spread its self around the car and my wallet.