I’m back and thanks to Alan, Fred and Paul I have some notes and pics to pass on to you.|
Morning notes – Alan Smith
08 May 2010 – John Berkeley R.P.T.
John makes Puzzles, threaded boxes and is a tutor and demonstrator. (Note: John donated all of todays pieces to the club. These will be raffled at the Summer events for the Club Charities.)
John sometimes uses various woods but mostly alternative materials based on Polyester Resin from GPS Agencies (www.ivoryalternative.com) as this material does not cause John the same respiratory problems that wood does.
John started turning a small piece of very figured olive wood to make a Chinese Hat box with a threaded lid,
This is the first piece that John teaches students as the threads are reversed with the male thread in the lid, making it easier.
The box was shaped on the outside and hollowed out.
John stated that on his lathe chucks, he takes off the corners on a grinder to help save fingers (one of his chucks was passed round to show this.)
The box was chamfered at the front edge and neck.
At this point, John talked about thread chasing using what he now recommends as the best starting thread, 16tpi.
The best speed is around 450rpm and a variable speed lathe is firmly recommended.
When you start turning for thread chasing, always bevel the threads slightly so that only the last few threads engage. This makes aligning the lid onto the box easier.
Johns rule of thumb when threading is “Arm rest on tool rest, thumb on tool rest, tool on tool rest.” The arm rest in question is the Bill Jones tool rest which John uses for many turning operations.
John uses Ashley Iles UniChaser chisels as this only requires a single chisel and not two such as the Sorby sets.
(Note: Sorby and Crown sets cannot be converted into Unichasers because of the negative rake on the thread cutters.)
John also noted that you must always have a full thread starting the cut on your tool as the first thread does most of the cutting. If you have a half tooth, this should be ground off leaving a full tooth at the start.
When cutting the thread, once you have started it off, always allow the chisel to pull itself across the work, do not force the chisel forward, but almost as important, do not impede the chisels progress either.
Once John had cut the thread, he finished the top half of the box and removed it from the lathe before mounting the lid and cutting the opposing thread. After some minor adjustments, the lid and box threads fitted perfectly.
The base of the box was completed at this point with tail stock support. Afterwards, a thread was cut into a scrap piece of wood and the lid was reversed and completed.
(John explained that if for some reason the lid jammed on the scrap wood as a result of the turning, you can ease the fit by cutting into the scrap wood just behind the thread as this would release the pressure.)
Notes about the Alternative Materials:-
It is a cast resin and should not be turned too fast (John turned at approx 1500 rpm)
Scraping is the best method with a point tool for detail.
Cutting too fast may cause it to shatter.
The dust is heavier than air, thus does not hang around like sawdust.
It is HIGHLY flammable (Don’t leave it around the grinder.)
Afternoon Notes – Fred Taylor.
After lunch John continued with the blue box in Cast Polyester Resin. He normally does the female thread first.
Sanded starting at 240 and finish with 1200 grit. John sells and continued with a 2 part polishing system, BGF (bloody good finish) Xtra Cut and Polish, as a finish on synthetic material. Xtra Cut is an abrasive and Polish is the finish.
These are obtainable from John via his website.
A carbide tipped cutter (Google “rotary chisels”) in a rotary tool was used to produce a scalloped rim the top box top. Silver cream was used to highlight the scallops. This may take some time to go hard. This cream is available from www.clarkcraft.co.uk £3.97 per tube.
The base had the male thread chased and then hollowed out
A pepper shaker was next.
The top was prepared as per the box. When the top was completed 6 points were marked on an outer ring, using the indexing system.
The holes were drilled with a rotary tool and small Axminster bit. Inside the ring another 6 holes were drilled and completed with a hole in the centre.
The bit size will depend on the size of the top and how much pepper is needed with one shake. . Turn the base, chase the thread and screw the top onto it to finish the outside.
Drill out the base and complete the final shape. Finish with BGF.
To finish the bottoms of the boxes, a scrap piece of wood was mounted in the chuck and a corresponding thread chased to mount the base to finish the bottom.
This completed a most enjoyable demonstration by John.
This report was complied by Alan Smith and Fred Taylor due to the absence of Graham Holcroft on holiday.
Note from the Chairman
Due to the very poor turnout we made a loss on the day of £140.
So where do we go from here?
We can’t afford to have too many like that so do we stop having demonstrators coming to us? Are we selecting the wrong people to demonstrate? It’s up to all of you to tell us how you want the club to run if we are to continue as a club.
The next meeting is on Saturday 12th June and Peter Blake is our demonstrator for the day. Pete always manages to come up with something interesting so please come along and make the day a success.
The following email was sent to Bert and he asked me to copy it to you. They meet on the 2nd Sunday of the month and a sales table costs £14 for the day.
The next market date is Sunday 13th June; the weekend prior sees the Hamstreet Country Show taking place in the village which last year received approx 8,000 visitors over the two days. A full colour page advert advertising the Hamstreet Farmers Market will be appearing in the free programme which will be handed to everyone attending. This additional advertising on top of the ongoing promotion leaves me to anticipate a phenomenal turnout on the day. With bouncy castles and ice-creams for the children in addition to creative activities, the market will provide a fun enjoyable atmosphere for the whole family to enjoy. If you would like to take part in any of the following market dates then please contact me by the end of this week so that stall bookings can be secured.
Market dates for 2010
Sunday 13th June
Sunday 11th July
Sunday 8th August – Extravaganza day including German sausages & French cheeses
Sunday 9th September
Sunday 10th October
Sunday 11th November
Sunday 12th December – Christmas Special
Should you wish to discuss any of the information in further detail then please do not hesitate to contact me. Many thanks
N.B. Hamstreet County Show are still looking for stall holders selling food to take part in the event, for more information log on to their website at hamstreetcountryshow.org or email firstname.lastname@example.org