Jan 2015

Bluewater Bulletin

Bluewater Model Engineering Society Sarnia, Ontario

Vol. 30 No.4 January 2015 Editor John Lovegrove

Our next Meeting will be on

Monday February 9th, 2014 @ 7:30 pm

Northern Collegiate Machine Shop (Rm. 148), Indian Road, Sarnia.

The January Meeting

There was no treasurer’s report this time but we assume there is still money in the bank. Bruce Mannerow got down to business and reminded those of us who look after club property to complete the necessary paperwork. Peter Esser had not been able to arrange the Maveric visit because his contact has been away. He will now aim for January 24th.

Bruce has made some progress with a club website. His recommendation is that we use Google because it is essentially free. It has some limitations, particularly the amount of storage available, but this should not be a major issue. There was some discussion on the subject but the general feeling was that this provided a good way to get started and gain some experience.

He also talked about CAD programs that are free to download. A list of the links to these is given later. In spite of having an outside workshop, he has managed to spend some time doing things and talked about the shear tool arrangement that is capable of getting a good finish on difficult-to-machine materials. Some drawings showing the arrangement used are included later.

Ed Spencer is looking for an iron foundry to get some castings made and asked if anyone knew about the Tiffany foundry in Orangeville and the Lea Avenue foundry in Paris. Some members knew about them but it was not clear whether they would take on small jobs. (Few foundries seem to want to.)

Tony Koolen has been working on the lost foam system for producing castings. This involves making a Styrofoam pattern and coating it with the stucco material used for texture on dry walling. When this has hardened it is buried in dry sand to give some support. The pattern just stays there and is vapourized by the molten metal when it is poured. It is capable of reproducing quite fine detail on the pattern but at the last attempt he had problems because the stucco was too thick, had not dried sufficiently and foamed up when the metal was poured. Hopefully he will have some good show and tell items at a future meeting.

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John Sibbick asked about an up-dated phone list of members. One is attached with this newsletter.

As discussed at the last meeting, I set up a CNC demo for 20^th December. 6 members came along and the item I produced to illustrate what can be done was brought along for show and tell.

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Show and Tell

As usual Tony has been busy. One novel item was a kind of linear motor. The outer part is a helical coil of bare copper wire with the turns separated slightly. The other part is a small battery with a neodymium button magnet at either end contacting the +ve and –ve terminals. The parts are all held together with duct tape but still allowing the periphery of the magnets to contact the inside of the coil. When the battery/magnet assembly is put inside the coil (the right way round) it runs straight down to the other end. I have not worked it out completely but it must rely on current flowing from one end of the battery, through the magnet, along the coil of wire then back through the other magnet and into the other end of the battery. The interaction of the current through the coiled wire with the magnetic field from the magnets must produce enough force to move the battery and magnet assembly.

I had a second shot at machining the helical grooves on the steering chain shaft for Tony’s traction engine (or at least the wooden try-out piece.). The earlier attempt was just a quick attempt to see how the helical machining worked out.

This time I carefully measured up the lay of the chains on the shaft and tried to reproduce this. It turns out that the pitch of the helix changes slightly at a point slightly over one turn from each end. I have therefore revised the G-code program to reproduce this. The next step is to make the real one in steel.

A pin was put in the bearing cap to ensure that the shells do not rotate in the housing (this could blank off the oil hole.)