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Bluewater Bulletin
Bluewater Model Engineering Society Sarnia, Ontario
Vol. 30 No.2 November 2014 Editor John Lovegrove
Our next Meeting will be on
Monday December 8th, 2014 @ 7:30 pm
Northern Collegiate Machine Shop (Rm. 148), Indian Road, Sarnia.
The November Meeting
This was Bruce Mannerow’s first meeting as president and after receiving the report from our Treasurer, he got down to dealing with some items of club business:
Peter Esser had indicated earlier that he no longer wished to continue as Secretary. Because the essential points of a meeting are captured in the newsletter and there is very little correspondence or other matters to deal with, Bruce suggested that the duties of Secretary and Editor be combined. I have therefore agreed to cover them both.
The next point was that Neil Blackstock still has some things belonging to the club at his home and he would like to clear them out. All of the items relate to the club track that went to Komoka some time ago. Ed Spencer said that they could make use of the items and so it was agreed that they should go to Komoka. Ed will arrange this with Neil.
Continuing with the club property theme, several members are custodians of items belonging to the club. Bruce would like to have an inventory of all club property and to have items such as our air compressors labelled as being property of the Bluewater Model Engineering Society. He will prepare labels and is asking that members let him know what items they do have so that the inventory can be prepared.
The last item of business was a club website: Most clubs have one of these nowadays to give information on activities and hopefully to attract new members. He has already carried out some preliminary investigations, looking at the various possibilities and the cost is likely to be ~$10/month. This appeared to be acceptable so he will try to firm up on a proposal that we can move forward with.
Turning to other items, Peter Esser knows someone who works for Maveric Canada in Wallaceburg. http://maverickcanada.com. They specialize in making parts in "exotic" materials for the aerospace, gas and oil industries using state-of-the-art CNC equipment. Peter will try to set up a visit for club members who are interested. This will probably be one Saturday morning. Peter will let me know and I will send the information to everyone on what has been arranged.
On a similar but much simpler level Bruce asked me if I could put on a model engineering CNC demo in my own workshop. I will find out who is interested, what they would like to see and go from there.
Continuing on the demo theme; Tony Koolen’s brother is still intending to put on a demonstration of casting resin - when everything can be set up.
From his internet searching Bruce comes up with all sorts of useful information. He talked about "Internet Archives:" https://archive.org Among other things this gives access to a huge number of old books (where the copyright has expired) on various aspects of engineering. One item he mentioned was the American Machinist’s Handbook; this is worth looking at, it goes back to 1909 (and you won’t find anything on CNC!)
Show and Tell
We tend to have a sit-down show and tell for small items followed by a stand-up show and tell for items large enough that they need to be displayed on a bench. Starting with the first category, Martin Beales had a "wobbler" that is used to set up items to run true in a 4 jaw chuck. The long arm on one side of the ball pivot amplifies the movement at the end of the short arm on the other side enabling accurate centering to be achieved.
Wobbler
Peter Esser had some parts from a clock he is restoring. He is currently attending classes on clock repair in Sombra to learn all about the trade. He also
Clock parts
passed around a catalog of tools and parts for clockmakers/repairers. Some of the items available are quite remarkable: http://timesavers.com
Following the discussion last time about preventing things going rusty I have acquired some silica gel capsules. This material has the capacity to absorb moisture so if the capsule is placed in a cupboard etc. it will reduce the humidity level so that condensation should be avoided when weather conditions change.
Silica gel cans
The can is perforated to allow air to circulate inside, the top contains an indicator that turns bright green when its adsorption capacity is reached. It is supposed to be OK for up to 55 ft3 and can be regenerated by heating to ~1200C for a few hours. This is a link to the supplier: http://www.silicagel.ca/
Moving on to the "bench" displays; Bruce has got back to working on his 18 pounder. He brought along part of the breech block carrier and the "chuck" piece he made to hold it for machining. (As is often the case with our hobby, the jig is larger than the work-piece.)
Bruce’s Breech Block Component and Holding "Chuck"
Murray Bennell brought along the mini rolling mill that he has made to produce miniature chequer plate, along with a sample of the product. The key part is the lower roller with crossing helical grooves. Murray and I spent most of one day machining these grooves making use of the 4th axis on my CNC mill together with a sine plate to tilt the roller at the correct helix angle. He then hardened the roller so that the grooves (in particular the edges) would hold up during use.
Murray’s Mini Rolling Mill
And a Piece of his Test "Product"
The next couple of items involve Tony Koolen and myself: He had a small gas regulator that needed a plug to seal off an opening. The thread turned out to be somewhat unusual; originally 1/8" British Standard Pipe Parallel (BSPP) but adopted as an ISO standard. The thread is 28 TPI and ~0.375 OD so I just set up and cut one using the CNC option on my lathe.
Gas regulator and plug
The other item in the works is a steering chain shaft for Tony’s Chase traction engine. He tried using a plain shaft and that was reasonably satisfactory but did not look authentic, so we will now try to make one with a helical groove. The middle shaft in the picture is the plain one he tried originally with the black markings showing the natural lay of the chains.
The item on the right is a steel blank ready to have the groove machined in. The wooden one is just to run a test machining to check the set-up. I think it is a job for the CNC mill again using the 4th axis (rotating table.) However I might try on the lathe. With the lead screw driven by a stepper motor, one is not confined to the thread pitches available through the normal geared drive from the headstock.
The last item is all my own; it is the crankshaft for my 4 cylinder Sealion. The crank pins and centre main have been rough machined on the CNC mill using an end mill with radiussed corners:
Crank shaft being milled
For me this is easier than turning these parts with a long overhang tool in the lathe.
For the meeting I had the crankshaft prepared for final grinding using my toolpost grinder. This will be carried out between centres and because the component is relatively slender, the force applied to the centres would cause some bending unless reinforcing is used. For this I cut some strips of steel and fixed them in place temporarily with epoxy resin. This is strong enough to stop the pieces coming out during machining but still allows them to be knocked out when required. They can also be cleaned up and put back in place for later operations.
Steering shaft
The reinforcing does not look very elegant but it does the job.
With reinforcing
Some Interesting Web-sites
I have quite a lot of links forwarded to me so I thought I should start a section to pass on the ones that seem to be worthwhile:
While I was working on the crankshaft, this link arrived from Brian Lawson:
<http://www.youtube.com/watch?v=81UjjSH2iFw> It shows a crankshaft being machined from a solid billet, it is amazing how essentially all of the machining operations are carried out on the same piece of equipment. Machining the off centre crank pins by moving the cutting head in a synchronized manner as the shaft rotates is something I have seen at an exhibition and it is quite impressive. One other impressive part was the "rigid" tapping where the tap is fed in and withdrawn with the rotation and axial movement synchronized. The machine has a really impressive tool set (that probably cost way more than my complete machine.)
I did contemplate programming the my CNC mill to machine the crank pins in a similar way by
synchronizing the Y and Z movements with the rotation and doing everything with the component mounted between the main bearing centres. However if you already have the centres for the crank pins available it is easier to use these and simplify the machining process (see the first crankshaft photograph.) If you mess up in any way with an eccentric machining operation the outcome will not be pretty!)
One company Bruce mentioned at the meeting was the Boggs Tool and File Sharpening Company: http://boggstool.com/. Apparently they do a good job of restoring files that have become dull from use.
Another link: http://joyofprecision.tumblr.com/
Is a blog by someone called Max Philips about his small scale precision machining activities.
Taking the next link: http://www.engineerguy.com/
If you click on the "Free PDF" icon in the upper right side it goes to a page about a mechanical computer with videos and a free pdf of the book. It is well worth taking a look.
The last two items forwarded by Bruce will be of interest to anyone who is into model gas engines.
http://modelengineeringwebsite.com/Blokker_I_C_ignition.html
http://modelengineeringwebsite.com/Blokker_alternatives.html
These are by Jan Ridders from the Netherlands and are about using the igniter from a gas lighter to provide the spark in a model engine. Most lighters use a piezo electric device but the one he has found, sold by a store called Blokker, uses a small battery and ignition coil. The websites explain how he has adapted these coils for use in model engine ignition systems. The attractive part of course is that these things are mass produced and available for a few $.
In fact the lighters use a capacitor discharge system: A high frequency oscillator "chops" the 1.5V battery output and this is fed to a tiny transformer that produces ~ 100V. This charges a capacitor that is then discharged across the ignition coil to produce the spark. It is amazing what sophistication and complexity is built into throw-away devices nowadays. The lighters are made in China and obviously available in Europe. I wonder whether they are available here? I have done a little research on the web but have so far found nothing.
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