Ve have, as they say, good news, und bad news; first the bad: the broken tap is still sitting in the Cirrus Crankcase. The good news is that the device to remove said tap is nearly finished and will be the subject of a "construction" feature in its own right early next year. And along the way to making the EDM, A GHT UPT got machined as well. Photos were taken which will be of interest to QUORN builders as they show the GHT ball handle making process. But all such things now go under the bench for a month or so as another, higher priority job takes center stage, as you will read below.
With 2006 drawing to a close, I'm feeling all introspective. The Model Engine News web site traffic has been increasing steadily since our move to the modelenginenews.org domain. In October, we broke through the 10,000 unique visitors per month barrier for the first time and have comfortably repeated the feat in November too. The number of page views averages about ten per visitor. Then we factor in the pictures referenced by a page to get the total "hit" count. This count broke through the magic million barrier for the first time in November. The total "hits" for 2006 will easily top 10,000,000 which shows, well, something for sure—don't you worry about that! Other website stats, notably error responses and my own webmail availability indicate that the hosting service I'm using is less than brilliant. So we'll be moving to a new host Real Soon Now. This will be transparent to you. The only thing you should see, touch wood, is a faster response time. And I'm going to continue my "no ads" policy for as long as I'm able, meaning keep those orders for the CD and DVD rolling in!
Speaking of which, the DVD of the web site will ship starting in December. It will contain the entire site as it stands in the month that the order is placed. With all the free space available on a DVD, I've decided to increase the size of the "cookie" by about one third again. It also allows me to include all the free plans issued to Members so far. Existing members who want to "upgrade" will be able to request a copy of the DVD for US$15 to cover media, printing, and shipping. To new Members, the DVD will be US$60 including air postage. The old CD version will still be available at US$50, although I'd like to phase it out. Payment will be via PayPal which has worked flawlessly since introduction of the CD, even though their "cut" is an insult (but I would say that, wouldn't I? ). We may even add a little shopping cart facility to make things easier for all concerned.
We have an in-depth review this month of a publication kindly submitted to us by its author. To quote another web site: With a few exceptions, books sent get listed, and possibly even commented on. With fewer exceptions, books not sent, don't. Or in my case, they get bought. Must be a lesson there someplace.
All that remains now is to wish you all, on behalf of The Motor Boys and myself, a very Politically Correct Festive Season Greeting. Or not, depending on your own, personal, sense of social ethics, geopolitical beliefs, preferences, and whim. And we'll see you again, on January 1, 2007.
Ron and The Boys
No, not a portrait of Ye Olde Editor—my nose is not that big. But as 'tis that time of year yet again, Model Engine News is pleased to reward (?!) our legion of loyal supporters with another free set of CAD plans. Just log into the Members' Area and page to the bottom of the growing list (must reorganize... soon...) This year, it's ETW's Cygnet Royal, a three cylinder, radial, high-speed steam engine that uses a rather fascinating orbital valve. At one time, cast iron cylinder castings were available for this engine, but I see no reason they could not be hogged from the solid. Aluminum with pressed in CI liners would also serve. Even if you don't build it, I hope you enjoy puzzling out how it all goes together and works. Non-members can order printed copies of the plan set by dropping us an email to get the cost for your part of the world.
2006 ME Exhibition Postponed
The Model Engineer's resident IC sub-editor, Nemett, designer of the NE15S, has emailed to let us all know that the 2006 Model Engineer Exhibition that was scheduled for December 29-31 has had to be postponed due to circumstances beyond their control. A notice to this effect will appear in the next issue of the Model Engineer, and a revised date notified when the problems are sorted out.
RIP Woking Precision
A reader emailed to tell me that it appears that Woking Precision, the English company that supplied castings for several of Edgar T Westbury's engine designs for oh so many years, is no more. This is sad for a couple of reasons. Woking has been around for a long time and I'm always sorry to see such a supplier close the doors. Even more so as Woking came under new management in 2002 and this was the first news item Model Engine News published when we went to the new format. At that time, Graham Varcoe pledged that, as the supplier of castings for the Sparey designs, he would do all that he could to correct the Sparey 0.8cc myth. He failed, but it was a nice thought.
All is not gloom and doom though. The Woking URL is currently doing a redirect to a news page on Hemingway's web site. Here the news is that Hemingway will continue to supply the ETW IC engine range and plan to revamp the line in the near future to provide full material kits with CAD drawings. Hemingway also provide kits for most of George H Thomas' designs for workshop tools. I've built just about all of these, the latest, as you'll read elsewhere this month, being the Universal Pillar Tool (UPT). These tools don't get used often—mostly when making other tools, actually—but when they get used, they work to perfection and are a source of great delight to me. It will be interesting to see what Hemingway (themselves under recent new management) do with the old Woking line. And while on the Hemingway topic...
The GHT UPT
Say what?! The hieroglyphics decode as the George H Thomas Universal Pillar Tool. I've mentioned GHT a number of times before. He wrote in the Model Engineer during one of their golden periods and it was his clearly written and perfectly photographed articles on the simple and effective tooling he designed that made the period Golden. So what's a pillar tool you might ask? Basically, it's a light weight gadget for supporting work and tooling so that drilling, tapping, punching, stamping, riveting, staking, and other -ing's can be done with precision. While contemplating the quick and dirty spark eroder, the UPT seemed like it would be just the ticket to hold it. Having a set of castings under the bench, out they came and soon there was cast iron dust everywhere. It's not finished yet—and I've no real intention at this time of making the sensitive drilling attachment—but the techniques involved have broader applicability; ball handles for the QUORN, for example. So click on the picture, or this link to visit the GHT Universal Pillar Tool page.
Systemé Loyal Revisited
Last month's edition described the obscure ETW twin poppet valve two-stroke called the Loyal. A reader emailed to call my attention an English company that glorifies under the name, The Engineers Emporium. Amongst their kits is one called the Pioneer pictured here which appears to be a model of the French engine ETW based his Loyal on. The casting kit is not cheap, but it's smaller than the monster ETW engine and looks like it would build into a nice model. The link to the to the Engineers Emporium has been added Links Page.
Also mentioned in passing last month was the Otto und Langen Gas Engine. This was essentially a cannon sat on its tail that, Jules Vern-like, continually tried and failed to shoot its piston into orbit. Gattafoni and Ambrosi's Antique Engine site has been in our links page for quite some time. These gentlemen have been busy with a Capital Bee. Amongst their new work is a model, seen here, of that original Otto-Langen gas engine. Note how the cylinder is cunningly disguised as a Grecian column! The "H" arrangement on top is a guide for the rack attached to the free floating projectile, err, piston. The gear it meshes with free wheels as the piston is going up, and adds spin to the flywheel as atmospheric pressure pushes the piston down again. Their site is well worth another visit, and not just because their link page mentions a certain magnifico sito de Ron Chernich... . Have a look at their model marine diesel featuring real, live working injectors too.
Annual Gildings Auction
Readers may recall that last year, Gildings in the UK held an auction of model engines and memorabilia. This has become an annual event, confirming that such stuff has become profitably "collectable" on a large scale, as if we didn't know that already! While I totally failed to warn all of you that this was about to take place last month, I can at least let you know that you can view what you missed out on by giving the URL for the 2006 Gildings Aero Engines Auction. Sorry 'bout that, chief.
Embalming for Fun and Profit
Lindsay Publications has a very quirky sense of humor that strikes a resonant chord with me, at least. They once offered a title "Preserving The Dead", complete with some rather gross illustrations, and we don't mean simple taxidermy! Browsing their Self Destruction section still yields a number of other gems such as "Backyard Ballistics", and the "Alcohol Producing Still". Lindsay reprints these, and other less alarming titles from books printed in past eras when such things were not greeted by the populace with as much shock and horror as they are today. Shows how times change, as does the availability of certain chemicals—don't get me started on ether...
Where all this is leading is to an entry that Les Stone uncovered in a 1941 issue of the Model Engineer. This article lists a few ways that metals may be treated to induce a color change in their surface. Substances like mercury and lead acetate, once considered only harmful to your average village idiot, are now considered harmful to everyone. That reflects poorly on either everyone, or just on our legislators (ok, I know it's more complex than that, but the madness has got to stop somewhere). However, equally harmful things like sodium hydroxide—caustic soda—can still be readily obtained (maybe even your average legislator's drains occasionally block up too), so read the little dissertation for what it's worth.
A Mills-ish Watzit
Our little group spotted a rather unusual engine on eBay this past month that claimed a Mills Bros heritage. We felt it looked more like a Dyno than a Mark I Mills 1.3. Certainly it was no known commercial Mills Bros product we could identify. Still, it finally changed hands for a good penny. Then Bert Striegler sent out photos of an oddity in his collection to muddy the waters even further. This unique engine has been added to the Watzit File.
New Books and Magazines This Month
This feels like part of a TV story arc. Readers will recall that as we closed last month's episode, the Cirrus Mk I project had suffered the dreaded broken tap in the very last hole. As the hole in question was one of the crankcase engine mounting pads, there was only one solution; that broken piece had to come out without damage to the thread. The tap had snapped obliquely, deep in the hole. When I tried to unscrew the tap, the faces jammed together and it broke a second time, just proud of the hole. The tap in question is 4-40 and in my experience, small taps like this just cannot be gripped for removal. The most practical approach is to burn out the offending metal, either chemically, or electrically. Strong acids are not my thing, so that narrows the choices to one: spark erosion. Now read on...
Spark erosion, frequently called Electrical Discharge Machining (EDM) requires some rather specialized and expensive equipment. Basically, a transient spark is generated between an electrode and the work. The high temperature produced vaporizes and removes a miniscule amount of material. This may not seem very effective, but if we repeat it quickly and keep it up long enough, metal in the shape of the electrode cross-section is eroded away from the target. This is a slow process and control of the electrode (which is being eaten away too) is critical. Commercial units are complicated and their internals are carefully guarded industrial secrets, but the technique is so useful that there have been quite a number of designs published for home construction. For those interested, a researcher at the University of Wyoming has compiled a list of most of these. Initially, I thought about building the quickest and dirtiest unit that could conceivably do the job. Then a reader suggested I look at a slightly more complex design.
So—at long last—we come to this month's book review: The EDM How-To Book by Ben Fleming, Fleming Publishing 2005, ISBN-0-9767596-0-8; 5-1/2" by 8-1/2", 168 pages, softbound, $19.95 in the US from Lindsay Publications, or the author. This book sets out to explain what EDM is, where it came from, how to make a relatively simple RC spark erosion machine, and how to use it. The photo on the back cover of the book illustrates the capability of the machine and one of the advantages of EDM, namely the ability to perform precision machining in hard steel; that "EDM" logo has been carved into the face of a file!
The book begins with a brief history of EDM (yes, the Russians really did invent it this time) and how it works. The bulk of the book is then devoted to describing the construction of the electronics, mechanics, and the all important dielectric fluid flushing and filtering system for the machine designed and developed by the author. The description of building the electronics is extremely detailed. Perhaps a bit too much so, but the author has set the scene by saying that his target audience are most likely competent machinists with no electronics experience rather than the other way around, so the amount of detail is justified. A nice touch is the table of voltages that should appear on all the socket pins of the two integrated circuits (IC's). Confirming these voltages with a simple volt meter before plugging in the IC's provides a high degree of confidence that the unit will probably work when the ICs are plugged in. It also ensures that you are unlikely to blow the chips due to a wiring error.
The electrode (anode) is positioned by a lead-screw arrangement. The author notes that other published EDM designs tend to use a stepper motor to drive the lead-screw that positions the electrode and maintains the spark. Driving stepper motors requires a lot of electronics. Ben sees this as unnecessary complication. Instead, he uses a simple DC motor with an integral 80:1 gear reduction to drive the lead screw. The electronics are reduced to a single servo motor control chip driven by a voltage comparator that maintains the spark set by the operator. Feedback maintains this spark as work and electrode erode. This is far simpler than the stepper motor designs, but accomplishes the same job.
The mechanics of the servo controlled head, or "ram", are based around a steel, cabinet drawer slide of the type that uses ball bearings in a cage between the fixed and moving rails. In my opinion, this is the greatest stroke-a-genius in the whole book. The precision of these pressed steel slides is quite astounding. It should be noted that unlike a lathe or mill, the ram is not subjected to mechanical force while in operation, although hydraulic forces can deflect the electrode. By mounting the ram in the mill quill, then bolting the work to a plate fixed to the floor of the tank, and the tank itself to the mill table, very rigid and accurate positioning is achieved. Even better, the unit can be removed and stored away easily when not in use.
The instructions for building the mechanics are less detailed than those for the electronics, but adequate and most builders will employ some variation to suite their set-up. More critical is the tank and associated flushing and filtering system. The book describes the importance of adequate electrolyte circulation and how to construct a suitable setup from readily available parts. The "electrolyte" may be a specially formulated hydrocarbon based fluid, or kerosene if you can't get that. As all sparking takes place at least an inch under the surface, the danger of fire is near to nil. Having a fire extinguisher handy is still a mighty good idea though.
With construction covered, the book describes in detail the process for setting up and taking the first cut. This is followed with suggestions for advanced techniques, including electrode selection and preparation. Finally we get a full parts list, including sources in the USA, and a very comprehensive glossary of terms that is worth reading through at least once.
Criticisms? Yes, a couple: the circuit diagram is just a wiring diagram, not a theoretical circuit. But a machinist would not know what to do with one of those, and anyone who does understand them can work it out easily from the chip manufacturers' data sheets. A bit more significant, the oil filter type used is not specified anywhere I could find although the part number is just about visible in one of the photos. This seems a bit of an oversight. I also wonder why a diesel engine oil filter is suggested when what we are filtering is close enough to diesel fuel as makes no nevermind? A diesel fuel filter with a remote mount that incorporates a water trap might be a better idea. But these are minor quibbles that are not of any great significance.
The author acknowledges that the machine described in this book uses the simplest possible spark generator circuit. For a more sophisticated and efficient generator, have a look at this paper titled The Garden of EDM (cute name ), but note that this design is untried and theoretical, while Ben's has been replicated many times with complete success. Ben also states that he is not a professional engineer, nor does he have formal training in the design of EDM equipment. This Get Outa' Goal disclaimer is quite wise in light of the voltages and currents involved and today's litigious society. Nevertheless, the photographic evidence in the book suggests that the capabilities of a machine built to the provided plans will be a useful workshop accessory. The writing is clear and the drawings should be easily followed by any model engineer. After reading this book, you will have a clear understanding of EDM and will be able to make a call as to whether it is for you, or not. You'll also understand the terms that appear on the web pages found by a Google search for "EDM". If you decide to take the plunge, there is an active Yahoo EDM group you can join dedicated to this machine where the author himself will answer questions. I'll give The EDM How-To Book a Gold Star and a Koala Stamp: recommended!
Engine Of The Month: GP II
This month's treat is an engine I never thought I'd get to see in the flesh, or at least a close relative to it. It was sent to me by a most kind gentleman in Denmark who said he'd discovered the Model Engine News web site 14 hours earlier and not slept since . This is no "hanger-queen" kept in a glass case, but a working engine flown by a former Danish team-race champion. Click on the picture, or follow this link to find out what it is and what makes it so unusual.
Tech Tip of the Month
As I type these words in late November, the Great Australian Water Crisis continues to get worse and worse. The Federal Government has even appointed a Minister For Water who is saying, in essence, every gram is precious and water rationing will be part of life for evermore; get used to it! And what has this got to do with engine building you ask? Patience, Watson, patience. We'll get there soon.
Content Warning! Now I realize that the bulk of Model Engine News readers are located in the USA where the MKS system of units (Meters, Kilograms, Seconds) is about as popular as a broken tap in a Cirrus crankcase, but don't turn off just yet, this too is significant.
Europeans may sniff down aristocratic noses at the "Imperial" system of units saying that the metric system is superior in every way while leaving the precise reasons unspecified. Some might say that's just what you'd expect from such a decadent culture, but consider this:
One cubic centimeter (1cc) of water
weighs one exactly one gram (1gm).
Say you have an engine with a complex combustion chamber shape and are wondering what the geometric compression ratio is. The cylindrical swept volume can be calculated by careful measurement and a bit of math, but what about that head cavity? Place the head on a set of sensitive scales and record the weight. Obviously the bathroom scales won't do for this, but electronic scales with 0.2gm resolution are easy to find and not expensive. Even better, they will have been made in China for the World Market and so and will have a gm/oz switch. Set to metric and add water with an eyedropper until the cavity is full. The weight difference in grams will be the head capacity in cc. Hmmm... maybe those Europeans are more than a bit justified in their smug, metric superiority. Yes, there will be a meniscus to spoil things, but you will be close enough for government work. Of course you could always fallback on the well known fact that one cubic inch (cuin) of water weighs 0.036127 pounds. Just be prepared to defend your assertion that this is easy, logical, and consistent and have a good calculator handy for the division.
I'd love to claim to have worked this out for myself, but the tip actually comes Mr LA Sullivan writing in the Model Engineer, volume 142, issue 3530, of February 6, 1976—and maybe I've even linked back to the polly's "every gram is precious" quote.
The engine is the ETW Seal and the artist is Charlie Tomalesky of Design Industrial who specialize in 3D modeling and commercial art such as this. Last month we mentioned the Sherline Craftsmanship Museum Seal Project. Charlie did this picture for that project, and work here for the next month goes on hold as I make pistons and rings for the Seal. To those who have been looking forward to seeing a finished, running Cirrus, don't despair, so am I! We'll be back on the Cirrus project as soon as this is done. By coincidence, the Seal bore is 0.625", the same as the Morton M5, another delayed project that I know other readers have been waiting a long time to see completed. So while I'm making rings for the Seal, a few more for the M5 might be a good idea...
MEW's Triple Bypass
Not to raise anyone's hopes, but word is circulating that MEW (that's Model Engine World, not Model Engineers' Workshop) may yet rise again under a new editor/publisher in 2007. The magazine was launched in May 1994 by John Goodall to bootstrap his engine trading business. He published 70 issues, the last being Feb/Apr 2001. Next Andrew Nahum produced seven issues between "New Year" 2002, and November 2004 (I'm still waiting patiently for issue #8 of my last paid subscription to arrive). All the ducks seem to be lined up for a new editor to now take over from Nahum. Like ECJ and SIC, MEW relied on contributed material. MEB has broken this model by paying authors and is thriving, so we wait with bated breath to see if the bar has been permanently raised. As they say, stay tuned...
Engine Finder 2.1
There are now 326 engines in the Engine Finder and I'm starting to think the whole concept is just plain broken. Is every engine pictured on this site referenced? Don't know; don't think so. Is there overlap between what the Engine Finder does and what the Site Search facility does? Yes. No. Maybe. Another problem is that while regular visitors may know that there's something new in the Finder from the "Updated" date stamp, how do they know which one(s) of ump-teen hundreds of entries are new? Beats the hell outa me, lieutenant.
One thing is for certain, the number of engines pictured on this site is going to grow. So while I ponder some automated way to create an engine index, I've applied an interim work-around. Below the main Finder drop-down list box is an another that contains only the additions made to the main finder in the last update. So if you've seen everything and just want to check what's been added lately, look there. This is not the perfect solution. When new entries are added, the old "New" list will be cleaned out, so it's possible to miss an update—unless you check religiously each month .
"GO" buttons have also been added to side-step a bug whereby you had to make an actual change in the selected entry to have a page appear. If you want to view the engine currently listed in the combo-box, just press the button.
A better solution to the whole issue might be to have two identical drop-downs, one sorted alphabetically as it is now; the other in "date added" order. Or a sort button? I'll think about it...
Dude, someone ate my cookie. Again!
What can I say? I did it. In the 0610 update there's a file named
index.html. That's the real culprit. To restore your link to the cookie, you need to copy the
index.html file from the top level
men directory of your CD to the same directory of your hard disk image. While the
index.html file on the web site changes monthly, that on the CD (and new DVD) never changes. I'll try to remember this in future while preparing the download zips. I humbly beg, etc.
Announcing the berth of a brand new Mancini is a great way to close this last issue for 2006. The engine was built from the plan in the Motor Boys Plan Book by our own Roger Schroeder. On the journey to making what is to our knowledge the first and so far only 21st Century Mancini, Roger found (ahem) a few technical difficulties in the plan. These have been corrected, and as announced last month, a download update is available from this site. Great job, Roger.