CAMS Review of 29 January 2008 Meeting

CAMS

Chesapeake Area Metalworking Society

Review of 29 January 2008 Meeting
Mason District Governmental Center
6507 Columbia Pike
Falls Church, VA

contributed by Charles Keeney

Editors Note: Unfortunately there are no contemporaneous photographs from the January 29, 2008 Virginia meeting so we cannot show you the visages of the collected membership. The photographs you see attached here are provided by the editor and were taken after the meeting.

The January 29, 2008 Virginia meeting began with the usual bargain hunting as club members walked around the various tables set up by members who wanted to sell their surplus inventory of stock, tooling and assorted wares. At the same time other members caught up with friends on the latest news and the status of the current project back in the home shop. Several select pieces of aluminum plate brought by Al Haraq never made it out of the parking lot and into the meeting room and were last seen that same night headed towards Rockville. Some of Al's aluminum did make it into the meeting however and most if not all went to new homes. Al, who is in the process of moving, also brought along a nice selection of books free for the giving and so when the official meeting began there were many happy faces. Alan Weber also brought a nice supply of aluminum and brass stock, much of which he sold. In addition to the stock, Alan also had the usual odds and ends that Alan brings.

Others who brought items for sale included Paul Milsback who had a number of items at what must have been great prices considering that most of it disappeared prior to the meeting start.

Rich Soby was quickly selling the EZY-Clamps that he had purchased in bulk from the manufacturer. Rich was able to negotiate a great deal on these stainless steel hold-downs and so he shared the wealth by passing along the savings and a goodly number of EZY-Clamps went to new homes. As of the end of the meeting Rich still had a few left for sale.

Here we see a photograph of EZY-Clamps holding down a block of aluminum. Note the sacrificial shims made of soda cans on the ends of each clamp. The tabs on the ends fold into the holes so they are not lost during repositioning. Based on the editor's experience, Seagram's Diet Ginger Ale cans are just a little too light for satisfactory results.

Chris Daniel was offering a great deal on socket-headed cap screws and other fasteners.

Brass and aluminum stock, a lathe mounted collet holder/stand, a vertical/horizontal 5C collet vise, Ezy-Clamps by the handful, books, an involute gear cutter, a gent's style dovetail saw, wrenches, a small acme screw and nut, tool bits, and many other bits and pieces too varied to mention were just some of the things adopted by new owners that night.

Although the photo quality is low, this is an example of a Gent's style dovetail saw.

Misc_Nits_&_Bits_R1.jpg

An odd assortment of "treasures". Of the two tool bits, one is already ground to a desirable shape, thus saving grinding time and the other is a new 3/8" X 1/2" HSS tool bit making it desirable for use on a shaper toolpost. The Acme screw and nut is 10 tpi and though grungy, shows little use. The gouge tool and the box end square wrench next to it are blacksmith-made items.

Sincere thanks to Al Haraq for a nice copy of Marks' Standard Handbook for Mechanical Engineers .

The formal meeting began when Chris Helgesen called the meeting to order. Introductions were made in the traditional CAMS round-robin fashion with each person introducing himself (himself, because, alas, there were no ladies at this meeting - or at least identifiable as such). Thirty CAMS members were present at the meeting. After the introductions concluded Chris opined about the great transfer of wealth that occurred at the recent Cabin Fever event in York, PA. There were many amen's to that sentiment as information was exchanged about who had scored what deal at the three day Cabin Fever auction and show. The CAMS member who scored the Emco Maximat Super 11 lathe in nearly new condition at the Cabin Fever auction was conspicuous by his absence and it was generally conceded that he had gotten what was perhaps the best deal at the event.

The discussion moved on to the CAMS-Club web site and the need to update it. Several members indicated an interest in participating in this process. As a side note, any and all members are invited to participate in maintaining the site; no special skills or talents are needed, as you can see. Anyone capable of calculating change gears has more than sufficient acumen to produce web pages.

The status of the new Practical Micro Design, Inc. (PMD) office was discussed early in the meeting. For those who do not know, PMD is owned by Steve Stallings, who was the coordinator/nucleus for the founding of CAMS. Steve also sells the PMDX breakout card for CNC applications through his PMD firm. In fact, Steve always has a table or booth at the Cabin Fever, Iron Fever, and NAMES shows. Steve has been very generous to CAMS and among the many favors extended to the club and its members, he has allowed it to use his previous offices for special events such as the CNC Special Interest Group meetings. It is hoped that Steve may once again offer his facility for future meetings after construction is complete and inspections passed. Per Steve, he is hopefully that he can re-host CNC Special Interest Group meetings again in the March or April timeframe. The collected members met this news with enthusiasm.

Tex Rubinowitz next spoke of a desire to initiate a gear-cutting Special Interest Group. The purpose of this group would be to assemble interested members in order to study the various ways of generating gears, discuss gear associated topics, and actually making some gears. It is known that several members already have valuable experience in gear hobbing and indexing and it is hoped that they could form the nucleus of the gear making Special Interest Group. Those attending past CAMS and CNC Special Interest Group meetings have seen some to the fine work that Tex has generated via CNC and several of us in the club have 47 tooth change gears at home on our Southbend lathes that Tex cut from stock. It is hoped that the group will learn to generate gears via several methods that will be practical in a home shop environment.

After Tex, Tom Hubin reported that the Maryland CNC Special Interest Group is awaiting word from Ernie Falcone on the new shop. Ernie, who has been kindly hosting the Maryland CNC meetings, has recently moved into a new shop and that has put a number of non-business-essential activities on hold. Tom reports that Ernie also has a new shop-bot.

Following Tom, Luther Dietrich gave a briefing on the new machine shop building at Tuckahoe Steam and Gas Association (TSGA). The outside shell of the building is mostly complete and now the focus is on installing drywall on the ceiling. For those who are not familiar with TSGA, several years ago TSGA approached several CAMS members about restoring some old machinery (lathes, mills, drill presses, planers, shapers, etc.) that had been donated to TSGA. At the time the average TSGA member was more focused on steam and gas engines and their operation. It was a great opportunity for some CAMS members to "fix things that weren't broken yet" and to actually repair and restore ones that had been broken prior to being received into the TSGA collection. Where else can one get a chance to tear apart a Dietz, Shumacher and Boye lathe, the Smith Mills 16" Shaper, a 1900s Pratt & Whitney hand mill, and other old iron? It has proven to be very symbiotic relationship for both CAMS and TSGA. See this link for additional information on the TSGA Machine Shop project:

http://www.tuckahoesteam.org/collectionspages/collectionsmachine.html

Charlie Savich spoke after Luther and gave a talk on several topics including the difficulties of doing electrical work on an old house, how to tell if a motor is hot, about how to mill a cut in a 5C collet indexer, and about making a spring arbor.

Don Nichols spoke next. Don's talk was on how to read eBay descriptions, particularly given the "often" poor knowledge of the seller. He then showed envious members a mint 2MT test bar with test standards and a .0005 dial indicator that he purchased at a very low price because the seller did not properly identify it as a 2MT test bar. Don also spoke on how to identify good insert tool holders from poor ones. Don stressed that good ones have a lot of steel backing up the insert to reduce spring and dampen vibration.

Chris Helgesen then retook the floor and told everyone of a project where he helped a neighbor in restoring a K&T disc sander. The sander disc backing plate needed truing but vibrated excessively when Chris tried to turn it on his lathe. Rich Soby noted that there are a number of techniques to deal with such challenges. One is to pour a low-melting fixturing alloy onto the back of the plate to deaden the plate. He also spoke about an old trick used by automotive machinists to turn brake drums. According to Rich savy automotive machinists will often tighten a band of leather around the outside periphery of the drum to deaden vibrations during turning operations.

Chris continued his talk by telling of some machinable wax he purchased at a good price at Cabin Fever. Machinable wax is a compound with plastic-like characteristics that can be machined, melted back to rod, bar or plate form, and then re-machined. It is very well suited for educational and prototyping purposes. Chris related that if the wax is re-cast into a large cross section, then it needs to be slowly cooled to avoid casting voids in the finished casting. This is not unlike cast iron in this sense. Chris also told the group about Overman's Charity Wax. This is a collection of formulas created over years of experimentation by Gary Overman for making home-brewed machinable, casting, and modeling waxes. Gary Overman has posted the formulas on-line at:

http://www.myheap.com/book/chapter-01/overmanwax/overmanwax.php.

Chris next passed around for inspection a Lifetime Carbide brand punch set he purchased at Cabin Fever and then finished his presentation with the announcement that he has now reached a milestone with his Herco CNC mill restoration. According to Chris, he is now cutting air and he passed around pen tracings generated on the Herco using CNC code. Congratulations to Chris on that.

There next ensued a general discussion of the virtues and vices of moving the quill versus moving the table when changing the Z axis on a vertical knee mill during a milling operation. It was agreed that fixing the quill and moving the table added in rigidity but Tex and others noted that locking and unlocking the table on a knee mill changes the workpiece's positioning by several thousands. The consensus was that the machinist must be aware of both problems and choose his approach with these factors in mind and compensate accordingly.

Dave Bluett spoke next on some of his past "chicken" posts. A "chicken" has come to assume the meaning of a cheaply gotten goodie in CAMS argot. Dave then showed some first rate thread gages that he had recently gotten as chickens from a previous employer.

After Dave finished speaking, Charlie Savich spoke again briefly on his quest for information on a backing-off device for use in gear making. Charlie had posted a message on the CAMS list recently mentioning that he was interested in any pertinent information that other club members might posses. Charlie passed around a binder full of information featuring patents, magazine articles, and other information that he has been able to put together. For those not familiar with a backing-off device, these devices provide the critical relief (clearance) required on items such as gear cutters.

Next Tom Hubin took the floor and spoke about an electric motor that has been causing him problems and requested opinions as to the best solution for his problem to which several members offered suggestions. Tom then spoke about a machining and design challenge he has been working on for many months. The fruit of his labors has now been translated to a viable commercial product because Tom has recently begun manufacturing and selling a device used for aiming laser beams and he stated that he has sold 30 of these to date so that is great news for him. Tom also spoke about some parts he has been making of Delrin. Tom also gave a white-board demonstration of a laser triangulation device he is developing. While briefing the club on this subject, Tom also covered some related topics such as red colorblindness as well as discussing the potential side effects of lasers emitting IR and that eye damage can occur in the IR, visible, and UV light spectrums. Tom mentioned in an interesting side note that glass blowers often suffer from "Glass blowers cataracts" with these being caused by the IR light waves given off by hot glowing glass.

Tom's triangulation device obviously captured some of the audience's interest, as there were a considerable number of questions from club members. Tom's hope is that he can develop the concept into an inexpensive optical probe to record dimensional characteristics of physical objects. This would allow users to "reverse engineer" physical characteristics into CAD files with the subsequent benefit that such a file could then be used to produce clones of the original prototype via CNC.

Alan Weber next showed some of his Cabin Fever acquisitions. Included in the finds were a type of adjust-tru chuck, a paired set of Federal standard and air gages, and a beautifully made Austrian cut knurling tool that appeared to be a Zeus brand. Cut knurling tools actually cut the metal instead of forging or swaging the knurling into the stock as do the majority of knurlers with which we are familiar. Here is a link to a near identical model:

http://www.zeus-tooling.com/images/datenblaetter/de/EN_RW_240-40-xx_00.pdf.

Charles Lessig brought several unusual curiosities in for the clubs examination. One was readily identified as a wooden tennis racket star clamp. The other was subsequently identified as a clinometer. Here is a link to a nearly identical gravity clinometer:

http://www.gilai.com:80/scripts/more/ssi568-surveying-Surveying+Instruments-no.html.

Fred Schoomacher spoke next. Fred began by telling the Club how he had cut the slot for a guide bar on the bottom of his Chinese made 5C spin indexer. Continuing his discussion about why it was necessary to cut such a slot, Fred related that the Chinese approach to product design is often "Find a popular design and then copy without question." The Chinese apparently chose to copy a spin indexer that did not have milled sides or a slot for a guide bar and so consequently neither did their clones. Fred then reviewed information that he had presented at the December 2007 Maryland meeting about how to make nut drivers. According to Fred the following is a quick translation of inch to metric measurements for small nuts:

Inch / Metric

.028 / 0.7

.035 / 0.9

.050 / 1.3

Fred noted that for fractional sizes at least, the size of the key for a socket head set screw is one-half the major diameter. Fred also spoke on the polarity of house current, showed a set of dial calipers that would measure both in decimal and fractional systems, reminded everyone that the PATINA spring sale and auction will take place in Damascus on March 15, 2008, passed a handout detailing how to make small hex nut drivers with information about hex key sizes, and passed around photographs of a Purdy shotgun being repaired along with special tools made only for repairing Purdy shotguns.

The formal meeting finally concluded around 11:00 p.m. that night and four hardy stalwarts found their way to a local restaurant using the excuse of a midnight supper as a thinly veiled excuse for continuing discussions about metalworking.

The editor requests that factual errors be brought to his attention.