The Sherline Miniature Machinist's Newsletter

Number 60, March 15, 2013

http://www.sherline.com

 


Customer Project of the Month

Stop Motion Dog/Tom Brierton

Though most animated cartoons are now computer generated, before that technology existed, each frame was individually hand drawn or photographed. A popular form of animation was done with clay models that were moved a little bit at a time and photographed at each stage to get the appearance of motion. ìClay-mationî required talent, time and a good, solid moveable matrix under the clay that could be manipulated to move in stages like the real being it represented. Shown here is the framework for a dog that Tom Brierton from Illinois created using Sherline tools. It duplicates all the joints and motions of a real dog. Friction is adjusted by tightening the fasteners at each joint so it can be moved but holds its position. Once covered with clay, it could be posed in any position a real dog could achieve. This photo was used in Joe Martinís book Tabletop Machining in the gallery of projects at the front to demonstrate the variety of things that can be done with tabletop machine tools.

You can see more workshop projects on the Sherline web site at www.sherline.com/workshop.htm.


Shop Tips

Inexpensive protection from chips and coolant for your DRO box /Tom Wheless

For many years, bailing wire was the farmer's universal remedy for securing anything loose. Then Duct Tape became the universal repair material. Now people are finding all kinds of uses for ZipLocÆ bags and not just in the kitchen. Campers and travelers find them handy for keeping electronics and matches dry or keeping liquids contained in case a container should leak in your suitcase. Anything electronic doesn't benefit from the machining environment, particularly near a mill that tends to throw coolant and chips in all directions. You want your DRO readout box close by so you can easily zero the axes when necessary and read the handwheel position and RPM displays, but you also want to keep it protected. Here is a simple, cheap solution.

While not overly elegant, this is a readily available, inexpensive and practical solution to keeping your DRO box clean. (Click on photo to view a larger image.)

ìI recently bought a Sherline DRO to accompany my Sherline manual lathe. I love the DRO and the additional precision and functionality it adds, but, as a retired electrical engineer, I worried about oil droplets and small metal bits migrating into the switches and connectors of the DRO and causing problems over time. So, I noticed a ZiplocÆ quart-sized heavy-duty freezer bag (dimensions: 8 x 7 inches or 200 x 180mm) would fit perfectly over the DRO box, and, kept partially closed with a small binder clip would still allow the wires to exit from the side. The plastic is transparent enough that I could still see the display and switches easily enough, and, when the plastic eventually becomes scratched, dirty or worn, I can easily replace the plastic bag for a few cents. See the photo above to see how the setup looks on my bench.î

óTom Wheless, Eagle, ID

To view this and 70 other shop tips for Sherline machinists see the TIPS page.


Product Spotlight

Fly Cutters, P/N 3052 and 7620

The P/N 3052 fly cutter comes with a brazed tip carbide tool and cuts about a 2" path. The #1 Morse taper is held in the headstock with an included drawbolt with special washer.

The P/N 7620 carbide insert fly cutter features a replaceable carbide insert with two cutting surfaces and can cut a path about 1-1/8" wide. A special wrench and attachment screw are included along with the drawbolt.

About Fly CuttersóFly cutters offer a great way to machine a flat surface and are the most economical way to remove material on the mill. They also leave an excellent surface finish. The cutter actually exerts less stress on the machine than you might expect. This is because it ìpeelsî the material off with little crushing action. If possible the cutter should swing a path wider than the material. If the material is wider than the cutting path, progressive cuts should overlap by about 1/3 of the previous cut. When using a fly cutter it is imperative that the part be securely mounted to the table. Also, note that chips coming off the part are HOT! A long sleeve shirt and eye protection are a must.

Standard Fly CutteróThe P/N 3052 fly cutter comes with a brazed tip º" tool, but there is no reason an easily sharpened high speed steel tool couldnít be used for many operations. A normal depth of cut in aluminum would be about .010" (.25mm) deep.

Inserted Tip Fly CutteróThe P/N 7620 fly cutter offers a good compromise between an end mill and a standard fly cutter. End mills are slow to remove a lot of material, but you can cut to a shoulder. A standard fly cutter is good at cutting an entire surface. The inserted tip cutter can cover a much wider area than an end mill but can still cut to a 90∞ shoulder. For non-ferrous materials the depth of cut can be .020" (.5mm). The spindle should run at maximum speed (2800 RPM) and the tool is fed fast enough that it is continuously cutting. A common beginner error is to not feed fast enough. Each cut should peel off a curly chipóand remember it will be a HOT one. For cutting steels, the RPM should be between Ω and full speed and a starting place for depth of cut would be .015" (.38mm). Back off the depth of cut if vibration seems excessive.

You should be able to obtain a good finish with this type of cutter. If you canít, try increasing the RPM if not already at full speed. A small amount of cutting oil will also help keep the chip from sticking to the cutter. Higher RPM also has this same effect, which is the reason for using higher RPM with carbide tools. Use of carbide inserts speeds up the process by eliminating the time spent re-sharpening conventional tools when working with hard-to-machine materials.

Additional carbide inserts can be ordered as P/N 7622 for $15.52 each.

Read the full instructions for the 3052 fly cutter.

Read the full instructions for the 7620 fly cutter.


Did you know?

ï When Sherline tools were first sold in the USA in the early 1970ís the cost of a Model 1000 lathe was $199.95. According to an inflation calculator on the internet, in 2012 dollars that same lathe should now cost $930.00. In reality, the current model 4000 lathe costs only $575.00 and is also a much more powerful and accurate machine. What a deal! The accessory line has also expanded from just a few accessories then to several hundred now.

ï Videos of cutsóTo see and hear a Sherline lathe in action cutting materials from Delrin and maple to stainless steel and titanium see the video link at the top of the home page or CLICK HERE. The cutting speed and feed rate for each cut is listed. This is a good way for a beginner to get a feel for a starting place when cutting various materials.

ï Can you use your DRO on a CNC machine?óYes. The DRO handwheels can be relocated to the rear shaft of a stepper motor if you decide to upgrade your DRO-equipped machine to computer control. The DRO does not interface electronically with the CNC driver box, but it does give you a cross-check on the operation of the CNC as well as retaining DRO function when using the machine manually. You also get the benefit of a continuous readout of your spindle RPM. CLICK HERE for instructions on how to make the conversion.


Upcoming Model Engineering Shows

2013Ö

ï Cabin Fever Expo, York, PA, April 12-14, 2013. The east coastís largest annual model engineering show has moved from its former January date. See http://www.cabinfeverexpo.com for more information.

ï North American Model Engineering Society Expo (NAMES), Wyandotte, MI, April 20-21, 2013. This is the oldest Model Engineering show in the USA and where the Joe Martin Foundation presents its annual award for excellence in metalworking craftsmanship. Sherline will also have a booth featuring our tools at the show. See http://www.namesexposition.com. This show retains its traditional late April date.

Send us your show details and we will post them hereÖ


Joe Martin Craftsmanship Foundation News

ï New Museum DisplaysóA digital slide show has been added to the display on Founder Joe Martin. It includes photos of his early days in Radio Control flying, products he has developed over the years and some of his other activities like sailing and sports car racing.

ï DonationsóA large collection of Model Engineer magazines along with some lesser known but interesting publications like The Model Maker, Ship Modeler and Steamboats were contributed by William B. Barker.

ï Groups Visiting the Museum

óThis past month has seen two special groups tour the Craftsmanship Museum. Joining us this month were:

††††††††††† February 26th: Volunteers from the City of Carlsbadís Visitor Center came as a group to see what our museum had to offer so they could speak from personal experience when promoting it to city visitors. We appreciate the effort the city has made to let people know about our museum.

††††††††††† March 9th: The San Diego Ship Modelerís Guild had about 10 members stop by for a tour. Ship models are featured in the San Diego Maritime Museumís display aboard the ferry Berkeley next to the Star of India in San Diego Bay. See the Club Visits page for a photo of the group.

ï Publicity

The museum is mentioned in this month's Southern California edition of the Auto Club's Westways magazine. CLICK HERE to see the ad. The publicity is reaching a lot of new people in the area. In addition, this month's issue of Car & Driver magazine features a full page article on our 2012 Craftsman of the Year award winner Gary Conley and his miniature V8 engines. CLICK HERE to view a PDF copy of the page.

Anyone interested in volunteering your services at the museum, please contact craig@craftsmanshipmuseum.com or call 760-727-5857 and ask for Craig.