The Sherline Miniature Machinist's Newsletter

Number 64, September 16, 2013

http://www.sherline.com

 


Product Spotlight

ï P/N 8760 4-axis CNC Stepper Motor Driver Box ($600.00)

Driver box, power supply, cables and backup software are shown. The driver box is the interface between your computer and the stepper motors of a CNC lathe or mill.

When Sherline developed the CNC system for the mill, we installed the drivers and power supply inside the computer box as a complete package.  For those who wish to run the stepper motors on their Sherline CNC-ready machines using a computer other than the one supplied as part of Sherline's lathe and mill CNC systems, we offer the 4-axis driver box and power supply as a separate item.

The anodized aluminum box contains four drivers.  Each outputs to its own cable, labeled X, Y, Z, and A, that plug directly into Sherline's P/N 67127 stepper motors.  These stepper motors are pre-wired with a plug to match that on the end of the driver box cables, making hookup easy and fast.  A 25-pin parallel cable (included) runs from the driver box to the parallel port on a computer supplied by the customer.  Power comes from an external power supply (included) that plugs into the box.  Also included is a CD that contains the correct version of the Linux operating system and EMC2 control program that Sherline uses in its CNC system, should you wish to install them on your own computer.  The operating instructions for CNC and a short course in writing G-code by Joe Martin are also included on a second disk along with a selection of free WindowsÆ utility programs.  The driver box has its own power switch and a bright red LED that indicates when power is on. It operates on either 110 or 220 VAC power (switchable). The chip for each individual axis is protected by a replaceable fuse.

Included are:

ï Driver box with 4 motor cables

ï 3.7 amp, 24 volt power supply with cord

ï 25-pin parallel cable*

ï 2 CD set with Linux/EMC2, utilities and instructions

ï Spare fuses

Minimum Computer Requirements:

In order to install and run a Linux based system from the CD's provided it is recommended the computer have at least the following minimum specifications:

ï Processor speed: 800 MHz or faster (at least a Pentium III class or equivalent processor)

ï RAM: 512 Mb (Sherline provides 1 Gb)

ï Hard Drive: 20 Gb or larger

ï 25-pin parallel port (printer port)*

(Single-board Dell and laptop computers are not recommended.)

*NOTE: A 25-wire parallel port is required because EMC2 was designed to be capable of running up to six axes simultaneously. Even though the Sherline driver box only uses four of those axes at one time, a 2-wire serial USB port cannot transmit data to multiple axes fast enough for glitch-free CNC operation.


Sherline Shop Project of the Month

Simple display stands for models/Tom Boyer, Rudy Kouhoupt, Paul Knapp

Here is a simple project that doesnít require any dimensions or instructions. Itís more of an idea-starter that can be adapted to many display applications. At the Joe Martin Foundationís Craftsmanship Museum in Carlsbad, CA, we have received the donation of many engines, vehicles and other items for display. Often they need some sort of display stand to either raise them up or to support weight; for example, to keep from flat-spotting rubber tires on an automotive model. Shown here are some simple parts turned on a lathe that offer support while complimenting the model. Donít get too carried awayóyou donít want to overpower the model you are displaying. Keep them simple and elegant. A countersunk 10-32 screw up from the bottom of a display base can be used to hold them in place if the model is on a wood base. Below are some examples for your consideration.

This º scale Riggles Midget racer is supported on jacks under the axels to keep the tires from getting flat-spotted.

The above examples of engine stands are turned from round aluminum stock. Note one of Paul Knappís engines is supported on four rods of unequal length to tip the engine at an angle. The ends are turned round using a ball end attachment.

These two examples include parts made using a milling machine.

To see more of exhibits at the on-line version of the Craftsmanship Museum go to www.CraftsmanshipMuseum.com. If you get a chance, visit the museum in person at 3190 Lionshead Avenue, Carlsbad, CA 92010. It is open Monday, Tuesday, Friday and Saturday from 9 AM to 4 PM (Closed Holidays). Admission is free.

Other projects done on Sherline machine tools can be found on the Workshop Projects page at www.sherline.com/workshop.htm.


Shop Tip(s) of the Month

4-Jaw Chuck Support Plate/Allan Marconett

(This tip is a repeat from a very early newsletter (#7). Since the number of subscribers has increased so much in the past 4 years, we thought a lot of new readers might enjoy this simple tip.)

1) The notches in the support plate keep small parts from falling into the chuck during setup. It gives a smooth, parallel support for small parts held in the chuck. (Click on any image to view a larger version.)

Cut a plate out of aluminum to allow small parts to be machined while being held in the Sherline 4-jaw chuck.  The example pix shows a brass slide valve being machined, with packing all around. The plate gives a flat support, the slots allow the jaws to get in close to the stock being machined.  Holes can be drilled or machined through the plate, as it is expendable.

The plate is a simple 2" x 2" square of 1/8" thick aluminum plate (could be round!), and may be cut out with a bandsaw.  Size is unimportant, and thickness can be changed to fit needs.  0.350" slots are cut in from three sides to clear the width of a jaw.  I leave about a 5/8" square of material in the center.  Leave less if desired. A three-jaw version could also be made with slots 120∞ apart.

2) Parts are held flat and parallel to the chuck ready for machining.

3) Machining finished.

4) Finished parts removed from the chuck.

Allan also offers these two tips about holding parts in a vise as a bonus:

1. While clamping stock in a machinist's vice or chuck, lightly clamp at first, then tap the stock lightly with a rawhide mallet to insure it is seated.  Tighten clamping or jaws afterwards.

2. Always use small rectangular packing on the moveable jaw of the machinist's vice to allow stock to seat squarely against the fixed jaw. Also, use accurate spacer blocks (or packing) under the stock, rather than attempt to seat it on the bottom of the vice.

óAlan Marconett  KM6VV

See the above as Tip #42 on the Sherline TIPS page along with many others. If you have a useful tip from your Sherline shop that you would like published, please send photos and a written description to craig@sherline.com.


Did you know?

ï Why does Sherline use a 55.5∞ angle on the mill and lathe bed dovetail? Often people believe this was done to make it difficult to copy. While that was the resultófor us as well as for our customersóit was not the original intent. When Harold Clisby first drew up the plans for the Clisby lathe in the 1960ís, he consulted the most respected book in the trade, Machineryís Handbook. It the issue that was then current, the ideal dovetail angle was listed as 55∞, so that is what he included in his design. Sherline Pty. Ltd. in Australia acquired Haroldís design and introduced it as the Sherline lathe. When Sears wanted to import them to sell under the Craftsman label, Joe Martin became involved as an importer. Somewhere along the line between Haroldís drawing and the parts we received from Australia to sell to Sears, the angle had crept off a bit to 55.5∞. Since by then many existing machines were already out there in the marketplace, it was no longer possible to change the angle and still have current parts fit existing machines. When Joe began manufacturing the machines in the USA we had to stay with the existing angle too, and so it remains to this day. Had Harold chosen a more standard 60∞ angle where standard cutters were available, it would have saved us a lot of money over the years compared to buying custom 55.5∞ cutters. While customers may accuse Sherline of trying to make it difficult to make a single part for their machine, in reality the decision 40-some years ago has been regretted by us to a much greater degree. However, since most customers never have to be concerned with the angle other than as a matter of curiosity, it does still function as an outstanding design to this day.


Upcoming Model Engineering Shows

2013/2014Ö

ï Black Hills Model Engineering Show, Next show--September 21-22, 2013, Rapid City, SD. The show is held the 3rd weekend of September each year. See www.blackhillsmodelengineeringshow.net or contact Clif Roemmich at modelbuff@rushmore.com

ï GEARS (Gas Engine Antique Reproduction Show), Portland, OR area, late September. See www.oregongears.com. New management for 2013!

ï Estevan Model Engineering Show, Estevan, Saskatchewan, Canada, October (Next show: October 19-2-, 2013 the weekend following Canadian Thanksgiving). For updates and info see http://estevanmodelengineeringshow.com/

ï Mid-East Ohio Model Engineering Expo, October 19, 2013,Muskingum County Fairgrounds, Zanesville, Ohio. Sponsored by Debolt Machine, www.deboltmachine.com.

ï April 26-27, 2014óNorth American Model Engineering Society (NAMES) Expo, Wyandotte, MI. Sherline will have a booth there and the Joe Martin Foundation will present its annual award to Metalworking Craftsman of the Year during the show. See www.namesexposition.com for details.

(Send us your show information and we will post it here.)


Joe Martin Craftsmanship Foundation News

ï New Craftsman Added to Online MuseumóThe newest craftsman to be added to the on-line Craftsmanship Museum is jeweler Bryan ìFenceî Freund. By trade he drove a garbage truck, but he had a desire to make knives and then jewelry and learned how to do it on his own. His interest in and knowledge of motorcycles led him to develop a line of jewelry that appeals to Harley riders. He also has built some very tiny Harley engine replicas from silver. Now retired from driving a truck, he can concentrate on making some more interesting pieces from silver, gold and precious stones. Some of his work will soon be on display in the museum in Carlsbad.

ï Groups Visiting the Museumó

††††††††††† August 23rd: Southern California Convertible Club

††††††††††† August 31st: Studebaker Driverís Club

††††††††††† August 19th: The museum hosted the meeting for the Docent League, a group of docents from the various museums in the San Diego Area.

See the Club Visits page for a photo of the groups. You are welcome to visit our museum with your club or group. Call to arrange a group visit.

New ExhibitsóA large collection of hand carved wooden aircraft from vintage to modern made by Ralph Sarosi was donated by long-time R/C flyer Joe Bridi. He included several paintings also done by Ralph Sarosi, a career Air Force pilot whose career spanned from P-51ís to modern jets who ended up flying chase planes for space shuttle landings at Edwards Air Force Base. Joe also donated a number of commercially built model ships.

Volunteers SoughtóAnyone interested in volunteering your time at the museum to help us show visitors around or to help out in the machine shop, please contact craig@craftsmanshipmuseum.com or call 760-727-5857 and ask for Craig.