The Sherline Miniature Machinist's Newsletter

Number 27, March 15, 2010

http://www.sherline.com


Sherline Workshop Project of the Month

A simple CNC aluminum and copper clock base/David J. Morrow

Why the "220 Clock?" The copper inlay as made from heavy copper ground wire from a 220 volt electrical cable. David Morrow used his Sherline CNC mill to cut the parts, but a manual mill with a rotary table could also be used. Here he describes how he went about making it.

Doing the copper inlayóìI started by milling four 1/8" wide x .050" deep arcs at about a 2" radius. At the ends of the arcs, I drilled holes just large enough to insert the ground wire out of a piece of 220 volt house wiring that I had in the basement. The other end of the wire was then fished through the hole at the opposite end of each arc and pulled as tight as I could with a pair of pliers. Next comes the noisy part. With a ball peen hammer and a small anvil, I pounded the copper wire down into the arcs. At each end, I had to persuade the wire to stretch out a bit so there were no gaps. After making sufficient noise, I resurfaced the piece with a few quick, shallow passes and then spent a little time in the sink with some wet/dry emery paper. It doesn't have to be perfect as the engine turning will just scratch it all up again.î

The first photo shows the raw aluminum stock with four slots machined using a ball end mill, holes drilled at each end and thick copper wire pulled tight through the holes. Two have already been pounded flat with a ball peen hammer. The second photo shows the finish after a skim cut was taken and the surface lightly sanded.

Engine TurningóWorking from the outside ring to the center, David used a round piece of ScotchBriteÆ pad glued to a custom-made aluminum mandrel and some oil on the part surface to create the engine turned pattern of interlocking circles. The second photo shows the part being cut from the raw stock. The center hole is sized to receive the clock.

An oval base was made using a similar technique and a brass stand cut and fitted to a slot cut in the center of the base. Countersunk screws behind the clock attach the face to the upright. The final finish on the edges is done with wet/dry 320 grit sandpaper under running tap water and the parts are coated with clear lacquer to prevent fingerprints and tarnishing.

 

The final resultÖ

Hereís the finished display base with a clock installed. This is not Davidís fanciest project, but it was only his second project with CNC. The inlay and engine turning techniques could be applied to other projects you may have in mind, whether done with CNC or manual tools.

For a more complete description of this and other more complex CNC projects from Davidís web page see http://www.ldrider.ca/cnc/cnc-index.htm.


Shop Tip of the month

Making horizontal clamps for milling flat material/David Gibson

The drawing above gives you the dimensions you need. Make four or more for good grip.

At a model engineering show in Oregon a young man stopped by Sherline's booth with a neat little project he had made. He was kind enough to give us four of the clamps to display in our showroom and gave permission to share his project with you. It would make a simple little "rainy day" mill project, and you will end up with some very handy table clamps when you are done.

David often holds oddly shaped parts and sometimes needs to mill the entire top surface. These clamps are attached to the mill table and secured with modified Sherline T-nuts. The part is then set on the lower clamp surface and held in place from the sides with the horizontal screws. You will need at least three clamps and perhaps as many as four or five for some parts. The more the better. Shown below are the size clamps David made, but once you see how they work, you could adjust the size to suit your particular needs. In fact, since providing us with the prototype clamps from which we took the above dimensions, Mr. Gibson has sent in some revised drawings of his own with more common dimensions. He now makes the overall length of the clamp 1.50" and the width .50" in steel or .625" in hard aluminum. He specifies the angle of the tilted face and drilled hole to be 5∞. The dimension from the bottom of the part to the centerline of the drilled hole should be .562" at the back of the part. The angled face extends all the way to the bottom rather than only half way down as shown here.

This and more than 50 other helpful tips for Sherline machinists can be found at www.sherline.com/pages/tips.htm. CNC tips can be found at www.sherline.com/CNCproj.htm.


Product Spotlight

Sherline introduces automatic oiling feature for mill X and Y axes

An oil reservoir keeps the X and Y leadscrews supplied with oil.

With the increasing popularity of Computer Numeric Control (CNC) on Sherline mills, keeping the leadscrews lubricated has become even more important, as the machines often are subjected to long run times and fast feed rates compared to manual machines. In fact, manual machines also benefit from the constant application of a small amount of lubricant, allowing your machine to perform better and last longer with less maintenance.

Pricing and OrderingóTo offset additional machining and parts costs, the price of all Sherline CNC mills that include the new oiler will increase by $25.00. Until the supply of existing mill saddles is used up, manual mills will not include the oiler and will remain at the present price, although customers will have the option to specify saddles with the oiling system for the additional $25.00 cost. Once the supply of saddles with no oil passages is exhausted all CNC and manual mills will include the oiling system as standard equipment at the new price.

For questions regarding pricing, availability and ordering, contact Kim Kapple or Charla Papp at sherline@sherline.com or call (800) 541-0735 or (760) 727-5857.


Did you know?

ï Sherline tools are sold world-wide. We now have dealers in 20 countries besides the USA. Designed for the world market the DC spindle motor will operate on any AC current from 100 volts to 240 volts, and all machines are available in your choice of metric or inch calibrations.

ï The Sherline factory in Vista, CA has a product showroom with one of every product we make on display and available for inspection. We also have demonstration machines set up for you to try. Fred Smittle, an experienced tool maker and machinist mans the shop to answer your questions. If you are in the North San Diego County area, stop by and visit the factory and showroom. See the CONTACTS page on our web site for a map.

ï To take a photo factory tour right now, CLICK HERE.


Upcoming Shows

ï The North American Model Engineering Society (NAMES) will host its next major exposition in Southgate, MI the weekend of April 24,25, 2010. This is the 21st annual presentation of this prestigious show. See www.modelengineeringsoc.com for details. Sherline will be a vendor at this show. In 2011 the show will move to Novi, MI.


Joe Martin Craftsmanship Foundation News

ï Last month a number of pages that had been in progress for a while all came together and we introduced four new craftsmen in the on-line museum. Several more are now being worked on for introduction soon. You can always check the ìWhatís Newî page to see the latest additions.

ï In February we sent out an e-mail that featured miniature V8 and V12 engines. If you didnít receive it yet, hopefully it will make the rounds of the Internet like the Young Park Corsair e-mail and you will eventually have it forwarded to you by a friend. If you would like to get on the Foundation craftsmanís e-mail list, contact craig@craftsmanshipmuseum.com and ask to be added so you receive future updates.

ï The museum was open Saturday, February 15th for the Model A Club and February 27th for a group from San Pedro, CA. They drove down in a motorhome and spent 3 hours touring the museum and Sherline factory. They stressed they were not an official club, just a group of men and women who like to see interesting things. Members of the Southern California Timing Association visited on March 13th. See the museumís CLUB VISITS page to see who has visited in the past. The museum will open at no charge on any non-holiday Saturday by reservation for groups of 8 or more. Call (760) 727-9492 for information. (Ask for Craig.) The next scheduled visit is the North Coast Corvette Club on April 3rd.

ï The Foundation will present its annual $2000 award for Metalworking Craftsman of the year to Michel Lefaivre at the NAMES show in Southgate, MI on April 24th.