The Sherline Miniature Machinist's Newsletter

Number 31, July 15, 2010

http://www.sherline.com


Sherline Workshop Project of the Month

Making a brass radiator for your IC engine/Tom Boyer

A Ωî square brass bar is drilled down the center and finned using a parting tool. Eight of these are required.

The Joe Martin Foundation Craftsmanship Museum machine shop recently completed a V-4 engine designed by the late Jerry Howell. Jerryís plans included a clever way to make a brass radiator using bar stock and simple tools. It consists of eight relatively easy to make (if repetitive) brass core tubes, a top and bottom tank and some aluminum side supports.

The first photo shows the eight radiator core bars on top of the bottom tank with a register piece across the top. The second photo shows the top tank. A US Quarter gives size reference.

Here is the completed radiator before the filler cap tube was soldered on.

Once all the pieces are made and fitted, solder paste is applied to all the joints, and the radiator is clamped to a Ωî thick aluminum plate. A few small pieces of lead solder are attached at points on the outside for reference and the plate is heated with a propane torch. As soon as the small test pieces of solder melt it means the solder paste inside has also done its job, and the radiator is allowed to cool before it is removed from the heating plate. Now all that remains is to attach the side plates with small socket head screws and solder on the radiator filler tube. The radiator cap is held in place with an O-ring, as the water does not get as hot as a full-size engine and pressures are not very high.

Some engine builders will use an automotive heater core as a radiator, making a top and bottom tank to make it look more realistic, but this radiator has a more scale thickness and looks good with vintage engines. Thanks to Jerry Howell for the clever design. If anyone needs more details on building a radiator like this, contact Tom Boyer at tom@craftsmanshipmuseum.com.

See more projects made by Sherline machinists at www.sherline.com/workshop.htm.


Shop Tip of the month

Two ways to mount a DRO box to your mill/Michael Gipe and Ronald Melvin

Michael A. Gipe of Saratoga, California e-mailed the digital photo below along with the following tip:

ìThe digital readout option for the Sherline mill is a terrific addition. To make it even more convenient, I mounted the display on top of the motor control housing with a 2" x 4" piece of VelcroÆ. The Velcro strips are available from any hardware store, and they come in two halves that stick together. Separate the pieces and glue one to the bottom of the DRO display box. Glue the other piece to the top of the motor control housing. To mount the DRO, just press it in place on the motor housing at any convenient angle for viewing. The sensor wires can be bundled together with a tie-wrap and attached to the motor power cord to keep them out of the way.

Mounting the DRO display this way puts it right at eye level for easy viewing while you turn the cranks, and it keeps it out of the way of metal chips. It is also easy to remove if you need to change the pulley position.î

NOTE: Velcro is also available in rolls or strips with a peel-off adhesive backing. Just cut it to length, stick one half to the DRO and the other to the motor housing (or any desired location) and you're done.

This eye-level mounting system makes the display easy to read and keeps it out of the way of flying chips. Be sure to bundle the wires to keep them away from the pulley.

Another method by Robert Melvin: Ronald Melvin has one of the neatest small shops around. In fact, a photo of his shop was used in a Sherline television commercial that ran on the Discovery Channel. The recent addition of a DRO to his mill caused him to look for a mounting system that allowed the box to be repositioned to several heights and orientations depending on whether he was standing up to do milling operations or sitting down with his face near the part when using tiny drills. This elegant solution could make a fun rainy day project, and allows the box to be positioned with the loosening and tightening of just one 10-32 hex bolt. Ron used materials that he had on hand in his scrap box, and sizes are not particularly important. In this case the support rod is made from 3/8" drill rod 12" long and the base is from 1.25" dia. 303 stainless. It is held to the baseboard with 8-32 screws going into T-nuts with points pushed into the bottom of the board. (Ron also mounts his machines to the board using these T-nuts, as it makes removal for cleanup quick and easy.)

Ron goes on to say, ìThe flat stock portion of the bracket for the DRO is 1" aluminum, with a corresponding 1" tapped aluminum flat stock piece fixed with mounting tape to the inside of the DRO case. This allows for easy removal of the bracket. The round portion is 1.5" aluminum, about 0.5" thick with a 0.1" nipple to stand off the adjustable link. The adjustable link is 303 stainless steel with a 0.050 slit. Obviously, materials used can vary, although I would recommend aluminum for the bracket itself just to keep down the hanging weight. I used the 303 because I happen to like it (even though I seem to have some allergic skin reaction to the nickel content) and I had the right sizes in my scrap bin. Actual dimensions are not critical in most cases and construction is obvious from the photos. The socket screws are 10-32, which is the same as most other adjusting screws on Sherline machines, so the same hex key will be readily available when adjusting the position of the DRO. The flathead screws are 8-32.î

Photo 1: An overall view of the mill shows the neat use of spiral plastic wire bundling material to control the clutter of wires from the box to the individual axes and the RPM sensor.

Photo 2: Side view of the adjustment mechanism shows the flat stock pieces. The mounting plate for the two attachment screws is fixed inside the box using double-sided tape to keep it in place and it is tapped to accept the mounting screws. The rectangular part is slit, allowing the single adjustment screw to control both rotation of the box and position of the bracket on the rod.

Photo 3: A close-up of the base shows the stainless steel mount that is attached to the board. Spiked T-nuts are mounted to the bottom of the board to accept the 8-32 countersunk screws.

Another view of the mounting mechanism. The mount has a slit in the piece that slides on the shaft. The vertical shaft is 12" long because Ron has a 15" tall Z-axis on his mill in place of the standard 11" column. For normal height mills the rod could be shorter than 12".

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


New Product Spotlight

A CNC Cam Grinder designed by Joe Martin and Pam Weiss

When building a working model engine, one of the more difficult components to make is the camshaft. There are ways to make a mechanical grinder to do the job and ways to make built-up cams, but this is one job where computer control really makes sense. A specially developed Sherline software program allows you to input simple measurements taken from your cam drawing and output the g-code needed to run the CNC stepper motors that control the rotation of the cam and the shape of the lobe.

The Sherline cam grinder was designed with the home shop machinist in mind. It incorporates many standard Sherline lathe and mill parts and features the solid, well-engineered construction you have come to expect from Sherline machine tools. If you are making a few cams for your own use, making cams for others for sale or a club looking to invest in a machine for use of all the members, this new machine is the first CNC cam grinder made for the model engine builder.

A close-up shows a cam blank for a º scale Offenhauser 270 about to be ground.

Features:

ï Powerful 1/2 HP grinder motor drives a 6î grinding wheel

ï 3 DC stepper motors with manual handwheels

ï Flexible way covers on Y-axis keep water and grinding debris off Y-axis leadscrew

ï Holds cam blanks up to 9î long (Long enough for a Challenger V8)

ï Black anodized finish on aluminum parts

ï Standard 1-year Sherline warranty

ï Built-in diamond wheel dresser

ï Laser engraved degree collar on spindle headstock

ï Coolant lines factory installed

ï Available with or without computer and drivers (for those who already have a Sherline CNC mill or lathe)

The new cam grinder is available complete with Sherlineís CNC computer, built-in 4-axis driver box, cables and software for $4500.00. If you already have a Sherline CNC system, you can purchase just the cam grinder and stepper motors for $3500.00.


Did you know?

ï Sherline was a vendor at the recent Western Engine Model Exhibition (WEME) in Vallejo, CA. A strong representation by both the Bay Area Engine Modelers (BAEM) club and the Southern California Home Shop Machinists (SCHSM) meant many fine-running engines on display. Also featured was the actual ìWorldís Fastest Indianî motorcycle built by New Zealander Burt Monro that set many land speed records in its class at Bonneville and was featured in the movie of the same name that starred Anthony Hopkins as Burt.

At Sherlineís booth Pam Weiss demonstrated the new cam grinder for the first time. The booth included a display for the Joe Martin Foundation as well. The second photo shows some of the crowd on the steam engine side at the WEME show on Saturday.

The ìWorldís Fastest Indianî motorcycle on display. In the background you can see technical artist/craftsman Michael Cooperís fanciful go-kart called ìmodified.î A set of castings for a small V8 was on display in the IC engine portion of the show along with some of the casting patterns. Ken Hurst is seen with some of his fine-running engines.

One of the exhibits was this tongue-in-cheek ìEPA approved corncob pipe.î


Upcoming Model Engineering Shows

ï Black Hills Model Engineering Show, Rapid City, SDóSeptember 18-19, 2010. See www.blackhillsmodelengineeringshow.net

ï Estevan Model Engineering ShowóOctober 16-17, 2010, Estevan, Saskatchewan, Canada. See http://www.estevanmodelengineeringshow.com/.


Joe Martin Craftsmanship Foundation News

ï Yesterday, July 14th, the museum had a visit from local TV host Larry Himmel. He and his interviewed museum director Craig Libuse and shop craftsman Tom Boyer, and the video footage appeared in a short segment on the CBS news on San Diego channel 8 that night. CLICK HERE to view the video or CLICK HERE to read the text version of the story. The video is also now posted on YouTube.com. We appreciate the coverage and hope it will make many more people in the area aware of our fine exhibits.

ï Two more wood projects made by Perry Henderson were donated by his son Phillip. Perry worked for a large construction company in Houston, TX and made models of construction equipmentósome of the quite large. In addition to his LeTourneau front end loader, we now have added a cement truck and vintage 1885 Daimler Benz motorcycle.

ï We returned from the WEME show with some fine additions to the museum. One exhibit that was loaned to us for the next 1-2 years is a 1/8 scale Bugatti Type 35 made by Fine Art Models. We also added quite a few books and magazines to our library. Gary Barns was kind enough to donate 10 books he has written documenting the complete history of tether car and tether boat racing from the 1930ís on. In addition, Mike and Toni Rehmus of Model Engine Builder Magazine passed on a huge collection of model engineering magazines from the late Richard Remington. In addition to filling in many holes in our collection of Live Steam, Home Shop Machinist, Model Engineer and other magazines, we also now have an almost complete collection of Modeltec magazines. Some duplicate issues of Strictly IC, Model Engineer and other magazines may be offered for sale to help raise money for the foundation.