The Sherline Miniature Machinist's Newsletter
Number 29,
Sherline Workshop Project of
the Month
A nested cube
machinists puzzle made using CNC/Tom Hubin
NOTE: This project can also be made using careful drilling and boring
operations without using CNC. Machinists made these fun puzzles for years
before CNC was available.
1. 
2.
3. 
4.
The photos above show various stages of the machining of the puzzle. It is simply a number of accurate boring jobs in a row.
This is a project done on my Sherline 5410 mill using TurboCnc 3.1a.
Directions for using g-code file
3cubes.cnc to machine 3 nested cubes. (File:
3cubes.txt copyright Tom Hubin,
1. Start with a 2-inch cube of 6061 aluminum. This can be a 2 inch length cut from 2 inch square bar stock.
2. Mill or fly cut the outermost 1.950" cube from the 2 inch stock. Be sure to machine something from all six sides so that the finish is attractive.
3. Label the six sides as top, bottom, right, left, front, rear.
4. Drill 3/8" diameter center holes into top, front, and right surfaces to a depth of 1.5". These three holes will pass completely through the innermost cube. I used the 3/8" end mill holder with a machine screw length 3/8" diameter drill bit.
5. Drill 3/8" diameter center holes into bottom, rear, and left surfaces to a depth of 0.75". These three holes will not touch the inside of innermost cube. That way the 3/8" diameter center holes through the innermost cube will be seamless.
6. Secure the 1.950" cube in a vise and use an edge finder to accurately locate the rightmost surface and the rearmost surface so that the center of the topmost surface is at (X,Y)=(0,0).
7. Load a 3/8" diameter x 5/8" LOC aluminum roughing end mill. Move it over the topmost surface. Lower the bit until it just touches the topmost surface. I usually do this by loosening the bit so that it drops down and touches the topmost surface. Then tighten the bit just enough so that it won't fall out.
8. Run the program. You will be prompted to touch the surface with the end mill. You have already done this so continue.
9 The bit will be raised and you will be prompted to tighten the bit and start the spindle at 2800 RPM, which is max spindle speed on a Sherline mill. Tighten the bit securely then start the spindle.
10. Stay near the machine, lubricating and clearing chips as machining takes place.
Here are the CNC files in various formats. Right click on a file to save it to your computer or open it with the appropriate program.
3CUBES.CPP (3cubes.cpp is a plain text Borland c program to generate the gcode file.)
3CUBES.CNC (3cubes.cnc is plain text gcode for TurboCnc 4.01.)
(NOTE: If you cannot open these files, try downloading the ZIP file that contains all the original files. To do so, CLICK HERE.)
The remaining 3cubes.* files are
binary files generated by the Borland C++ compiler but are not needed.
*.txt, *.cnc, and *.cpp are plain text files and can be read and modified with
just about any DOS, Linux, or Windows text editor. DOS Edit command can be
used. I use the shareware DOS text editor PcWrite. Microsoft Notepad, WordPad
and Word are Windows text editors that can be used.
Here are some websites to help visualize the nested cubes:
http://www.dakeng.com/gallery.html—Dan Statman's dime sized nested cubes. Small and very very classy.
http://www.grapevineglassworks.com/landscapes/cube.html—Artwork showing nested cubes with no hole through the center.
http://www.geocities.com/barxe/cubering.swf—Animation showing something similar but here just for fun.
http://www.token.crwoodturner.com/magiccube/—Shows inner cubes detached so as to tumble freely within outer cubes.
—Tom Hubin
thubin@earthlink.net
See this and other CNC projects
at http://www.sherline.com/CNCproj.htm.
Shop
Tip of the month
Adding an
electronic RPM readout to your lathe or mill/Normand Ouellette
By adding a Sherline DRO to your lathe or
mill you get a readout of RPM in addition to the X, Y and Z position readouts.
However, they cost $325 and $395 respectively. If you want just the RPM
readout, here is a way to get it for less money. You also get the bonus of a
readout of engine run time and a reminder of lubrication intervals. Normand
Ouellette shows you how.
The readout unit is glued to the top of the headstock on the lathe. The
second photo shows the sensor glued in place using epoxy. The last photo shows
the readout box glued across the headstock
so it reads properly on a mill.
“I just
finished installing anRPM/Hour meter on my new lathe and mill. I ordered the
“SenDEC” RPM/ Hour meter. This will allow you to keep track of the oil interval
on the lathe or mill and set the closest RPM needed. I ordered from SenDEC the
unit that sells for about $70*, took it out of the wrap and glued it to the
headstock with epoxy. Here’s how:
1. Glue the meter on top of the headstock with a dab
of epoxy as seen in the first photo
2. Glue the magnet on the shaft with a drop of epoxy
as seen on second photo
3. Glue the probe on the headstock out of the way with
some epoxy as seen in the second photo
That’s it.
Installation took about 10 minutes.
The part
number is Part#: SFT806-0222 hr and rpm meter. Here is the link: http://www.sendec-products.com/index.php?option=com_content&view=article&id=110&Itemid=136
It
keeps track of RPM from 10 to 6000, total hours count of the unit is up to 10,000
hrs (then it needs replacement) and it in reminds you of a service interval
every 4 hours of operation for lubrication.”
—Normand Ouellette,
*NOTE:
Current price of the gauge on their web site is $89.95. It may be available
from other sources if you do a search.
This and more than 50 other helpful tips for Sherline machinists can be found at www.sherline.com/tips.htm.
Product
Spotlight
Adjustable Tailstock Tool Holders
One of the advantages of
the Sherline lathe is the ability to swing the headstock so that tapers can be
cut without the use of a compound slide. The down side of this adjustability is
that the lathe has moving parts instead of being machined in one piece or
pinned for perfect alignment between headstock and tailstock. The normal
alignment can be adjusted to within a few thousandths of an inch, which is all
that is normally needed for most jobs; however, some jobs, particularly in
watch making or when using tiny drills require near dead-on alignment. For
those jobs, adjustable tool holders are available.
How they work
The #0 Morse taper of the
back plate of each of these tools goes into the tailstock spindle. The front
plate of each is held to the rear plate with two screws that go through
slightly oversize holes. This allows some adjustment between the front and rear
plates so that the tool held in the front plate can be adjusted until it is in
perfect alignment with the drive spindle in the headstock. The various front
plates hold a live center, a drill chuck, a threading die or various tools you
can make yourself for special jobs. This is a good way to take full advantage
of the versatility of your Sherline lathe without sacrificing absolutely
perfect headstock-to-tailstock alignment when it is needed.
To read the instructions on
how these tools are used CLICK
HERE.
P/N 1201—Adjustable Tailstock Live Center
($65.00)
P/N 1202—Adjustable 1/4" or 3/8"
Tailstock Chuck Arbor ($45.00) Thread on either a 1/4" or 3/8"
Jacobs or Rohm drill chuck for perfect centering.
P/N 1203—Adjustable Tailstock Tool Holder
($45.00) Use a split collar you turn yourself to hold a variety of sizes of
boring or other round shank tools of your choice. This holder is also designed
to hold the P/N 2085 WW collet
adapter or the P/N 2086 8mm collet adapter, allowing tools to be held in WW
collets in the tailstock.
P/N 1204—Adjustable Tailstock 5/32" Chuck
Arbor ($45.00) Instead of a thread, the front plate has a male #0 Jacobs
taper to press on a 5/32" Jacobs chuck with the ability to hold very small
drill bits.
P/N 1206—Adjustable Tailstock 1" Die
Holder ($60.00) A ring is included so it can be used to hold 7/8"
diameter threading dies as well.
Did you know?
• Sherline attended the North American Model Engineering Society (NAMES) Expo in late April. See a few highlight photos from the show at http://www.sherline.com/names10.htm.
•
Sherline’s Home page has recently been redesigned to make navigation a little
easier. The navigation bar at the top has white type on black for easier
readability and there is a prominent link to our new Facebook page. Other items
have been condensed or re-located so you get to the important part—the main
menu—much quicker.
• Find links to instructions for all of Sherline’s accessories at http://www.sherline.com/accessor.htm. This is a tremendous resource for the new machinist who hasn’t yet purchased these accessories but wants to know how they are used.
Upcoming Shows
•
The next show Sherline will be attending is the Western Engine Model Exhibition in
Joe Martin Craftsmanship Foundation News
The Joe Martin Foundation recently closed
escrow on a new $1.7 million, 16,500+ square foot building that will soon be
the new home of the offices, machine shop and museum. Only ½ mile west of our
present facility, it is actually located in the city of
•
Two new craftsmen have been added to the on-line museum. Roberto Heijmans of
the
• Last week the museum was visited by over 30 members of the Temecula area Early Ford V8 club. CLICK HERE to see the “Club and Group Visits” page for some photos.
•
Michel Lefaivre barely
beat the volcanic ash cloud out of
•
Two significant items were added to the museum last week. Les Cade donated a ¼
scale Rider-Ericson Sterling pump engine and Dandelyn O’Connor donated a model
of a