By popular demand, we are including some photos of projects that are really too big to be made on Sherline tools. If a potential customer were to ask if this operation could be done, we would say "No, you need a bigger machine." But modelers are among the most resourceful craftsmen in the world, and many find it a challenge to make things that everyone else said couldn't be done. The people setting up these operations are experts with their tools and know how to get more out of them than was ever intended and still get good results. This page is in no way intended as a recommendation for setups like this, but if you use small tools and occasionally run into a part that is a bit too large but needs to be done anyway, perhaps some of these setups will give you some ideas of how to accomplish the impossible.
For those who would like to see a good movie that represents the attitude involved here, I recommend going to the video store and renting Flight of the Phoenix, starring James Stewart, Richard Attenborough and Peter Finch. If ever a movie represents what can be done by a good modeler, that one is the best. It is about a cargo plane that crash lands in the Sahara desert. The only way out is to rebuild the wreck into a smaller plane that can fly them out using the one remaining good engine and the parts and tools at hand. The "engineer" who directs the process turns out to have only built model airplanes before, but his modifications work. To him this is no different than a model airplane project using full-size parts. Even if you've already seen it, it's worth watching again for inspiration.
Charlie Lear recently ran a little experiment to see how large a part he could turn using a mill instead of a lathe. Check out his very comprehensive web page at http://steammachine.com/millturn for the results.
1. An oak model display case by Jerry Kieffer
2. Machining large steam engine castings by Pam Weiss
3. Cutting 7" and 14" diameter gears on a Sherline mill by Mark Jones
4. A portable metal door jamb router from a Sherline mill by Gregg Roos
To display his tiny steam engine models at shows, Jerry wanted to protect them from curious hands while still making them easy to see. He designed an oak case with an angled glass front and glass top. He decided to add to the challenge by making it on the same tools he used to make the models displayed within. Despite the availability of larger woodworking tools, Jerry took on this project just for the fun and challenge of it. Obviously it took a lot longer to do this way, but when you are doing a project for pleasure and not for profit, sometimes taking the long way around can add to the satisfaction. There is a picture of Jerry with the finished display case on page 325 of Joe Martin's book Tabletop Machining. If I can find the original picture, I will scan it and add it to this page later.
Cutting a 12" wide by 3/8" thick solid oak plank with a slitting saw
Machining the angles on the corner of the framework
Sanding the top of the display case panel
Polishing the edge of the display case front glass panel
NOTE: More about making wooden finger-jointed display boxes on small machine tools is covered in the special "Common Threads" edition of Home Shop Machinist published in November, 2001.
Pam is a Sherline employee who maintains our large factory equipment. She is also an excellent race car mechanic and machinist on all size tools. At home, she uses Sherline tools to work on her model trains and to build gas and steam engines, guns and clocks. She is currently building a running scale model of a Porsche flat six racing engine, some photos of which are included in Joe Martin's book, Tabletop Machining. The castings shown below are from a steam engine casting kit that is far too large to be made on Sherline tools, but Pam wanted to see if she could do it.
Finishing the outer edge and back edge of a large wheel. The headstock is lifted using a riser block to get an additional 1.25" clearance. By turning the headstock at a 45° angle and using the compound slide at a 45° angle with a cutting tool also angled at 45°, Pam was able to finish the outside and back faces.
The gear teeth are being cut into the wheel using an involute gear cutter on a long arbor. The wheel just clears the table using the standard vertical rotary table setup. A chuck mounted to the rotary table holds an arbor that secures the wheel by its center hole. The small closeup shows the nice tooth form.
This casting is huge for a machine of this size, but an oversize tooling plate was designed to hold it. Several step block clamps are used to hold the casting down while an inserted tip carbide fly cutter is used to flatten a surface.
Mark Jones has enclosed photos of the setup he used to cut large aluminum gears for the azimuth of a amateur-made 10' binocular telescope. Normally, the 4" rotary table in the vertical position can handle a gear blank that is slightly larger than the 4" table, but that's about it. Even so, that's a pretty big gear for a machine this size. Mark, however, needed to cut some REALLY BIG gears, so he figured out a way to do it with the equipment he had on hand...a Sherline CNC mill.
Here is a photo that pushes even this extreme setup to its limits--a 14" diameter aluminum gear being cut in the same manner. (Click on any of the above photos to open a larger version of the image.)
The clamping fixture under construction and in place on the job site. (Click on any photo to view a larger image.)
Gregg had a requirement to route out the holes for deadbolts on a number of metal door jambs that had already been installed in a building. He could not take the frames to his milling machine, so he brought his milling machine to the job site. He made a special fixture that allows him to mount his 5400 mill to the jamb or the door itself and machine out the holes on-site. He even used his own toolbox for a counterweight to keep the head from sagging when mounted vertically. Here are some photos of the project and what Gregg had to say about how he did it.
The head needed to be offset, so Gregg used a block of aluminum to relocate the headstock spacer block to mount the headstock. Note the eye bolt to attach the rope for the counterweight.
"I had to
machine a strike on an installed full size clear anodized aluminum door jamb in
place. After the door was installed and tiled into place the client added a
deadbolt. Essentially the work piece was 7' tall and 7" wide. The solution was
to make two fixtures: a large offset mounting block that rotated the milling
head 90 degrees in 2 axes, and a clamping fixture that mounted the mill to the
door jamb. I designed the clamping fixture so that it could adapt to both doors
and jambs, since I have had similar tasks in the past on large metal work
pieces. Even a full-size milling machine can’t cut a mortise in the edge of a 3'
wide metal door, much less be taken to a building site in the passenger seat of
my truck. All the work to make the fixtures was performed on my 5400 mill using
the fly cutter and boring head attachments.
Because the mill is used on its side there was far more weight on the X-axis leadscrew, plus a twisting action. It was simple to add a counter-balance on the center of gravity—just a pair of pulleys and one of my tool boxes (the rope and eye-bolt in the photo). It offers very smooth and effortless vertical travel.
The finished mill in place machining out the strike hole for the deadbolt. In the first photo, the rope attached to the eye bolt leads up over a pulley and is attached to Gregg's tool box, which is used as a counterweight.
My current
project will have 60+ metal clad doors and jambs. Changes? Bring it on!
—Gregg Roos
San Francisco CA
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