For a while now, I've been thinking about a CNC mill. Back in June 2006, I started exploring options for upgrading my Sherline 5400 mill with one of the retrofit kits that are on the market for these mills, but it looked like costs for hardware and software was going to run $3-6k and then projects would still be limited to the fairly small work envelope and modest cuts that are part and parcel of the Sherline mills.
A friend suggested looking into the Tormach mill and a look at their web site (www.tormach.com) indicated that they might have a pretty well designed bench top mill with much larger work envelope that was capable of some heavier cuts than the Sherline or even my Clausing 8520 manual mill. The Tormach has a work envelope of 18" x 9-1/2" x 16-1/4" (X/Y/Z) and uses an R-8 spindle with a VFD-controlled motor driven at spindle speeds of 300-1750 or 800-4500 rpm via a 2-step pulley. The cost (~ $7k for a basic mill) was quite a bit higher than a Sherline retrofit but the advantages were many and with a bit of budget squeezing it looked like it might be doable from a cost standpoint. A potential show stopper was that the mill would have to fit into the basement shop in our townhome. Garage tools turn rusty in days and the thought of machining in the garage at ambient conditions during Chicago winters or summers was not appealing. Another issue was the weight and size of the mill (1130 lbs and 80" wide x 44" deep x 86" high with the deluxe stand) as the only basement access is through the garage, a utility room and down a stairway through 29-1/2" doorways. Buying just the mill itself and fabricating a stand might have simplified things somewhat, but the stand includes flood coolant, a roomy chip tray, provision for a monitor/keyboard arm, internal storage and also has the benefit of being ready to assemble with no design or fabrication necessary.
A bit of study with the Tormach brochure (available on their web site) and playing around with the shop layout in Visio revealed that it just might fit in an alcove in the basement if some tools were rearranged, but the weight and moving logistics were still issues. A call to Tormach was encouraging as it sounded like the mill might be separated into small enough parts that the weight and size could be accommodated. Disassembly of the mill voids the certification for the alignments and accuracies but I got the impression that Tormach would stand behind the project so long as nothing stupid was done during disassembly or re-assembly.
Another concern was quality of the mill, since it is produced in China, although the circuit boards are built in the US. A visit to Tormach's offices was arranged to see one in person and discuss some of my concerns in more detail. The visit was very encouraging as Greg Jackson (Tormach) took a couple of hours out of his Saturday to demo the mill and answer all my questions. According to Greg, the mill is made to their design specs with what I suspect are custom castings and Tormach evaluated several factories before settling on one that was willing to meet their criteria. This was important to me as most of the other "hobby" (read as affordable) CNC mills on the market are retrofitted manual mills whereas the Tormach is designed from the ground up for CNC milling.
Greg was careful to explain that the mill is designed for prototype or short run operations and that certain design compromises were made to keep the cost low. Among these are the use of stepper motors and limiting the mill to 65 ipm maximum feed rates to save wear and tear that would result from faster rates. Professional CNC mills use servo motors which incorporate position feedback so that the system always knows where it is - steppers can lose steps if aggressive feeds are attempted and they also have much higher rapid speeds which are important for part throughput in production mills that are run 24/7. For me a "professional" CNC mill was out of the question, from cost, size, and weight standpoints and my needs don't include making dozens, much less hundreds or thousands of parts, so the compromises seemed acceptable to me. He also demonstrated their TTS tool holder system which makes it easy to preset and change milling tools without the need for a tool changer.
Some more time was spent mulling over cost and moving issues, but the decision to buy the Tormach mill was made in early August 2006 and an order was placed for a pretty well equipped mill, including the deluxe stand, monitor/keyboard arm, 8" RT 4th axis option, a full set of the TTS tool holders, the high speed spindle option, a spindle bracket to be used with a wood router, SprutCAM Expert 4.0 CAM software, and some miscellaneous cables. Delivery was estimated for late mid-September to early October and I planned for a week of vacation, in the vain hope that this would be enough time to uncrate the mill, assemble it temporarily in the garage to check the certification specs, tear it down, move it to the basement and re-assemble it. The story of how that progressed is presented on the pages below.
Anyone interested in buying a Tormach is encouraged to visit the Tormach web site and browse through all of the documents available there. The document on their design philosophy is instructive and unique in my experience and the complete manuals for the mill and accessories are also available. I've heard that they maintain a database of owner locations and will put prospective buyers in contact with owners in the area that may be willing to accommodate visitors.
Last edited: 12/17/2006