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| Legacy of a Legacy The makers of the Legacy have made changes to the product line since I bought my system but fundamentally the product has remained the same. Manual or expensive electric cranking of a lead screw controls both the router X-axis movement and Drive Center rotation via a series of gears. Manual operations also control the Y and Z axis. After having used my system for a short while I decided that to get the most benefit from the machine it would need to be improved specifically in the area of ease-of-use. Don't get me wrong, the machine isn't "hard" to use, it's more like "inconvenient". Making fluted columns and such is the forte of the machine but this is rather tedious work. In fact, I characterize everything but the most simple X-Y work as Very tedious to Extremely tedious and error prone; at it's best, the operations are just plain tedious and inconvenient. |
| A Paper Legacy With this in mind I set about looking for a way to relieve this tedium as well as greatly reduce the common errors made by the system and operator. I eventually came up with a paper design for a machine that would be driven by two electric motors that would entirely replace the existing gear train. I named this the Legacy Electric Drive (LED for short). The resulting design was still mostly manually controlled with electronics taking care of X axis and lathe drive movement, synchronization, indexing, and other important tasks. Because I didn't want to be tethered to a PC, my design was to use a stand-alone micro-controller directed by the operator. Even only controlling 2 of the four axis, the design promised to offer a ten-fold increase in the usefulness and capability over any Legacy model. For all intents and purposes it would make the stock Legacy look barbaric by comparison even though it would still be classified as a manually operated machine.. |
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| Well, I never got around to creating
this control system and my Mill fell into some disuse mainly because of the original
problem; it's quite a bother to set the thing up and create even simple parts with it.
Most of the operating time is pretty boring and although the motor drive system
I made relieved some of the tedium, it basically only changed the level of it from
unacceptable to undesirable; not enough of an improvement to make the system fun to use. Time passed but I never forgot about the increase in capability and ease of use improvements the LED offered. Although the manufacturer never improved their basic system design to anything remotely close to the LED, events in the industry have moved forward significantly. Basic CNC technologies have made rapid advances in software, hardware availability, and component cost |
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| Another Tool
Path A complete OEM turn-key CNC system is still quite expensive, much more so than typical Legacy Mills and the basic ones do not operate on a fourth axis which is what is needed to do lathe or ornamental work in the round. In order to get the forth axis going requires either additional expensive add-ons or a completely different CNC setup, basically a CNC lathe which are even more ridiculously expensive for some reason. A small flat bed commercial CNC router capable of using a mid-size router is currently pricing out at about $6000 - $8000 (circa 2008) with the forth axis adding cost to that and this is really the rock bottom of turn key systems. The term "turn key" is somewhat of a misnomer as well since nearly all mid size and up systems require significant owner assembly and setup. Obviously, for the majority of us, these options are prohibitively expensive. |
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| There is another option however. Enterprising and motivated individuals have trail-blazed paths to do-it-yourself CNC machines. A huge amount of information can be found on the web regarding home-made CNC lathes (round turning types), vertical mills (metal working types), and routers (flat beds). Many of these machines can be built from commonly available materials, welded steel, aluminum plate / extrusions, and even plywood. Plans for machines exist for free or modest fees as well as volumes of information on the electrical and software aspects needed to bring these designs to life. While I won't pretend that building your own CNC router would be easy, there is so much information available there isn't any need to engineer one from scratch. |  |
| A CNC non-ornamental lathe has already been done numerous times, mostly on a metal lathe platform and these are rarely outfitted with routers but there isn't any reason they couldn't be. If all that was desired was non-spiral spindles and the like, the technology is all ready to go right now. Ornamental turning is much more complex however. There are several individuals who have made what amounts to CNC Rose Engines, that is one way. The other is basically the same as what ShopBot and other flat bed router OEM's do, that is to mount a motorized chuck to the bed. | |
| Legacy CNC Recently (2008) Phantom Engineering has started to dabble into the world of CNC. Aside from the obvious replacement of the gear trains, they have installed drive motors on three of the axis which entails replacement or upgrading the stock z axis so it can be moved with a screw. The current CNC solution as of this writing consist of three kits one marries to an existing Legacy mill platform. It appears that the systems are running off of the common Mach 3 control software with a small Excel utility to short-cut to common spiraling operations. |
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| What is interesting to anyone
familiar at all with CNC is that the linear drive and rail systems are basically the same
as the manually operated machines. While an ACME screw is not uncommon as a CNC
drive control, it is for the length used. Most commonly, belt and racks are used at
this length because there is a concern with something called "whip" developing
in a screw of that length. Also and more importantly, the rails are not any kind of ball bearing sort of slide like every other CNC system I have ever seen; it looks like the standard plastic glides running on extruded aluminum t-slots. On my manually operated machine I have not found this to be a particularly precise system, I'm very curious as to how they are able to achieve good CNC accuracy with this type of rail system. While Phantom Engineering makes a lot of claims as to the affordability of their CNC kits, that might be open to interpretation. A typical 1200 model mill runs about $3100. The basic components to turn this machine into a CNC machine total up to $5100. That adds up to about $8200; kind of a lot for something that doesn't even run on ball bearings and you have to do 90% of the assembly on. This price also doesn't include shipping, a router, or a PC to run the system so total system cost is likely to be over $9000 for even the basic kit. |
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| Crystal Ball If I look into my crystal ball (which is no better than yours fwiw), I foresee (at some point) some main-stream manufacturer coming up with a Router Lathe that would look very much like a traditional lathe but utilize a router instead of a standard tool rest. The base machine would be capable of all of the same rounding work the Legacy can do now but probably be very limited in flat work. Additional accessories would expand the capability of the machine such that it would be able to perform some rose engine work too. |
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My belief is that there are two obstacles for a commercial Router Lathe. The first is vision by the manufacturers themselves; I don't think they perceive a market for such a tool therefore it probably looks like a risky endeavor to them. In my opinion, such a tool would be eagerly sought after judging from the response received by the CarveWright machine. The second obstacle I see is software. To be appealing to main-stream woodworkers, the tool must be bundled with easy to use design software. What I would like to see is an electric incarnation of the Holtzapffel lathe or even a decent electronically controlled rose engine. |
| My Direction The cost of even the cheapest large format commercial systems are just way out of my league therefore they are basically not an option. It appears that even on these commercial systems there is a lot of owner assembly / adjustment / experimentation involved as well. If there is a lot of owner work involved anyway, I'm thinking, why not build the whole thing! I've researched the free and fee CNC router plans currently available and believe that a reasonably sized basic XYZ router table can be constructed and brought to life for somewhere between $2000 - $4000. Adding a 4th axis would not be very expensive. As of this writing, the design known as "Joe's 4x4" is about the best fit for me. |
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