25 x 37 Dual Leadscrew Machine
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A
simple solid table |
 This machine was designed to have a larger
cutting area while remaining simple and inexpensive. It has proved to be popular because of its straightforward design and low cost. Full scale paper templates for a number of components are now included with the plans. These simplify construction. The table is built from framing lumber rather than sheet stock. This eases construction while giving a solid product. It lessens the need for a table saw, and is stiffer than the same size of MDF. This machine was designed to not need a base, and to be able to cut a 2 foot x 3 foot piece of stock with the base attached. Experience has shown that this 25 x 37 dimension approaches the largest practical size for a table that uses cheap leadscrews which are carried by skate bearings.  The
pipe and channel rail systems use inexpensive home-center components;
the picture on the left shows how sturdy they are.The bearing system prevents uplift while remaining cheap and simple. This durability is required to push a trim router to its potential. Unsupported rails will permit chatter, and require shallow cuts. The leadscrews are placed outside of the rails to improve the cutting-area to footprint ratio, and to help reduce dust accumulation. |
| The
belt tensioning system is simple, and forgiving
of misalignment. The inexpensive leadscrews do not permit high speeds. Better quality Acme rod can increase the speed of the machine. Acme is not addressed in the plans because the machine was designed to be as inexpensive as possible. However, more information about the product is given on the Acme Page and upgrades are straightforward. The machines
were all designed to use the stepper and drive systems from Xylotex and
HobbyCNC. The recommended software is Mach3 or TurboCNC.
These suppliers work with the Do It Yourself market, and supply documentation and help forums for their products. The prototype of this table uses the Xylotex 269 oz.in. package which gives good cutting forces with 30+ ipm rapids. The Xylotex 425 oz.in. steppers deliver higher cutting forces but slower rapids with the cheap threaded rods. Dampers and/or Acme leadscrews with lower thread counts greatly improve the 425 oz.in. steppers' performance. The HobbyCNC 200 oz.in. system also works with this table, but the rapids on the X axis are slightly slower; the difference in power between the 269 and 200 oz.in. systems is noticeable. HobbyCNC now sells a 305 oz.in. system; it performs similarly to the Xylotex 269 oz.in. system. Using Geckodrives with a larger power supply increases the performance of the smaller steppers on all of the tables. Templates for this machine include:
The plans for this machine are included in the 5 Plan set. |