25 x 37 Dual Leadscrew Machine
| The plans for this machine are in the 5 Plans Manual. |
 This machine was designed to answer the requests for a larger low cost machine that was similar to the original 17 x 20 table. It has proved to be popular because of its straightforward design and low cost. Full scale paper templates for a number of components are 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. The newer 25 x 25
machine
is an updated version of this 25 x 37 table. The 25 x 25 is
designed to be simpler, use fewer parts and tools, and to more easily
allow upgrades to
Acme leadscrews. Acme leadscrews permit better speeds.
This 25 x 37 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 home-center components;
the picture on the left shows that they are sturdy.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 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. These plans do not include directions
for the software and electronics.
This information is covered by the
recommended software and stepper suppliers.
These plans do address the Step per Unit values needed to configure the software. 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. HobbyCNC's 305 oz.in. system performs similarly to the Xylotex 269 oz.in. system with this machine. Templates for this machine include:
The plans for this machine are included in the 5 Plan set. |