Frequently Asked Questions

What type of router/spindle do you recommend for the machine?

First, it all depends on your application. The questions to ask yourself are:

  • Are you planning on running the router 40 hours or more a week?
  • Are you planning to take as big of a cut as you can possibly get? Something like cutting a 3/4" plywood in one pass with a compression bit?
  • Are you going to be using the machine to generate a large portion of income? If so, will you be in a major bind if the machine goes down for a day or 2?

If the answer to any of those questions are yes, you need to think seriously about using a spindle. We recommend an spindle that is at least 2.2KW. It can be 80mm, 100mm or a square body type spindle. We also recommend using an air cooled spindle over a water cooled spindle. The air cooled setup is significantly simpler and there is less chance of something breaking down. If you need help sourcing one of these, we can help you.

If you don't want to spend the money on a spindle, at a minimum you want to run a larger 3HP router. We recommend the Porter Cable 7518 series router for this. The reason why we recommend these systems: we've had customers wear out a DeWalt router every 2 months on a production schedule like that. The general purpose routers were never designed for that type of workload and you will probably find yourself having to replace them at a rapid pace. If you do decide to use a router, we strongly recommend keeping a spare around just in case you need to replace it.

If you answered no to the above questions, we generally recommend at least a 2 HP router to use with the machine. In the shop, we use the Hitachi M12VC. The Porter Cable 690 is another one we recommend. In reality, any of your name brands (Bosch, DeWalt, Makita, Milwaukee, etc.) will work well. We do have mounts for all of these routers. Please check with us if you can't find what you need.

Why use Rack And Pinion Drives? What are the advantages of rack and pinion drive over leadscrew?

It really all depends on the application.

For axis lengths longer than 36", we recommend the Rack and Pinion system. There are several problems with the ACME drive at longer lengths:

  • At high speeds, a long ACME Drive screw (aka "leadscrew") is subject to a whipping effect and essentially turns into a jump rope as it spins. This forces you to run the axis at slower speeds than you normally would. The Rack and Pinion Drive doesn't have this problem because the gear rack is secured to the table at every 4" and is rigid regardless of the length.
  • The top end speed of a ACME Drive System is around 250IPM at short lengths, even less at longer lengths. The Rack and Pinion drive can easily move at 1500IPM+. When the machine is traversing a long distance, the Rack And Pinion Drive System can get to it's destination 6 times faster than a leadscrew.

For Axis lengths shorter than 24", we recommend the ACME Drive system:

  • Because of the short distance, the Rack and Pinion drive doesn't have time to accelerate to top speed and is about as fast as a leadscrew drive.
  • The leadscrew has a better step resolution than the Rack and Pinion.
  • The Rack and Pinion drive is very bulky, especially for short axis. For instance, on the Z-Axis of our machines, it's almost impossible to fit a rack and pinion drive into the space. Leadscrew drives fit right inline with our linear motion rails, are very compact, and don't get in the way of things.

For axis lengths between 24" and 36", either will do fine. We elected to go with the Rack And Pinion on the X-Axis to keep the velocity and acceleration profile the same as the Y-Axis.

What performance expectations can I reasonably expect?

Using a 1/2-10 5 start ACME Screw (what our Z-Axis uses):

  • The resolution of the leadscrew is 2 turns per inch.
  • A standard 1.8 degree per step stepper motor has 200 steps per turn.
  • Most controllers use microstepping to achieve a finer resolution. For instance, the G540 creates 10 microsteps per step on the stepper motor
  • The total resoltion: 2 turns per inch * 200 steps per turn * 10 microsteps per step = 4000 steps per inch or 0.00025" per step.

Using our rack and pinion drive:

  • The R&P system has a pinion with a 1" pitch circle. The total linear distance traveled per turn of the pinion is 3.14159".
  • The pinion is connected to a timing system with a 3:1 reduction.
  • A standard 1.8 degree per step stepper motor has 200 steps per turn.
  • Most controllers use microstepping to achieve a finer resolution. For instance, the G540 creates 10 microsteps per step on the stepper motor
  • The total resoltion: (200 steps per turn * 10 microsteps per step) / (3.14159" / 3 per turn ) = 1909.9861 steps per inch or 0.0005326" per step.

Now in practice, the backlash on the system is going to limit accuracy and repeatability. With our machines, out of the box you can reasonably expect and we guarantee accuracy and repeatability to be within 0.002-0.005" per linear foot. With a little tweaking, our users are reporting getting 0.001" accuracy on smaller feature parts.

What size motors are the best for my machine: Nema 23 or Nema 34 motors?

Ask yourself the following questions:

  • Are you going to be making money from the pieces created by the machine?
  • Are you going to be running the machine more than 30 hours a week?
  • Do you need to push the performance of the machine to the limits?
  • Are you Tim The Tool Man Taylor and want the most powerful tool you can get?

If you said yes to any of the above questions, you should seriously consider the Nema 34 motors. While both sizes of motors will work well with the machine, the larger Nema 34 motors will allow you to remove material at a much higher rate.

To be clear, the size of the motor is not a indicator in what material you can cut. Both the NEMA 23 and NEMA 34 sizes will cut hardwoods, manufactured woods like plywood, plastics, aluminum and other non-ferrous materials like fiberglass, bronze, and brass. The ability to cut those materials are impacted much more by the rigidity of the machine and having the proper bits with the right feed rates.

So, what's the advantage of the NEMA 34 size? The main advantage is the machine can make far more aggressive cuts. The job of the motor is to push the cutting bit through the material. Nema 34 motors can take deeper passes through material and improve cutting speeds, especially on larger machines. As an example, you can cut 3/4" baltic birch plywood in one pass with a 3/8" compression bit using NEMA 34's. With NEMA 23's, you would need to take it in 2 passes because the motors are not strong enough to push through all that material without straining and losing steps.

Our general recommendations are:

  • If you are using the machine for regular production work, you should be able to take a larger cut and save some machine time. This provides a fast return on investment. If you would like help calculating the ROI, please contact us and we'll walk through your specific situation.
  • If you are doing hobby work or small production runs, the NEMA 23 motors will likely be sufficient.