CNC Router

The adventure begins by building infrastructure for the machine. A solid, flat table was built, a dedicated computer was found and an old computer case was scavenged to house the isolation board and motor drives for the machine. A new 120 volt outlet was installed and a network wire was routed to the area. The first couple of pictures show the infrastructure progress and subsequent photos will detail the actual machine build. I expect this blog will be lengthy because I will take several build photos so others can see whats involved if they decide to build a CNC from a kit. In case you’re wondering, I’m building a Pilot Pro 2626 DIY kit from PDJ Inc. My options included a control pendant, limit and home switches and an isolation board. Software includes VCarve Pro and Cut 3D from Vectric, and Mach3 from ArtSoft.

Building the stand

A neighbor had a pair of steel workbench legs which he graciously gave to me. Two hours of wire brushing and then a little welding and painting made them look like new. Some angle iron was cut to support the top and wheels were added for mobility. Next up, a cabinet needs to be built below to house the control modules.

Completed Bench

A week later, the bench is ready to accept the Pilot Pro CNC. The box has built in ventilation using filtered air from front to back. Inside will house the computer and control circuitry that will drive the machine. The computer screen shows the Mach3 post processor dialog.

Motor Drive Cabinet

I managed to piece together a complete motor drive enclosure from 2 old desktop PCs. Lots of fans will provide rapid air movement to keep things nice and cool.

Measuring Runout

I purchased a set of precision collets for my Porter Cable 690 router not only for the precision, but also for accommodating bit shank diameters from 1/8″ through 1/2″. My TIR (total indicated runout) at 1″ was less than 0.001″ which is pretty good for woodworking.

Control Box Components

PDJ sent the components for the control box in advance of the machine components so I could get a head start with wiring. Here we see the power supply, motor drivers, the control pendant, limit switches, UC100 USB adapter and the ISO3 Mach3 board.

Fitting Components in Enclosure

I cut a piece of masonite to fit inside an old computer carcase for mounting the control components. The parts were placed to accommodate wiring and air flow.

Control Box Nearly Complete

The ISO board is wired to the stepper motor drives and the 48 V power supply feeding the drives in in place. Two noteworthy items if someone is building a PDJ kit: a male serial port from the ISO board is not included so you will have to find one, second, the ISO board relay is rated at 10 amps maximum. My Porter Cable 690 router is rated at 11 amps so I added a relay (lower right in the picture) to take care of the current draw. The only thing left to do is wire the motors and limit switches but I have to wait for the final parts shipment!

Sub-base

The CNC machine’s sides are connected by a 3″ tall plate so I decided to add risers to the table. Another layer of particle board will be fastened to the risers and T-tracks will be secured to it. Finally, a layer of MDF will be added so that the top will clear the plate by 3/16″ and the top of the T-track will be recessed 3/8″. The rational is that I will surface the top with the router leaving 1/4″ above the plate. I should be able to re-surface it a couple of times before replacing the MDF. Everything else stays put.

Pilot Pro 2626 DIY Parts

The parts have arrived, at least most of them. A few of them are on back order and UPS managed to break a package and a linear bearing fell out. Oh well, these will keep me going for a while.
My first impression is that the Pilot Pro 2626 DIY parts are very substantial and high quality. The parts are nicely labeled and the stepper motors are pre-wired. The Z axis is assembled and ready for mounting.

Base Layer

Three pieces of 3/4″ particle board were screwed to the risers to provide a platform for the T-tracks and spoil board.

T-Tracks

Next, the T-tracks were screwed through the particle board and into the riser blocks.

Finished Spoil Board

Finally, strips of 3/4″ MDF were screwed into the particle board base. The surface sits 3/16″ proud of the Aluminum plate that ties the sides together and all the fasteners were counter bored 3/8″. My rational for this set-up is the spoil board can be surface planed and still have a good 1/8″ that can be surfaced a couple of times before the MDF strips need to be replaced. The hole pattern is symmetrical so parts are interchangeable. The T-track spacing was determined by the X axis limits and the reach of the hold down clamps. There are no dead spots that a clamp can’t reach on the spoil board.

Spoil Board Complete 1

An unobstructed view of the built up spoil board

Spoil Board Complete 2

The spoil board showing height relationship to end plate

Beginning the build

The CNC machine build begins with lightly knocking off any high spots on shim parts 11A using 320 grit emery. Subsequent photos will closely match Phil’s YouTube assembly videos but will show greater detail.

Labeled Hardware

Hardware included in the Pilot Pro 2626 DIY Kit was clearly labeled.

Shim-Rail Assembly

The shims are sandwiched between the linear rails and the 8020 beams. No washers are used here. Notice that the linear rails are marked with arrows. Although no mention was made of this and although the rails look perfectly symmetrical, I mounted all the rails with the arrow pointing upward. A nice feature of the T-nuts is the spring loaded ball bearing that keeps the nut in place inside the cavity after the parts are slid into place.

Shim-Rail Assembly

A photo of the shim and rail with the T-nuts in place before sliding into the 8020 side support

Table Mounting Brackets

The T-nuts for the table mounting brackets are shaped differently than the linear rail T-nuts in that they can be inserted through the track instead of sliding in from the end.

Table Mounting Brackets 2

I took off the end plate to slide the table mounting brackets with T-nuts attached before I realized that this was not necessary. These T-nuts can be inserted without sliding in from the end.

Lead Screw Support

The lead screw support gets mounted so part of the support extends beyond the edge of the 8020 rails.

Linear Bearing Mounting

The linear bearings have the little black “keeper” installed with the bearing. Simply line up the bearing with the track and slide the bearing unto the rail and the “keeper” drops out and can be discarded.

Linear Bearing Positioning

Whereas the Y axis linear rails are mounted to the sides of the 8020’s, the gantry rails are mounted to the top of the 8020’s. The above photo shows the Y axis bearings – notice the two different size linear bearings, the longer mounted toward the front of the machine.

Gantry Rails

The gantry 8020’s with the linear rails mounted to the top. When the 8020’s are attached to the gantry mounting plate, they are turned 90 degrees so the linear rails face forward.

Gantry Mounting Plate

The gantry mounting plates are milled on one side. They are mounted with the milled side against the linear bearing blocks. The plate with the stepper motor mounting holes is on the left side of the machine.

Gantry Installed

The two 8020’s are mounted between the gantry mounting plates with the linear bearing rails centered. The above photo shows three of the 4 bearing blocks installed because I’m waiting for a replacement for the one that UPS managed to lose when they smashed my package.

Z Axis Assembly

The Z axis assembly is mounted to the bearing blocks as shown in this photo. It’s important to watch the PDJ Inc. YouTube videos on the screw tightening procedure so everything slides properly.

Movable Lead Screw Brackets

The moving lead screw brackets are secured to the ball bearing with the screw hole recess pointing toward the bearing.

Lead Screw Ends

The ends of the lead screws differ. The left shows the motor (rear) end and the right shows the forward (front) end of the screws. One axial ball bearing is installed on the front and two on the rear.

Front Stop

The front stop is installed about 1/4″ from the end of the linear bearing. The remainder of the space is an allowance for the router which is mounted on the forward face of the Z axis.

Lead Screws Installed

Installing the lead screws is very easy. The motor sides have two axial bearings and the thrust washer is tight against the support. The other end gets one bearing and the thrust washer is adjusted to apply a slight amount of tension to the lead screw. “Slight” is the operative word here because if too much tension is applied, the axial bearings will prematurely fail.

Super PID

I purchased a Super PID to control the router speed. The enclosure has MDF sides, a plywood back and a clear plastic front because the Super PID has a digital readout. The heatsink was scavenged from a computer motherboard. A fan will be mounted on the back and draw air into the enclosure from the filtered air supply inside the cabinet below the CNC machine.

Completed Machine

The final parts arrived and were installed. A little software tweaking and Wahlaaa! a working CNC router. The above photo shows the completed machine with my first V-carving of a Celtic knot in a piece of MDF.

Close-up of Celtic Knot

Here’s a closer look at my first carving with my Pilot Pro CNC router. Lots of potential here so now I have to work on design and marketing.

Table Revision

After using the CNC for awhile, I decided to remove the risers under the spoil board in order to give me more Z axis travel. For the times I want to make a long Y axis piece, I will either add a temporary riser or remove the end plates for an unobstructed flat surface.

CNC Setup

This job was longer than my Y axis bed so risers were used to elevate the work above the machine ends.

Updated Spoil Board

I decided to make the spoil board the same size as the cutting limits of the machine. This allowed me to take a surface cut across the entire bed assuring it is in perfect alignment with the gantry. It’s interesting how the design of this machine changes with experience.

Cooling Fans

The stepper motors get extremely hot when operating so I added an 80mm CPU cooling fan to each motor. PDJ offers the fans as an option but I purchased these from Amazon, strapped them on with wire ties and powered them from a 12V tap off the power supply. I inserted a thin piece of wood between the fan and the motor as a standoff and heat buffer because it seemed to be the right thing to do. I cut a 1/2 hour job and the fans really kept things cool. Five minutes after the job the motors were luke warm – fantastic!

New Stepper Motor Standoffs

I decided to make new standoffs for my stepper motors because the post type were cumbersome when removing or mounting the motors. I added a thin piece of gasket material between the machine and standoff to act as a vibration damper but I’m not sure it does any good. This mounting method is the best of the three I’ve tried and it’s a keeper.

Gecko 540 Drive

After owning the Pilot Pro for nearly two years, I decided to replace the PDJ motor controls with a Gecko 540 drive unit. I had some Y axis racking issues and limited rapid travel speeds that I simply could not resolve despite hours on the phone with Phil at PDJ. His support was excellent and I will continue to recommend the PDJ Pilot Pro to anyone looking for a solid CNC router. When I made the switch to the Gecko drive, I also replaced all of my motor control cables with shielded wires and took special care to ground everything properly. Since I made the conversion, I have not had any racking issues and I can run the machine at virtually any speed I want without problems.