ShopBot PRSalpha, PRSstandard Assembly Manual

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ShopBot PRS: Assembly Manual

These assembly instructions apply to both PRSalpha and PRSstandard models of ShopBot CNC’s. Note that there are different sections for connecting each type of tool to the control box. Make sure that you are using the correct connection section for your ‘alpha’ or ‘standard’ PRS model.

The boxes are very heavy! Several components are heavy! Make sure you have help or proper handling equipment when moving or positioning boxes or parts.

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Contents

Assembly Manual .................................................................................................... 1

Table Surface Considerations..........................................................................................................................3

Electrical Precautions ......................................................................................................................................4

Overview of Your ShopBot PRS CNC Tool......................................................................................................5

Assembling Your ShopBot...............................................................................................................................7

Tools You Will Need..........................................................................................................................7

Unpacking and Getting Your Work Area Organized: .........................................................................8

Connection to Electrical Service......................................................................................................................9

Overview of the Assembly Process ...............................................................................................................10

Off and Running….........................................................................................................................................10

Assembling the Table ............................................................................................. 11

Table Parts............................................................................................................ 12

Assembly Steps ..................................................................................................... 14

Step1.1: Attach a Machine Glide to the Bottom of Each of the Table Legs....................................................14

Step 1.2: Attach the Table Legs to the Table Sides.......................................................................................14

Step 1.3: Attach the First Upper Table Support .............................................................................................16

Step 1.4: Slide the Cross Supports into Position ...........................................................................................18

Step 1.5: Working on the other End of the Table where the Legs are still temporarily attached to the Outside

of the Table Sides..........................................................................................................................................19

Step 1.6 Square and Level Table .............................................................................. 20

Table Surface (probably attach later?) ...................................................................... 21

Suggested Materials......................................................................................................................................21

Attaching the Table Surface...........................................................................................................................21

Installing the Gantry .............................................................................................. 23

Installing the X-Rails and Getting One Rail Straight ..................................................... 23

Slide the X-Rails onto the Table ....................................................................................................................23

Set the Front Side X-Rail and Check for Straightness...................................................................................23

Adjust the Position of the Rear X-Rail............................................................................................................24

Putting the X-Car on the Rails and Using it to Align the Rear X-Rail ............................... 25

Lower the X-Car onto the X-Rails ..................................................................................................................25

Use the X-Car as a Guide to Align the Rear X-Rail .......................................................................................26

Mounting the YZ-Car and adjusting its lower wheel bearings ........................................ 27

Place YZ-Car on the X-Car............................................................................................................................27

Attach the Lower Wheel Bearings on the YZ-Car ..........................................................................................28

Adjust the Lower Wheel Bearings on the YZ-Car ..........................................................................................29

Attaching the Motors .............................................................................................. 30

Put the Pinion Gears on the Motors...............................................................................................................30

Mount the Motors...........................................................................................................................................31

Set the Mechanical End Stops for the X Axis.................................................................................................33

Run the X-2 Motor Cable through the Aluminum Beam.................................................................................34

Mounting the Router or Spindle................................................................................ 35

If You Have a Porter Cable Router ................................................................................................................35

If You Have a High Frequency Spindle:.........................................................................................................36

After Mounting the Router/Spindle............................................................................ 37

Wheel Guards........................................................................................................ 37

Proximity Switches ................................................................................................. 38

Install the Proximity Switches ........................................................................................................................38

Y-axis Targets................................................................................................................................................39

X-Axis Targets. ..............................................................................................................................................40

Z-Zero Plate Holster ............................................................................................... 40

PRS Y-axis EChain Installation ................................................................................. 41

Secure cables and wiring......................................................................................... 46

Run the YZ Wiring .........................................................................................................................................49

Neaten up the Wiring at the Back Side of the X Car......................................................................................49

Create a Cable Loop on the way to the Control Box......................................................................................49

Hooking Up to the Control Box ................................................................................. 50

Do’s and Don’ts ..................................................................................................... 50

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Hooking Up Your PRSalpha ...................................................................................... 51

Powering the PRSalpha Control Box.............................................................................................................51

ShopBot Configuration PRSalpha: US Standard, 60Hz..................................................................51

ShopBot Configuration PRSalpha: European Standard, 50Hz .......................................................51

Mount the PRSalpha Control Box..................................................................................................................52

Explore the PRSalpha Control Box................................................................................................................53

Inside the PRSalpha Control Box ....................................................................................................54

Open the Roxtec Fixture................................................................................................................................55

Plug the Motor Cables into Drivers ................................................................................................................55

Connect the Emergency Stop Switch and the 3-Button Pendant...................................................................56

Installation .......................................................................................................................................57

Connect Cables from the Proximity Switch and Z-zero Plate.........................................................................58

Seal the Cable Entry......................................................................................................................................59

Ground the ShopBot PRSalpha.....................................................................................................................59

Connect the USB cable from PRSalpha Control Box to computer.................................................................60

Hooking Up Your PRSstandard ................................................................................. 61

Plug the Motor Cables into your PRS Standard Control Box .........................................................................61

Connect the Cable from the Remote-Stop Switch .........................................................................................61

Connect the Cables from the Proximity Switch and Z-zero Plate...................................................................62

Ground the ShopBot PRSstandard................................................................................................................62

Connect the USB cable from PRS Standard Control Box to the computer ....................................................63

The Remote Stop Switch...............................................................................................................................63

Mounting the Switch ........................................................................................................................63

If you use screws to mount the Remote Stop Switch:......................................................................63

Mission Accomplished! ............................................................................................ 64

Table Surface Considerations

You will need to supply sheet material for the deck of your table. We recommend 3 sheets of material to give the table good rigidity. See discussion of the options at the end of the Table Assembly section. As a start you will need one layer of cabinet grade ¾” plywood for the bottom support layer – it will take several sheets to cover the work area if your tool is larger than 4x8.

if you are installing a vacuum hold-down system, you will need to decide on specific materials for your plenum and bleeder board.

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Electrical Precautions

MOTOR CONNECTIONS - DO NOT CONNECT OR DISCONECT ANY MOTOR WIRE CONECTORS WHILE YOUR CONTROL BOX IS TURNED ON !! During the process of a

‘hot’ connect or disconnect there is a high load put on the motor driver circuitry which is very likely to damage the motor driver. A damaged driver means that motor does not run correctly. Also, do not unwrap the heat-shrink surround that keeps your motor cables connected to the motors. It is intended to help keep all connections permanently secure.

STATIC DISCHARGES – Electronic circuits are very sensitive to static and power surges, and your Control Box is no exception. Please have your electrician follow the wiring and grounding instructions in the wiring section to help prevent static from damaging components of your tool. In particular, avoid doing any vacuuming around your tool before you have grounded both the tool and your vacuum system. Large static build-ups can occur inside a vacuum collection system and discharge accidentally through the wiring of your ShopBot.

INDUCED CURRENTS - The stepper motors on your tool become significant little generators if they are manually turned. They can generate sizable voltages in your control box if you push the X or Y-axis of your tool around physically. Occasionally it may be necessary to move the tool by hand, but try to minimize such movement and when you must do it, make the move slowly. If you need to do a lot of manual movement, unplug the motors on the axis you are moving - having shut down the power first as noted above.

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Overview of Your ShopBot PRS CNC Tool

Note that the diagrams in this manual depict a generic ShopBot. Depending on the size and shape of your tool, the table layout may look a little different (fewer or more legs, different shape, etc.).

Before you unpack and start to assemble your ShopBot PRS tool, let's go over the some of the major components and get familiar with the terminology and directions we'll be using:

THE TABLE To get us located, refer to the orientation diagram above and imagine looking

at the tool from the position of the little man in the drawing. From this position, we'll call the lower left hand corner of the work area the tool's 0,0 (or home) location. The X-axis is the long length of the table and values increase going to the right from where you are standing. The Y-axis is the narrow width of the table (or front to back from your position on the long side) and values increase as you move away towards the back. The Z-axis is the vertical movement or the plunging and withdrawal movement of your tool. Decreases in Z values are plunges down by your cutting tool. Increases are movements of the cutting tool up.

Still looking from the position of the little man, consider the furthest away X-axis track that the bearings ride on to be at the back of the tool, the track nearest the little man to be at the front, the left side the left, and so on. As you're positioning your tool in your shop, keep in mind that you will typically be loading sheet material from the left or right side so you should be sure to leave yourself some room to move around at one or both ends of the tool.

We'll use the words or 'car' to refer to the entire moving unit of a particular axis. The big gantry is thus the X Car, and the one that rides on it, the YZ Car.

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The electrical cabling will be arranged along the back of the tool, so this is the part of the tool that can be placed nearer a wall, obstruction, or where there will generally be less action. Note, however, that it is best if you are able to walk around and access your tool from all sides. The wiring for the Y and Z axes will be attached to a clear plastic Wire Guide. The Wire Guide arches out from the back right hand corner of the X-Car to the front right of the YZ-Car, as seen from the little man. Note that the X-Car mounts with the sloped side (front of car) to the left.

THE X-AXIS. The X-axis is the basis for your tool's right and left moves (as seen by you as

the little man in the front of the diagram) -- it's the long axis on a standard ShopBot. Note that the distance between the tracks on the X-axis is wide. Because of this span, we power the X-Car movement with 2 motors, one on each side. The X-Car is driven by a rack and pinion power transmission system. The gear rack is mounted on the bottom of the long X rails and engaged by the pinion gear on the motor shaft.

THE Y-AXIS. The Y-axis provides the front to back movement of your ShopBot (the short

axis for a standard ShopBot). Note that the Y-axis rides on the X-axis. The gear rack for the Y axis is mounted in the face of the X-Car beam.

THE Z-AXIS. The Z-axis is vertical, rides the face of the YZ-Car, and moves the cutting tool

up and down. The drive system for the Z-axis is also rack and pinion. The Z axis is springloaded to counterbalance the weight of your router or spindle.

THE ROLLING GEAR. Throughout your PRS ShopBot, precision motion bearings roll on

hardened stainless steel rails to provide your tool with smooth travel.

THE CONTROLS. Your ShopBot is moved and controlled by a personal computer (running

Windows XP or Vista) that you provide. In the ShopBot Control software, signals are streamed from the PC's USB port through a USB cable to the ShopBot Control Box. The Control Box is placed near the tool and provides the driving power to the motors. The Control Box also receives incoming information from other devices such as your Z-Zero Plate and Proximity Switches.

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Assembling Your ShopBot

Tools You Will Need

• a wrench set with TWO wrenches of the following sizes 7/16”, 1/2”, 9/16”, and

3/4”(the type with box end on one side and open end on the other works well).

• a socket wrench set with a 6” extension

• an Allen wrench set

• a drill for a couple of holes in the sheets of material you will use for your table

surface (say 1/4” and 7/16”)

• a good tape measure, a carpenter's square, and a level (a six foot one that you can

use for a straight edge would be good)

• several Quick Clamps or large C-clamps to temporarily hold things and act as STOPS

• Misc: the odd screwdriver, adjustable wrench and pliers, utility knife, electrical tape

(in a color that you can mark on) or masking tape, marking pen, your wits, etc.

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Unpacking and Getting Your Work Area Organized:

You will receive a large shipping crate with the already-assembled X-Car and YZCar. One of the large cartons inside the crate holds the ShopBot Control Box. The motors and motor cables are packaged together. The long package with the rails and table sides will usually be strapped to the top of the shipping crate.

You can unpack the rails and cars so that you can identify them and have them ready. Be careful not to damage the gear rack on the bottom of the rails. Unpack and lay out the parts bags on your work surface.

Don't worry about the Control Box for the moment; you can set it aside until we're ready to connect your ShopBot.

We've pre-assembled most components of your tool to make things go a little more smoothly. In many places, bolts or hardware are loosely fit in place to show you their intended location; you may have to remove them to attach the part.

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By way of giving you a little guidance: It takes one of us about 6 hours to assemble a ShopBot, so we think you should be able to put your ShopBot together over a pleasant weekend if you've already read through this Assembly Manual. Of course, the IRS thinks that preparing your 1040 should take 2 hours and 43 minutes, with a further 23 minutes for copying, assembling, and mailing the form!!

There are several stages in the assembly process where having a helper or two will be useful to you. In particular, you will want help unloading and unpacking, getting the table assembly started, and putting the X-Car on the rails.

Please remember that several of the components are very heavy!

Connection to Electrical Service

The Control Box for a PRS alpha tool needs to be connected to your electrical service by a licensed electrician. This connection can be made at any convenient time, before or after you complete assembly of the tool. The electrician does not need to be present when you plug the wiring from the tool into the Control Box. However, it may be best to wait until the tool is assembled and in its final position before having the electrical service hooked up. Waiting will allow you to make sure you have the Control Box positioned in the best location for your tool. The complete wiring diagrams for connecting the Control Box can be found inside the door of the Control Box and will be needed by the electrician to correctly wire the box into the electrical service.

If you have purchased a high frequency spindle and/or a vacuum blower, these will also need to be wired by a licensed electrician. The electrician will wire the spindle into the Control Box and connect the appropriate electrical service. The electrician will also wire your blower to the correct electrical service.

The Control Box for a PRSstandard tool plugs into a standard 110v/15A (or 220v international) circuit. However, if you have spindle or blower, you should have an electrician do the wiring for these accessories.

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Overview of the Assembly Process

Assembling the Table.

This has the most parts, the most steps, and will probably take the most time. A helper is useful at the start, but not essential for this project. A couple of saw horses or other supports will help you out. See the section of MEASURED ASSEMBLY DRAWINGS for your specific size PRS (fixed table) for dimensions.

Installing the X-Rails and Gantry

Take your time to align the parts correctly. This is critical in terms of getting your tool running true. You will need help to lift and position the X Car on the rails.

Attaching the Motors

Mounting Your Router or Spindle

Your cutting tool needs to be attached to the front of the Z axis beam. A helper is useful, but not essential for this project.

Wheel Guards, Proximity Switches, Z-zero, and Echain

More to install, then tidy up all the wiring and make sure you are ready to roll.

Connecting Your Tool to the Control Box

Note there are different sections for the PRSstandard and the PRSalpha.

Off and Running…

Stopping the ShopBot

How to stop the ShopBot with the E-Stop, 3-Button Pendant, Remote Stop Switch and the “S” key.

Taking a Test Drive

Ok, let’s go for a little spin, then we’ll review a couple of other things you will need to attend to before you get into production.

Surfacing the Table Deck–

Here’s a first CNC project: Surfacing your table.

Squaring and Adjusting the X-Car

You shouldn’t need to adjust, but you will want to read about setting your End Stops square.

Table Drawings with Measurements

Use the one for the size of the table you have.

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Assembling the Table

These are general assembly instructions for our steel and aluminum extrusion tables. For specific dimensions and part identification, refer to the included Measured Drawing (located at the back of this section) specific for the size ShopBot you are assembling. The Measured Drawing plans show the dimensions of the tools, the spacing of the cross supports, and the correct position for the table surface. NOTE that the number of legs on each side of the table differs according to the size ShopBot you are assembling.

Take a look at Step 1.6 before you start. The goal of this assembly process is to have a square and correctly dimensioned table at the end point. In the final step you will be attending to getting the table square and the table sides exactly dimensioned for your tool.

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Table Parts

Upper Support (note beveled ends in upper support)

Lower Support

Cross Support

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Table Gusset

1/2Bolt

Table Leg

1/2Flat washer

1/2Hex nut

1/2Lock Washer

5/16 Bolt 5/16 Flat washer Tee nut Machine Glide

(w 5/8 nut and

(in several sizes)

lockwasher)

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Assembly Steps

Step1.1: Attach a Machine Glide to the Bottom of Each of the Table Legs

Screw a Machine Glide through the 5/8” nut in the bottom of each Table Leg. Place a 5/8” lock washer and hand tighten a 5/8” hex nut on the Machine Glide. Do not tighten at this time (see Step 5). Repeat for all legs.

Bottom of Table Leg showing Machine Glide assembly

Step 1.2: Attach the Table Legs to the Table Sides

Place 5/16” bolts, flat washers and T-nuts at the eight holes on each of the Table Legs.

Looking down on table leg Attach the first leg to the inside of the Table Side by sliding the T-nuts into the side channels on the Table Side. Square the Table Leg to Table Side and tighten just enough to

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hold the pieces securely in place. Keep in mind that you will want to tighten all nuts securely at the end of the table assembly when you square the table. If you tighten all fasteners too much now, you won’t be able to square the table later.

Temporarily attach the other Table Leg to the outside of the Table Side. This leg will be moved to the inside of the table in Step 1.4.

Repeat for the other Table Side. Use saw horses to temporarily support the side assemblies as you continue.

Table Sides with legs attached

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Step 1.3: Attach the First Upper Table Support

Attach the first Upper Table Support to the end of the table. Start it on from the side with the temporary outside leg. Slide the T-nuts for the Upper Table Support into the bottom channel of each Table Side on the far end. Then slide the Support all the way down and close to the Table Leg, leaving approximately 3/16” between the leg and the upper support for the Gussets.

Insert the Gussets between the Table Legs and the Upper Table Support and attach using ½” Hardware Assemblies.

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Attach the Lower Table Support to the bottom holes in the Table Legs using ½” Hardware Assemblies.

Lower Table Support showing attachment to Table Leg. .

Your table should now look like this:

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Step 1.4: Slide the Cross Supports into Position

Attach two 5/16” Hardware Assemblies to each end of the Cross Supports. Then slide the Tnuts into the bottom channels of the Table Sides and slide the Cross Supports into position. Refer to the Measured Drawing for your table size for proper spacing of the Cross Supports.

Cross Supports in position

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Step 1.5: Working on the other End of the Table where the Legs are still temporarily attached to the Outside of the Table Sides

Install 5/16” Hardware Assemblies on the Upper Table Support and slide it into position. Notice that the lead edge of the support inserts first, this time

Attach the Gussets on this end to the Upper Table Support . Use ½” Hardware Assemblies. Your table should look like this.

Move these Table Legs to the inside.

Attach the Lower Table Supports to the bottom holes in the Table Legs using ½” Hardware Assemblies. Attach remaining bolts on gussets. Your table should now look like this:

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Step 1.6 Square and Level Table

Set the table where it will be used. Plan to spend a little time getting it square and adjusted to the exact correct width measurement. [SEE DRAWING & TABLE BELOW]

Set the legs perpendicular to the Table Sides with a square and tighten.

Level the tops of the Table Sides across and diagonally using the Machine Glides. Then tighten the 5/8” nuts on the Machine Glides.

Measure the table across both diagonals. If the measurements are not the same, the table is not square. You will need to shorten the longer diagonal by one-half the difference of the two diagonal measurements. With a mallet or hammer & protective block of wood, gently tap the end of the table side at one end of the longer diagonal to shorten as needed. Adjust the table until the measurements across the diagonals match.

Then, work to adjust the distance between the rails to the exact spacing indicated in the table below. It can be helpful to cut a measurement gauge from a 2x4 to use to set the distance between the table sides. Make sure the gauge distance is right and giving you the correct outside to outside measurements.

Tighten all hardware once the table is measured and square. Check the diagonals and the distances frequently as you move around the table tightening the bolts.

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========== WORK AREA

WIDTH DIMENSION 48” (121.92cm) 60” (12.40cm) 72” (182.88cm) Outside to Outside of Table Sides 64.5” (163.83cm) 76.5”(194.31cm) 88.5”(234.79cm) Gauge between Rail Spacing 61.5”(156.21cm) 73.5”(186.69cm) 85.5”(217.17cm)

==========

Table Surface (probably attach later?)

The deck surface of your table is created from several sheets of plywood or MDF. It makes logical sense to consider how you will install the deck at this time, but most customers find it more convenient to wait to do the final attachment of the table surface until after the tool is fully assembled. At the moment, you’ll probably want to just lay a sheet or two of plywood onto the cross supports to use as a work area. But we’ll explain the table surface now.

Suggested Materials

For your Table Surface or Deck we recommend 3 layers of material to provide good rigidity.

• Support Board (bottom layer)

¾” Shop grade or cabinet grade plywood or better (birch, maple, poplar…hardwoods)

• Plenum Board or 2nd Layer if not installing a Vacuum System

¾”Medium Density Fiberboard (MDF) or ¾” High Density Polyethylene (HDPE) or Another sheet of ¾” plywood if not installing vacuum

• Spoil Board

½” LDF or 5/8” MDF surfaced on both sides to a thickness of 3/8” or ½”-¾” MDF if not installing vacuum

Attaching the Table Surface

Refer to the Measured Table Drawing for your tool for positioning information for the table surface. The drawings also show how to position multiple sheets if your table is larger than 4x8. You will center the support board(s) in the X direction. There should be about 1.5” of material past the end support at each end. In the Y direction if your material exactly

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matches the tool’s work area, center the support board(s) in the Y direction between the front and back table sides. For example, for a 4x8 tool, a 4x8 sheet should be exactly centered. If your sheet material is oversize, then for all tool sizes locate the front side of the sheet 6.75” in from the front side of the tool.

Clamp the sheet(s) in position, then attach through the holes in the cross supports with the 3/8” by 1.5” carriage bolts that are included in your parts. Use, every-other diagonal hole in an alternating pattern in the Center Cross supports; every hole in the end supports.

From under the table, at each hole in the Upper End Cross Supports and alternating holes in the center Cross Supports, drill a ⅜” hole through the Support Board

Countersink the holes on the top of the Support Board with a spade bit.

Insert the ⅜” x 1½” carriage bolts down through the Support Board, Upper End Cross Supports or center Cross Support and attach with flat washers, lock washers and nuts.

If you are putting a vacuum hold-down system on your ShopBot. Please see the documentation for the vacuum hold-down system for more information on installing your plenum and bleeder board.

If you are not installing vacuum. Then attach a second layer to the support layer board using countersunk drywall or plastic screws. When your tool is operational, you will be able to surface this layer, and then attach a final sacrificial or working layer to your table.

The choice of actual material and methods for attaching your table depends on the nature of work you will be doing, the kind of hold-down system that you use, and the experiences that you gain with various materials. Your table surface is likely to evolve over time.

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Installing the Gantry

Installing the X-Rails and Getting One Rail Straight

Slide the X-Rails onto the Table

• Mount the X-rails with 5/16 bolts and T-nuts. Slide these nuts into the top track of the

table sides as you did with the table legs and cross supports.

• After you get both rails in position, hand-tighten the bolts.

• BE CAREFUL SLIDING THE RAILS ONTO THE TRACK. IT IS VERY EASY TO PINCH

YOUR FINGERS WHEN INSERTING THE NUTS INTO THE TRACKS AS YOU SLIDE THE RAIL ON.

Set the Front Side X-Rail and Check for Straightness

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• With bolts “finger tight,” move along the X-Rail on the front side of your tool,

aligning the aluminum bar on the inside exactly flush with the inside of the table side.

• Then start at one end further tightening the bolts.

• As you continue to lock the front X-Rail in position, slide your 6ft level or straight

edge along the outside edge of the rail to check for straightness. Nudge the aluminum bar slightly if it needs adjustment.

• When you’ve got the front side rail in position and straight, fully tighten all the bolts

on the front side rail.

Adjust the Position of the Rear X-Rail

You’ll use a tape measure to set the initial position of the rear X-Rail. Always make these kinds of important measurements from the 1” mark on the tape. Do not trust the accuracy of the clip at the end of the tape.

• Consult the chart below for the exact distance, outside edge to outside edge, for the

rails.

• Use the tape to check the distance at each of the bolts, and adjust where necessary.

Try to get within 1/32in of the distance. Note that the edge portion of the rails is ¼” wide, so there will be a 1/16” mark that should fall on the exact centerline of the ‘V’ of the rail.

• Tighten these bolts on the rear rail down just a bit. But note that you are probably

going to need to adjust the rear rail again slightly, after putting the X-Car in place.

========== WORK AREA WIDTH ========== DIMENSION 48” (121.92cm) 60” (12.40cm) 72” (182.88cm) Outside to Outside of Rail 65.812”(167.16cm) 77.812”(197.64cm) 89.812”(228.12cm) Outside to Outside of Table 64.5” (163.83cm) 76.5”(194.31cm) 88.5”(234.79cm)

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Putting the X-Car on the Rails and Using it to Align the Rear X-Rail

Lower the X-Car onto the X-Rails

The X-Car is fully assembled and ready to be placed on the rails. This is a 2-4 person operation as the car is HEAVY! Note that the car goes on the rails so that the sloping edge of the X-Car faces towards the left when you are at the front of the tool.

• As you put the car in position, seat the wheel bearings on the front side X-Rail and

then place the rear bearings over the rear X-Rail. You may find it easier to lay the Car over on its back first, with the beam across the rails and engaging only the bearings on the back of the X-Car. Then, when you are ready, you can stand it up and engage the wheel bearings on the Car’s front end. You may need to loosen the rear X-Rail at this point and adjust it slightly so that the bearings come into exact alignment.

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Detail

• Put a C-Clamp across the rails at each end of the table to create a temporary end

stop to prevent the X-Car from rolling off the table while you are carrying out the next tasks!

Use the X-Car as a Guide to Align the Rear X-Rail

Note that the weight and rigidity of the cars, their wide wheel base, and the selfcentering nature of the V-groove wheels will take care of slight errors in the rails, but you want to get the rails as well aligned as you can.

• Roll the car down to the middle bolt of the X-Rail so that you start the process from

the center of the table and work out to the ends.

• Clamp the side of the X-Car on the straightened, front rail so that the wheel bearings

are centered and locked onto the rails.

• Move back to the rear rails. Loosen up all the bolts a tad. Then make whatever

adjustment is needed to get the rails perfectly under the rear bearings.

• Work on this progressively over the rear rails, moving out from the center. There

should be enough adjustment in the rail to allow you to get the rear rail perfectly aligned over its full length.

This is the hardest step, so take a deep breath and congratulate yourself when you’ve gotten it accomplished!!!

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Mounting the YZ-Car and adjusting its lower wheel bearings

Place YZ-Car on the X-Car

The YZ-Car is a single piece that is ready to be placed onto the rails that cross the face of the X-Car beam.

• Roll the X-Car up to the far left side of the table and clamp it in place to make the

installation easy.

• Remove the lower wheel bearings before setting the YZ-Car in place. Notice that

these bearings are on an eccentric (adjustable) bushing and that there is a small, precision washer behind the bearing and bushing. This washer is critically important.

• After you have removed the lower bearings, lower the YZ-Car down onto the rail,

seating the upper bearing wheels on the upper Y-Rail. The car will sit in place on these top bearings.

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Attach the Lower Wheel Bearings on the YZ-Car

With the YZ-Car in position riding on its upper wheel bearings, you can install the lower bearings. Study the diagram below because the parts in this assembly need to be installed exactly as indicated. Note that the assembly incorporates an eccentric bushing (having an off-center hole), which will be used for the final adjustment of the bearing. This bushing has a small precision washer behind it. This washer is critical for the alignment of the car and for the normal operation of the bearing. (We’ve put extras in the “Extra” bag, just in case you might drop one.)

• Insert the bushing into the wheel bearing, then insert the bolt so it protrudes just far

enough through the bushing to hold of the precision washer.

• The trick to the whole operation is to slide the wheel in from the side of the car, after

you have placed the ‘V’ of the wheel over the track. When you get the wheel directly behind the hole in the car, push the bolt through.

• After pushing the bolt into place, put the washer on, and start the lock-nut. Leave

the assembly loose while you install the wheel bearing on the other side.

• When both wheels are in place, make sure that both are fully seated on the rail.

• Find the black mark on the edge of the eccentric bushing indicating the narrowest

spot. Put this side closest to the rail. Then, tighten down the ¼” bolt with 7/16” wrenches.

+ 65 hidden pages

ShopBot PRSalpha, PRSstandard Assembly Manual

Specifications and Main Features

Frequently Asked Questions

User Manual