Gantry Replacement: CMC 8500

Head appearance may vary from model shown, but the connections are the same.

Never pull/push on the drive shaft to move the gantry.

Use the gantry arm to move/pick up the gantry.

Do not pick up the head using only the blade depth knob or the head cover.

Pick up the head by holding the “D-Shaped” upper and lower head plates.

Turn the shut off valve on the Blue airline, and unplug the Blue airline before removing the Straight Line Trimmer.

Turn the bottom locking knob Clockwise to loosen.

Turn the top locking knob Counter-Clockwise to loosen.

Slide the Straight Line Trimmer off of the Board and set aside in a safe place.

Click reset motors button on the cut preview and click OK on the release motors prompt.

Push blade cartridge release down to eject the blade cartridge.

Turn off the air.

Remove the hood from the gantry by unscrewing the screws that holds it in place and set aside.

Move the gantry to the right side of the board until the Footblock is off the board.

Disconnect the head power plug (square connection) from the head grabber arm.

Disconnect the air to the head by untwisting the two air fittings.

Remove the two 5/32” screws and set aside.

Roll the head down the gantry until it rolls off the gantry, taking care not to drop it.

Remove the front right 3/16” stop screw from the alignment plate on the left bottom rail (located on the top of the bottom rail) and set aside.

Loosen the back left screw and T-Nut and slide the alignment plate to the end of the rail to remove.

If your model only has a stop screw without the alignment plate, remove the stop screw.

Remove the 5/32” Allen screws and washers from the lower gantry plate.

Disconnect the airlines to the gantry by untwisting the air fittings.

Disconnect the board cable by turning the locking ring until it comes away from the gantry.

Loosen one full turn only the 3/16” Allen belt tensioner screw from the right bottom side of the lower rail marked with a red dot.

Only loosen it enough so that there is some movement in the belt tensioner; about one full turn.

Belt tensioner springs should be visible.

Locate the belt tensioner hole on the end of the belt tensioner.

Place the 5/32” Allen screw and washer we removed from the lower gantry plate into the belt tensioner hole.

Tighten the Allen screw until belt tensioner is flush with the rail and the springs are not visible.

Go back and tighten the 3/16” Allen belt tensioner screw on the right bottom side of the lower rail marked with a red dot.

Lift the drive belt end out of the belt tensioner slot.

Pushing the drive belt end to the right may assist in getting a hold of it.

Wind up the drive belt, and rubber band it.

Repeat these steps with the upper rail.

Move the gantry to the left to dislodge the belt anchors.

The belt anchors are sunk into the left ends of the rails and are attached to the drive belts.

Lay the belt anchors over the drive belts and rubber band them together.

Hold the gantry on the bottom and along the gantry arm and gently roll the gantry off the rails on the left side of the board and set aside.

The gantry only weights about 30 lbs, but it is large and awkward, so having a second person standing in front of the CMC helping may be beneficial.

Before installation, look at the bottom set of gantry wheels.

The bottom wheels are spring-loaded, the top wheels are on a center-pivot.

Move the top set of wheels as needed for ease of installation (picture shows gantry being put on rail from back).

Before installation, look at the top set of gantry wheels.

Both sets of wheels are spring-loaded.

Wheels may need to be eased over the rails (picture shows gantry being put on rail from back).

Hold the gantry near the left side of the CMC and line up the upper then lower wheels of the gantry to the center channel of the rails.

Carefully ease the Gantry onto the left side of the Rails, taking care that all the wheels line up.

Make sure that the Toothed Belt lies within the channel on either side and is not pinched between the Gantry and the Rail.

Upper and lower Gantry ends must be slid on at the same time.

Roll gantry past where the alignment plate was removed.

Slide in the alignment plate from the end of the rail.

Replace the 3/16” stop screw into the alignment plate and into the left bottom rail.

If you only have the stop screw, replace the stop screw.

Roll the gantry so it lines up to the alignment plate.

Loosely tighten the back left stop screw, then the front right stop screw, repeating until the alignment plate is secured into position.

Roll the gantry to the far right of the board and back to the left to make sure it moves smoothly.

Lightly pull the coiled drive belt toward the right to take up the slack and pull the belt anchor into place flush with the end of the CMC.

Remove the rubber-band from the drive belt and pull the loose belt end to the right, making sure that the drive belt is not twisted and that the teeth are facing down toward the board into the rail channel.

If necessary, rotate the alignment pulley so that the red mark is on the top.

Line up the red mark of the drive belt to the red mark of the alignment pulley; this may require moving the gantry a bit in either direction.

Pull drive belt to the right to take up slack.

Do not move the gantry after red marks line up.

Slide the screw of the belt end into the belt tensioner slot.

Go back and make sure red lines are still lined up.

The screw of the belt end snaps into the belt tensioner slot.

Remove the 5/32” Allen screws and washers from the belt tensioner.

Leave the gantry where it is.

Loosen one full turn only the 3/16” Allen belt tensioner screw from the right bottom side of the lower rail marked with a red dot.

The belt tensioner should spring fully into place.

Repeat steps 1 through 10 with the upper rail.

Place the two Allen screw and washer into the holes provided on the lower gantry plate.

Place them so that the screw protrudes only slightly from the back of the plate.

Go back and snugly tighten the 3/16” Allen belt tensioner screw from the right bottom side of the lower rail and the right bottom side of the upper rail marked with a red dot.

The board cable connects the gantry on the CMC to the Driver Pack, which is a shoebox-sized peripheral.

Connect the male end of the board cable to the back of the Driver Pack by aligning the pins and turning the locking ring until it seats itself and locks into place.

Connect the female end of the board cable to the back of the gantry in the same manner.

Move the gantry to the far right of the CMC and back to the left to make sure the board cable does not get caught on anything.

If the board cable is obstructed, this will affect the cuts.

Follow the airline with the red connector from the top of the gantry and connect it to the right side of the air regulator by inserting the red connector on the end and twisting it into place.

Follow the airline with the blue connector from the top of the gantry and connect it to the matching blue airline on the back of the board.

Make sure that none of the airlines are crimped.

Turn on the air.

Move the gantry to the right edge of the CMC.

Point the head so that the Footblock faces toward the CMC and the wheels are close to the bottom of the gantry.

Line up the wheels on the head to the center channels of the gantry arm and ease the head onto the gantry.

Roll the head up the gantry until it lines up to the head grabber arm on the right side of the gantry.

Holding the head in position so that the head lines up neatly to the head grabber arm, replace the two 5/32” screws, making sure they go into the head grabber arm and into the head and tighten firmly.

Connect the air to the head by twisting the two air fittings together, matching colors.

Connect the head power plug (square connection) to the head grabber arm.

Lift the head up so that the Footblock does not strike the side of the board and move the gantry to the left.

Turn on the air.

The head is installed.

Go to the cut preview screen.

Manually move the head and the gantry to the middle of the board, and click the power button.

The head will align to this position.

Locate the Head Wheel Adjustment Allen Screws by looking at the left side of the Head just under the Blade Depth Adjustment Plate.

They are located next to the Head Wheels and are marked with red dots.

Do not touch the Allen Screws attached to the Wheels themselves.

Loosen each Head Wheel Adjustment Allen Screw until the Wheels are loose; about two full turns.

The Wheels are spring-loaded and will pop into place.

Grasp the head with both hands and gently rock it back and forth to ensure that the wheels are lined up to the gantry grooves.

Retighten the head wheel adjustment Allen screws consecutively; tighten the top screw half a turn, then the bottom screw half a turn, back to the top and continue until they are both tight.

Check each of the head wheels to make sure there is no movement.

There are the two visible wheels on the left side of the head under the blade depth adjustment plate, and two wheels on the backside of the gantry, which can be felt by hand.

They should sit firmly into the gantry groove and be difficult to turn. If not, repeat these steps of loosening the wheels, gently rocking the head back and forth, then retightening the wheels.

Reinstall the hoods onto the Gantry, replacing the screws you removed earlier.

Look at the backside of the Trimmer and locate the T-Nut on the glides.

Make sure that the T-Nut lines up with the glide on both the upper and lower sections of the Trimmer.

Holding the Straight Line Trimmer steady (a second person helps here), carefully slide the Trimmer onto the channels on the right side of the Board, making sure that the T-Nuts slide into the channel of both the upper and lower rails.

Move the Straight Line Trimmer to the right until it stops.

Slowly tighten the bottom locking knob COUNTER-CLOCKWISE until it is snug.

Slowly tighten the top locking knob CLOCKWISE until it is snug.

Plug in the Blue Connector airline from the ST 500 into the Blue shut off valve on the “Y” Connector.

Turn on the Blue shut off valve on the “Y” connector to turn on the air.

Do a test cut. Cut a 2x2 square, with 2” borders, NOT cutting the outside. Measure the border to the opening and make sure it measures 2”. If it does not, adjust the Horizontal Home in the Configurations Screen accordingly.

• If the border is too big, decrease the Horizontal Home.

• If the border is too small, increase the Horizontal Home.

Do another test cut. Continue making adjustment until it measures 2”. If you need assistance, call Customer Support.

Make sure that the Gantry is straight. Cut a rectangle that is about 2x24”, NOT cutting the outside, with 2” borders.

Measure the borders to the opening at the bottom of the mat closest to the vertical clamps, then measure the borders to the opening at the top of the mat closest to the vertical clamps.

If the borders are not measuring 2” in both places, call Customer Support for assistance.

Check both sets of wheels at the TOP of the gantry.

Make sure all of the wheels make contact with the top rail, and that they don’t spin freely.

Make sure they are making contact with the top rail.

If any of the wheels are not making contact, contact customer support.