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Rotary Hook Inspection And Adjustment Procedures For XTS and XT Machines

This document does not apply to the EMT16 and EMT16Plus

 

Introduction

These instructions are for the XT and XTS machines with PN# 31058-19 or earlier mainboards.  This also applies to first-generation Bravo machines.

The 6 hook adjustments cover:

  1. Needle Case Calibration (Needle Centering)
  2. Needle Depth
  3. Hook Timing
  4. Needle To Hook Gap
  5. Rotary Hook Support
  6. Needle Plate Centering

This entire procedure can take from :30 to :90 minutes depending upon how many of these corrections are necessary.

These steps should all be performed in order; as the later adjustments are dependent upon the accuracy of the earlier steps.

 

-Needle Case Calibration (Needle Centering) & Needle Depth are needle specific and should be checked for all needles.

-Hook Timing & Needle-To-Hook Gap are set to specification on the Closest Needle (see Adjustment #3 below)

-Rotary Hook Support & Needle Plate Centering are not needle specific and can be done with any needle.

 

Preparation: Disassembling Hook Covers

  1. Make sure the AMAYA OS is launched and running on your computer and your machine is ON.

 

  1. Close any menus and click the Reset Design icon. mceclip0.png

 

  1. If necessary, perform the Trim Immediate command:

    trim_immediate.jpg

 

  1. Remove the Bobbin Case (1st image below), Needle Plate (2nd and 3rd images) and Hook Guard (4th and 5th images). Older model machines might have a different style of Hook Guard (6th image). Do NOT Remove the Rotary Hook Support (aka. Retaining Finger) (7th image).

 

 mceclip1.png      mceclip2.png     mceclip3.png     mceclip4.png      mceclip5.pngmceclip6.png

 

  1. In the Melco OS, got to Tools > Maintenance as shown below.

 mceclip7.png

  1. Click on the Head Timing

 mceclip8.png

  1. Disassemble Hook Covers is now Completed.

 

 

ADJUSTMENT #1: Needle Case Calibration (Needle Centering) XT & XTS

  1. Hold down the Needle Case button + Left Arrow to color change to needle position 1.

 mceclip9.png

  1. Lower the needle to the Bottom Center position by holding down the Adjust button + the Down Arrow.

 mceclip10.png

  1. Check to see where the needle is in relation to the rotary hook center post. If the needle is centered directly over the bobbin post skip to step 7.

mceclip11.png    mceclip12.png

 

 

       4. Bring the needle up with the Adjust button + Up Arrow.

 mceclip13.png

  1. Micro-step the needle using the Trace button + the Left or Right Arrows. If the needle was left of the post, Micro-step with the right arrow. If the needle was right of the post, Micro-step to the left. Micro-steps are 0.08mm so you might need to jump it a few times to notice a change.

 mceclip14.png

  1. Lower the needle to the Bottom Center position by holding down the Adjust button + the Down Arrow, to verify. Repeat steps 3 through 6 until the needle is centered on the center post that the bobbin snaps into.

 mceclip15.png

  1. Bring the needle up with the Adjust button + Up Arrow.

 mceclip16.png

  1. Move to the next needle by pressing the Needle Case button + Right Arrow.

 mceclip17.png

  1. Repeat steps 2 through 9 till all 16 needles are centered. Centering is independent and must be done for each needle.

 

  1. After all 16 needles are centered click on the Calibration tab and the Get Table

 mceclip18.png

  1. Click OK for the conformation message.

mceclip19.png 

 

  1. Needle Case Calibration is now Done.

 

 

 

ADJUSTMENT #2: Setting Needle Depth XT & XTS

At the current time it is only recommended that people who have received Melco Technical Training perform the Needle Depth procedure on XT and XTS machines.

 

 

ADJUSTMENT #3: Hook Timing XT & XTS

  1. Click on the Information Tab and make sure you are using RSA Revision is higher than 1.56

 mceclip20.png

  1. Click on the Head Timing

 mceclip21.png

  1. Remove the Tabletop. Find the C number, Closest Needle number, and the z-axis position for hook timing. They are noted in the bottom right corner of the main PCB tray.

 

 mceclip22.png

 

  1. Replace the Tabletop.

 

  1. Use the Needle Case and Left or Right Arrow buttons to move the needle case to the closest needle noted in the machine casting.

 mceclip23.png

  1. Replace the needle.

 

  1. Bring the needle down to the hook timing position. Enter the z-axis position from the casting, rounding the decimal point down, in the ‘Set Position’ text field and Click the ‘Goto Position’ button.

 mceclip24.png

  1. Micro-Step the ‘Current Z Position’ up to the z-axis position from the casting using the Trace + Up Arrow. If the ‘Current Z Position’ is greater than the z-axis position from the casting, click the ‘Goto Position’ button for again.

 mceclip25.png

  1. Inspect the hook timing by standing directly in front of the machine, and check that the Hook Point is even with the left side of the needle.

mceclip26.png

This is the Hook Point.

 

mceclip27.png

An example of correct hook timing.

 

mceclip28.png   mceclip29.png

Left:  hook too far counterclockwise.  Right: hook too far clockwise.

 

  1. If the Hook Point is even with the left side of the needle skip the rest of the steps in this section.

 

  1. Bring the needle up with the Adjust button + Up Arrow.

 mceclip30.png

  1. Spin the hook using the Adjust button + Right Arrow, till you can loosen (do not remove) the two recessed Do Not loosen the 3rd raised screw on the flat surface.

 mceclip31.png

mceclip32.png

  1. Bring the needle down to the hook timing position. Enter the z-axis position from the casting, rounded down in the ‘Set Position’ text field and Click the ‘Goto Position’ button.

 mceclip33.png

  1. Micro-Step the ‘Current Z Position’ up to the z-axis position from the casting using the Trace + Up Arrow. If the ‘Current Z Position’ is greater than the z-axis position from the casting, click the ‘Goto Position’ button for again.

 mceclip34.png

  1. Loosen the raised screw.

 mceclip35.png

  1. Spin the Hook Point so it’s even with the left side of the needle. Tighten the raised screw.

mceclip36.png

An example of correct hook timing.

 

  1. Verify the timing is correct.

 

  1. Hook Timing is now Done. On XT and XTS machines Needle to Hook Gap MUST be done after Hook Timing.

 

ADJUSTMENT #4: Needle to Hook Gap XT & XTS

If not already there, use the machine keypad to move the needle case to the closest needle noted in the machine casting. Also make sure you are at the correct ‘z-axis position’ for ‘hook timing’. (see Step 3.2 above).

  1. On XT and XTS machines Hook Timing MUST be done before Needle to Hook Gap. If not already complete, follow the steps for ADJUSTMENT #3: Hook Timing XT & XTS.

 

  1. Inspect the gap between the Hook Point and the needle.

mceclip37.png

mceclip38.png   mceclip39.png   mceclip40.png

Left:  gap is correct.   Middle: gap is too small.   Right:  gap is too big.

 

  1. Try to floss a piece of 40 weight thread between the needle and the hook point. If the thread snags and catches, the needle to hook gap is most likely too small and needs to be widened.

 mceclip41.png   mceclip42.png

  1. Twist four 40 weight threads around each other to create one thicker thread, and floss that between the needle and the hook point. If the thread does not snag or catch, the needle to hook gap is most likely too large and needs to be tightened.

 

  1. The gap between the needle and the hook point should be 0.1mm (.004”) which is between 1 and 3 thread widths. If the gap is correct skip the rest of the steps in this section.

 

  1. Loosen the raised screw.

 mceclip43.png

  1. Adjust the hook to needle gap. Adjust until the gap between the needle and Hook Point is 0.1mm or 1-3 thread widths.

 

  1. Tighten the raised screw

 

  1. Verify the Needle to Hook Gap and Hook Timing are correct.

 

 

10. Spin the hook using the Adjust button + Right Arrow, till you can Tighten the two recessed

 mceclip44.png

 mceclip45.png

  1. Bring the needle up with the Adjust button and Up Arrow.

 mceclip46.png

  1. Needle to Hook Gap is now Done.

 

ADJUSTMENT #5: Rotary Hook Support Adjustment

  1. Insert the Hook Retaining Finger Gauge between the Rotary Hook Support (Retaining Finger) and the Hook Basket. If the gauge does not slide in easily, do not force it. Forcing it may scratch the highly polished surface of the Rotary Hook Support or Hook Basket, which could damage the hook and result in excessive thread breaks.

mceclip0.png   mceclip1.png

Left:  the Hook Retaining Finger Gauge.  Right:  Correct placement of the gauge.

 mceclip2.png   mceclip3.png

Left: Hook Support (Retaining Finger).  Right: Hook Basket.

 

  1. The Hook Retaining Finger Gauge should slide between the hook support and hook basket with no resistance.

 

  1. The tip of the Rotary Hook Support should be flush with the top of the Hook Basket.

 mceclip4.png

 

  1. If Steps 2 and 3 are correct skip the rest of the steps in this section. If they are not correct, proceed.

 

  1. Use the 2mm Allen wrench to loosen the 2 screws holding the Rotary Hook Support.

 mceclip5.png

  1. Position the Rotary Hook Support in the notch at the top of the rotary Hook Basket.

mceclip6.png 

  1. Insert the gauge between the hook support and hook basket and set the correct placement of the Rotary Hook Support. Review steps 3 and 4 in this section for the correct placement.

 

  1. Tighten the 2 screws holding the Rotary Hook Support.

 

  1. After tightening the screws, verify steps 2 and 3

 

  1. Rotary Hook Support Adjustment is now Completed.

 

#6: COMPLETION: Reassembling Hook Covers and Needle Plate Centering

  1. In the Melco OS, got to Tools > Maintenance as shown below.

 mceclip7.png

  1. Click on the Head Timing

 mceclip8.png

  1. Bring the needle to head up by holding down the Adjust button and the Up Arrow.

 mceclip9.png

  1. Attach the Hook Guard.

 mceclip10.png   Or  mceclip11.png    mceclip12.png

 

  1. Attach the Needle Plate, but do not tighten the screws fully.

 mceclip13.png

  1. Lower the needle to the Bottom Center position by holding down the Adjust button and the Down Arrow.

 mceclip14.png

  1. Wiggle the needle plate left and right till the needle is in the middle of the hole. Tighten the screws for the needle plate. Verify the needle is centered in the hole as you tighten the screws.

mceclip15.png   mceclip16.png

The image on the left shows correct needle plate centering.  The right image shows incorrect centering.

 

  1. Bring the needle to head up by holding down the Adjust button and the Up Arrow.

 mceclip17.png

  1. Reinstall the Bobbin Case.

 

  1. Reassembling the Hook Covers and Needle Plate Centering is now Completed.

 

VERIFICATION PHOTOS:

To verify hook adjustments check the following pictures:

mceclip18.png

 

mceclip19.png

 

mceclip20.png

 

 

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