High-speed, Computer-controlled Buttonholing Indexer

The AC-172N-1790 is a high-speed, computer-controlled buttonholing indexer which achieves higher productivity and consistent buttonholing of top-center plaits.

Product features

  • The preset mechanism helps increase productivity!

    What is the preset mechanism?

    It is the facility that allows placement of the material to be sewn next on the preset board while the sewing machine is engaged in the sewing of the current material.
    Since the automatic buttonholing indexer carries out buttonholing successively, the operator conventionally has had waiting time while the sewing machine is in operation (for buttonholing). JUKI's preset mechanism allows the operator to place the subsequent garment body to be sewn on the preset board while the sewing machine is still engaged in the sewing of the current garment body (so-called overlapping work). Consequently, the operator now can use his/her waiting time effectively during operation to achieve increased productivity.

  • Sub-clamp device which enhances applicability of the sewing machine to vertical-strip patterns

    The sewing machine comes with a newly-developed mechanism which prevents slippage of the material at the time of its delivery from the preset board to the sewing machine. This helps increase applicability of the sewing machine to buttonhole vertical-striped garments.
    The independent sub-clamp mechanism of the carriage unit on the sewing machine head securely clamp the material upon delivery of the material from the preset board to the sewing machine, thereby preventing the material from slipping out of position. As a result, the sewing machine is allowed to achieve accurate buttonholing of top-center plaits with consistency.

Basic performance

  • High-performance indexer mechanism

    A stepping motor controls material feed amounts in increments of 0.1 mm to feed materials with both consistency and accuracy. The machine is able to sew 1 to 20 buttonholes and stores 20 different stitching patterns in its memory.
    The sewing machine is provided as standard with a facility that moves the carriage unit synchronously with the operation of the sewing machine during sewing, thereby enabling accurate and unfailing feed of the material while preventing material slack.

  • The sewing machine comes with the LBH-1790 head, which is highly evaluated in terms of functions and performance

    The AC-172N-1790 is equipped with the highly-evaluated LBH-1790 as its machine head. The needle thread tension is changed over without fail at bank parts and bartacking parts of a buttonhole by means of the highest sewing speed of 4,200 sti/min and the unique active tension (electronic thread tension control mechanism), thereby achieving beautiful-shaped buttonholes.
    In addition, fastening stitches prevent the seams from unraveling at the end of sewing. It is also possible to program other stitching styles such as double buttonholing.

  • Indexer operation panel

    The adjusting keys which are frequently operated by the operator for adjusting buttonholing are arranged in a similar configuration to the standard panel for the LBH-1790. The operator is therefore able to directly adjust the buttonholing to achieve improved operability.

  • Oil stains on the sewing product are eliminated

    Thanks to our advanced dry-head technology, no lubrication is required expect for the hook section. This eliminates oil stains on the sewing product. Only a minute-quantity of clean oil is fed to the hook section from the oil tank. The machine can be completely changed into a dry-head machine by replacing the hook with an optional non-lubricated hook.


    It is a device for automatically stacking garment bodies after having been buttonholed. (Space-saving type stacker built inside the main body)
    The stacker, which clamps even narrow garment bodies without fail, increases the efficiency of the material taking/stacking operation, thereby helping further increase productivity.


    This switch is operated with the knee to actuate the sewing machine (sub-clamp device).
    The knee switch can be turned on by the operator with his/her knee while he/she still holds a garment body on the sewing machine with both hands. As a result, the operator is able to place the material securely on the sewing machine to reduce the time required for  accurate positioning of the material. Needless to say, a hand switch is also provided.
    In addition, if the operator turns on the switch after having placed the material on the sewing machine, the sub-clamp device will automatically bring the subsequent material to the sewing position after the completion of buttonholing of the current material to allow the sewing machine to immediately start the next buttonholing. This function works effectively, especially in cases where the operator is operating two or more sewing machines or is carrying out other work simultaneously.


Model name AC-172N-1790
Machine head LBH-1790(exclusive machine head for AC)
Max. sewing speed 4,200 sti/min (normal:3,600 sti/min)*
Sewing dimension Standard : Width 4mm x length 25mm
(Max. Width 6mm x length 120mm by repiacing parts)
Cloth trimming length 6.4~19.1mm (1/4~3/4 inch)
Lift of the work clamp foot Max.14mm
Needle DPx5 #11J~#14J
(Needle installed at the time of delivery #11J)
Feed system Stepping motor
Feed direction Right (for men's garments) or left (for ladies' garments)
Unit of feed amount 0.1mm
Number of patterns
that can be input
20 patterns
Number of buttonholes 1~20 pcs.
Power requirement 3-phase 200~240V, Single-phase 220~240V
Power consumption 1,000VA
Compressed air and
air consumption
0.5MPa (5kg/cm²) 240Nl/min
Dimensions 1,910(W) x 850(D)x920mm(H)
(Up to the preset table surface)
Total weight 300kg
Presetting device Provided as standard
Stacker Provided as standard
Pair stacking Possible

*"sti/min" stands for "Stitches per Minute."


A Buttonhole
(0.1mm steps)
B Total feeding
C Distance from the
top end of the
garment body to
the first buttonhole
D Distance from the
front side end of the
garment body to
the buttonhole
Applicable size of
the garment body
to be sewn

Non-lubricated hook (option)

Name of part Part No.
RP hook (asm.) 40006345
RP bobbin case 40006349
Hook sleeve (asm.) 13729603
Screws SS8660612TP(4pcs.)

*By the installation of nonlubricated hook, the machine is changed to be a fully dry-head machine. (In this case, the maximum sewing speed will be 3,300sti/min)

When you place orders



inch mm Mark
1/4 6.4 F B2702047F00
3/8 9.5 K B2702047K00A
7/16 11.1 I B2702047I00
1/2 12.7 L B2702047L00A
9/16 14.3 V B2702047V00
5/8 15.9 M B2702047M00A
11/16 17.5 A B2702047A00
3/4 19.1 N B2702047N00
7/8 22.2 P B2702047P00
1 25.4 Q B2702047Q00A
1-1/14 31.8 S B2702047S00A
Guage THROAT PLATE PRESSER (Stitch width 5mm): A×B 4×25 PRESSER (Stitch width 5mm): A×B 5×35 PRESSER (Stitch width 5mm): A×B 5×41
Specification P/N Remarks A×B P/N Remarks P/N P/N
Standard: S 40027553 S5 1.4×6.2 B1552781000A Mounted on machine B1552782000 B1552783000
For knits:K 40027554 K5 1.2×6.2 D1508771K00A   D1508772K00 D1508773K00