Causes of bad stitch draw-in

If the stich is not drawn in well while sewing, the causes often are:

• the bobbin thread is too tight
• the turning of the bobbin thread is uneven
• the bobbin thread is too loose
• the feed is unsteady or does not match temporally to the sewing mechanism
• the stich hole or the sewing foot slot are not rounded well
• the thread is twisted too much

For double lockstich sewing machines, needle and bobbin thread must be calibrated to each other in a way that the plaiting of needle and bobbin thread is drawn into the middle of the fabric layers. This ensures a maximum elasticity and durability of the seam.

The bobbin thread tension mechanism consists of a brake spring and a tension spring who are fastened on the outer side of the bobbin case and press to the case wall. While threading, the bobbin thread will be led behind the tension spring. The bobbin thread tension mechanism is meant to brake and control the roll-off of the bobbin thread. The tension can be adjusted by a screw..

Bobbin thread mechansim: Bobbin case wall (Spulengehäusewand), fastening screw (Befestigungsschraube), tension spring (Spannungsfeder), bobbin thread (Greiferfaden)

The thread tensions for the double chain stitch are adjusted correctly when the needle thread creates a point-shaped loop on the bottom side of the fabric and when the hook thread can be drawn easiliy through the loop. The regulation of the hook thread tension can be made by a disc tension or wheel tension.

Causes of skip stiches

Skip stiches happen when the hook point could not catch the needle thread loop.
This can be caused by:

• bent needle
• needle is not inserted correctly
• the relation of the needle to the hook or vice versa has changed (needle bar rise, distance between hook point and needle, height of needle to the hook point)
• needle thread loop is not created (needle thread is too elastic or too tight); the movement of the thread take up spring is too big
• the throat plate (needle plate) is bent downwards or the stitch hole is too wide
• the fabric does not rest correctly on the throat plate
• the pressure of the presser bar is too low







Skip stich

Benefits of the M-Type series for maintenance and repairs

The M-Type, the best selling triple feed machine for medium heavy duty sewing ever, offers not only unbeatable sewing performance but also a lot of benefits with regard to service and maintenance.

The biggest advantages are:

• Low service and repair cost due to 30% less mechanical parts than in the former 767 series. Less parts reduce the probability of defects and save cost for stocking spare parts.
• Only 5 tools for the adjustment of the complete machine. Who is using different machine types like flatbed, postbed, long-arm, etc., will appreciate that the same tools can be used for all types. It will also save time for technician training.
• Quick machine cover disassembly. Only 10 screws must be unfastened to disassemble all covers before you can already start servicing the machine. This will save valuable working time.
• Many sewing gauges of class 767 and other Dürkopp Adler machines can be used. Who has some gauge parts of those machines on stock can use them on the M-Type, too. See an overview of the usable parts. Also a couple of  piping and zipper feet of other machines are used on the M-Type.
• An oil control glass with warning light will avoid late oil recharge and will increase the machine lifetime.

Servicing the machine can be supported by a preventive maintenance plan. With this plan, all maintenance work and spare part consumption can easily be documented.

Open product overview M-Type




Dürkopp Adler M-Type class 867-140342

Preventive Maintenance for Dürkopp Adler M-Type machines

The revolutionary modular concept of the medium-heavy duty M-Type series of Dürkopp Adler facilitates the maintenance not only of a single machine but also of more machines of the same series with different equipment. Due to the usage of assembly modules, most of the mechanical spare parts in different machine classes are equal.

This makes the whole maintenance and repair process much easier: If the technician knows one M-Type machine class, he knows all classes and will recognize most of the elements in other M-Type classes. With this, the spare parts stock can be reduced. The maintenance for all M-Type classes is equal.

This enables us to standardize the preventive maintenance. Dürkopp Adler has developed an M-Type maintenance plan which fits for all classes and can be used even for previous triple feed machines of Dürkopp Adler. With the maintenance plan, all maintenance measures can be documented and all following measures can be implemented. There is also a useful table to note the wear & tear parts which must be ordered.

So, the responsible service manager can lead, control and repeat a standardized preventive maintenance and make sure that the productivity in his company or department will be as high as possible.