best overlock machine

Industrial Machines

This guide has general information about industrial overlock machines and gives an overview of some popular industrial overlock machine models that are now in production. The recommendations given in this guide are my recommendations and opinions. Compare them with your requirements and decide what will work for you. I have no connection of any kind with the companies that make these machines. My criteria for recommending machines is value, reliability, ease of use and flexibility. The prices that are listed were at the time of writing of the book and may change.

Industrial sergers (usually called overlock machines) are built for continuous use in a production setting although they can also be used for small business or serious home use. Industrial sergers run at speeds of 4000 SPM to 9000 SPM depending on the model.

Industrial sergers are made for a specific range of stitch types, needle sizes, thread and fabrics. Make sure to get the right machine for the applications you need. There are many sub-models with special capabilities (Sub models are different versions of a model like 747A or 747B). Take your time and do your research!

Most industrial sergers can only make one stitch type. For this reason they are used primarily for high quantity production in a factory environment or for applications like hemming in an alteration shop that require the same stitch all the time. For product design work or small quantity work that requires a flexible machine that can make several stitch types a semi-pro (home) machine like the Juki MO-655 or MO-735 is preferable. The home machine is adjustable to a wide range of needle sizes and thread thicknesses. Most industrial machines can be converted from one sub-model configuration to another (such as from light to heavy materials) but this involves ordering parts that must be changed (feed dogs, loopers, needle plates, etc) and readjusting the machine with the new parts. This is expensive and time consuming.

Manufactures

Juki is the world leader in industrial overlock machines. I usually use them to compare other machines against. There are many other companies that make good industrial sergers of similar design such as Siruba, Pegasus, Brother, Rimoldi, Gemsy, Yamata (China Feiyue), etc. Siruba and Gemsy are now making direct drive machines with built in servo motors.

Service and parts – Check for service and parts availability in your country and city before you buy a machine. You can get parts and service for Juki almost anywhere in the world.

Tables and motors

Most industrial sergers are mounted in heavy tables and use large external motors mounted under the the table, although there are some new models that have direct drive servo motors built into the body of the machine. The external motors are the same as those used for industrial sewing machines.

Industrial sergers use recessed mountings in the table and can not use the same tables as industrial sewing machines. The tables have a hinged front section that lifts up for access to the lower parts of the machine for threading.

Lubrication systems

Industrial sergers have a lubrication system with an oil pump and oil reservoir. The lubrication system allows the machine to be used many hours a day at high speeds with little wear of the moving parts. When industrial sergers are shipped the oil must be drained and then replaced before the machine is used again. If the oil is not removed during shipment the oil may leak from the machine. Some models have oil free bearings or reduce oil bearings in the needle bar and the feed dog area to prevent oil contamination of the fabric going though the machine.

Needles

Most industrial overlock machines use the DCx27 needle system, some heavy-duty models use a DOx5 needle system. A standard duty machine will be set up for needles of about size 11 to 14. Heavy duty models are set up for size 16 or 18 needles and very heavy models are set up for size 21 or 23. Some industrial machines are set up for a certain application with a set needle size and require readjustment of the looper clearance to change needle size. Read the owners manual and specifications for your machine for recommended needle sizes to find out if adjustments are needed before you change needle sizes.

Features & Capabilities

Some of the features and capabilities that differ between models are as follows:

  • Stitches, threads and needles – Most common are:

 

  • 3 thread (1 needle) type 504 Overlock stitch.
  • 4 thread (2 needle) type 514 Overlock stitch.
  • 5 thread (2 needle) type 516 Safety stitch (504 overlock + 401 chain stitch).

 

  • Needle gage – This is the distance between the needles on two needle machines. For most machines it is between 2mm and 5mm. This is a set distance, it can not be changed so make sure that you get a machine with the needle gage that you need.
  • Easy to operate controls – Some models are laid out with the controls in locations that make them easier to operate.
  • Differential Feed – Most newer machines have differential feed. Differential feed uses separately adjustable feed dogs (one in front of the needle and the other behind the needle) to stretch or compress the fabric and prevent bunching or miss-feeding. This is a big advantage when sewing hard to handle fabrics such as knits or fabrics with slippery surfaces.
  • Top feed – Some heavy-duty machines have upper feed claws that move similar to a walking foot sewing machine. This is called “top feed”, “upper and lower feed” or “tractor feed” depending on the manufacturer. Some models have two sets of top feed claws (front and back) to allow differential feed on both the top and bottom of the fabric.
  • Standard or heavy-duty – Most models have both standard duty and heavy-duty sub-classes. The standard sub-classes are set up for small and medium sized needles and feed dogs with finer teeth. The heavy-duty sub-classes are set up for larger size needles, loopers with extra clearance, feed dogs with course teeth and possibly some other modifications like longer stitch lengths and higher foot clearance (standard foot clearance is 6mm or 7mm, heavy models have a foot clearance from 7mm to about 11mm.
  • Stitch length – Most newer standard duty machines can vary the stitch length from .8mm to 4mm. Most heavy duty machines can vary the stitch length from 1.5mm to 5mm. Some models have a set stitch length that can not be changed.
  • Overlock Stitch width – This is the width of the overlock portion of the stitch. For three and four thread machines this is the total stitch width. For safety stitch machines the needle gage is added to the overlock stitch width to the the total width of the safety stitch.
  • Double take up – Some models have thread take up mechanisms for both the needle threads and looper threads for more even tension and allowing lighter tensions when desired.
  • Maximum Speed – Industrial overlock machines have a maximum speed from 4000 SPM to 9000 SPM depending on the model. The actual top speed when in use is determined by the motor speed and the drive ratios of the pulleys. In most cases machines are set up so they run at less then the maximum speed. This is for increased reliability and to provide a safety margin for difficult conditions (thread or fabric problems, feed problems, etc).
  • Oil free needle bar – Some models have oil free bearings on the needle bar to keep oil from getting on the fabric as it is being sewn.
  • Direct drive servo motor – Some models now have motors that are built into the body of the machine. These machines have no drive belt. This reduces complexity and improves reliability. These machines are far more portable.
  • Cylinder bed – Some machines have a cylinder bed (like a free arm on a home machine) that can be changed to a flat bed.
  • Auto chain cutter – Cuts the chain automatically at the end of the seam.
  • Accessories – Cut fabric collector bags, vacuum collectors, tape feeders, elastic feeders, auxiliary puller feed systems.

New machines

Because of modern manufacturing processes such as CNC machining the cost of many types of industrial machines have decreased over the last 20 years. Computer aided design has resulted in smoother running more reliable machines.

The following machines are the best value in their price range and are all good machines. If this is your first industrial machine check out the availability of parts and service in your location, or just get a Juki machine. Juki’s may be slightly more expensive but they are serviced by just about all industrial service shops anywhere in the world.

Make sure that you match the machine to your needs. Industrial sergers are not as generalized as home sergers, they are set up for a more specific range of stitch types and materials. If you need to sew heavy fabric make sure to get a machine that is set up for heavy fabric and make sure that the machine can accept the needle sizes you need and can make the stitch types you need. Some industrial sergers can only make one stitch type and are set up for one weight of fabric. Take your time and do your research!

Gemsy GEM737F, GEM747F, GEM757F ($599 ot $699 on-line sellers) – These standard workhorse 3, 4 and 5 thread models come in a wide range of submodels. “H” models are heavy duty with size 18 needles. Check for availability of parts and service in your country. Gemsy makes a large range of other models as well.

Yamata (China Feiyue) FY737A, FY747A, FY757A and similar models ($780 eBay sellers) – These standard workhorse 3, 4 and 5 thread models come in a wide range of submodels. Availability of parts is good in the US because Yamata has an office and distribution center in Florida, check for availability of parts and service in your country. Yamata makes a large range of other models as well.

Siruba 700K series (737, 747, 757 and similar models) ($850 on-line sellers) – These standard workhorse 3, 4 and 5 thread models come in a wide range of submodels. “UX” submodels are heavy duty. Availability of parts is good in the US because Siruba is distributed by several large industrial dealers, check for availability of parts and service in your country. Siruba makes a large range of other models as well.

Siruba 700Q series Direct drive ($1295 eBay sellers) – These machines have built in servo motors and the motor electronics are also built into the body of the machine. This results in energy efficiency and the machine is more portable. 3, 4, 5 and 6 thread models come in a wide range of submodels.

Juki MO-6700 series (6714S $1487 Amazon) – These standard workhorse 3, 4 and 5 thread models come in a wide range of submodels. “H” submodels are heavy duty. A wide range of attachments are available for these machines. “6700D models are semi-dry head machines (needle bar and upper looper do not use oil).

Juki MO-6900 series (6916S $1750 Amazon) – High speed models (8000 SPM) with improved tension systems. There are 3, 4 and 5 thread models that come in a wide range of submodels. “H” submodels are heavy duty. A wide range of attachments are available for these machines. “J” models are for extra heavy materials and have tractor feed “C” models are cylinder bed.

Merrow Machine – This is one of the only surviving US based sewing machine companies. They make many types of overlock machines and they will make custom machines for your specific application (even if you only need a single machine). Check out their web site to get more info about their models.

  • The MG-3 series models are hemming machines and make a 3 thread overlock stitch type 504. They can also be used for many decorative applications and make the classic merrowed edge.
  • The MG-4 series models are 2/3 thread and make a type 514 stitch. The MG-4FO makes an improved flatlock type stitch for active-ware and other applications.
  • The 70, 71 and 72 series models make the butt seam stitch type 501. Some models of these machines are very heavy-duty and can sew carpet and other thick materials.
  • The 18 series models make a single thread crochet stitch.

Used Machines

In general there is little reason to buy a used industrial overlock machine unless it is fully tested, running perfectly and is being offered at a very low price. The reason is that very good new machines are now available for under $1000. Because most industrial overlock machines are specialized for a specific type of work it is unlikely that a used machine is of the correct subclass for the type of work that you need. Be sure to check used machines for leaking oil seals around the needle bar, loopers and feed dog area.