Stitching Wire

• Round Bookbinders Wire Chart
• Flat Bookbinders Wire Chart
• Standard Diameters Chart
• Spools

Stitching Wire:

Stitching Wire has evolved as the industry has changed. Stitching wire is now a highly tuned part of the printing world. Quality of Finish, Size, Cast, Camber, Tensile, Path of Wire, Spool Sizes, and De-spooling Equipment are all major factors in how stitching wire is going to perform in the field. With the continued demand for increased run speeds and overall profit, high quality stitching wire and proper machine setup are a must.

Quality of Finish:

An ideal wire is chrome-like in appearance with special friction reducing additives to resist peeling and flaking while providing a superior workability in all bending and forming applications. 

Cast and Camber (Helix):

Commercially produced, stitching wire is not straight. Each spool size has a desired curvature of the wire. The radial or circular curvature is known as “Cast.” Cast is measured as the diameter of a free turn of wire. The axial component is referred to as “Camber.” Camber is measured at the offset in the ends of one turn of freely hanging wire. A large cast and small camber are characteristics of a high quality wire. This allows the wire to go into the stitching head smoother, producing less drag, and will provide fewer dropped stitches. The stitching head will work more efficiently with less energy and maintenance.

Wire Tensile:

Wire Tensile is the pull required to break the wire and is measured in pounds per square inch (PSI). The higher the breaking point, the stiffer the wire. High quality stitching wire has a tensile range of 135,000 to 165,000 PSI. A tensile above 165,000 PSI will wear out parts in your stitching head prematurely, causing maintenance costs and down time. High tensile wire can also wear out the knives in a trimmer section prematurely. The increased hardness of the stitching wire will nick a trimmer section’s knives more severely when struck during saddle stitcher jams. A tensile below 135,000 PSI will cause the stitching wire to be soft and not properly form a stitch.

High tensile stitching wires are available in the industry, but the cost benefits of using a high tensile wire with a thinner diameter on thicker applications is outweighed by the cost of premature wear on stitching heads and trimmer section knives. 

Path of Wire:

A clean path for the stitching wire from the spool to the stitching head is critical in getting a positive stitching outcome. The stitching wire coatings can be easily chipped, scraped, and damaged by running the wire past an unprotected steel bracket, worn wire guides, spring tubes, and dirty felt pads. These areas must be checked frequently and rotated or replaced on a regular schedule. Wire guide springs and felt pads are a normal wear part on any stitching head.  Flat spots on guides and springs along with a dirty felt pad wiping system can cause flaking issues that will jam your stitching head, stop production, and cause additional maintenance and repair costs.

The Right Size Stitching Wire for the Job:

The majority of the stitching wire used in today’s binderies and in-line stitching operations is 24 and 25 gauge. The difference in size from 24 Gauge (.023”) to 25 gauge (.0204”) is .0026”. This small amount may seem insignificant, but means a lot in terms of yield.

A 24 Gauge wire has 8,496 inches per pound of wire and 25 Gauge has 10,800 inches per pound. This amounts to a 21.3% difference in product yield, which translates into 21.3% more staples if you use 25 Gauge over 24 Gauge. In simpler terms if you imagine a staple or stitch being 1 inch, you would have 2,304 more staples by using the 25 Gauge wire over 24 Gauge

Choose the right wire for the job.

25 gauge stitching wire’s recommended thickness of work is 1/16 to 7/32 of an inch

24 gauge stitching wire’s recommended thickness of work is 1/16 – ¼ of an inch

These are only suggestions as paper type, density, coatings, and stitcher set up can change the stitching wire size required.

Physically check the size of your stitching wire and don’t believe what is on the label until you are sure. An oversized wire that is labeled 25 gauge but is actually larger in size means you are not getting what you are paying for.

Oversized wire substantially affects the yield of your wire along with increasing the amount you end up paying at the post office in postage.

Spool Sizes and De-Spooling Equipment:

Stitching wire comes on many different spools and generally range from 5 lbs to 1600 lbs in size. Primary usage and machine type determines the size spool you require, but running speeds and space availability also play a role. Stand alone stitchers that are hand fed usually use 5 or 10 lb spools. Collators with stitchers used for short runs of 5 to 10,000 books can also use this type of spool. Saddle stitching longer, mid-range runs will use 35, 40, 70, or 100 lb spools. High speed saddles stitchers, and web operations using in-line stitchers will use 200, 250, 1,000, and 1600 lb spools. A larger spool of wire has both economical and production advantages. Larger spools cost less per pound of stitching wire to manufacture. Larger spools require fewer spool changes during the manufacturing process.

Different size spools have different characteristics that can give the end user advantages. For instance, as stated earlier, a larger circle diameter improves the performance of stitching heads with less friction due to less straightening required and fewer dropped stitches. The larger diameter spools such as the 200, 250, 1,000 and 1600 lb spools have larger circle diameters improving stitcher head performance since less straightening is required.

Proper de-spooling equipment is essential to compliment the high quality wire you use. Matching the correct de-spooler with the spool is essential to problem free production.

Stitching Wire Data Table - Number of stitches in 1lb. of Wire

Round Bookbinders Wire

Flat Bookbinders Wire

Standard Diameters

Spools

US ID	5# Euro	5#	10#	35# Euro	40#	70#	100#	200#	200#	250#	1000#	1000#
Photo
Int. ID	GB2	5	10	BS15	BB20	BB35	K355	DC100	MP100	MN125	RR500	FB500
Weight of wire
Kg	2,3	2,3	4,5	16	18,5	32	48	91	91	113,5	454	370
Lbs	5	5	10	35	40	70	100	200	200	250	1000	815
Ø Flange
mm	132	130	152	300	202	255	355	355	355	378	595	572
Inches	5 1/8	5-1/4	6	11-13/16	7-61/64	10-3/64	14	14	14	14-7/8	23-1/2	22.5
Ø Arbor
mm	18	16	16	52	32	33	36	125	125	32	79	559
Inches	11/16	5/8	5/8	2-3/64	1-17/64	1-19/64	1-27/64	4 9/10	4 9/10	1-1/14	3-1/8	22
Ø Barrel
mm	66	70	89	212	110	118	224	220	220	188	313	305
Inches	2 5/8	2-3/4	3-1/2	8-11/32	4-21/64	4-41/64	8-55/64	8 2/3	8 2/3	7-7/16	12-5/16	12
Overall Width
mm	58	62	110	100	179	166	200	355	355	357	613	660
Inches	2 3/8	3-1/4	4-1/4	3-15/16	7-3/64	6-17/32	7-7/8	14	14	14	24-1/8	26
Skid weight
Kg	58	907	907	1143	907	1016	816	816	816	680	907	370
Lbs	2000	2000	2000	2520	2000	2240	1800	1800	1800	1500	2000	815

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