Scraper Bars

The scraper bar is an integral part in the operation of a lithography press. Scraper bars are interchangable, the correct width must be used. Scraper bars are precisly machined to apply even and uniform pressure from the pressure head of the litho press through the tympan, paper and plate into the pressbed.

Length

A minimum one inch margin, from the edge of the drawn area to the edge stone or plate, is essential. The proper sized scraper bar is wider than the paper and more narrow than the stone or plate. The availability of the correct size scraper bar is essential when printing and proofing. Use of an over sized scraper bar will damage the strap and eventually the scraper bar. Undersized scraper bars will not print the entire image correctly.

Variety

A well equipped lithography shop needs to have an extensive selection of scraper bars. It is advised to have scraper bars in a comprehensive range of sizes. The printable area of your largest litho press should be the upper limit of this range. Each litho stone as well as the common plates sizes used by your shop should have scraper bars associated with them. Other scraper bars should be selected as intermediaries in increments of 1/2" to 2". This ensures that there will be a scraper bar available for every conceivable width of print.

Quality

Bar

The design of Takach scraper bars has been fine tuned to achieve the finest print quality while maintaining durability. In order to achieve crisp images the scraper bar must have the proper bevel. If the scraper bar beveled is too sharp excessive wear will occur to the strap. If it is too broad it will produce a coarse impression.

Strap

The strap is a protective wear strip it is advisable, especially in educational settings, to use a strap to protect the scraper bars precision machined surface. These modern UHMW plastic straps provide an extremely low friction surface to reduce printing friction, and are therefore preferable to traditional leather straps. Many private print shops prefer to use scraper bars without straps, as this configuration results in the least amount of friction.

Materials

Polyethylene (plastic)

Polyethylene scraper bars have been sold to satisfied customers worldwide. UHMW plastic strap installed on each bar.

Maple (wood)

These scraper bars are made from the same hard rock maple as our floor model press beds, these scraper bars will provide many years of dependable use. UHMW plastic strap installed on each bar.

Purchasing

Sets

Maple scraper bar sets or polyethylene scraper bar sets save 10% compared to buying individual scraper bars.

• 114" stock set includes:
  • 10"
  • 12"
  • 14"
  • 16"
  • 18"
  • 20"
  • 24"

Or specify any combination of custom lengths that add up to 114"

• 130" stock set includes:
  • 10"
  • 12"
  • 16"
  • 18"
  • 20"
  • 24"
  • 30"

Or specify any combination of custom lengths that add up to 130"

• 170" stock set includes:
  • 12"
  • 16"
  • 20"
  • 24"
  • 30"
  • 32"
  • 36"

Or specify any combination of custom lengths that add up to 130"

Individual

Scraper bar any length of up to 48"

Individual polyethylene scraper bars

individual maple scraper bars

Please note: Last 3 numbers in Item # specify the length of bar desired. 

Example: To order a 12" polyethylene scraper bar,  Item # would be 1300120 for a 12 1/2" bar, Item # would be1300125
Example: To order a 12" maple scraper bar, Item # would be 1301120 for a 12 1/2" bar, Item # would be 1301125

Repair Services

Re-plane and Re-strap

Re-planing is a professional service that requires the scraper bar to be sent to Takach Press where damage to the scraper bar will be assessed . The bevel of the bar will be machined to the optimal condition and the bar will be re-strapped with a low friction UHMW plastic strap. Replane and restrap service (any length scraper bar) $16.00 Bar

Replacement Straps

When a scraper bar strap becomes damaged it can be replaced in the litho shop minimizing down time.

Replacement straps are friction reducing 48" long UHMW plastic may be purchased in bulk. (10 strap minimum)  $4.00 per strap

Care and Maintenance of Scraper Bars

Selecting a Scraper Bar length for Printing

Prior to printing select a scraper bar which has a width larger than the paper to be printed on but smaller than the plate or stone. A margin on the litho stone is needed. It should be at least one inch on all sides. This margin allows for an area of printing pressure engagement and disengagement on the leading and trailing side of the print. The side margin allows for an area which is needed when selecting a scraper bar that is larger than the paper to be printed and smaller than the plate or stone.

Alignment of the Scraper Bar in the Litho Press

A center mark placed on the surface of the scraper bar is aligned with the center of the scraper bar housing. The plate or stone to be printed is then centered under the scraper bar. Centering of the scraper bar is crucial to achieving even printing pressure along the width of the print.

Lubrication During Printing

When printing both the scraper bar and the tympan sheet should have a coat of tympan grease to reduce damage of the strap due to friction. Lubricate the scraper bar strap and tympan often when printing. Excessive wear to the strap and the tympan may occur when lubrication is not present.
Tympan Grease

Cleaning and Storage

The scraper bar should be cleaned of lubricant after printing as well as wiped clean before printing. If the scraper is left with greasy then dirt, dust and other particulates may stick to the grease. These particulates will damage both the scraper bar and the tympan if not properly cleaned prior to its next use. Scraper bars should be stored with the strap facing up to prevent damage to the strap surface when being slid around.

Assessing Damage

Damage to the surface of the scraper bar or to the strap can cause a distinctive printing problem. The emergence of a light streak the length of the print is telltale of damage. Inspection of the scraper bar, the strap and the tympan. Look for damage such as excessive wear, nicks, scratches, dirt or dust. If an improperly size scraper bar was used that was larger than the stone or plate printed then deep gouges will be present in the strap. If this is not corrected early the damage will advance quickly to the scraper bar itself. If the scraper bar is damaged it can be replaned and restraped by Takach Press.