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Hints and Tips

DUAL MASTER

Before grinding

Clean the cutting units before grinding. A good visual inspection means problems can be spotted and fixed before they become an issue.

Always check that the mower that you are about to grind has good bearings. Poor bearing will affect the grinding results and the quality of cut.

Sequence for grinding

Spin grind first to remove any taper in the reel. This produces an even reel to work from. Once the reel has been trued by spinning, there is no need to make any adjustments to the position of the unit on the grinder for relief grinding. The relief grind will then be perfectly even across the width of the unit.

Setting Relief angles

Set the adjuster for fine positioning of the blade rest in the centre of its travel and get close to the required relief angle using the coarse adjuster for grindstone height first. Use the fine adjuster only for final setting relative to the angle gauge.

Setting traverse stops

Use the LED indicator on the operator panel for initial set up. Set the fine adjusters on the traverse stops in a position of mid adjustment and position them so that the led just changes state. This is the switch trigger point. Before any actual grinding use the fine adjusters to set the stop and reverse points exactly where required.

Maintenance and Service

Remember to clean the Rails on the Dual Master at the end of each days grinding.

For good results dress the stone regularly on the Dual Master.

If machines are not being used for several days, lightly oil the rails on the Dual Master, but remember to wipe off before use.

Visually inspect any new stone for cracks and/or damage before fitting. DO NOT use a damaged stone.

Ensure that there is no dirt or debris between the sleeve and nut flanges and the sides of the grindstone.


As with any precision machine, a small amount of time and trouble taken on routine maintenance and cleaning will show benefits in overall efficiency and component life.

NOTE: Failure to carry out appropriate cleaning and maintenance will invalidate the warranty agreement between Bernhard and Company and the machine owner – operator.

  • Lubrication – A small amount of light oil should be applied to sliding and rotating surfaces of feed screws, slides, etc. and to the traverse chain as required, at approximately 3 monthly intervals, depending upon the work load of the machine.
  • Traverse chain – This should be adjusted as required by removing the cover at the left hand end of the machine and adjusting the position of the traverse chain idler sprocket.
  • Guide Rails – These should be kept as clean as possible. There are felt wipers fitted to the carriage cover but these will not remove all dust and debris. Wipe the rails down daily and spray with Bernhard Clean and Lube spray, WD40® or similar at the end of each days grinding.

NOTE 1: Always wipe the rails clean of oil or spray before ANY grinding as these will cause dust and debris to during grinder operation.

NOTE 2: Rolling action of the carriage bearings along the guide rails may eventually result in the appearance of narrow ‘flats’ on the rails where the bearings run. These flats may be work hardened areas which have no effect on machine accuracy or (if cleaning is not effective) grinding debris rolled and compacted onto the rail surface. This can affect grinding and should be cleaned off with a soft scraper.

  • Index mechanism – This should be cleaned after each days grinding. Sliding surfaces can be sprayed with WD40® or equivalent but should be wiped clean before grinding.
  • Torque control clutch – This may squeak or squeal for a while with no problem but if it starts to ‘squeak’ badly, it should be stripped and any friction washer dust removed. The Friction washer can be replaced if excessively worn.