Used Type 51 AR 21 82.7″ Knife & Surface Grinder

Machine Information

Main Machine Base:

  • Box/Cellular Construction – extremely Heavy throughout
  • Entire Base is Stress Relieved
  • Interior of Base is very open for easy access (lots of clearance) and cleaning (Bed Knives and Tub)
  • Easily Aligned and Leveled from outside along the length of the machine.

      (We will be happy to discuss our recommendations regarding the important foundation requirements under the machine).

Machine Ways:

  • The Reform Carriage Design allows Easy Access for Operation and Wheel Changing and Adjustment from the front of the machine (not the rear of the machine as on some competitive machines).
  • Machine Ways were Precision Machined prior to installation of Hardened Precision Ground Way Strips (Steel Bands) on the Tops of the ways as well as the rear side guiding ways.
  • The Carriage Rides on Hardened Precision Ground Steel Bands (Wear Strips) along the length of the base on the tops and sides of ways which can be easily and inexpensively replaced if need be after some years of use. This way if ever damaged or as they wear then they can be easily and inexpensively replaced in order to maintain the accuracy of the ways and machine. This is important as there is always the possibility of damage and /or wear. The long term life of the accuracy of the machine is fairly easily maintained and after years of operation with proper cleaning & maintenance the machine ways can be easily restored for improved accuracy if desired
  • Adjustable Way Wipers also included. As a result of having the way wipers and the replaceable steel bands – Accordion Way covers are not required where they are required for machines equipped with hardened way in order to protect them as any wear or damage will affect the grinding accuracy of such a grinder.

Grinding Head Carriage

  • The Carriage is Wide with Maximum Distance between bearings in order to get maximum stability and accuracy while operating. The carriage is Stress Relieved and is made of oversized, non-distorting, vibration-damping material
  • The Carriage Design also provides Even Load Distribution and Maximum Rigidity.
  • The Grinding Head Carriage is carried on 4 Horizontal Re-adjustable with race roller bearings
  • 4 other bearings are used for Carriage Side Alignment. This system ensures a very accurate, easily adjustable carriage transmission system.
  • Grinding Motor Slides – Grinding head mounted on long hardened and ground flat guide and are adjustable for wear.



  • Precision Grinding Motor – 11 kw / 15 HP – 1750 RPM (continuous duty rating), Dynamically Balanced & Manufactured by “Reform Motor Division”
  • Extra heavy duty, high precision Grinding Head Motor Spindle, mounted in precision taper roller bearings.
  • Any bearing play can be easily taken up with a special nut assembly on the bottom of the grinding head motor.
  • Motor is Totally Enclosed, sealed and windings are encapsulated in Epoxy.
  • Head is Slewable (Tiltable) for Concave & Surface Grinding.
  • Head is Cross-Adjustable for precision hollow positioning
  • 10” Diameter Grinding Wheel & Backing Plate


Downfeed & Control Of Grinding Head

  • The Vertical Feed of the Grinding Head is through the use of a Precision Motor Drive Motor which is directly coupled to a Vertical Heavy Screw (with Special Nut Assembly), completely eliminating any play, which might develop over the life of the machine.
  • For highest grinding precision, the downfeed screw is axially pre-tightened with a combined thrust-radial bearing corresponding to the grinding motor and carriage weights, in order to ensure automatic weight balancing. The guide ways, & spindle gear are mounted under covers, additionally protected with wipers and the maximum up/down movement pre-tested with limit switches.
  • Power Rise and Fall to grinding head assembly via electrical control giving you positive quick and exact positioning as desired
  • Automatic Mechanical Down-feed System utilizing a Special motor(for quick up/down) enables the operator to preset the machine with a Set Finish Point so that the grinder will proceed at a certain amount of down feed per stroke, back and forth and when the down feed cycle is completed then the machine goes into the Spark-Out Cycle, which is a preset number of strokes back and forth.
  • Note: With this the operator can do other jobs with the machine automatically grinding and then with auto shutdown at the end of the preset program.

Grinding Programs

  • Grinding Cycle
  • Roughing
  • Finishing
  • Spark Out
  • Return of Head to Start Position for Re-start
  • Mechanical Automatic Down feed is Infinitely Variable .0002” to .008” per pass (0.005 to 0.2 mm/pass)