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Call us at 905-624-5536
H.H. Roberts Machinery Limited
1324 Matheson Blvd E., Mississauga, Ontario, Canada. L4W-2Z7, Fax 905-624-9065

HH Roberts / Topwell 4-GL

  • RG model has a back geared head delivering great torque at low rpm.  15 to 750 rpm in low and 75 to 6,000 in high.
  • GL model is direct drive without back gear and is a good simpler head for light alloys and plastic. Speeds are 75 to 6,000 rpm
  • the spindle motor is 3 Hp and can deliver 4-1/2 Hp (30 minutes).  It is a true inverter motor balanced to 7,200 rpm with a integral constant speed blower for cooling.
  • the drive is like a machining center with no vari-discs or mechanical brakes to rob power.  Amost all the power is delivered to the cutter.
  • 12" x 50" table with hardened top  ( 10" x 50" and 10" or 12" x 42" optional )
  • available for 208V, 230V, 460V 3 phase and optionally 220/1/60
  • 32" x 16" travels with the power feed. 35-1/2" without power feed
  • hardened and ground X and Y axes with Turcite counterslide on saddle
  • hardened and ground vertical slideways
  • two peice leadscrew nuts for excellent backlash reduction
  • power feed on table - standard
  • central lubrication system
  • the vector drive head is an in house development that is enjoying success as a replacement head for older Bridgeport's and Bridgeport clones. Click here for details.
  • # 30 or # 40 spindle to accept Cat-V, BT or NMTBA tooling.
    The 40 taper spindle has 3 heavy lower bearings.
  • Acu-Rite , Heidenhain or Fagor readouts
  • coolant system
  • chip pan
  • side splash guards
  • riser blocks
  • cross slde feed
  • knee lift
  • ballscrws on X and Y
  • Elesa delux round handwheels with folding grips
  • air power draw bar
  • E-stop button
  • Halogen worklight
  • timed automatic central lubrication system
  • built in transformer for 120 volt accessories like DRO, power feed and worklight.
Differneces between the 3 and 4 series.

The saddle is 22" wide, about 2" wider than the # 3 models.

The column is heavier, in fact it is the same as that on the #5 models.  The slideways on column and cross slide are box ways with large contact
HH Roberts / Topwell 4-GL advanced knee mill with electronic vector drive head
showing the box ways on the column and knee of the Topwell 4-GL milling machine

spindle bearings on # 40 taper spindle

The top spindle is Towpell's special # 40 taper. There are 3 sets of high precision P4 bearings
at the bottom and a single bearing at the top. This gives extra rigidity and vibration resistance.
We normally set these up to use Cat-V-40 tools.
For comparison, below it is a standard spindle in a Bridgeport type R-8 spindle at the bottom with
only 2 high precision bearings at the bottom.   

Click here to download our knee mill catalogue. Above is the 4-GL with the slideway chip guards removed to show the box ways on the column and the knee.  The power feed is standard equipment. The Anilam digital readout shown, is an option.
Specifications 4-GL 4-RG
Table size 1070 x 254mm, 1270 x 254   or  1270 x 305229mm
10" x 50", 10" x 54"   or  12" x 50"
Table travel 914mm
36 " with optional table
Cross travel 400 mm
15.75 "
Knee travel 406 mm
16 "
Quill diameter 85.725 mm
3 3/8"
Quill travel 127 mm
Ram travel 508 mm
20 "
Spindle motor 3 HP continuous, 4.5 Hp 30 minutes
Spindle taper R8 (Opt.NT-30 or NT-40)
Quill power feeds 0.0381, 0.0762, 0.152 mm / Rev.
Spindle speeds 50 - 4,000 or
75 - 6,000
Lo 15 - 750
Hi 75 - 6,000
Weight 1550 kgs
3,410 lbs
The main differences between this model and the #3 model of the series is the saddle and knee construction.  The # 4 models have a wider saddle running on box style ways, while these # 3 models have traditional dovetail ways.  The column ways are also box ( or square) ways on the # 4 mills and the # 3 models have dovetail ways.  The heads and tables are the same on both.