Docstoc

The first time I saw this Bandsaw was

Document Sample
The first time I saw this Bandsaw was Powered By Docstoc
					     USER REPORT
     JET VBS-18MW
     Metal Wood Bandsaw
     by Anthony Burnett

     T
            he first time I saw this Bandsaw was       on the obvious physical changes
            at the Brisbane Timber & Working           between this and previous JET
            with Wood Show (Photo.2). The              Bandsaws.
     doors were open and even from a dis-                  Over the past decade or more,
     tance I could see the wheels rotating             JET has gained a great deal of
     slowly. When I got right up to the mach-          respect for the strength of the
     ine, I thought at first it was a variant of the   underlying frame on which their
     JET 18" bandsaw made solely for cutting           machines are constructed.
     metal.                                                Until recently, JET Bandsaws
         It took a moment to realise it was a          had a rectangular, welded steel box
     variable speed machine that would be              section column that tapered on one
     equally at home cutting wood, metal and           side from bottom to top. This has
     many other materials. That made it much           been replaced on the 18MW by a
     more interesting, particularly when I dis-        triangular section column which
     covered that the machine could be quick-          appears and probably is, even
     ly converted from one use to the other —          stronger (Photo.3). The rest of the
     the longest part of the conversion being          construction (for the top wheel
     the blade change!                                 structure and base), is also of thick,
         The word revolutionary is often ap-           welded plate steel, consistent with
     plied without much meaning but in this            the strength of the column.
     instance, it may be justified. I’ve discov-           The strength and integrity of a
     ered that there have been other bandsaws          bandsaw’s construction are vital to
     with low speed capabilities though none           its function. If there is any move-
                                                                                                                                        Photo.1
     I can locate so low as this, and if there is      ment in the head of a bandsaw
     another machine with the same capabili-           when cutting forces are exerted on
     ties right now, the manufacturers must be         the blade, the blade will move
     keeping it well hidden.                           slightly and the cut will go off track.        work. Jason Burgmann of Benchworks
         Having eventually got my hands on a           No amount of adjustment can be made to         (Emu Plains, Sydney, NSW), however,
     VBS-18MW, I found that in addition to its         compensate for this, since the degree to       suggests that it is possible to actually feel
     ability to handle materials that no one           which the blade wanders depends on the         the movement in some machines by
     would sensibly offer to a conventional            force applied, so the operation of the         pulling on the worktable while shoving
     wood bandsaw, it has specific benefits for        machine can become a nightmare.                hard against the machine’s head with the
     the woodworker, too.                                  I have always thought that the only        other hand (Photo.4). Certainly, if you try
         Before discussing its cutting versatility,    way to assess the integrity of construction    this on a JET Bandsaw, you will feel no
     however, a few comments are warranted             of a bandsaw is by using it for a variety of   ‘give’ at all.
     Photo.2: First seen at the Brisbane               Photo.3: The new triangular column on          Photo.4: Jason Burgmann (Benchworks,
     Timber & Working with Wood Show                   the VBS-18MW                                   Emu Plains, NSW) does the shove test




44      Australian Woodworker      September/October ’08
    Another difference between the
18MW and earlier JET bandsaws is the                                                                    Table 1
slight curvature of the front panels on the                                                             Material                Speed
doors. This is probably not just a cosmet-                                                              Steel St37                40
ic change (though the curves are attrac-                                                                Carbon Steel C15          40
tive) since the new panels are more likely                                                              Carbon Steel C45          20
to resist the temptation to vibrate.                                                                    Alloy Steel               20
    The major features of JET 18" Band-                                                                 Stainless Steel           20
saws were covered in a USER Report on                                                                   Copper                    20
the JWBS-18X which appeared in Issue                                                                    Titanium                  20
#133 (June, 2007) of The Australian                                                                     Cast Iron                 20
Woodworker. The editor has, however,                                                                    Brass                     40
asked me to include a brief discussion of                                                               Al-bronze                 40
these for those who may not have access                                                                 Aluminium                 70
to that Issue. But first I want to concen-
trate on the special characteristics of the
VBS-18MW.                                                                                            up to a few millimetres thick. This is the
    The unique feature of this bandsaw is                                                            kind of material most likely to be encoun-
its ability to be set up quickly to cut at 20,                                                       tered in a workshop that handles both
40, 70, 250, 450 or 820 metres per min-                                                              metals and wood.
ute.                                                                                                     In every case, the cutting action was
    The highest speed of the JWBS-MW is                                                              fast and easy to control. Heavier materi-
                                                 Photo.5: New curved doors should                    als can of course, be cut, provided the
820m/min, little different from the blade        reduce chances of vibration
speed of a standard JET 18" bandsaw                                                                  work is undertaken with care. There is no
which is far too high for cutting metals.                                                            shortage of power from the gutsy 3hp*
                                                 pulled out to its maximum limit. The                motor. (An optional 3.8hp 3-phase motor
    The speed demanded for safe, efficient       lever has two positions — IN for high               is also available.)
cutting of metals varies from about              speeds and OUT for low speeds.
20m/min for hard steel through to about                                                                  I was interested to see whether the
                                                     The locking knob on the motor height            heat developed by cutting might be a
70-75m/min for aluminium. As men-                mechanism is then released. The long
tioned later, other materials, such as plas-                                                         problem. It certainly didn’t appear to be.
                                                 lever (on the left in Photo.5) is used to lift      This is probably due to the length of the
tics and PTFE require medium speeds and          the motor to its top position where the
trying to cut these or any of the metals on                                                          bandsaw blade compared with the much
                                                 locking knob is tightened to hold it up             shorter lengths of either a hand operated
an ordinary woodworking bandsaw is a             while the belt is changed to achieve the
recipe for disaster.                                                                                 or powered hacksaw blade. This gives the
                                                 required speed. The mechanism is shown              heat more time to dissipate before the
                                                 in Fig.1. A toothed belt (Photo.8) con-             same teeth are used again. For example, a
Cutting metal                                    nects the bottom (motor) pulley to the top          cutting rate of 20metres/min is equivalent
   Before starting to cut metal on the           (wheel) pulley .                                    to 333mm/sec. The length of the blade is
bandsaw, the dust collection hose must               Once the belt is in the desired posi-           3480mm, so it takes about 10 seconds for
be removed from the 100mm port. This is          tion, the locking knob is again released,           the same teeth to re-present at the cut.
to stop damage to the hose and dust              the lever lowered to the bottom of its trav-            One comment is relevant with respect
extractor by hot swarf. The two swarf            el and then pushed down slightly to firm-           to heating, however. This is that it is wise
trays (Photos.7&8) must be in position.          ly tighten the belt before screwing in the          to support thin walled tubing (in a wood-
(The swarf tray at the bottom of the base        locking knob.                                       en vee block, for example) to avoid the
cabinet would usually be left in place but           The three metal cutting (Low Gear)              tube collapsing while being cut.
I can imagine times when it might be             speeds are 20, 40 and 70metres/min. The
convenient to re move the one at the                                                                     *1.75hp output power
                                                 use of these speeds is defined Table.1.
back of the worktable.)                              The material used to test the machine          Photo.6: The motor drives the machine
   Next, a suitable fine tooth metal cut-        for this Report could be classified from           through a gearbox— the gear knob is in
ting blade must be installed. A ‘starter’        light to medium — light gauge steel and            the centre, the motor lifting lever is on
blade is supplied with the machine and           aluminium tubing through to solid steel            the left and the securing knob is at the
suppliers such as Henry Bros (Vineyard,                                                             top.
Sydney) can advise on blades for specific
purposes.
   Finally, the correct speed must be set.
This is simpler than changing blades.
   First the gearbox selector (Photo.5) is

           Worktable

Toothed                          Fig.1
Drive
Belt
                                  Gearshift
Bottom                   Gearbox
Wheel

Speed
Changing
Pulleys

                                 Motor




                                                                                                  Australian Woodworker   September/October ’08     45
                                              cutting dense hardwoods is confined to
                                              blade choice alone. The ability to select
                                              a lower speed doubles the options avail-
                                              able to the operator.
                                                 The lowest of the High Gear speeds is
                                              250 metres/minute which is very useful
                                              for cutting materials such as plastics,
                                              which are a real headache for most
                                              workshops. Attempts to cut plastics on a
                                              standard high speed (wood cutting) saw
                                              generally result in melting the plastic; the
                                              kerf often becomes so distorted that the
 Photo.7&8: There are two swarf trays —       cut pieces are unusable.
 back of the table and inside the base
                                              Other Features
                                                  All the parts of the machine, from the
                                              cast metal wheels for the height adjust-
                                              ment and blade tensioning, to the rack
                                              and pinion and single point re-saw              Photo.10: Machine uses quickly
                                              guide, have a solid feel to them. This          adjusted US Carter guides
                                              robust build of the Bandsaw is reflected
                                              in the machine’s 210kg weight.                  rear thrust bearing the correct distance
                                                  The overall dimensions of the JET           from the back of the blade throughout its
                                              VBS-18MW are 970mm x 1070mm x                   entire travel.
 Cutting Wood and other Materials             1900mm and it has a large (485mm x                 Blade tensioning is by way of a cast
    Many buyers of this machine will          485mm) heavy cast-iron worktable sup-           metal knob under the top wheel case. A
 want it because it can handle a wide         ported by sturdy trunnion bearings. The         lockable tracking adjustment is provided
 variety of materials, but even those         table can be tilted from 450 to 100 and         on the back of the same case and a small
 whose work is largely devoted to cutting     has an adjustable stop to allow quick re-       window permits the operator to watch
 wood will find that the VBS-18MW offers      setting to 900.                                 the movement of the blade as the adjust-
 them a substantial benefit.                      The maximum depth of cut is 300mm           ment is made.
    Table.2 lists some of the materials for   and the maximum width of cut, 400mm.
 which the various High Gear speeds are       The quoted minimum size blade is 3mm,           Summary
 suitable.                                    the maximum, 30mm.
                                                                                                  I believe that bandsaws are like cars.
    As pointed out previously, the top            A JET representative told me that the       No matter what you buy, it has to be a
 speed is approximately equivalent to that    cast iron bandsaw wheels are balanced           compromise — but the versatility of the
 of a standard 18" woodworking bandsaw        after the tyres are fitted. I did as suggest-   JET VBS-18MW makes it less of a com-
 and therefore appropriate for general        ed and ran a hand around behind the             promise than most.
 cutting of wood. But the machine also        inner edge of a wheel to detect the bal-
                                              ancing holes.                                       It can cut not only wood and metal, it
 provides a slower speed — 450m/min                                                           can also cut a variety of other materials
 –— which the manufacturer recom-                 The 18MW shares the same multi-             for which the optimum cutting speed is
 mends for Tropical Hardwoods.                point guide system fitted to other JET          very different to that of commonly used
 Normally, the setting-up of a machine for    Bandsaws. As reported in the previous           woods.
                                              USER Report on the JWBS-18X, this is an
                                              excellent system which is easy to adjust.           As a general workshop machine, it
                                              Each guide set, one above, the other            doesn’t seem to have a rival — certainly
     Table 2                                                                                  not one that I can find. Even in a work-
                                              below the table, consists of a pair of high
     Material                  Speed                                                          shop devoted primarily to woodworking,
                                              grade bearings which are brought to near
     Polyamid, ABS Plastic      250           contact with the blade. Another similar         the occasional (once a month, once ev-
     Tropical Hardwood          450           bearing takes the thrust forces created         ery few months) need to cut metals will
     PTFE                       450           when the workpiece pushes the blade             probably make prospective bandsaw
     Hard Rubber                820           back during a cut.                              buyers contemplate its purchase. The dif-
     Plywood                    820                                                           ference in cost may well be outweighed
                                                  All of the adjustments could be made        by the ability to do things in-house that
     Wood                       820           and the wing nuts nipped tight without          would otherwise have to be subbed out,
                                              tools. As on the 18X, the eccentric cams        or worse still, got around in some other
 Photo.9: Cutting is fast and accurate —      that move the lower guide rollers to-           way.
 note fine tooth ‘metal’ blade                wards and away from the blade, are
                                              adjusted by rotating the knurled ends of            That said, it has to be understood that
                                              shafts which are brought out, almost to         this is not a replacement for a motorised
                                              the edge, underneath the table. Barked          hacksaw — the kind of machine that is
                                              knuckles are eliminated and the fiddle          fitted with continuous cooling and used
                                              factor is almost zero.                          for cutting 75mm thick pieces of carbon
                                                                                              steel.
                                                  The upper guide mechanism is
                                              mounted at the lower end of a rack and              But it will do light and medium work
                                              pinion assembly (same as the 18X) which         much faster than such a machine and
                                              raises and lowers to accommodate mate-          with at least the same degree of accuracy
                                              rial of differing heights. A height gauge is    AND it will double as an excellent band-
                                              provided as well as a locking knob.             saw for wood and other materials.
                                                  Again, as shown in the 18X USER Re-             The r.r.p. of the JETVBS-18MW Band-
                                              port, the height adjustment rack and pin-       saw is $2850 (ex-Brisbane, incl. GST)
                                              ion mechanism can be adjusted to com-           and it is available from JET TOOL Stores
                                              pensate for wear that would otherwise           throughout Australia. (Call 07 33753288
                                              make it difficult or impossible to keep the     or e-mail info@jet-tools.com.au for loca-
                                                                                              tion of nearest dealer.)                 w


46   Australian Woodworker   September/October ’08

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:29
posted:5/5/2010
language:English
pages:3
Description: The first time I saw this Bandsaw was