Comp Rev of DVR: Part III cont. (very long)
Lyn J. Mangiameli
discusses modifications and accessories that can increase the comfort
and capabilities of the lathe. There will be one more installment to
follow, but that only will discuss changes that have been made since the
earlier parts of the review were written, and make corrections,
revisions, or expansions as appropriate. As usual, a formatted version
of this article, complete with accompanying photos, will be published in
Fred Holder's periodical, More Woodturning.
http://www.fholder.com/Woodturning/woodturn.htm
Comprehensive Review of the Nova DVR 3000: Part III (cont.)
Having used a DVR for almost nine months now, I ve found a number of
adjustments, modifications and accessories that have made my DVR more
comfortable and increased its capabilities. In this section I m going to
describe the things I ve tried, and give you directions and sources so
that you can apply them to your own lathe, should you choose.
The locking handles of the banjo and tailstock have long been a weakness
of the Teknatool lathes. The manufacturer has made several changes in
these handles over time and model, but they remain somewhat
uncomfortable and awkward to use. The good news is that relatively cheap
modifications can greatly improved this aspect of the DVR. For around
twenty dollars, you can outfit your DVR with comfortable, effective,
durable handles, greatly easing the day to day use of the lathe.
The banjo is locked using a short metal lever. This 4 inch locking lever
is the same as that supplied for the tailstock, and in both cases is
over an inch shorter than the one that came on the Nova 3000. This
shorter length is necessary on the tailstock in order to clear the
tailstock hand wheel, and for that purpose is acceptable. However, for
use on the banjo, the lever is both too short and too small in diameter
to be truly comfortable. Fortunately, you can improve upon the handle
quite easily and cheaply. Reid Tool Supply is a good source for
replacement handles (Reid calls them Gear Levers), and looking through
the pages of their catalog you will find you can obtain several sorts of
handle styles and lengths (something between 4.5 and 6.5 inches will
work the best). My favorite solution is to scavenge an original Nova 3K
handle, or lacking that, to obtain a basic steel shaft that is threaded
on one or both ends (e.g., Reid # GLS-170). Over either of those shafts
I use the Ergostyle soft touch push fit handles (Reid # ESP-85). These
push fit handles are not really push fit for the 10mm metric sized
Nova levers, so you must ream them out with a 10 mm drill bit to get
them to fit putting a little hole in the end will also help release the
internal air as you push them on. I like these handles so much that I
don t mind going to these extra steps and use them for both the banjo
and the tailstock levers. The firm molded rubber of the Ergostyle
handles gives you a 7/8 inch diameter by 3.35 inch long gripping
surface, rather than the hard 10mm (essentially 3/8 inch) diameter
surface of the steel levers. Regardless of the levers you obtain, make
sure they have the M10 x 1.5 threading that is necessary to screw them
into the Nova mounting holes, and use a good wrap of Teflon tape or some
thread locking compound to keep these coarse threads tight against their
mating surfaces.
The locking lever for the tool rest is as much an aggravation as that
for the banjo. It is not infrequent that a hand grasping the banjo
locking lever is squeezed up against the tool rest post locking lever
(or vice versa). I ve found the solution is to use a
ratcheting/adjustable handle, not unlike those found on many
mini-lathes, but much heavier duty. Again, Reid Tool has the KHX-345
metal handle, which has the necessary M12x1.75, one inch stud. This is
one of my favorite modifications to my DVR. This big secure handle gives
a good solid grip, and can be adjusted to whatever angle is most
conducive to operation or getting the handle out of the way.
Before leaving this area, I want to point out a simple adjustment that
can be made to the banjo locking mechanism. Some find, either upon
receiving the lathe, or after a period of use, that the banjo does not
lock down quite as tightly as might be desired. A simple improvement can
almost always be attained by sliding the banjo off the bed, turning it
over and tightening the bolt that attaches the locking plate to the
locking mechanism. This bolt is countersunk and has a socket for an 8 mm
Allen wrench. It will already feel tight, but if you apply force, it
will usually tighten about an additional quarter turn. I ve done this on
two Nova 3ks and my current DVR, and in each case it has improved the
locking action. While you have the banjo upside run a file along the
bottom side of the banjo housing, just enough to smooth over any
variations in paint thickness and remove any casting flash doing so will
improve how smoothly your banjo will slide, as well as allow it to lock
down more securely. One last thing while you have the banjo off is to
lightly oil the slide. This can be done from the top side as well, by
removing two plastic caps. Lubricating the locking mechanism is
discussed in the DVR manual and is basic maintenance for these lathes.
If ever you find the banjo is seeming to become difficult to position
freely, it is usually that the slide portion of the locking mechanism is
due for a little lubrication.
Moving to the headstock, one of the problems I have with the DVR is the
flat panel touch pad controls. Of particular concern is being readily
able to identify and activate the STOP control. While I d like to see a
redesign of the control panel, to incorporate raised controls, I ve
found a very cheap and simple means to allow for immediate visual and
tactile identification of the STOP pad. I simply stick a .25 inch
diameter hemispherical bumper of clear plastic over the center of the
STOP touch pad. These are the sort of plastic bumpers designed to be put
on the bottom or sides of objects to protect walls and other contact
surfaces from marring and/or to reduce sliding. They can be purchased
for pennies at most home centers and hardware stores. After cleaning the
surface of the control pad with alcohol, the plastic bumper is pressed
on over the center of the Stop area of the pad. The clear plastic allows
one to still read the print below, the raised bump allows one to easily
find the stop control, with or without vision, and by being place right
over the sweet spot of the touch control it insures consistent
activation. I ve used one of these bumpers for several months now and
the pressure sensitive adhesive has kept the bumper in place. Should one
accidentally strip it off some day, it costs next to nothing to apply a
new one.
The DVR, with its ability to freely spin after power is cut, calls out
for a hand wheel. However, because of the unusual M 20 x 1/5 left hand
internal threading at the outboard end of the spindle/motor shaft, not
just any hand wheel will work. At this time, there are three hand wheels
available to fit the DVR, one vacuum adapter that can serve double duty
as a hand wheel, and one adapter that will allow you to make your own
hand wheel.
Two of the hand wheels come from Teknatool, the original Nova 3K hand
wheel and a new hand wheel intended specifically for the DVR. The
original Nova 3K hand wheel screws directly into the end of the
spindle/motor shaft. It has a narrow rim that is small in diameter, is
bored through such that it will allow use of the stock knock out bar,
and has an internal shelf within the wheel that will allow the Teknatool
vacuum adapter to be seated and held with a set screw (more on vacuum
adapters in a moment). The new DVR hand wheel is an evolution of the 3K
version, but with a wider rim that is cross drilled to allow the knock
out bar to be threaded through and used to develop considerable
restraining force if a faceplate or chuck should become stuck on the
other end of the spindle. Basically the new hand wheel expands on, as
well as replaces, the functions of both the 3K hand wheel and the
extraction nut that originally came with the DVR. Its wider rim allows
for a larger area to grasp, but the large cross drilled holes make the
wheel a little less hand friendly than the 3K version. However, the DVR
hand wheel has one feature that is a great improvement over the 3K
model. On the DVR hand wheel, the rim portion is drilled through and
countersunk in four places parallel to the spindle axis. This allows for
a shop made hand wheel to be easily attached to the outboard face of the
rim, allowing one to attach a wooden wheel of whatever diameter one
might like. In my opinion, this is a great help and makes the new DVR
hand wheel a real winner. Again, like its predecessor, the DVR hand
wheel will accept both the standard knock out bar, and the Teknatool
Vacuum Adapter. My understanding is that DVRs now come standard with
this hand wheel, and that there are several different ways an owner of
an earlier DVR might obtain one.
If your DVR didn t come with a hand wheel, or if you desire a more
traditionally styled hand wheel, BestWoodTools [BWTs] offers the
excellent hand wheel they originally designed for the Nova 3K. This hand
wheel comes with a larger 4 inch wheel that is made of nicely finished
aluminum. This is a very nicely machined and visually appealing hand
wheel, but it does have two drawbacks. One, it lacks any flats or means
to use a crossbar that will help with those rare times when a chuck or
faceplate becomes stuck on the spindle. The other, is that while it is
drilled out to take the standard crossbar, the center hole is not
threaded to allow for additional attachments (a problem shared by the
Teknatool hand wheels as well). I ve discussed this with BWTs and they
have developed a drawing of a modified version of their hand wheel that
would include flats to take a wrench (thus performing the Extraction Nut
function), outboard threading that would allow attachment of the Oneway
vacuum adapter, and an inset with a chamfered edge that creates a
seating area for the EZ vacuum adapter. I m not sure if this version
will ever actually come to pass, but it will be a great hand wheel if it
ever does.
Finally there are two solutions for hand wheels, neither of which were
intended as such, but which can work fairly well. The first is the
Oneway Rotary Vacuum Adapter. This massive vacuum adapter is almost as
large in diameter as the Teknatool hand wheel and allows a firm hand
grip to be achieved. It also has a single deep round socket on its side
that will take a 3/8 inch round bar for tightening (Oneway supplies such
a bar with most of their faceplates) and which can help achieve leverage
when the adapter is used in place of the Extraction Nut. Oneway makes a
special version of the spindle mount adapters it uses with its chucks,
to allow the vacuum adapter to mount to the internal threading on the
outboard end of the DVR and 3K spindles. Unlike the other previous hand
wheels, this Oneway vacuum adapter does not allow for use of a knock out
bar, unless the adapter is removed.
The last solution is to obtain just the Oneway taper lock adapter used
to fit their vacuum adapter housing to the Nova threading. One can then
turn a hand wheel of the size and thickness of one s choice, making the
center hole slightly tapered to match the taper of the Oneway adapter,
then use the four holes in the adapter flange to screw or bolt your
turned wheel to the adapter. This method allows for a very nice and
compact hand wheel, though one should be aware that adding a large
diameter wheel may obscure your view of the indexing port on the
outboard side of the headstock. This arrangement still allows use of a
knockout bar (although it will require you to use a slightly smaller in
diameter one than comes with the DVR).
As one can see, there are a lot of hand wheel possibilities, which is
good, as a hand wheel does much to make the DVR easier to use. The chart
below summarizes the approximate dimensions of the hand wheel options
discussed (approximate because the actual dimensions are a mix of
fractional, decimal and metric).
Handwheel
(dimensions approximate) Outside Diameter Rim Width Inside Diameter Knockout
Bar Size Custom
Handwheel
Nova 3000 3.1 inches .5 inches .52 inches .5 inches No
Nova DVR 3.1 inches .5 inches .52 inches .5 inches Yes
BestWoodTools 4.0 inches .75 inches .52 inches .5 inches No
BestWoodTools-DVR 4.0 inches .75 inches .52 inches .5 inches No
Oneway Vacuum Housing 2.4 inches 3.4 inches N/A N/A No
Oneway Adapter only 2.4 inches 3.4 inches .46 inches .44 inches Yes
I have already brought up the issue of adapters that will allow for the
use of vacuum chucks on the DVR. There are three adapters commonly
available that allow one to attach a vacuum source to the outboard end
of the DVR (and Nova 3K). The largest and most expensive is the one
discussed above, which is made by Oneway, The Oneway approach uses a
taper lock adapter to allow their bearing housing to screw directly into
the outboard end of the headstock spindle. The vacuum adapter itself
uses a pair of sealed ball bearings fitted into a steel housing to
couple the fixed hose from the vacuum pump to the rotating spindle. It
is rugged, reliable and well balanced, though it tends to squeal a bit
and overheat when the lathe is used at speeds over 3000 rpm (speeds that
my lathe never normally sees). It is only suitable for use as part of a
high vacuum, low volume system, that is, one that uses a vacuum pump or
venturi valve as its vacuum source.
Teknatool, offers a vacuum adapter that mounts directly into either of
their hand wheels. It uses a single sealed ball bearing that fits into a
shelf inside the rim of their hand wheels and is secured by a setscrew.
The Teknatool adapter is meant to be used as part of a low vacuum, high
volume system that uses a common shop vac as the vacuum source. For use
with such a system, it has bypass inlets that allow a small airflow to
be maintained at all times to insure the shop vac will receive a cooling
airflow. Fortunately these inlets are tapped and can be closed with set
screws, allowing a relatively simple modification to be performed that
will make the Teknatool adapter work just fine as part of a high vacuum,
low volume vacuum system. I m not sure if it was by design or chance,
but the inside diameter of the Teknatool adapter is sized just perfectly
to use a 1/4-18 NPT tap to thread the bore so that it will take a
standard brass air fitting. These fittings will allow easy connection to
the usual sizes of vacuum hose. This system is more compact than the
Oneway, allows for quicker removal (and later replacement) for those
times when one needs to use a knockout bar, and is generally cheaper
than other vacuum adapter systems. The only drawbacks are minor, mine is
a somewhat less balanced than the Oneway, and thus has a little more
vibration (mostly noticeable at high rpm where vacuum chucking is not
used), it requires one to come by the tap and setscrews to make the
modification, and unlike the others, it is not readily adaptable for use
on other (future) lathes from other manufacturers.
Another vacuum adapter is the E-Z vacuum chuck adapter. This adapter
basically consists of a threaded rod that slips through the headstock
spindle, a self centering rotating air fitting that connects to the rod
on the outboard send of the spindle (which allows for a quick disconnect
of the vacuum hose) and a #2 MT vacuum fitting that fastens to the rod
inside the spindle. The outboard fitting will seat well into the
Teknatool hand wheels, and the proposed BWT s hand wheel, but will be
more troublesome to obtain a good seal against the bare spindle, because
of its internal threading (that can cause a slight, but vacuum
destroying leak). Like the Oneway, the E-Z Vacuum Chuck Adapter is
suitable only for high vacuum, low volume vacuum systems.
There are other systems that use an adapter that is screwed onto the
inboard end of the spindle, much like a chuck. Vicmark makes one
suitable for a low vacuum, high volume shop vac set up. The Sierra Mold
Corporation s VacuuMaster Vacuum Chuck Assembly looks somewhat like a
typical scroll chuck, but serves as a rotary adapter allowing a high
vacuum, low volume line to be connect to the front of the lathe
(particularly valuable for those lathes from other manufacturers which
lack a through bored spindle). Since these sorts of front mounted
adapters tend not to become so integrally attached to the lathe, I ll
save their discussion for a later article on vacuum chucking. But before
I leave the topic, I want to discuss one more thing.
Whichever of the high vacuum, low volume systems you might use, it is
quite helpful as well as prudent, to install a vacuum gauge so that you
can monitor the vacuum developed, and detect any subtle (or not so
subtle) drops in pressure that might indicate a leak. To be valuable, it
is important to have the gauge in clear sight. I have found an excellent
location with respect to the DVR is to have the gauge rise above the
outboard rear of the headstock. This is easily achieved by making or
obtaining a small L bracket (I scavenged one from the parts kit that
comes with the Moffet lights), then drilling and tapping a small hole in
the headstock itself (see photo). I ve found this location to be ideal
for me, and to have the advantage that it keeps the gauge in line of
sight when I am using the lathe with the headstock rotated to the left.
(see accompanying photo).
The final thing I m going to talk about in this installment is the Nova
3K/DVR Outrigger. This is a very heavy duty cast iron outboard tool rest
support, which bolts directly to your bench or the outboard end of the
lathe bed, or both. When bolted to both the bench and the lathe bed, I
believe it helps stabilize the outboard end of the lathe bed on which
the headstock is mounted. To allow for easy direct mounting, the end of
the lathe bed comes with holes predrilled and tapped for M12 x 35 bolts
that are included with the Outrigger kit. Those considering bolting the
Outrigger mount to the lathe, or both lathe and bench, must pay special
attention to the dimensions of the mount, as it has a huge boss that is
designed to extend forward from, and below the height of the bench. The
spacing recommended by Teknatool is different than the spacing I found
to work best for me, and may differ again for you depending on the type
of bench you have and whether you can/are willing to cut out a portion
of the bench for access. If you know you are going to wish to add the
Outrigger at a later time, it is wise to plan your bench and install
your lathe after having a look at the Outrigger mount and/or obtaining a
tracing of the mounting block s footprint.
The Outrigger provides very steady support to a secondary rear mounted
tool rest of your choice. It is composed of a rugged mounting block
discussed above, a massive 14 inch arm which is slotted, and a 10 inch
tall tower which receives a standard 1 inch diameter tool rest post. The
arm attaches to the underside of the substantial boss on the mounting
bracket, and is held in position by a thick downward facing M16 rod and
a large deep round M16 threaded nut that is cross drilled for a lever. I
suspect this arrangement is quite sufficient, but I chose to replace the
round nut and lever with a hex nut and a full size 15/16 inch (or 24 mm,
either will do) wrench for ultra secure tightening. When unlocked, the
component parts move quite smoothly given their weight and size. The arm
can articulate through a wide arc, and the tower for the tool rest post
can be moved (and locked) along the length of the arm s slot, allowing a
radius of up to about 12 inches. This flexibility allows the outrigger
to function for a wide range of shapes and sizes of turnings; basically
for those with diameters up to 29" and thickness (distance from the
spindle) up to 8.5." It is obviously meant to be used with the headstock
swiveled fully or partially towards the front of the lathe, but it also
offers opportunities to approach the rear of a large turning when the
headstock is fixed in its standard position. When swiveled all the way
around towards the tailstock, it can sometimes serve as a secondary
banjo for use with very long tool rests that require two points of
support. When not in use, the arm will tuck out of the way easily,
either along the end of the bench, or along the front pointing away from
the headstock. At those times, it makes a great place to store an extra
tool rest and to hang my compressed air hose.
I don t use my outboard rest often, but when I do, it is invaluable.
Though not cheap, the cost is well justified by the weight and strength
of the components, as well as the added function. This is an outboard
tool rest system that is worthy of the name, and will significantly
expand the ways in which you can use your lathe.
Originally I had planned to discuss in this last section my means of
modifying the DVR controls to make them movable and thus capable of
remote placement. On the surface this should not pose that much of a
challenge, as the internal circuit board and exterior control box are
joined by a standard 26 pin flat computer cable attached to standard
computer connectors on the circuit boards at each end. However, my
attempts have not proven successful, with unreliable and anomalous
control operation occurring each time I had an extended cable in the
system, which returned to normal when the original cable was replaced. I
don t have the electronic sophistication to troubleshoot this, so I ve
abandoned my attempts but would be happy to learn of the experiences of
others who might wish to explore this possibility. However, I have hope
that an effective, indeed even better, solution will not be long in coming.
I have also decided to leave out my discussion of bowl saving and the
excellent Kelton Balancer, instead each will soon be the subject of a
freestanding review. In both cases I decided that it was important that
the discussion of these products not be lost to those less interested in
the DVR, though both significantly increase the capabilities of this lathe.
So that s it for the basic review. Next month I shall briefly revisit
the entirety of the review, answering some questions I posed earlier,
retracting some complaints that have been resolved or turned out not to
be valid, and discussing the identifiable factory changes and
modifications already made in the DVR since the time I first started to
write about it.
Sources:
BestWoodTools: http://www.store.yahoo.com/bestwoodtools/index.html Best
known for their modular tool rest system and spindle adapters, they make
the outboard hand wheel described earlier.
Craft Supplies: Woodturners Catalog (Craft Supplies):
http://www.woodturnerscatalog.com/index.html source for Teknatool
products including the Outrigger, extra bed sections, hand wheels,
vacuum adapter and Nova chuck wrench. Source for the Oneway vacuum
adapter and outboard taper lock adapter.
ENCO: http://www.use-enco.com A stockist of basic parts and raw
materials. Good source for steel rods for making smaller or extended
knock out bars. Also a good source for the Bondhus T handled Allen
wrenches needed for DVR disassembly and maintenance.
KMS Tools: http://www.kmstools.com Good source for Teknatool products
including the Outrigger, extra bed sections, hand wheels, vacuum adapter
and Nova Chuck wrench.
Oneway: http://www.oneway.on.ca Information on the Oneway rotary vacuum
adapter, vacuum guage kit, and taper lock adapters.
Packard Woodworks: http://www.packardwoodworks.com Source for Nova chuck
wrench. Source for the Oneway vacuum adapter and outboard taper lock
adapter.
Reid Tool Supply: http://www.reidtool.com A stockist of basic parts like
drill stock, hand wheels and handles. They also have the Bondhus tools.
Teknatool: http://www.teknatool.com/ Information on the DVR, and the
many parts and accessories Teknatool makes available for it.
Woodcraft: http://www.woodcraft.com Source for Outrigger, bed
extensions, hand wheels, vacuum adapters and Nova wrench.