I failed the nickel test on startup of my Jet JWTS CS 240V saw. It gives me
a bit of a bang when it starts from the torque which causes the nickel to
fall. Do most properly setup 240V saws pass the nickel test? I could see how
a 120V would take longer to spin up and perhaps have less of an initial
jolt. Just curious...
The nickel test refers to the smoothness of operation once the tool is running.
If you DAGS in this group I believe you will find a lot of discussion on this
start up bang and a few fixes. JG
my 1948 unisaw passes the test on startup and shutdown about 50% of
the time. if i set the nickel up while its running it will stay there
till i move it. i've even cut some 6/4 oak while the nickel was there.
it stayed there..... skeez
my 1948 unisaw passes the test on startup and shutdown about 50% of the
time. if i set the nickel up while its running it will stay there till i
move it. i've even cut some 6/4 oak while the nickel was there. it
I don't have a unisaw, but my HF saw passes the nickel test. Even
during start up, or shutdown. Haven't tried it while cutting wood tho.
I didn't have a nickel, sot used 5 pennies. They wouldn't stand up, but
lay flat OK. They stayed on the saw, no prob, altho they did move
around a bit. I was doing it right, wasn't I?
I haven't tried the nickel test on my new Grizzly yet. I have to build a jig
to hold the nickel for the crosscut. Oooooooooooohhhhh...
Induction or universal (brushed) motor ? Most cheap saws use brushed
motors, because of their high start-up torque. They're stable when
running, but they make one hell of a bang when they start.
The "nickel test" means little when the saw is running idle. A really
stable saw is one that doesn't vibrate, even during a heavy rip.
Do whales have krillfiles ?
This is not due to running the saw at 240volts as opposed to 120volts. The
voltage that is applied to the coils of the motor is the same no matter
which way you wire it. The vibrations that cause the nickel to fall are due
to imbalances somewhere.
Try taping 5 pennies together. Most saws will pass this nickel test.
I have a new Jet 14 inch @120V with a 1HP motor. It would not pass the
nickle test until I changed the stock belt to a nylon link belt. BIG
difference, very smooth, and passes the nickle test at start up about 50% of
My PM66 passes the nickel test, now and ten years ago. A 240v motor
will have a smoother startup than a 120v. I tried the nickel test on
my Delta 16.5" drill press and the the nickel rolled off somewhere and
never did find it. Did not try the test on my DJ-20 (yet), but it's a
very smooth-running machine.
Nickle test - bah! Now the dimes test, one near the front corner of
table, square to the blade, and one on the far corner paralleling the
Definitely helps to have the table top level to begin with and the
mass you've got the better. Robland's X31 weighs about 1100 pounds,
100 lbs of that being the three, 3 hp TEFC motors. When one starts up
can hear the "kick" but can't feel it. Of course there's a lot more
time on a combi but once they're tuned they stay that way.
I have a three year old Jet Cabinet Saw (Left Tilting - 3HP). The
nickel rotates 5 degrees counterclockwise each time I start it, but
Try a different nickel, the first one I tried was so chewed up it
wouldn't stay standing with the saw off.
I can't try the nickel test. After shelling out the bucks for a table and
planer within 3 mos. of each other I don't have a nickel left to test with.
If you guys can all send me some I'll be sure to let you know how it all
Joey in Chesapeake
Haha Joe. I'll send you a nickel.
I can stand the nickel while its running. Its actually super smooth while
running and cutting. I wonder if a nylon link belt will reduce the jolt of
startup? The jolt is pretty violent! Actually a lot of the noise and
extravagance of it may be the blade guard rattling around on the table - its
connected pretty close to the motor mount.
Thanks for the replies.
My General starts with an authoritative jolt, and it's pretty much
immediately up to 4000 rpm. That's with a heavy WWII, and the heavy
cast iron moving parts this saw is equipped with. Once it's running,
I could probably stand a dime on edge, so I don't worry about it.
AFAIK, electric motors develop max torque at 0 RPM, so I kind of
expect the jolt on large motors rated for continuous HP connected to
heavy moving parts. My smaller DC, contractor's saw, jointer, drill
press, etc... motors have less of a start-up jolt, so I always thought
of it as a horsepower and mechanism weight thing.
The jolt could also be related to the size and quality of the starting
FWIW, the General has a noticeably smaller jolt when starting with a
very light blade. I would also imagine small wiring, even if
technically correct, would lessen the jolt.
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