Beginners Question: Belt tension
Frank Tkalcevic
belt. The manual that came with the lathe was pretty vague on how the belt
tension lever is supposed to be used. There is a section in the manual that
discusses replacing the belt and changing speeds. In this section and on a
label on the machine there is a warning: "to avoid breaking the belt, move
the tension lever towards the front of the machine before starting".
Initially I assumed this just means loosen the tension before starting to
move the belt between pulleys (which is pretty obvious because they don't
budge otherwise). However, I now suspect this means only apply tension
after the machine has been started. Is this the case? Should I also
relieve the tension when switching off?
Any help will be appreciated.
Thanks,
Frank
sunworshiper
Sounds funny to me. Sounds like what I call belt slapping machines.
And lost there too. Can't possibly adjust it everytime you turn it
on. I need to get a new belt for my shaper and can't even think which
dead end is first. Like that AL post about getting the help to help.
Bad belt or you or your machine is doing something wrong.
Larry Meile
tight enough to not slip when taking a reasonably heavy cut
(heavy, that is for the Atlas!). The lever is moved forward
only to change the belt position.
Some belts are designed to run only in one direction. This depends
on the way they overlap at the joint. Were you, perhaps, running
it the wrong way?
Larry
Frank Tkalcevic
"what's the belt tension lever for?"
My lathe is a chinese built lathe, a CQ-6123, 115mm centre height, 500mm
between centres. There is a large external lever used to push an idler
pulley onto the belt to apply tension. There are only two settings: on and
off. When the tension is on, the idler puts a lot of extra tension on the
v-belt. It seems excessive, but I've not used anything like this before.
There is no obvious way to adjust the tension.
The actual belt seems quite small too. Its only about 5mm wide and deep.
The new one I put on (my only spare) is starting to show signs for wearing
already; on the top of the V, the string/cord, embedded in the rubber V, is
fraying at the edges. The last belt did this. Then the strings in the belt
started breaking until finally it snapped them all.
I've only be running the lathe at its lowest speed, 100rpm. I don't know if
this is part of the problem. Again, I'm new to using a lathe. The higher
speeds are a bit spooky. I'm afraid the beast is going to launch something
at me.
"Larry Meile" <meile~spam...@bc.edu> wrote in message
news:3AAC86...@bc.edu...
Gunner©
Gunner
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>I've probably made my question sound too advanced; it should probably read
>"what's the belt tension lever for?"
>
>My lathe is a chinese built lathe, a CQ-6123, 115mm centre height, 500mm
>between centres. There is a large external lever used to push an idler
>pulley onto the belt to apply tension. There are only two settings: on and
>off. When the tension is on, the idler puts a lot of extra tension on the
>v-belt. It seems excessive, but I've not used anything like this before.
>There is no obvious way to adjust the tension.
??? Then how do you change the belt? Its been my experience that most
belt driven (at least commercial ones) run best with about 1/2-3/4"
pinch slack. Pinch both sides of the belt together and it should have
about 3/4" combined flex before it stops. Hardinge go out to 1.5" on
the long belts. Are you sure that your belt is even the right type and
length and that tensioner is not supposed to be part of the loop? If
the belt is way short.. that tensioner will simply flap in the breeze
as its bypassed. They generally are there for a reason... but.. I dont
mess with Chinese lathes much. YMMV
XPRTEC
From: "Frank Tkalcevic"
Frank, on all my equipment, whether it be lathe, drill press, milling machines,
or saw; they all work the same.
LOOSEN belt to change belt to different pulleys.
TIGHTEN belt to run. The turn on power.
Bob Unitt
Tkalcevic <fra...@bigpond.net.au> writes
>The actual belt seems quite small too. Its only about 5mm wide and deep.
>The new one I put on (my only spare) is starting to show signs for wearing
>already; on the top of the V, the string/cord, embedded in the rubber V, is
>fraying at the edges. The last belt did this. Then the strings in the belt started
>breaking until finally it snapped them all.
Are you sure the pulleys are in line ?
--
Bob Unitt (UK)
Wild Bill
pulleys to change spindle speeds.
The design of this speed selection/belt tensioner setup can place a lot of
startup load on the motor (especially at the higher spindle speeds although
you mention that you're only using the lowest speed).
The lever is intended to remove all or most of the spindle (and feed gears)
load from the motor during power application to the motor.
The lever should be pulled toward the lowest belt tension position before
the motor power is turned on. After the motor has started, the lever should
be moved to it's fully applied/engaged position.
The belt failure could be caused by misaligned pulleys or running the motor
for long periods of time with the tension disengaged.
You might want to closely inspect the grooves of the pulleys for roughness
or consistent groove width.
Checking the tensioner parts and the other rotating parts for rotational
smoothness and applying proper lubrication to the parts' bearing surfaces
may improve belt life.
Everything should rotate fairly smoothly, without any noticable noises.
If you find any abnormal roughness or binding in the spindle or the other
rotating parts, you might get some help with replacement parts from the
seller.
You don't necessarily need to disengage the belt tensioner before you turn
the motor off, but you should remember to disengage it each time, after you
turn the motor off.. then restart the motor and engage the tensioner.
HTH
Bill
...............
Frank Tkalcevic wrote in message ...
Jack Hayes
answer is to purchase belts in large numbers, once they roll over they are
trying to tell you their time has come.
JACK
Frank Tkalcevic
"Jack Hayes" <at...@cyberbeach.net> wrote in message
news:3AAD2047...@cyberbeach.net...
fxst99
got one of those lathes too
Once it is running then you drop the lever down and once its off for
the day lift the lever
I found that unless Im doing heavy cuts it can stay in the upper
position.
rgds
Pete ('nother one)
fxst99
lathe gets used at least every couple of days for 3-4 hours
Rgds
Pete ('nother one)