This has me stumped. I was cutting a piece of half-inch plywood on a
contractors' table saw. The piece as about 15" wide. I was most of
the way through when I started to hear a sound that was a little
louder than usual. I completed the cut, and as soon as I did, the saw
began to squeal very loudly.
I turned it off and checked. Nothing wrong on top, but when I looked
at the back, I saw that the motor had fallen all the way down. The
motor pivots, and a screw in a slot usually keeps it from dropping too
far. The screw had broken off. But of course, gravity usually keeps
tension on the belt, and the belt holds the motor up.
I checked everything I could. All screws were tight. The motor
mounting plate appeared to be in the same position as usual. But the
belt was suddenly way too long to hold the motor up. (The squealing
sound was the belt rubbing against the saw housing.) I use a link
belt on the saw, so I tried removing six links. When I put the belt
back on, the motor was back into its usual position. (I replaced the
broken screw too, even though it doesn't actually hold anything). I
tried making a couple little test cuts, and it seems to be fine.
Can anyone explain what happened? I had been using the saw all
afternoon, and everything had seemed fine. I can't imagine that a
link belt could suddenly become a lot longer, so something else must
have happened. Can anyone think of an explanation? Is there anything
I should check before using the saw again?
On Sat, 09 Aug 2008 17:24:01 -0700, rjbonn wrote:
> This has me stumped. I was cutting a piece of half-inch plywood on a
> contractors' table saw. The piece as about 15" wide. I was most of the
> way through when I started to hear a sound that was a little louder than
> usual. I completed the cut, and as soon as I did, the saw began to
> squeal very loudly.
>
> I turned it off and checked. Nothing wrong on top, but when I looked at
> the back, I saw that the motor had fallen all the way down. The motor
> pivots, and a screw in a slot usually keeps it from dropping too far.
> The screw had broken off. But of course, gravity usually keeps tension
> on the belt, and the belt holds the motor up.
>
> I checked everything I could. All screws were tight. The motor
> mounting plate appeared to be in the same position as usual. But the
> belt was suddenly way too long to hold the motor up. (The squealing
> sound was the belt rubbing against the saw housing.) I use a link belt
> on the saw, so I tried removing six links. When I put the belt back on,
> the motor was back into its usual position. (I replaced the broken
> screw too, even though it doesn't actually hold anything). I tried
> making a couple little test cuts, and it seems to be fine.
>
> Can anyone explain what happened? I had been using the saw all
> afternoon, and everything had seemed fine. I can't imagine that a link
> belt could suddenly become a lot longer, so something else must have
> happened. Can anyone think of an explanation? Is there anything I
> should check before using the saw again?
If the saw in question is a craftsman model, I think I know what
happened. I had one a while back that did something close to that. The
motor mounting plate cracked diagonally, allowing the motor to twist,
which shortened the distance between the motor and arbor pulley. The part
(cast metal plate which the motor is bolted to, springs, and two metal
rods that connect it to the saw) was something like 12 bucks from sears.
I chose to epoxy and bolt a 1/8" steel plate on the back of their casting
rather than buy another part. (If the first one broke, why wouldnt the
second?)
Hope that helps.
-Tim
On Aug 9, 5:24=A0pm, [email protected] wrote:
> This has me stumped. =A0I was cutting a piece of half-inch plywood on a
> contractors' table saw. =A0The piece as about 15" wide. =A0I was most of
> the way through when I started to hear a sound that was a little
> louder than usual. =A0I completed the cut, and as soon as I did, the saw
> began to squeal very loudly.
>
> I turned it off and checked. =A0Nothing wrong on top, but when I looked
> at the back, I saw that the motor had fallen all the way down. =A0The
> motor pivots, and a screw in a slot usually keeps it from dropping too
> far. =A0The screw had broken off. =A0But of course, gravity usually keeps
> tension on the belt, and the belt holds the motor up.
>
> I checked everything I could. =A0All screws were tight. =A0The motor
> mounting plate appeared to be in the same position as usual. =A0But the
> belt was suddenly way too long to hold the motor up. =A0(The squealing
> sound was the belt rubbing against the saw housing.) =A0I use a link
> belt on the saw, so I tried removing six links. =A0When I put the belt
> back on, the motor was back into its usual position. =A0(I replaced the
> broken screw too, even though it doesn't actually hold anything). =A0I
> tried making a couple little test cuts, and it seems to be fine.
>
> Can anyone explain what happened? =A0I had been using the saw all
> afternoon, and everything had seemed fine. =A0I can't imagine that a
> link belt could suddenly become a lot longer, so something else must
> have happened. =A0Can anyone think of an explanation? =A0Is there anythin=
g
> I should check before using the saw again?
I'm not familiar with the link belts but if nothing loosened up then
my guess would be one of two things.
1) The belt was never fully tight and the motor was resting on the
screw. The screw backed out and the motor dropped all the way down.
I find this scenario unlikey because if the belt was never tight you
would have had squealing or slipping at some point.
2) The belt 'wore in' and dropped all the way down into the pulley
grooves. Again I don't know about link belts but a regular belt
should not bootom out in the pulley. There should always be a slight
gap at the deepest part of the pulley when the belt is fully seated.
Are you using pulleys specifically for the link belt?
Check your pulley alignment carefully. This can be a PITA on a
Contractor saw but a framing square or some other straight piece of
metal should let you know if they are lined up or not. The pulley on
the motor should be adjustable on the shaft to line things up.