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Delta Unisaw Operating Noise

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Forum topic by mc79 posted 477 days ago 1394 views 1 time favorited 24 replies Add to Favorites Watch
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mc79

23 posts in 697 days


477 days ago

So I just upgraded from a Ridgid to a new Delta 36-L51x – 5hp Table Saw. I just finished set up (except for the fence/rails) and decided to power it up for a test. When I hit Start, there is a loud clunking noise when first starting and then after that is the normal noise with vibrations/rattling coming in and out. So it will “vibrate” or make a vibrating like noise for say 4-5 seconds and then it will smooth itself out and sound “normal” for a few seconds and then the vibrating noise returns and this cycle repeats. Shutdown sounds perfect.

So my 2 questions are about the loud clunk/bank noise at startup and then the cycle of vibration and smooth running that ensues after that. I’m definitely not a pro so I’m hoping for a little guidance in what I need to check/adjust. I did check the blade alignment to the miter slot which is about .0015-.002”, which is great for me.

Video below (a little loud so watch your computer volume):



24 replies so far

View TheDane's profile

TheDane

3716 posts in 2287 days


#1 posted 477 days ago

The elevator wheel was turning counter-clockwise … doesn’t appear to be locked down. Not sure if that is related to other issues, but …

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View mc79's profile

mc79

23 posts in 697 days


#2 posted 477 days ago

Yeah I noticed that when watching the video. I tightened it after the fact but it is still making the same noises.

View Loren's profile

Loren

7387 posts in 2272 days


#3 posted 477 days ago

Take the belts off the arbor and start the motor with no
load. Does the noise persist when the arbor is not
turning?

-- http://lawoodworking.com

View Mark Davisson's profile

Mark Davisson

483 posts in 1941 days


#4 posted 477 days ago

When fiddling with my link belt the other day, I mistakenly mounted it next to the trunnion pulley (around the outer flange of the pulley) rather than on the trunnion pulley. It made that kind of sound when I fired it up.

-- I'm selfless because it feels so good!

View toolie's profile

toolie

1737 posts in 1253 days


#5 posted 477 days ago

the clunk sounds louder than what i experienced in a 70s unisaw i refurbished. make sure the locking bolt that secures the motor to the motor mounting bracket is tightened down, after the motor’s weight stresses the 3 belts.

the other operating noise sure doesn’t sound pleasant. as suggested above, start taking operating parts out ofd the power train to isolate the causal factor.

-- there's a solution to every problem.......you just have to be willing to find it.

View mc79's profile

mc79

23 posts in 697 days


#6 posted 438 days ago

Update…

Thanks for the replies..I’m just now getting back around to trying to fix this noise vibration issue and the loud bang at startup if possible (more concerned about the vibration). Just for background – this saw was just purchased as New Old Stock from a old dealer that purchased it new from Delta back in 2006 or whenever these were built (36-L51X-BC50). It has been sitting in its original crate unopened since they received it and I bought it as is. Don’t know if any warranties would apply in my situation but hopefully its an easy fix. I am still a noob on these types of adjustments. I had a Ridgid TS that I didn’t really have to make any adjustments to so this is a little new to me.

When I shot the 1st video the saw was up on a sturdy funiture dolly. I was hoping getting it settled into its permanent home (on a Delta Mobile Base) would solve the vibration issue but it hasn’t changed at all. I have just opened up the cover and removed the guard/splitter to take a look. I haven’t really dug in too far yet. I’ve posted some pictures below of what the motor and belts look like. Hopefully someone can spot if its something extremely obvious in the photos below. (the belts are all on the pulleys – I don’t know what the tension should feel like on them.). The motor does seem to be over towards front quite a bit almost to where it is touching the outer gray cabinet wall. This makes the belts angle towards the front as they go down to the bottom motor pulley. I’m not sure if this is how it is supposed to be. The picture in the manual is a little hard to make out but the motor looks a little more centered in the space than what mine is. Can you guys take a look and let me know if anything jumps out at you? I’ve taken quite a few pics of everything I had easy access to.

Top Arbor Pulley Nut on outside facing me

Notice Belts going Diagonal

Botom of belts on Motor Pulley

Motor up very close to the Front Base of Cabinet

Arbor Pulley/Belts (top view)

View NormG's profile

NormG

4088 posts in 1628 days


#7 posted 438 days ago

Does sound like the motor maybe hitting something at startup

-- Norman

View patron's profile

patron

13000 posts in 1965 days


#8 posted 438 days ago

were the belts on when you opened the crate
you mentioned that it sat for years un-used

could it be the belts have some ‘hot spots’ on them
(they could be stiff and settled into a permanent figure
that is not round at rest
but more oval in shape by now)
where they were curved around the pulleys
those spots would thump as they hit the pulleys

maybe they need replacing
with some more flexible ones

as suggested above
try the motor without the belts on
at least you will know how the motor is on it’s own
and can work from that

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View toolie's profile

toolie

1737 posts in 1253 days


#9 posted 438 days ago

as good as unisaws are, getting to the belts and motor can be challenging. isolate the cause as motor or arbor generated. i’d remove the top, which will greatly simplify diagnosing what’s going on. remove the wings and note the location of any spacers between the table (two man job to execute carefully and safely) and the cabinet. it’s IMPERATIVE that any spacers be replaced exactly as initially installed otherwise future alignment operations may be compromised. if there aren’t any shims, then just proceed cautiously. the ‘70s vintage unisaw i refurbished didn’t have any shims, and it presented a bit of a challenge getting things realigned when reinstalling the top. then remove the belts. this video covers how to put them on sequentially. just reverse the process:

https://www.youtube.com/watch?v=aVDihfPsuaI&feature=relmfu

the intermittent rattling noise sounds a bit like the noise made by the defective arbor bearings in my 70s unisaw. replacement of the bearings is the only remedy. if the noise is coming from the motor, it’s usually the bearings.

one of the (what appears to be) capacitors seems to be a bit close to the opening in the cabinet for the motor. those motors have quite a bit of torque, so it may be moving at start up. start the saw and see if the motor is jumping, causing that capacitor housing to hit the cabinet.

the link above is part of a series of videos dealing with older uisaws, but a lot of the techniques may be helpful to you. some things changed slightly over the years , so proceed cautiously. you may want to contact these guys, who seemed to know unisaws quite thoroughly:

http://www.sawcenter.com/

-- there's a solution to every problem.......you just have to be willing to find it.

View TorxNut's profile

TorxNut

58 posts in 521 days


#10 posted 438 days ago

as good as unisaws are, getting to the belts and motor can be challenging.

I have one and sure can’t agree with that. Unless you’re referring to the newer X series, which I know little about, the earlier Uni’s have easy motor and belt access. I’d try a lot of other things before I pulled the top that would require lots of realignment.

Bill

View CessnaPilotBarry's profile

CessnaPilotBarry

885 posts in 734 days


#11 posted 438 days ago

The General 650 I had for 11 or 12 years always had a BANG on the first few starts of the day if I hadn’t used it for a week or two. It would eventually go away, after use, but it would return if it sat for a while.

It was the belts taking a set. Until the belts flexed a bit, the mechanism would coast to a stop in the set, allowing the bang to happen more than once.

If I used the saw a lot, there was no bang, until it sat for a while again.

-- It's all good, if it's wood...

View mc79's profile

mc79

23 posts in 697 days


#12 posted 438 days ago

”could it be the belts have some ‘hot spots’ on them
(they could be stiff and settled into a permanent figure
that is not round at rest
but more oval in shape by now)”

UPDATE:

I did remove the belts and they do seem stiff and have settled into oval shapes (picture below)...I started the motor by itself with no belts on (video) below and did not hear the noise. So does that isolate to either arbor or belts? The belts were on the pulleys when I received it so it has been sitting like that for 6-7 years unused. Does it sound like this is the problem and should I replace those before examining the arbor (i did check the set screws on the arbor pulley and they both seemed to be tight)? Anyone have any recommendations on types of belts that are good quality and reasonably priced? Thanks!

Oval Belts:

Running Noise with No Belts on:

View CudaDude's profile

CudaDude

107 posts in 932 days


#13 posted 438 days ago

I wouldn’t lose much sleep over the “bang” at startup. When I got my well used Unisaw it had the same noise. Like Barry suggested, once I started using it regularly the noise went away, and when I haven’t used it for a while it comes back on the first couple startups.

-- Gary

View bbc557ci's profile

bbc557ci

541 posts in 698 days


#14 posted 438 days ago

I bought a used Uni last Saturday from a guy who said the saw had not been used in about 4 years. like yours, weight of the motor had been on the belts. Mine would rumble for a few seconds after start up, and I was concerned about that. Rumble got much milder after running for a while. I took the blade off and started the saw while observing the belts, and they do not appear to be running/turning smoothly at all….they’re “jumpy”. As mentioned above, I’m pretty sure they’ve taken a set from sitting so long with the motor weight on them, and bet you’re in the same boat. I let mine run for a few minutes a couple of different times. Now the “rumble” is way less so I think the belts have re-shaped some. Regardless I plan to replace the belts with a matched set from Delta.

I get a minor noise/low boom sound on start up, and attribute that to the INSTANT power/rpm’s on start up. Hit the go button and it just lights up immediately. Would be nice if it had a “soft start” feature.

-- Bill, central NY...no where near the "big apple"

View patron's profile

patron

13000 posts in 1965 days


#15 posted 438 days ago

here is a set o 3 belts
for your model saw
$44.83

http://www.ereplacementparts.com/3vblts-26116-p-89186.html

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

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