Replies

1. 
   oldusty | Mar 22, 2008 06:29am | #1

   Smitty ,

               Sounds like it is not a tension problem as long as nothing is flexing at startup , perhaps it is an alignment of the pulleys problem , eye ball them to see if they are in line with each other or use some sort of a straight edge .

           good  luck             dusty

1. 
   SmithWerks55 | Mar 22, 2008 06:37am | #2

   Hi Dusty,

   I've adjusted the pulleys to be coplanar so that doesn't seem to be the problem.  When the motor starts and stops, the belt flares out and slaps the inside of the pulley cover.  Once it's running it's very smooth.  I've tensioned the belt until there's about 1/2" of deflection (at rest) but that hasn't solved the problem.  I suppose it's not the end of the world but the noise is a little disconcerting.  

    

1. 
   oldusty | Mar 22, 2008 08:23am | #3

     If it's not the tension and it's not the alignment and it runs smooth once up to speed that is different . Is the motor mounted tight with no movement ?

        I guess I would try to make the belt a bit more tight just to rule it out

                 good  luck          dusty

2. 
   Glaucon | Mar 22, 2008 07:12pm | #5

   If you've checked for coplanarity, adjusted the tension and everything is good and tight, you have 3 options:1. Call and talk with SC- their customer service is pretty good.2. Ask JohnWW on this board (he is generally spot-on with diagnosing and recommending fixes for machinery).3. Consider a PowerTwist belt. Often the stock belts that come with jointers are of the same caliber as the stock blade that comes with a new bandsaw.Good luck,Glaucon

   If you don't think too good, then don't think too much...

1. 
   PeterDurand | Mar 22, 2008 08:35pm | #6

   Hi Glaucon,addendum to my previous post, changing to a power twist was the first thing I tried. Unfortunately that did not help.Cheers,Peter 

   Better life through Zoodles and poutine...

1. 
   SmithWerks55 | Mar 22, 2008 08:53pm | #7

   Thanks for taking the time to reply, guys.  I e-mailed SCT but haven't had a reply yet.  I'll phone them after the long weekend and see if they have any words of wisdom.

   Failing that, I'll just have to follow that sage advise - live with it! 

    

2. 
   JohnWW | Mar 23, 2008 07:59pm | #8

   I was going to comment on this anyway, but being my name came up, here's my take on on the problem. For several reasons, rooted in basic physics, belts will flutter, sometimes dramatically, when a machine starts up and slows down. No matter how you adjust the belt, or change the brand and type of belt, it is almost impossible to completely control the phenomenon. The long belt runs and poorly designed motor mounts on most woodworking machines only make the problem worse and harder to correct for. The flutter is also basically harmless, but it is certainly annoying.The simple solution, at least for the belts striking the covers, would be for the manufacturers to just make the covers a bit larger. On all of the import machines the design of the covers is probably done by someone who isn't that knowledgeable about machinery but who is trying to use as little sheet metal as possible, hence there isn't a sufficient room around the belt. Good motor mounts, that would be easy to adjust, are probably too much to hope for.The best I can suggest is to move the motor to the end of the mounting slots so the motor is as close as possible to the machine. This usually squares up the motor to the belt run and minimizes the length of the belt. Then, after checking that the motor pulley is in line with the machine pulley, use a link belt to get the the tensioning right. Unfortunately, link belts ride higher in the pulleys so they are often closer to covers but overall I have had some luck taking this approach.The amount of flutter can be affected quite dramatically by small changes in the set up, the process is not unlike tuning a guitar. Switching to a different brand of belt, or changing the tension and alignment of the pulleys, sometimes in the "wrong" direction can often get the belt in a sweet spot where the flutter is reduced quite a bit, so it is worth experimenting if you have the patience.John White

1. 
   jimmy | Mar 24, 2008 12:12am | #9

   This seems to be a problem with Steel City, Griz, Shop Fox etc, on the 8" jointers...

2. 
   PeterDurand | Mar 22, 2008 07:02pm | #4

   I had (have) the same thing happen with the then new Griz 8" jointer with the shelix type cutters. There was a thread about it a while ago and I can't find it now.

   If I remember correctly a friend of mine (who works in physics and engineering) explained that it is because the mass of the head and the mass of the motor are substantially different so the force of acceleration and deceleration will trigger a certain phenomena which gives us the clatter.Clear as mud huh? It was to me too. And don't ask me why this only appears to be noticed in jointers.

   In any event, don't over tighten to the point where you will have bearing troubles in an attempt to solve this. The advise given to me at the time was to live with it or install an idler pulley to dampen the vibration. I lived with it.

   Hope this helps.

   Cheers,

   Peter

    

   Better life through Zoodles and poutine...

3. 
   gb93433 | Mar 24, 2008 02:38am | #10

   I have seen that as a rather common problem with motors mounted on rubber mounts but not if the motor is not mounted on rubber feet.

1. 
   SmithWerks55 | Mar 24, 2008 05:23am | #11

   Thanks for your comments, guys.  John, it's nice to have your confirmation of my assumptions.  In looking at the machine, I surmised that if the pulley cover (and the belt opening) were an inch or two wider the problem would disappear.

   I've been waiting on a reply to my e-mail to SCT - my next step will be a phone call tomorrow.  If that doesn't produce a solution, my next step was going to be what I call "fit and fiddle" until I'm happy with the operation.

   Other than this disconcerting noise (which is certainly not the end of the world), the jointer seems to be well made, runs smoothly and produces a nice result.

   Thanks again for your time.

    

1. 
   Nathan Barnard | Mar 28, 2008 10:16pm | #12

   I just got the Grizzly 8" parallelogram and it does the same thing (belt slaps around on startup and shutdown). I've got everything lined up, and never noticed it until I put the guard on (used it for a week before finding the guard and installing it). If there was more clearance then it wouldn't be a problem. I've just decided to live with it. If it bothers me I might just take the gaurd back off again. I had similar issues with my unisaw belts and found that loosening the belts took away the jolt in the belts.

1. 
   SmithWerks55 | Mar 29, 2008 05:40am | #13

   Hi Nathan,

   This seems to be a common problem, from what I can gather.  If the manufacture just cut a wider opening I think the problem would disappear.  I called Steel City about my machine and the "tech" advised me that it was caused by the torque of the motor moving (or stopping) a stiff cutterhead.  He said it should disappear after everything gets "run in".  I've been too busy to do much about it since then (it's not the end of the world) but once I have some spare time I'll fiddle around with the belt tension or just replace the belt altogether.

   Thanks for your comments.

      

1. 
   SplinterGroup | Mar 29, 2008 07:20am | #14

   Check out "soft start" and "induction motor" on an internet search and you'll find there are a number of products designed to either limit the in-rush current or control the voltage or some similar plan to prevent this. Basically the motor is accelerating faster than the belt and the cutterhead can for a moment. 

   Besides the belt shutter, there is a waste of electrical energy in an uncontrolled start up. In industry where there are a lot of large motors the soft-start modules are supposed to pay for themselves by energy savings and reduction of mechanical wear. There is sometimes a process consistency improvement so scrap reduction may factor in as well.

   It's the electrical equivalent of flooring your car at every light, and spinning the tires for a few feet. Neat, but hard on the car and the pocketbook.

   Motor controllers with any sophistication don't find their way into woodworking equipment (or enough industrial stuff actually) because of cost vs benefit. We're all doing high-fives to get a simple magnetic starter. Pretty sad, but there you are.

   I'm about to pull the trigger on a Griz 8" parallelogram jointer, so it's good to know what to expect.

   The larger guard is simple enough and would be a help in reducing the irritation factor.

   I may have to try a changeout to a polybelt (multi-vee) setup with new pulleys, or some other mechanical answer as I know it will bug me... even though it's pretty harmless.

2. 
   JohnWW | Mar 30, 2008 06:43pm | #15

   The electronics that allow you to soft start a motor only work on three phase motors.John White

3. 
   PeterDurand | Mar 31, 2008 05:11am | #16

   It also slaps when decelerating. Ya gotta live with the physics. 

   Better life through Zoodles and poutine...

4. 
   SplinterGroup | Mar 31, 2008 06:32am | #17

   There are some for single phase these days. Check out http://www.softstartdirect.com/  and you'll find some smaller, single phase ones. Used to be they were all for large motors; some are now make for the less than 5 hp applications.

   Still pricey.

5. 
   Nathan Barnard | Mar 31, 2008 04:09pm | #18

   My 15" 3hp planer (which I bought at the same time as 8" grizzly jointer) doesn't have any belt slap, and starts very smoothly. It has the same diameter cutter, but twice as long (2x more mass). I wonder how Grizzly made it "soft start"?

6. 
   JohnWW | Mar 31, 2008 05:26pm | #19

   Your belts are probably slapping also, but there is enough clearance between the belt and the covers that the belts aren't hitting the sheet metal and making noise.John W.

7. 
   JohnWW | Mar 31, 2008 05:29pm | #20

   The starters will work with single phase incoming current but the motors still have to be three phase. The single phase controls create, thru electrical magic, a three phase output.John White