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Excessive scroll saw vibration?

Tooleo's picture

Just purchased a new Dewalt 788 scroll saw and am somewhat unimpressed. As I have no previous experience with scroll saws I can't be certain if I was sold a lemon, or if my expectations are simply too high.


 My problem is that the saw vibrates badly at higher speeds to the point where following the line becomes a challenge, particularly in tight radius turns. This saw fails the nickel test instantly, even at almost the lowest speed. With the speed set between 80% and full the nickel will slowly dance towards the edge after it falls over.


 My main reasons for purchasing this saw are that I've read that it is manufactured in  Canada by the same folks who produce the Excalibur saws and that it runs so smoothly. I was disappointed to find that my saw was manufactured in Taiwan and wonder if that may be the reason my saw doesn't perform like the Canadian  made saws I've read so many good things about.


 Am I unreasonable in my expectations or is this kind of vibration typical?

Mackwood's picture

(post #97336, reply #1 of 6)

Tooleo,


I was interested in a scroll saw a few months back and found that the DW did not exactly have a stellar reputation with dedicated scrollers.  There are several sites where "dyed in the wool, card carrying scrollers" hang out.  I washed them out of my "favorites" after I decided to postpone the purchase or I'd post the link.  Someone will probably post one in response to your question. 


Vibration was a problem in several posts but usually after a period of use.  The large (.032"), non-adjustable front to back movement of the blade was a big issue for several users.


Good luck,


Mack


 


 


"WISH IN ONE HAND, #### IN THE OTHER AND SEE WHICH FILLS UP FIRST"

"Close enough for government work=measured with a micrometer, marked with chalk and cut with an axe"

mbl's picture

(post #97336, reply #2 of 6)

Dear friend,

First of all, make sure the ss is well bolted to the surface where you'd use it. The surface, table or bench, needs to be as rigid as possible.

These machines tend to resonate, depending on how and where they are mounted to. Resonate means vibration relating to their natural frequency of movement. It affects a range of frequency. Getting resonance or not may be a matter of coincidence with the table or bench used. Of course, the heavier the platform, the less it can vibrate. It also has to do with the table or bench not sitting properly on the floor. Had a similar problem here. Due to re-arranging of shop, had to re-mount the ss to another place on the same bench. Where initially mounted, there was no vibration, and could stand a dime on its table through all speeds. But just reloacationg it on the same bench, as per new needs, led to bad vibration. It was fixed with rubber shocks as described.

The problem may be solved by using shock-absorber means at the mounting of the machine and at the table or bench legs.

A material that has been found to be effective is 'mouse-pad rubber' or something similar. It'd be a medium hardness rubber about 1/4" thick. Cut strips wide enough for the bolts to go through and use them as spacers. If needed, strips can be cut and fixed under the legs of the table or bench with some silicone glue, followed by air-gun brads or hammered brads.

Good luck.

-mbl-


Edited 8/17/2004 12:55 pm ET by mbl

forestgirl's picture

(post #97336, reply #3 of 6)

It should not be vibrating like that.  I have a small Delta that runs pretty darned smooth at all speeds, the DeWalt should do at least as well and probably way better.


Go over to:
http://www.justwoodworking.com


and go to their Scroll Saw forum, they are a very active bunch and know quite abit about the various saws. 


Also, I did a search there on "DeWalt" and "vibration" and it looks like it's a known problem with DeWalts (not all, just some).  Sounds like you should really request a replacement (not a fix at a service center).   Here's a quote posted on August 4.  Source was not given:

Excalibur in Canada has not been making the DeWalt since February of this year. Manufacture of the saw is now being done somewhere in the orient. The quality has apparently taken a major dip as a result. Apparantly to the point where Excalibur in Canada (Sommerville) is putting out a letter explaining why they are not responsible for the quality of the current machines coming onto the marketplace.


I also took a quick trip to the DeWalt web site.  If you register here:
http://www.dewaltservicenet.com/serviceNet/logon.asp
and then search for documents on the DW788, you'll find some articles on repair and adjustment.


One recommendation was to go to http://www.scrollsaw.com .  I guess there's a DeWalt tune-up section there.


forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Another proud member of the  "I Rocked With ToolDoc Club" .... :>) 

forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

Tooleo's picture

(post #97336, reply #4 of 6)

Thank you all for taking the time to share your ideas / expertise with me.


 I tried bolting the saw directly to a massive built in workbench with rubber pads as suggested, but the vibration persists. I gave the saw a close inspection today and realized that along with the roughly .032" front to back movement inherent to the short parallel link design, the saw blade is also orbiting .025" from side to side. The lateral movement is equal between the upper and lower arms, so the blade remains perpendicular to the table throughout the stroke. That may be why I didn't notice right away, the sawn edges were quite square.


 I have no desire to keep a saw that isn't capable of producing accurate cuts (that's what a scroll saw is all about, no? ) so it will return to the store. Most likely I'll end up with an inexpensive Delta unit and put the extra cash towards some nice mahogany for a new bed. There is no place in my shop for a yellow tool, I should have known better by now....


Cheers,


Tooleo

drhamel's picture

(post #97336, reply #5 of 6)

I've had a Dewalt 788 for about 6 months now and haven't had a bit of trouble with it.  Just luck of the draw, I guess.  Come to think of it, I haven't had any problems with any of the Dewalt tools I have, corded or cordless. Yellow tools definitely have a welcome place in my shop.

 

Tooleo's picture

(post #97336, reply #6 of 6)

I didn't intend for the closing remarks in my previous post to sound like a vicious attack against DeWalt, I'm just venting. There are several other yellow tools in my shop and I have had reliable service from some of them, but I've been burned by sloppy quality control on others. Enough that my faith in their products is gone. My 'luck of the draw' has been very poor indeed. 


Cheers,


Tooleo