rick_b

Unfortunately I have been side tracked by a bedroom update and haven't had a chance to try anything with this machine for awhile. I will be getting back to it soon I hope and will post an update. Rick

Well I stepped away from this saw again. Once it got cold outside I had no more excuses . This saw has two problems - noise and a motor speed control that seems to cause the speed to surge and/or slow down a bit as the speed control is increased. I've decided to focus on the noise issue - assuming the speed problem is unrelated to noise. Following are the steps I have followed so far: 1. Secured to saw to the benchtop - a VERY slight improvement to noise level but not enough to even consider victory. Noise presented as slight at lower speed setting of 1, increases with a knocking sound at 2 and 3, knocking reduced but still noisy at 4, knocking worse at 5 and knocking much less but still noisy at 6 through 8. 2. Applied a layout bluing to top and bottom of tension rod cover and retested. No indication of damage to the bluing which would indicate that something was contacting the cover. 3. Checked all upper and lower arm and chuck connection fasteners and retested - no change to noise levels 4. Adjusted tension rod one full turn CW - Noise/knocking seemed better but still unacceptable 5. Adjusted tension rod a second full turn CW - knocking significantly worse at speed 2 and above 6. Adjusted tension rod a third full turn CW - significant knocking at higher speeds - 5 and above 7. Adjusted tension rod 4 full turns CCW (3 back to starti g point +1) - Serious knocking goes away but still very noisy at various speed 8. Adjust tension rod 1 full turn CW - back to initial start point So now I'm lost - can't really tell where the noise is coming from even with a stethoscope. The next step is to remove the left side covers and test the machine to see if that helps identify the noise source. I don't have a lot of hope for success but/I am open to any suggestions. In addition to the noise I believe there is something wacky with the speed control causing the surge/speed variation but that's a problem for another day. And oh yeah - I stripped a threaded hole in the upper rocker mounting casting 0 least of the issues at this point. Rick

Thanks Ray - I do have a stethoscope but that didn't seem to help. I'll try getting it clamped downand using it again. How far back did you remove material on the underside of the cover? Rick

I've been fooling with this for several days. Did a little more grinding on the underside side of the cover cap - no improvement. adjusted the tension rod 2 turns clockwise - no improvement maybe a little worse. Couldn't get tension beyond #3. Adjusted the tension rod 4 turns counter clockwise (2 back to starting point then 2 more). No noticeable improvement - could adjust tension up beyond #3. I'm at a point where it sounds like the noise is coming from everywhere so I stopped. I should note that the knocking is hardly noticeable at low speeds (1,2,3) much louder at mid range and then quiet again at higher speeds. I feel like I'm really chasing a ghost - I'm going to have an objective third party (LOML) listen later today and get her opinion. I'm pretty close to offering this free to a good home. I do have a second DW788 with a non - working switch so I'm not sure how it performs from a noise perspective but I could start inter changing parts - the 2nd machine is a type 2 but I don't think there are major parts differences. Suggestions welcome Rick

Thanks Ray - I appreciate the feedbck Rick

No problem Larry - I think we are now on the same page. Now to figure out where to go Rick

So here are a few pictures of How I think the cover plate is assembled. Please feel free to point out if I don't have this right If we agree this is correct then the grinding of the leading edge of the bottom side of the cover plate (as shown above) doesn't seem to have anything to do with the tension rod - at least directly. I have seen this grinding operation recommended in several places but never have seen a why? Rick

Folks - please don't take this as argumentative but I absolutely don't see how the tension rod can go under the cover plate. The cover plate (part 80) only has one hole and it is threaded for the bolt thatv attaches part 26 to the cover plate. Part 26 has a cam surface that the L in the tension rod fits in and provides the tensioning function. If the tensioning rod is under the cover how does the L go through the cover and into the part 26 cam surface? I'm sure we are having some vocabulary issues with over/under, etc Rick

That's a very deceptive picture. I don't believe there is any way the tension rod can be assembled under the cover but I'm going to take a second look in the morning Rick

I'm confused - the tension rod fits on the other (top) side of the cover. Not sure how the rod is hitting on the underside of the cover? I' m sure there is something obvious I am missing Rick

Yesterday I spent some time with the saw...First thing I did was disassemble the left side covers and check all linkage fasteners and bearings with specific focus on the connecting rod area. All were tight with no apparent bearing issues. I should mention that I had previously disassembled all bearings, cleaned, inspected, re-greased and reassembled. I didn't find any bearing wear issues - doesn't mean there were not any just that I didn't see any. Next was to try and get the top arm parallel with the bottom arm - this was an effort to compensate for no real spec on tension rod and wedge positioning. Following is a picture of the final wedge position. After reading about the cover plate modification I decided to try that. I milled a bit from the underside I put the cover plate back on and removed the assembly from the machine. If I manually manipulate the rocker arm it still contacts the underside of the cover but that may be exceeding the "normal" movement of the arm. After these adjustments the noise was still there - better but still fairly loud at higher speeds. I also ran it with the cover plate off (an obviously no tension) and it seemed better. Actually it sounded more like the noise was coming from the bottom arm but at some point it gets difficult to tell. Not sure what to do next - I may try adjusting the tension rod clockwise a turn or 2? Also - try to get it bolted/clamped down just to eliminate that variable. Any other suggestions? Thanks Rick

Thanks for the greetings folks! Rick

So I have read that the tension rod should go clockwise and counter clockwise. I have done both to no avail. Is there some spec or dimension that indicates approximately where the tension rod should be? Rick

Good morning folks - I just joined your group based on a recommendation from an acquaintance. He thought maybe you folks could give me some guidance in resolving a scroll saw noise problem. I bought a used Dealt 788 scroll size that had some noise. I went through the Bob Brokaw videos and did a tear down to inspect bearings and sleeves - all seemed OK so I cleaned and re-greased. I did replace the large connecting link on the motor shaft. After putting everything back together the noise was no better - maybe a little worse. I read were a common problem was the tension rod so I adjusted that several times in both directions (CW and CCW). No improvement! I ended up walking away from it in frustration for over a year. Now I am back at it. Below are links to youtube videos of the noise level. I the first video I ran it ona set speed, shut it off, chnaged the speed level and started it back up. In the second I simply adjusted the speed while the machine was running. i adjusted the tension rod again CW three turns. The noise improved at low speeds but develop a real bang at higher speeds. I think I have noticed that the noise has always been speed dependant. So I'm looking for any help in diagnosing this problem Thanks Rick

Good morning folks - I am Rick Bruner from Winston Salem NC. My current motivation for joining this group was a recommendation from an acquaintance. I am not currently a scroller but do have a Dewalt 788. I am retired 10 years and enjoy woodworking and vintage machine restoration. Hopefully I can get some help with a frustrating situation with my scroll saw. I plan on making a separate post regarding this issue. Rick