My $50.00 DW-788 Scroll Saw

[John Smith]

This is my latest "Barn Find" that needed a little love.

(a tutorial on how to re-pack a bearing with new grease)

 

 

 

Edited July 21, 2022 by John Smith

[Dak0ta52]

Great find!

[Hawk]

Nice find! Awesome job restoring it.

Chris

[amazingkevin]

Good job!!! best deal i ever got of 12 dewalts was $80.00. i too found a site saying the connecting rod was a culpret.

[OCtoolguy]

The racket you are hearing at high speed is coming from the tension rod. It needs adjusting and there is a spot of the aluminum cover that it is contacting that needs to be filed down just a tad. There is a good write-up here at http://www.scrollsaws.com that tells/explains about it. Check it out and make the awful noise go away.

Congrats on a real great "barn find".

 

[John Smith]

thanks, Ray - yeah, I saw that tip on grinding off the corner of the plate and did it while I had it apart.

I've only ran the saw that few minutes in the video - I just don't have the energy or ambition right now to do anything. (just recovering from Covid-19). When I finally get my stamina back, I'll take some time to get it fine-tuned and start cutting some projects. I haven't had a decent scroller since the late '70s. So this is quite an addition to the shop.

[OCtoolguy]

1 hour ago, John Smith said:

thanks, Ray - yeah, I saw that tip on grinding off the corner of the plate and did it while I had it apart.

I've only ran the saw that few minutes in the video - I just don't have the energy or ambition right now to do anything. (just recovering from Covid-19). When I finally get my stamina back, I'll take some time to get it fine-tuned and start cutting some projects. I haven't had a decent scroller since the late '70s. So this is quite an addition to the shop.

If you've already filed it down it either needs more and/or the rod needs adjusting. It's probably too long and needs shortening. 

Get well!

[John Smith]

I pretty much made it flat from the rear to the front on the belt sander like this example. I'll spend some time in the trouble shooting section of the link you provided when my mental capacity improves (LOL if there is such a thing). I think that replacing and repacking all the greased fittings made a huge difference. Now, just to get it fine-tuned to run like a sewing machine. I can see now that a new potentiometer is in the near future.

thanks again for the kind words

 

[John Smith]

well, I took the "nose" apart AGAIN today to care of two bearings I didn't get in the first go-around.

so I twisted the tension rod two turns to the right to tighten it up and sanded the tunnel off the top plate down a lot more. Cut the groove a tad deeper in the blade chucks, And very carefully put it all back together trying to make sure everything aligned properly. I notice a considerable drop in the "noise level" with the additional modifications I made. I accidently found something that sort of surprised me. when the machine is running at full tilt, I backed off the tensioning lever from 5 to 3 and and clicking, clacking or other noise just subsided down to nothing. Moving the lever back to "5" max tension, the noise picked up quite a bit and seems to be coming from the upper arm where the tensioning rod is. So, next time I have the opportunity, should I back it out one turn ? Tighten it one more turn ??

other than that, it is running 50% better than yesterday and I'm very satisified with it as it is (so I'm going to leave it alone for now).

thanks again for the tips and notes.

[OCtoolguy]

32 minutes ago, John Smith said:

well, I took the "nose" apart AGAIN today to care of two bearings I didn't get in the first go-around.

so I twisted the tension rod two turns to the right to tighten it up and sanded the tunnel off the top plate down a lot more. Cut the groove a tad deeper in the blade chucks, And very carefully put it all back together trying to make sure everything aligned properly. I notice a considerable drop in the "noise level" with the additional modifications I made. I accidently found something that sort of surprised me. when the machine is running at full tilt, I backed off the tensioning lever from 5 to 3 and and clicking, clacking or other noise just subsided down to nothing. Moving the lever back to "5" max tension, the noise picked up quite a bit and seems to be coming from the upper arm where the tensioning rod is. So, next time I have the opportunity, should I back it out one turn ? Tighten it one more turn ??

other than that, it is running 50% better than yesterday and I'm very satisified with it as it is (so I'm going to leave it alone for now).

thanks again for the tips and notes.

At that point, it becomes an experimental situation. What is happening is that when you "tension" the blade, it is pulling that wedge toward you and forcing the upper arm up to apply tension. So, essentially, when you back off the tension from 5 to 3, you are "lenthening" the rod. So if that makes the noise go away, I'd turn the rod out a thread or so. That way, you can have the tension set at 5 but in actuality, it is at about 3. Not sure that is a good thing as you need to be able to have high tension is some cases. What I'd try to do is figure out why, when set at 5, it is making noise. I think the noise is coming from the upper connecting rod, as they call it, contacting the underside of that cover. So, you might have to take some more off of it. I'm pretty sure that is where the knocking is coming from and it only happens at high speed. You are on the right track though. Once you are done, you will have a very good understanding of how the mechanism works. I'm not sure why it doesn't happen to the bottom connecting rod. Probably because there is nothing there for it to bang against. If you could nail down exactly where the upper con rod is hitting that cover, you could probably file it down a bit. Instead of the cover. Try taking more off the cover as that's the easiest spot. I had to really take a bunch off of mine. If I still had the saw, I'd take a pic for you.