Delta 20A Multiplex RAS question

[Robert Meyer]

I have this saw from my Grandfather. It is still very usable though with a fairly small blade. However, it takes over a minute for the blade to come to a complete stop upon powering off. It has a single phase 110v motor. Is there an easy fix to get the motor to "brake" upon powering off?

[Myk Rian]

New motor bearings.

[david brum]

Agree with Myk. That's the classic symptom.

[Robert Meyer]

I'm a bit puzzled. If the bearings were bad wouldn't the shaft tend to slow or grind down? The motor runs very smoothly and shows no runout or wobble. It just takes forever to slow and stop. Still, it wouldn't hurt to replace the bearings. Will the motor need to be completely broken down to replace bearings? It does have a mandrel on the front. Looks like a large job. Should I try it myself or take it to a repair shop?

https://lh5.googleusercontent.com/-cYrQx35VIIs/UQH2A7h8iWI/AAAAAAAAA7k/5JstqxOJt7s/s700/Delta%252020A%2520Multiplex%2520RAS%2520motor.jpg

[Mike Heidrick]

You in a hurry for it to stop?

[Biff Johnson]

I have the same saw and I love it. Unfortunately the motor has taken to smoking but I hate to trash the thing for now it will have to be "shop art"

[Bill ThompsonNM]

I don't follow the comment about bad bearings either. From what I've seen, some RAS motors have no brake, some a mechanical brake and others an electrical brake. My dewalt with good bearings coasts a very long time unless I use the press to stop mechanical brake. I wouldn't worry about it. Leave the saw on for repetitive cuts with a flip stop for alignments.

[Steve Rozmiarek]

Anything you do to stop the motor faster, not the blade, can unscrew the arbor. There are ways around it, for example, Felder machines use aggressive electronic braking, and pinned saw blades. It's probably possible to retrofit a RAS with enough effort, but it would be a job. Just park it behind the fence and be careful is my approach.

I don't follow the bearing remarks either, but maybe its because new bearings have a little more resistance than good used ones.

[Mike Heidrick]

The arbor on my delta RAS is reverse thread and has a set screw on the nut.

[Ed Edwards]

Bob

Bill appears to have given you a legitamate answer, I don't know where the others are coming from...
I liked the "quick stop" feature on my RAS, until it quit working

[david brum]

I don't follow the bearing remarks either, but maybe its because new bearings have a little more resistance than good used ones.

That's the idea. Old sealed bearings have very low resistance because the grease is dried up and the bearings can roll very easily. That also means that they aren't lubricated, so they are on the brink of burning out. The next symptom is usually a high pitched howl. If you think about it, the bearings on that saw are at least 50 years old.

Even with new bearings, it takes a while for the blade to coast down on older RASs without brakes. With new bearings though, it should be something like 20-30 seconds.

BTW, those are the exact symptoms that I experienced with my 1956 Dewalt MBF.

[Steve Rozmiarek]

The arbor on my delta RAS is reverse thread and has a set screw on the nut.

Mike, does your saw have braking? I guess double nutting would probably work too.