Delta 12" Arbor Runout RAS

[Frank Booth]

I just took apart completely almost, all the way down to the column bearing, a 1980's, I think, Type 1 Delta 12" RAS. The thing would be great to have but I checked the runout after I was getting mixed results on some cuts and it's at 8-10 thou out.

I re-checked the runout a dozen times against the fixed arbor flange and then against the arbor itself and then with the blade on and every time it was out about the same amount - 8-10 thou.

This has the older motor on it; the cream colored plastic motor.

Can this be fixed? If so can that motor be removed properly without special tools? Looks to take a special tool or tools.

I will use this for precision so if it cant be fixed then she will be gone I hate to say.

Thank you for any help.

Frank Booth

[TDKPE]

Frank Booth said:

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I just took apart completely almost, all the way down to the column bearing, a 1980's, I think, Type 1 Delta 12" RAS. The thing would be great to have but I checked the runout after I was getting mixed results on some cuts and it's at 8-10 thou out.

I re-checked the runout a dozen times against the fixed arbor flange and then against the arbor itself and then with the blade on and every time it was out about the same amount - 8-10 thou.

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What exactly is running out, and what are you measuring against? The shaft doesn't matter as much as the flange, as it's the flange that defines plane of the blade. It sounds like the blade has some 'wobble' type runout, if I'm hearing you correctly.

Frank Booth said:

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This has the older motor on it; the cream colored plastic motor.

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It's not plastic; it's cast aluminium. And it's epoxied together and not rebuildable. I just threw one out, in fact, but I had taken it apart to see why it's not rebuildable. Glue. And no motor shop would touch it (three-phase, with fried windings).

Frank Booth said:

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Can this be fixed? If so can that motor be removed properly without special tools? Looks to take a special tool or tools.

I will use this for precision so if it cant be fixed then she will be gone I hate to say.

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It's easy to remove and replace, and the new (third generation) motors fit directly onto it, and accept the second generation blade guard (post-'Plus 10' style) without modification. The newest motors have extruded aluminium motors (no paint), and are 2 hp vs the 1.5 hp you have. And they're serviceable.

If the motor is sound and the bearings good, you may be able to get a machine shop to mount your motor in a lathe, supporting the frame solidly but with the arbor secured in a chuck, and take a light cut on the arbor flange to true it up. Sort of like how they turn brake rotors right on the car these days. The other end of the shaft is available for locating with a live center if you take the little brake off, but I would try to support the shaft in its own bearings, as that's how it operates in actual use. If the shaft is bent a little, referencing the flange to it would sort of defeat the purpose of truing the flange to the actual rotational center vs the physical center.

If you want precision, look at the ways for the carriage. They're probably replaceable hardened rods, which can be rotated 180 degrees to present a virgin surface for the carriage rollers. Which can also be replaced, if needed. That would make it essentially a new saw, as far as wear goes. My old Plus 10 style, which is essentially the same saw (it morphed into the 12" over time), does not have those rods, and the ways are ground into the arm. Not good.

[Kudzu]

TDKPE said:

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If you want precision, look at the ways for the carriage.

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I was sitting here thinking how the heck runout would cause an inconsistent cut? It could make a wider cut but is should be the same width. With the speed the blade is spinning even it is wobbling it is going to cut consistent. Did not sink it it was a RAS saw and sounds like TDKPE is probably in the right track. Not familiar with the Delta but that track being worn makes total sense!

[TDKPE]

That occurred to me too, that a wobbling blade just makes a wider cut. Like a wobble dado blade. Unless it's inconsistent. Like with bad bearings.

Or worn ways. Like mine. Which can't be repaired without regrinding the ways in the cast iron arm.

I've thought about retrofitting, if possible, with the hardened rods like the later versions have, but I make due as it is, and use it primarily for rougher work for now. Maybe some day.

[YSU65]

I have a 10" Delta 'Red Star'. When I first started to look at blade wobble, it was not good. Then I noticed that the original owner had the outside washer inboard of the blade. When I put it in its correct position outside of the blade, much better run out.

Red Star?? Did it come from Russia? Nope, Cleveland - I think....Tom

[Delta007]

The factory allowable spec was .001 per inch of blade diameter.
Your 12" has .010"?
Stop chasing your tail and just use it.
HTH

[Frank Booth]

Thank you for the detailed response TDKPE. It's definitely the arbor that is out and I do realize that it's just basically a slight wobble cut now as the saw is dialed in and will cut square; you just have to take your time on the cut and make sure the wobble works it's way through properly. 10 thou is just a little much, but thinking about it I guess it's not too big of a deal. This was one of the very first machines I bought and I didn't check the runout when I bought it; it was so cheap I was just thrilled to get it for that price. The ability to cut dadoes on the RAS is awesome; long boards are a breeze with that thing plus it does not lack in power no matter how thick or hard the material is you throw at it.

Bummer to hear it's not a rebuild type motor. Usually back then they made stuff you could work on properly. I checked the price of the new motors form Delta..... $1,250! No way.

The ways are not worn at all. The guy I bought this from didn't use this saw too much. Everything about this saw was in good to great condition EXCEPT for the bearing at the base of the column which makes me think someone really cranked on the saw against the base perhaps and kinked the bearing against the shaft; once I fixed that it lowers and raises like butter. I took it all apart and checked it all out. Re-oiled and greased what needed to be and gave it a good once over.

Thanks for the detailed response!

[Frank Booth]

Good point Delta007. My table saw has .001 runout which I am very happy with of course. I just wanted my RAS to be in that ballpark. Perhaps I can find another motor or saw for that matter when someone sells their RAS around here. They seem to be on the cheaper side which baffles me; these things are awesome. Maybe if I use it I will find that this wobble isn't that big of a deal.

[cvillewood]

I rebuilt one of those saws and the motor windings burnt out. Rewinding it was cost prohibitive and so was a new one as you pointed out, so I scoured CL nationally and found one for sale and the guy was willing to part it out and ship the motor. Took a couple months of searching and many times being told "I just sold it" or "I only want to sell locally".

[Frank Booth]

I was just scouring the net myself and couldn't find one; at least in the search i did. I'm sure there is one somewhere to be found. But I do see them for sale around here and for cheap; I'll never understated why these don't get the love. Amazing machines.

That being said.. I feel foolish as all get out. I went down to the shop to check it all out again this time with well thought out resolve and lo and behold..I made a couple errors. My wife wasn't too terribly surprised I don't think.

I tilted the head to 90 degrees and noticed that the inner arbor flange is literally stuck; from a bit of rust or something. I noticed it wasn't quite all the way back; just a tiny bit. I tapped it gently and it went back flush where it's supposed to go. I now have some lubricant soaking into the flange to see if I can knock it loose.

I rechecked the runout and it went down to 4 thou. Then I wiggled the entire assembly and again I found that the yoke is the tiniest bit loose. I took it off and tightened it back down. Re-checked the runout and it went down to 3 thou.

I feel foolish for not realizing these issues earlier. Thank you guys for the help! It helps just to talk about it. This has been an issue on this saw that has bothered the heck out of me and now I can move on.

I'm building some adirondack furniture with a bit of a twist. I'll post some build photos later.