Quick Question on Accufence

I am planning to add an Accufence to my old Powermatic 66. I want to build an extension table that butts flush up to the table. So here is my question - Do I really need the back rail or can I use the Accufence as reliably without it?
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On 1/1/19 1:29 PM, Onorbit wrote:

If it's like the Biesemeyer fence, all the clamping is done on the front rail with no involvement from a back rail.
So you could probably take off the back rail with no issues. I would just make sure the back rail isn't acting as a structural rail for the saw table/assembly in any way before removing it.
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On 1/1/2019 1:50 PM, -MIKE- wrote: ...

Not that familiar with the Model 66, eh? <VBG>
Them there's 100-lb solid cast iron extensions, there, good buddy! The rear rail serves only as locking feature for the original fence.
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Thee Unisaw isn't much different, except that the back rail *is* there for structure so the bolts into the top (and the iron) are in sheer, rather than tension.
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On 1/1/2019 1:29 PM, Onorbit wrote:

I had one of those fences, made by Jet. Anyway Yes you need that rail, not so much directly for the fence but to hold up and support the table extension that the fence will rest on. If the extension table does not have enough support to stay on the same plane as the TS table or if the extension bows your fence will reflect those deviations.
The back rail is only to support the extension table that the fence will rest on.
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On 1/2/2019 12:24 PM, Leon wrote: ...

The back rail has absolutely no function to support the wings on a PM 66; they're precision-milled castings bolted to the main table...
When mine was manufactured (still in McMinnville, TN), they were still being surface-ground at the factory in place before being removed again for shipping...they quit that later to control some of the costs, but they're still milled flat w/ square, true edges to mate the main table casting.
I don't know what they're now shipping for fence options; the "classic" 66 had just a couple of 5/16" bolts with a formed nylon washer to fit the round shape that bolted through oversized holes on the table to let it be (the rail) adjusted to the table, not to help support the table wings at all...
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On 1/2/19 1:10 PM, dpb wrote:

We're not talking about the side extensions. We're talking out an out-feed table.
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On 1/2/2019 2:15 PM, -MIKE- wrote:

Well actually the OP he never mentioned out feed table. I read extension table to mean "extension table". And yes if you add an extension table, and especially if you add to a 50" rip capacity the back rail is needed to support and prevent sag of the extension table.
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On 1/2/19 3:03 PM, Leon wrote:

Oops... yeah, I guess he didn't. Next time I need to read gooder.
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On 1/2/2019 3:56 PM, -MIKE- wrote:

;~0 eats all goot!
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On 1/2/2019 4:56 PM, -MIKE- wrote:

I took him to mean out feed table as well. Extension wings could also be what he meant. At any rate, IF he meant out feed table then there is no need to butt the table to the saw. In fact a bit of space is desirable to allow fingers under the wood to easily lift wood from the table.
If he meant extension wings, then the back rail should have not interfere with butting a table to the saw. It might be needed as Leon explained but should in no way interfere with the task.
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On 1/3/2019 7:29 AM, Jack wrote:

Actually the support bar on the back side might ease attachment to the back of the saw for the out feed, if that was what he meant.
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On 1/3/2019 1:19 PM, Leon wrote:

Yes, that's how I use mine. Bonus is t leaves just enough space for my fingers to get under a piece of wood I just cut. I also have a cabinet on wheels that butts up that table.
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On 1/2/2019 1:10 PM, dpb wrote:

Understood but if you have or add the 50+" rip capacity the fence needs a side extension that will be approximately 8~10" wider than 50". IIRC most saws will have side extensions but not that far out from the blade.
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Thanks for the input. I have a right wing side extension now and a table. M y wing extension table is supported with a steel frame tied to the saw, so a back fence rail isn’t needed to support the wing extension.
I currently have an old (1st generation) Excalibur Fence with 50” r ip. I am asking about the back rail because I want to build an outfeed tabl e with a dust collection system underneath. I would like to build the outfe ed table so it can be butted flush to the saw table with no gap. To do this I will need to change my current fence which isn’t great (because it has the old c channel rails). It seems to me from looking online that an accufence doesn’t really need a back rail to function. I was hopin g to hear from anyone using an Accufence, Jet Exacta, or Beys w/o a back ra il. Sorry for the confusion.
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