Page 1 of 4

520 rail misalinged?

Posted: Thu Feb 16, 2023 11:24 am
by hfmann
Well - dang dabit it I think.

I found the front of my 520 fence floating quite a bit above the table when locked in place. At the back it is right on the table top. I sure don't know how many years ago I upgraded to the 520 rails. So I can't find the alignment gauge the upgrade manual calls for. I'm assuming my front rails are not spaced correctly from the table top. Anybody know of a way to correct this situation without buying another gauge from SS?

thanks,

hal
lots of space under front of 520 fence when locked on rails.
lots of space under front of 520 fence when locked on rails.
2023-02-16 10.45.55.jpg (148.72 KiB) Viewed 1072 times

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 11:51 am
by DLB
I use the gauges, but I have a theory:

Using the fence and a feeler gauge or similar to set the gap between the main table and the bottom of the fence as a standard:
Main table first, adjust the front rail for the correct gap with the fence located left and right positions. this should set the front rail parallel to the table.
Do the same for the rear rail on the main table.
Using a straight edge, set the extension table surface coplanar with the main table.
Using a straight edge, set the front and rear extension table rails to the main table rails.
Using tubes, lock a floating table between main and extension tables. Use a straight edge to ensure table surface is coplanar, or adjust rails until it is. Repeat for the other floating table. (If you have long tubes you can do both floating tables with one setup.)

I don't know the 'correct' gap, but if you want to try this I'll measure two samples. Let me know what/how you want to measure and I'll do it the same way. It occurs to me that typical dial/digital calipers will work well, using the top of the fence to the table rather than measuring the gap.

- David

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 12:07 pm
by hfmann
Wow David,

That is super helpful and detailed info. Before you go to all the trouble to measure, let me see how much and how fast SS can get a alignment gauge to me. I can tell I've got some work to do to get everything lined up right. Thank you.

In the meantime though, I never thought about a gap between the bottom of the fence and the main table. I' always assumed the fence sat right flat on the table. The next time you get a moment and feel like measuring that, I'd be curious to know.

thanks,
hal

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 12:14 pm
by dusty
This might help.

Dimension is not critical so long as it it the same at all points along all rails.

My sketch shows 33/64" but that might actually be 1/2" if I remeasured. A 1/64" error is easy to achieve with a caliper unless you are real careful and somewhat skilled. That does not describe me!

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 12:19 pm
by hfmann
Outstanding Dusty,

I assume that is a drawing with the actual measurement of the SS alignment and setup gauge.
edited: Ooops, now I see you note the measurements don't have to be precise, just uniform in all places. Thanks.

Thank you.

hal

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 12:25 pm
by dusty
hfmann wrote: Thu Feb 16, 2023 12:19 pm Outstanding Dusty,

I assume that is a drawing with the actual measurement of the SS alignment and setup gauge.
edited: Ooops, now I see you note the measurements don't have to be precise, just uniform in all places. Thanks.

Thank you.

hal
The sketch is intended to depict actual measurements of my gauges. It does lack high level of precision" :rolleyes: :rolleyes:

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 1:44 pm
by DLB
hfmann wrote: Thu Feb 16, 2023 12:07 pm In the meantime though, I never thought about a gap between the bottom of the fence and the main table. I' always assumed the fence sat right flat on the table. The next time you get a moment and feel like measuring that, I'd be curious to know.
Approximately 0.050". I had small variance between front and rear measurements and slight difference depending on measuring with a feeler gauge Vs digital calipers, but all within a couple of thou.

- David

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 3:30 pm
by hfmann
DLB wrote: Thu Feb 16, 2023 1:44 pm
hfmann wrote: Thu Feb 16, 2023 12:07 pm In the meantime though, I never thought about a gap between the bottom of the fence and the main table. I' always assumed the fence sat right flat on the table. The next time you get a moment and feel like measuring that, I'd be curious to know.
Approximately 0.050". I had small variance between front and rear measurements and slight difference depending on measuring with a feeler gauge Vs digital calipers, but all within a couple of thou.

- David
Interesting. I used a digital gauge and difference between front and back was .07.

hal

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 5:54 pm
by DLB
hfmann wrote: Thu Feb 16, 2023 3:30 pm Interesting. I used a digital gauge and difference between front and back was .07.
Hmmm. Getting back to your first post - yes, that's what you said. Maybe a different problem than rail alignment? On mine, sample of one, a dime I measured at 0.051" will fit under the fence at both ends but is very snug in the front. A penny (0.060") won't fit under either end, not even close. The contact points are hard rubber (or similar) pads on the front fence casting and a nylon (or similar) block on the rear. I'm calling the front the infeed side for table saw operations. I measured with the locks in the locked position.

- David

Re: 520 rail misalinged?

Posted: Thu Feb 16, 2023 7:03 pm
by hfmann
David,

I too wonder if there is some other problem. I used a digital depth gauge to measure the top of front (infeed) and back rails from top of the table. They were both equal at .49. I don't know if they are supposed to be the same. Certainly a puzzlement.

And, I don't even know if this is a problem because the fence is absolutely perpendicular to the surface of the table and also aligned parallel to the miter gauge slots. The ONLY reason I noticed this is I was trying to solve I problem I had using a tenoning jig that rides on the top of the fence.

thanks for your help.
hal