Blade alignment with table top

[steve-norrell]

I have been having a problem with aligning the blade so that it is exactly 90 degrees to the table top. I have used carpenter squares and a newly purchased engineer square and they seem to give different results, depending on where the squares are placed.

After much pondering over a couple of days and about twenty cups of coffee I realized that the top of the table is not perfectly flat in that some items (such as the accessory table, SMT, and added miter-track tables) are not exactly level with the fixed parts of the table just to the right or left of the blade. Of course, the Ryobi ZCTP is not even close to level. And, I have seen it written that the SMT is designed to be slightly (0.2 in, or so) above the main table.

Question: What is the best reference point to use for aligning the blade and leveling any add-ons to the table top? And, when doing a cut, which part of the table should support the piece being cut to ensure an end that is as perfectly squared as possible.

Thanks for the help, again!

[mschrank]

You'll get more input on this, but I'll point out that this saw is a bit different in that you don't align the blade to the table. Rather, you align everything else (SMT, rip fence, miter slot tables etc) to the blade.

The main table body may not align to the blade, and that's okay. Some can't accept that, and have gone to some trouble to get it all aligned, but it's really not necessary since nothing is referenced off the main table.

Regarding you other comments regarding the fact that the accessory items aren't level with the main table...

As you've pointed out, the SMT is slightly higher by design (less friction on the workpiece during crosscuts.

I'm not sure what to tell you about the accessory table...mine is dead even with the main table (I think..?). Maybe you might have to file down the tabs that nest into the rails...?

I don't have the miter track tables, so can't offer any advice on that one since I've not seen how they attach.

[LarryG]

Mike, he's talking about the blade's perpendicularity to the table.

Steve, I reference short workpieces off the main table, longer pieces off the SMT. One of the reasons I like having the dual miter slot table installed on my saw is that it not only allows me to use a miter gauge for shorter workpieces, but also gives me a wider level working area (because I have the DMST shimmed so that it's perfectly flush with the main table). On most of the cuts for which I use the SMT, the slight amount by which it is higher than the main table is moot since it is farther away and any slope it imparts is more shallow. BTW, I'm pretty sure you made a typo with that 0.2" ... more like 0.02", which is about a strong 1/64th.

My accessory table also sits dead flush with the main table (or is within so few thousandths that, again, the difference is moot).

As Mike said, the design of this saw is a little unusual and learning to deal with these issues is all just part of the fun ...

[gmack5]

Of course, the Ryobi ZCTP is not even close to level. And, I have seen it written that the SMT is designed to be slightly (0.2 in, or so) above the main table.
Thanks for the help, again!

I think you'll find that the difference in the SMT height above the Main Table is closer to .020" than 0.2" as you've stated.

The idea is to keep your work-piece from "dragging" on the Main Table. To assure that the cut is reasonably square, maintain a positive downward pressure between the work-piece and the SMT, NOT the Main Table.

I'm sorry, I failed to address your original Question properly.
The Top of your SMT and the Top of your Main Table should be "parallel". You should therefore be able to Adjust the perpendecularity of your Saw Balde to the Main Table and it would also then be perpinduclar to the SMT surface.

In other words, let the work-piece "float" above the Main table. Do not push the work-piece down against the Main table while making a Cross-cut.

[mschrank]

Mike, he's talking about the blade's perpendicularity to the table.

Er...oooops. Thanks for clearing that up Larry!

[Tom Miller]

I chose to lower my SMT to be only 5-10mils above the main table. I did it by replacing the plastic shims on the SMT (that rest on the rails) with something a little thinner (a few pieces of metal foil tape). There have been discussions on these forums that you might find interesting/useful.

To measure blade perpendicu...uhhh, perpen, uhhh...dicularicity (whew, got it!) you either need to shim your throat plate, or make sure the horizontal leg of your square registers on at least a couple points of the main table. But you'll want to shim your throat plate, anyway.

I'd recommend shimming your DMST, too, like Larry mentioned.

You might also want to do at least a quicky check for side-to-side flatness of the main table, using a straightedge.

Regards,
Tom

[steve-norrell]

I think you'll find that the difference in the SMT height above the Main Table is closer to .020" than 0.2" as you've stated.

The Top of your SMT and the Top of your Main Table should be "parallel". You should therefore be able to Adjust the perpendecularity of your Saw Balde to the Main Table and it would also then be perpinduclar to the SMT surface.

Also Mike and Larry!

You guys actually answered most of my questions. The issue of perpendecularity is the main one and, if I am understanding your messages, it would be best if I can use the main table or the SMT. I should be careful not to use the dual miter table, avoid using an accessory table, and never rely on the throat plate.

I think another problem is that I hold the piece being cut over different parts of the table, slightly changing the angle with the blade each time. Steve (me) has to get consistent and also make sure that the various parts of the table are as parallel with each other as possible.

Oh, I did mean 0.02in, not 0.2in.

This is truely a learning experience. Thanks to all.