Contractor Saw Alignment

[ssmith1627]

Hey guys. Trying to get myself up to speed on how to get a saw set up properly. What a concept huh ? I just feel like I can never get a truly square cut using my miter gauge and I want to figure out why.

I just bought a magnetic base that will hold a dial indicator so I'll continue to work with that to try to test for arbor runout. But I did build a jig that slides in the miter slot and can hold the indicator either up against the blade or the fence.

What's acceptable runout for the blade ? If I leave the jig in one place and spin the blade through a revolution I get results of about .007" of runout and that is repeatable. The number seems high to me. I need to reverse the blade on the arbor and see the results there as well. That may cancel out any arbor runout and give me an interesting comparison.

I will also test with other blades. Just wanted some feedback from you guys. As you can tell from my other posts, it helps me to say things out loud and get opinions. The different ways that different people say the same thing helps them to sink in and make sense to me.

Something I read today was interesting. They said to align the miter gauge fence to the miter gauge's bar instead of trying to align to the blade. The argument being that if the blade isn't perfectly parallel to the miter slot you still won't get a square cut. I plan to test that out as well.

Aligning the blade to the saw is going to be interesting. Getting at those bolts on a contractor's saw doesn't sound like much fun. The manual is very lacking in these areas so I appreciate your thoughts. I have a Delta saw (36-979).

Steve

[Tom Hintz]

i have a story (with video) on setting up a table saw at the lilnk below. check it out as it might have answers to several of your questions.

http://www.newwoodworker.com/basic/tsalign.html

The point about aligning the miter gauge to the slot (or its guide bar) is right on the money. If you stop and think about it, it can't work any other way unless the blade is dead on parallel to the slot. Squaring it to the blade is fast and easy, but not nearly as accurate as aligning it to the miter slot itself. I have a story on that also at the link below.

http://www.newwoodworker.com/squrmitrgag.html

[ssmith1627]

Thanks Tom. Your articles are exactly what I started with. Also a little from Fine Woodworking. It's just always helpful to get some more info from the guys here. I like to hear the same things over and over ! haha Helps them sink in to my thick skull.

I guess there's no blanket statement you can make. I just wanted to hear what some others thought was acceptable and not acceptable runout for the blade and the arbor. My test last weekend was with a $50 Freud blade. I didn't see anything in the manual about acceptable arbor runout for my saw.

For the fence, I have to first get a handle on the blade / miter slot parallelism. If those two aren't aligned and I use a jig running in a miter slot to align the fence, I could be making things worse instead of better. I feel like I can confirm that because my efforts to align the fence have not produced any better results.

Oh how nice it would be to have someone to show you these things in person the first time around !

Thanks for your time. It's appreciated.

Steve

[ssmith1627]

Any experience with these ? Contractor Saw PALS ?

http://www.in-lineindustries.com/saw_pals.html

I did a quick search on the forums here and didn't see a lot said about them. Thought that might be a nice way to go to get and keep the alignment I'm seeking.

Steve

[LarryG]

When one of the WW mags tested either blades or saws, can't remember which, they aligned the various contenders to within 0.001". On my PM2000, I had runout similar to yours with an inexpensive DeWalt blade; with my 40T Forrest WW2, it's within 0.001" to 0.0015" depending on which gullet I use for the test.

My fence (Powermatic close of a Bies) is also within 0.001" when checked at the two ends, but has about a 0.003" hump out in the middle. I figure that's plenty good enough, since a 64th is five times that much.

[LCHIEN]

if your cut is straight but not truly square - e.g. 90°, then that rules out
blade wobble and blade not being parallel to the miter slot.
The only thing that can be is that the miter fence is not 90° to the miter slot.

[ssmith1627]

I saw a note on Tom's side about "coving" at the end of a board cut with a miter gauge as a result of the slot not being in alignment with the blade. That's interesting and not something I'd seen before. I have noticed when using a stop block attached to my fence and a workpiece against the fence of my miter gauge that the end of that board is not perfectly flush to that stop block. Again, part of the hint to me that things are not what they should be with my saw.

But I have tried repeatedly to align the miter gauge to the blade without success. I have spent a great deal of time trying to get repeated square cuts. It is not horribly off, don't get me wrong. But it's not what I want. I take the edge of a 12x12 piece of plywood and put it against my miter gauge and cut off one edge. I place a mark there so I know which corner I just cut. I then put a triangle square up to it or a carpent's square and the end simply isn't square.

I'll keep testing. But thanks for the conversation. It helps.

Steve

[cgallery]

I think you can do better than .007 on blade runout. Have you tried a different blade? Also, I would suggest using a 3M pad to clean the arbor flange and the washers. Mind you, don't sand or file these. Just want them clean (small amounts of sawdust that look inconsequential are amplified by the radius of the blade).

[MikeMcCoy]

Any experience with these ? Contractor Saw PALS ?

http://www.in-lineindustries.com/saw_pals.html

I did a quick search on the forums here and didn't see a lot said about them. Thought that might be a nice way to go to get and keep the alignment I'm seeking.

Steve

Steve - that's one of those things you'll be kicking yourself in the butt for NOT getting before. Install was only about 20 minutes and adjustment (I haven't had to in the six months the PALS have been on) should be in the low minute numbers.

[Tom Hintz]

Sorry, forgot the runout part of your question.
It seems most blade manufacturers allow a maximum of 0.001" per inch of blade diameter as acceptable. You will find that the better blades almost always run under 0.004" of runout, measured just below the gullets.
As mentioned in another response, be very sure that the arbor flange and the flange washer are totally clean as it does not take much gunk or dust to hold a blade more than a few thousandths out of line.

[ssmith1627]

Hopefully you guys don't mind me reviving this thread. Belated Merry Christmas to all !

I've had some time to do a little more testing with my saw's alignment. The PALS are on the way but in the mean time I'm still trying to come to grips with this runout issue.

I tried testing the blade runout with a jig and with a magnetic base for a dial indicator. I get the same results. I remove the ZCTP so it doesn't interfere. I also removed the belt from the motor -- should I or shouldn't I ? On that part I wasn't sure.

I rotate the blade with the jig in one place and I see runout of 0.006 to 0.008 inches. I tried with a 2nd blade, same result. I cleaned the arbor, the arbor flange and the washer and tried again but got the same basic results. It's repeatable.

I'm not testing for miter slot alignment at this point. Just runout. The jig stays in one place and I keep even pressure on it. I can even spin the blade so that it's moving freely without my accidentally applying any side pressure. I can find the extreme for one direction, set zero on the dial indicator and then spin the blade and you can see the range of motion on the indicator.

I used the extensions for the indicator arm and tilted the indicator to put the tip against the flat surface on the arbor flange, the area where the blade would rest. I barely see the needle move as I turn it through a revolution. MAYBE 1/4" of one thousandth of an inch if anything. That almost confuses me more. Obviously the testing with the blade is about 4" further out and any runout would be exaggerated but the two still don't seem to agree.

Any ideas ? What am I not understanding here ?

One other question -- sorry for the long note ! -- do you guys hear ANY sound when you turn the arbor shaft to spin it or spin the blade ? I hear random, not constant and not frequent, clicking like noises. I have nothing to compare this with so I don't know what's normal and what isn't.

As always, thanks for your time. It's appreciated.

Steve