Dial Indicator Fun on the TS

[Jim Summers]

Hello All,

I finally got hold of a dial indicator and made a nifty bracket so that it will fit tightly in my miter slot. All of this in an effort to get my miter slot and blade in the .001 range of parallel.

Believe it or not I was able to achieve it. Tightened the table back down and rechecked and it was still within .001. Tilted the blade to make sure nothing was hitting at any angle, all good. Got the miter gauge itself square to the blade using a machine square.

Decided to make a few test cuts and noticed some light under my square when I was checking the cuts.

I put the dial indicator back in place and checked things again, making sure I was on the same tooth. For some strange reason it was out-of-whack by .005??

I did check the arbor runout and it is in spec. Less than .001 on either side of 0.

Tonight I am going to check all of the bolts on the trunions and motor mounts to see if they need to be snugged.

Any other ideas or suggestions?

TIA

[Brian Dormer]

Maybe your blade tilt stop is not a perfect 90 degrees?

[Noah Katz]

Maybe there's some clearance in the pivot arcs between the trunnions and the carriage.

Try just grabbing the arbor/carriage assembly and pushing it around while watching the indicator.

[Ted Miller]

Not only check the same spot on the blade by flipping the blade back and forth with the dial indicator. Run the indicator the length of the blade to see if the blade is out of whack. No blades are perfectly flat. Also some tables are very testy, I tighted all the bolts a little at a time while still checking the blade to miter. This will drive you crazy, I have literally spent hours messing with my blade to miter and blade to fence since I have to have it less than .001...

[glenn bradley]

Got the miter gauge itself square to the blade using a machine square. Decided to make a few test cuts and noticed some light under my square when I was checking the cuts.

Did you make the test cuts using your miter gauge? A machine square may or may not do an adequate job to get you to a "no light" position. The five-cut method is more reliable on sleds and miter gauges/fences.

Let me dig up a description for you . . . . here you go:

http://benchmark.20m.com/articles/TheFiveSidedCut/TheFiveSidedCut.html

[Jim Summers]

Thanks guys.

I'll check all tonight.

And I definitely will prepare myself for a long process of getting it to behave. I was reading another thread regarding this topic and one person said "if you have enough patience"! I think I understand what he meant now.

Thanks again.

[Jim Summers]

Did you make the test cuts using your miter gauge? A machine square may or may not do an adequate job to get you to a "no light" position. The five-cut method is more reliable on sleds and miter gauges/fences.

Let me dig up a description for you . . . . here you go:

http://benchmark.20m.com/articles/TheFiveSidedCut/TheFiveSidedCut.html


Thanks for the link.

For the test piece, how square would it have to be? Would it skew the results if it is a little out of square to start with? Maybe that error is builtin?

Many Thanks

[Jason Beam]

The 5 cut method is unaffected by the squareness of the test piece at the start. The nature of the 5 cuts eliminates any pre-existing errors.

[Jeff Miller]

One side has to be perfectly straight, use that side against the miter gauge to start with;)

[Jim Summers]

One side has to be perfectly straight, use that side against the miter gauge to start with;)

Makes sense.

I had a few minutes to do some quick tests. Seems that I did not raise the blade 100%. When I raised it 100% things fell back in line on the dial indicator. But I did have it a 99.99% and it reads at .005 diff. I am confused.

I am going to do the 5 side later.

Thanks again

[Howard Acheson]

What kind of saw do you have? Is it a cabinet saw or a contractor saw? One possible reason is that the trunnion is out of alignment and when you tilt the blade is makes the parallelism go out of whack.

[Bill Huber]

I was redoing an old craftsman and use a Superbar with a dial indicator basically the same thing you have. I had taken the trunions and lifting system out of the saw and done a complete cleaning and adjusting of everything I could.
After putting it all back together I jacked with it one whole night and could not get it the way it should be. I then order a Master Plate and a set of Saw PALS and with the 2 add tools I got it set to .001 within 40 min, and that is putting on the PALS.
I think of the 2 items the PALS made the most difference, the Master Plate was a great help.
The PALS will only work on a contractor saw.


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

http://mastergage.com/display_product.asp?id=3

http://mastergage.com/display_product.asp?id=4

[Jim Summers]

Doing a 5 cut test on a piece of mdf that is 8"x8" I was able to get the final slice to have a .014" difference. Doesn't sound like much, but I am sure when I start working on large panels and stuff it will definitely be an issue.

The odd thing is when I raise the blade to max height and check I am at .001. Then when I lower the blade to cutting height, sat 7/8" it goes to about .003 - .004 out. Why can't the miter slot alignment be done with the blade set to 1.5" ?

I am working with a new PM2000 cabinet saw. Less than 30days old.

I really do not want to have to go into the cabinet and mess with the trunions.

Ideas / suggestions??

TIA

[Bill Huber]

Now understand that I am no expert in this area in anyway, heck I just learned to spell table saw last week.....

It has to be that the arbor is not parallel with the table, the image is a quick drawing of what I am talking about. Now it is exaggerated just a little to show it better.


http://i.pbase.com/g6/87/15787/2/77036057.cZHfDf4k.jpg

[Jeff Miller]

Now understand that I am no expert in this area in anyway, heck I just learned to spell table saw last week.....

It has to be that the arbor is not parallel with the table, the image is a quick drawing of what I am talking about. Now it is exaggerated just a little to show it better.


http://i.pbase.com/g6/87/15787/2/77036057.cZHfDf4k.jpg






Bill thank you I was going to try to explain that to him in words because thats what I would think that the problem is.

You made it easier to explain that way:D

[Jim Summers]

Bill thank you I was going to try to explain that to him in words because thats what I would think that the problem is.

You made it easier to explain that way:D

I apologize for my slowness on this. But I still am not picturing which way the arbor is not parallel. With the table / miter slot, or what I would call vertically / not at 90 degrees to the table?

I will try and think it through, but it seems to me that if it is out of alignment by only .001 at full blade height it would be .001 when the blade is at 1" height also.

Thanks again.

[Jim Summers]

Wow, when I posted the previous message, I could not see those images you did. Very nice.

That makes it a little clearer for me. So it sounds like when I raise the blade and it hits the stop, it is knocking the arbor out of parallel. Then when I drop it down the arbor goes back to parallel and that allow for the change.

So a possible solution would be to make sure again that the bolts are tight? Or maybe even do the miter slot alignment with the blade raised to just off the stop?

Many Thanks

[Greg Mann]

It sounds like you need to do the alignment just below the point that you hit the stop. Hitting the stop is putting the arbor housing in a bind, but if that is where it is when you align the blade that becomes the only place where it will be aligned. Sinc you don't use the saw with the blade all the way up, or mostly don't, then align it below that position. I would then avoid using the saw tight against the limit of travel,now knowing that will be a source of error. This type of skew is common in many tools when the physical stop that limits travel is not perfectly in line with the mechanism that initiates the movement. It creates a skew commonly called hysteresis.

[Dan Forman]

When using the 5 cut method, the larger the piece you start with, the more reliable your results will be, and it will be easier to correct the error, as your corrections will be larger. The directions I saw started with about a 24" square, which I guess would require a sliding table or cross cut sled.

Dan

[Bill Jepson]

Jim,
Everything you're doing sounds good. The "5 cut" method is a good way to check your alignment. One thing I didn't see anybody mention is, "Are you sure of your square?" As a long ago machinist I'm always skeptical when people start talking .001 inch accuracy on anything but a machine tool surface. Heck if you have EVER dropped your square it's probably off. In one of the shops I worked in we had some time on our hands and measured 10 different guys 6" square on the Brown&Sharpe Coordinate measuring machine. (better than 50 millionths accuracy guaranteed) We found 1 count 'em, 1 in 10 that was in spec. (.001 in 6 inches) The worst was out .010 in 6 inches. This was a Mititoyo square that the owner had admittedly beat up a bit. One of the Starretts we measured was off by .008. An old and obviously battered one as well. But some of the Groz squares are built to a claimed lower accuracy, and I question how good the cheap ones are going to be. If you are within .015 on a 5 cut that isn't bad. Being .030 off in 4' or so will easily get you by when you have to allow for expansion of the panel anyway! You can really chase your tail when trying to get truly .001 accuracy when cutting wood. Just the pressure you apply against the fence can foul you up.
Good Luck,
Bill Jepson

[robert micley]

i have a friend who is a building contractor and great woodworker.all this dial indicator stuff is bull to him.he use a straight edge and tape measure.the tension in the belts turning the blade can affect the dial indicatoe.just tightening the bolts can affect a few thousands.if you want to be super perfect how about measuring the parallelism from one end of table to another rather than just from one edge of blade to the other.pressure against the fence will affect the parallelcut.check your miter saw-i bet those people who are saying their miter saw is dead accurate have not really held a 45 or 90 degree square against the wood up to the light.

[Jim Summers]

Jim,
Everything you're doing sounds good. The "5 cut" method is a good way to check your alignment. One thing I didn't see anybody mention is, "Are you sure of your square?" As a long ago machinist I'm always skeptical when people start talking .001 inch accuracy on anything but a machine tool surface. Heck if you have EVER dropped your square it's probably off. In one of the shops I worked in we had some time on our hands and measured 10 different guys 6" square on the Brown&Sharpe Coordinate measuring machine. (better than 50 millionths accuracy guaranteed) We found 1 count 'em, 1 in 10 that was in spec. (.001 in 6 inches) The worst was out .010 in 6 inches. This was a Mititoyo square that the owner had admittedly beat up a bit. One of the Starretts we measured was off by .008. An old and obviously battered one as well. But some of the Groz squares are built to a claimed lower accuracy, and I question how good the cheap ones are going to be. If you are within .015 on a 5 cut that isn't bad. Being .030 off in 4' or so will easily get you by when you have to allow for expansion of the panel anyway! You can really chase your tail when trying to get truly .001 accuracy when cutting wood. Just the pressure you apply against the fence can foul you up.
Good Luck,
Bill Jepson

I am using a new Groz 6". Is there any home shop way of verifying the square? The box it came in claims some .0000xxxx accuracy. But like you say who knows really. That is why I purchased a new square, was because I didn't really trust what I had. I have a couple of combination squares I could do some basic line drawing comparisons with I guess.



When using the 5 cut method, the larger the piece you start with, the more reliable your results will be, and it will be easier to correct the error, as your corrections will be larger. The directions I saw started with about a 24" square, which I guess would require a sliding table or cross cut sled.
Dan


I will try the 5cut again when I can get by a box and get some material. But to help me understand, the 5cut is helping me get the miter gauge square to the blade? I still need to get the blade and miter slot parallel before proceeding to the miter gauge phase?
Quick, must grab for the ibuprofen!




i have a friend who is a building contractor and great woodworker.all this dial indicator stuff is bull to him.he use a straight edge and tape measure.the tension in the belts turning the blade can affect the dial indicatoe.just tightening the bolts can affect a few thousands.if you want to be super perfect how about measuring the parallelism from one end of table to another rather than just from one edge of blade to the other.pressure against the fence will affect the parallelcut.check your miter saw-i bet those people who are saying their miter saw is dead accurate have not really held a 45 or 90 degree square against the wood up to the light.

Not sure, but that is how I discovered that my first cuts after alignment were not dead on. Which then lead to the discovery that I was out of parallel again. More ibuprofen please!

[Mike Goetzke]

I was redoing an old craftsman and use a Superbar with a dial indicator basically the same thing you have. I had taken the trunions and lifting system out of the saw and done a complete cleaning and adjusting of everything I could.
After putting it all back together I jacked with it one whole night and could not get it the way it should be. I then order a Master Plate and a set of Saw PALS and with the 2 add tools I got it set to .001 within 40 min, and that is putting on the PALS.
I think of the 2 items the PALS made the most difference, the Master Plate was a great help.
The PALS will only work on a contractor saw.


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

http://mastergage.com/display_product.asp?id=3

http://mastergage.com/display_product.asp?id=4


Don't want to steal the thread but I'm new to cabinet saws too. My new Uni was 0.005" off on the blade measurement. Closest I could get after tightening the bolts was around 0.001" to 0.0015" due to movement after tightening the bolts.

Now for my question - with all these cabinet saws out there why hasn't someone come up with (or maybe they have and I havn't found it) a device similar to pals. I have seen one but it required you to remove the extension wings. Seems like you could somehow connect a jacking screw device on the extension wings or table top and push against the cabinet to dial in the alignment.

Also - I shouldn't have built a device to slide my dial indicator along my Biese fence, it varies by about 0.004" along it's length. Don't know if this is typical or not (doesn't seem to be much?).

Mike

[Brian Dormer]

I might be wrong (experts - please correct me if I am) - but a cabinet saw, due to the way the table and trunions are built - doesn't need PALs.

On my hybrid saw (which is close to a cabinet saw in most details) - the table has 4 bolts to the cabinet and the trunions have 4 bolts to the cabinet. To adjust, I loosten 3 of the 4 bolts holding the table down and tap a corner with a rubber mallet. (You haven't lived until you have spent an hour trying to move a 200 lb slab of cast iron ONLY .003 inches).

My rip fence has about a .002 bow towards the blade in the middle. .004 is close to what I'd consider "panic time" - but if the rest of the saw is adjusted, it's probably acceptable.

[Walter Yamamoto]

I believe Brian is correct - contractor saws can use the pals because pals is used to adjust the position of the trunion. Cabinet saws have stationary trunions - the position of the table is moved to adjust parallelism to the miter slot.

My personal experience in adjusting my table (a humble Delta 36-650 contractor) is the following.

Raising the blade COMPLETELY throws the working reading off because raising my blade all the way up actually makes the belt and pulley at the arbor assembly press against the table top and shifts the arbor by an ever so small amount. I have to raise the blade just short of "all the way" so the belt and pulley does not press against the table top.

I have noticed that adjusting the trunion without the weight of the motor bearing down on the belt and pulley throws it off enough to irritate me, so I leave the motor and belt attached so the adjustment takes the pressure into account.

PALS MAKE ADJUSTING LIFE A HELL OF A LOT EASIER FOR ME!

With the above caveats, I am usually able to get it to less than .001 with a little patience - maybe 20 minues or so.

[Jim Summers]

I believe Brian is correct - contractor saws can use the pals because pals is used to adjust the position of the trunion. Cabinet saws have stationary trunions - the position of the table is moved to adjust parallelism to the miter slot.

My personal experience in adjusting my table (a humble Delta 36-650 contractor) is the following.

Raising the blade COMPLETELY throws the working reading off because raising my blade all the way up actually makes the belt and pulley at the arbor assembly press against the table top and shifts the arbor by an ever so small amount. I have to raise the blade just short of "all the way" so the belt and pulley does not press against the table top.

I have noticed that adjusting the trunion without the weight of the motor bearing down on the belt and pulley throws it off enough to irritate me, so I leave the motor and belt attached so the adjustment takes the pressure into account.

PALS MAKE ADJUSTING LIFE A HELL OF A LOT EASIER FOR ME!

With the above caveats, I am usually able to get it to less than .001 with a little patience - maybe 20 minues or so.

I am going to redo the alignment process again with the blade raised to almost the top but not all the way up. Hopefully sometime this weekend. I'll let ya'll know what I find out.

Thanks again

[Phil Thien]

I am going to redo the alignment process again with the blade raised to almost the top but not all the way up. Hopefully sometime this weekend. I'll let ya'll know what I find out.

Thanks again

That is the correct method. The blade raising mechanism is non-linear at the very end of its range. So the correct method whenever aligning a table saw (or drill press or jointer or whatever) is to go to the limit, then back off a half or full turn.

[Brian Dormer]

That is the correct method. The blade raising mechanism is non-linear at the very end of its range. So the correct method whenever aligning a table saw (or drill press or jointer or whatever) is to go to the limit, then back off a half or full turn.

Hmmm... that's a new one on me. Better go check my TS alignment....

[Jim Summers]

Hello All,

Wanted to finish off this thread. Got everything lined up now. I am pretty sure the main reason I had trouble after doing the first alignment was that I had max'd out the blade height. By rolling back down a turn and a half from top, I aligned everything and am now able to adjust the blade to desired heights and maintain alignment.

Thanks again for all of the tips and help.