Truing, As Best You Can, Shopsmith Table Tops

[jsburger]

OK, now here is the rest of the story.

To answer your second question Dusty, they were aligned one on the right and one on the left. Remember, this a MK 7 which some have said eliminates the alignment issue since both ends are the same. That may be true if both ends actually are the same. Remember I have four main tables here. Three had the way tube and table support tube holes at 90 degrees and one did not.

Well, my right hand end casting appears not to be the same as the left one. After zeroing the gauge on the blade and checking the table tops and way tubes, I checked all three table support tubes. As you can see the left hand extension table tubes and the main table tubes are fine. However, the right hand extension table tubes are not 90 degrees to the way tubes. They are tilted slightly to the left.

DSCF1659.JPG (339.41 KiB) Viewed 1327 times

DSCF1660.JPG (298.67 KiB) Viewed 1327 times

DSCF1661.JPG (304.28 KiB) Viewed 1327 times

As a result when you swap the tables end for end they no longer line up left to right. They are still fine front to back. They are both off very close to the same amount and in the right direction given the tilt of the right hand end casting holes. The straight edge placed at the back of the tables shows the same result.

Left table on right side.

DSCF1663.JPG (184.72 KiB) Viewed 1327 times

Right table on left side.

DSCF1664.JPG (279.83 KiB) Viewed 1327 times

I also measured the left hand table tube installed on the right end. It is off (within the tolerance of the gauge) the same as when the other table was installed on that end.

Edit: Correct picture now.

Left table on right side.

DSCF1669.JPG (328.58 KiB) Viewed 1325 times

The results of the Wixey on the table top is consistent with the amount the right end casting is off. Both tables are off the same amount and in the proper direction.

Left table on right side.

DSCF1667.JPG (348.65 KiB) Viewed 1327 times

Right table on left side.

DSCF1668.JPG (353.61 KiB) Viewed 1327 times

So in my case with a bad end casting the tables are not interchangeable. Just because the castings are the "same" does not necessarily mean they are all machined perfectly. Of course my right hand one could be within the print tolerance but in my opinion if it is that is a very loose tolerance.

[BuckeyeDennis]

Pretty much every time I use a real spirit level, I first test it on a reasonably level surface. First I note the bubble position, and then reverse the level (end for end) to make sure that I get the same reading in that orientation. Only then do I know that the bubble (that particular one, at least) provides a good absolute-zero reference.

John, does the "spirit level" on your Wixey pass that same test?

[jsburger]

Your dining room table top with all of the leaves installed is coplanar If one of the leaves warps, it ceases to be coplanar.

With that, I believe I am coming to the conclusion that we had a communications problem. It is good to hear that your tables are coplanar and that they are level. From what you have said, I believe you use the blade as your primary reference surface during alignments and that is what most people do. If you zero the Wixey on the blade, then you want 90° to be the result of all readings on the table tops UNLESS you are deliberately tilting.

Play with your Wixey. You have to get real comfortable with it if you are going to rely on it. Check the blade and then check all of the vertical surfaces on the Shopsmith. You will find that they are pretty close to dead on. Likewise, check the table and then all the horizontal or near horizontal surfaces. Doing this now while the Wixey is new to you will help to establish your confidence in the Wixey so that when it tells you something you don't want to hear, you will take action.

Mine is good as long as the batteries are good. I believe that some improvements have been made in that area (more battery power and auto shutoff).

How does the blade appear to be 'dead level' with the way tubes? The gauge on the blade reads 00 and the gauge on the way tubes reads 90. Did I say this? If I did I must have overdosed on my pain killers!

Same difference but I am inclined to say blade = 90° and Way Tubes = 0°.

Yes, I used the blade as the reference surface since it is fixed and the relationship of the tables to the blade is what matters.


"Did I say this? If I did I must have overdosed on my pain killers!"
No you didn't say it JPG did.

I too am inclined to say blade = 90° and Way Tubes = 0° but with the blade being the reference surface in this case I think the other way is correct.

[jsburger]

Pretty much every time I use a real spirit level, I first test it on a reasonably level surface. First I note the bubble position, and then reverse the level (end for end) to make sure that I get the same reading in that orientation. Only then do I know that the bubble (that particular one, at least) provides a good absolute-zero reference.

John, does the "spirit level" on your Wixey pass that same test?

Yes it does.

[BuckeyeDennis]

Pretty much every time I use a real spirit level, I first test it on a reasonably level surface. First I note the bubble position, and then reverse the level (end for end) to make sure that I get the same reading in that orientation. Only then do I know that the bubble (that particular one, at least) provides a good absolute-zero reference.

John, does the "spirit level" on your Wixey pass that same test?

Yes it does.

Hmmm. Then we still don't have an explanation for that anomalous main-table tilt reading you got earlier. I had thought it might be because the Wixey was facing the opposite side of the machine, as compared to the other measurements.

My own main table has some flatness issues right where you set the Wixey. And since the base of the Wixey is so short (about 2", scaling from the table), I suspected that could lead to a significant localized slope variation. BUT, I just measured the flatness of my own table in that spot with a good Starrett straightedge and feeler gauges, and I only get a height variation of about 0.003" across that 2" span. That's a slope of only about 0.1 degrees -- no where close to the 0.5 degrees that JPG noted.

[jsburger]

Pretty much every time I use a real spirit level, I first test it on a reasonably level surface. First I note the bubble position, and then reverse the level (end for end) to make sure that I get the same reading in that orientation. Only then do I know that the bubble (that particular one, at least) provides a good absolute-zero reference.

John, does the "spirit level" on your Wixey pass that same test?

Yes it does.

Hmmm. Then we still don't have an explanation for that anomalous main-table tilt reading you got earlier. I had thought it might be because the Wixey was facing the opposite side of the machine, as compared to the other measurements.

My own main table has some flatness issues right where you set the Wixey. And since the base of the Wixey is so short (about 2", scaling from the table), I suspected that could lead to a significant localized slope variation. BUT, I just measured the flatness of my own table in that spot with a good Starrett straightedge and feeler gauges, and I only get a height variation of about 0.003" across that 2" span. That's a slope of only about 0.1 degrees -- no where close to the 0.5 degrees that JPG noted.

Look at the pictures in post #194313. That is the one that shows the anomaly on the main table.

The blade level shows 90.3 from vertical. Both end tables and the way tubes show 0.3. That is exactly as it should be and reflects the out of level floor. As you know the Wixey level function is a true digital level and does not get zeroed out when you zero the angle reading.

OK, I just went out and checked the main table again. It has not been moved since I did the other checks. It checked correct this time.

IMAG0230.jpg (187.13 KiB) Viewed 1307 times

So chalk it up to an electromagnetic anomaly in the local area at the time of that measurement. Don't laugh, Little Mountain is about 20 miles north west of me and the Air Force has a facility out there where they do Electromagnetic Pulse (EMP) research on nuclear hardened components. It is line of sight, I can see it standing in my back yard.

Seems one needs to be wery wery careful with the Wixey. At least as Dusty said if you don't get the expected results check further. That is not a direct quote but that is what he meant.

I aligned the extension tables to the main table with a 48" Veritas straight edge and a 0.002" feeler gauge. My main table is low on the right front corner by about 0.006".

[dusty]

One of my jobs in my second career with a major Defense Contractor was to perform EMI/EMC/EMP testing to prove that the products we were delivering to the customer met ALL of the environmental specifications. EMP testing was one of the harder tests to pass. We even did Nuclear Survivability Testing and even that was more likely to pass than EMP.

I have doubts that the testing at Little Mountain is causing problem. Facility Certification is also difficult to achieve and to maintain.

[jsburger]

One of my jobs in my second career with a major Defense Contractor was to perform EMI/EMC/EMP testing to prove that the products we were delivering to the customer met ALL of the environmental specifications. EMP testing was one of the harder tests to pass. We even did Nuclear Survivability Testing and even that was more likely to pass than EMP.

I have doubts that the testing at Little Mountain is causing problem. Facility Certification is also difficult to achieve and to maintain.

I was just kidding Dusty. You did see the didn't you?

I also meant to say but forgot... I am about 300 miles east of Roswell, NM and Area 51 so that can't be the cause.

I had a Top Secret clearance when I was on active duty because of working with nuclear weapons. As an Air Force civilian I worked with an Electrical Engineer who was assigned an extra duty to inspect and maintain all the clean room certifications on Hill AFB and Little Mountain. We had lots of off the record conversations so I know a little bit about Facility Certification.

[BuckeyeDennis]

That HOLD button on top of the Wixey looks like it might be easy to press accidentally. Is there a HOLD-status indicator on the display?

Looking back at the "anamoly" photo, there's a little black square showing on the side of the triangle thingy. But it's not showing on your most recent (correct) photo. What does that mean?

[jsburger]

That HOLD button on top of the Wixey looks like it might be easy to press accidentally. Is there a HOLD-status indicator on the display?

Looking back at the "anamoly" photo, there's a little black square showing on the side of the triangle thingy. But it's not showing on your most recent (correct) photo. What does that mean?

I have never pressed the hold button that I know of. The buttons are actually far enough apart to not actually press them accidentaly. At least for me.

As far as the the black square (diamond) not showing, I don't know. Probably a software issue?? Some times it is there and sometimes not. It is obviously intended to indicate which way the tilt is.

There is a Hold status indicator.