How Flat is a Flat Table?

[keakap]

Again! the edge is the skinny sides. Is it really balancing on the skinny edge? I would like to see that spinning!

I realize(IIRC) the SE is 36" long. What are its dimensions in the other two rectilinear planes?

My FTP connection died of mold and old age.
The forum won't take MPG files.
I refuse to log into You Toob.
So try a 'zip' file: spin_zone[ATTACH]10328[/ATTACH]

[keakap]

...asking for the purpose of education and understanding how flat do the tables need to be to meet all of our demands.

Excellent point.

I wish I had made it at the very beginning, and said that "it's off" a bit here, a tad there, a skosh on the other side, yada yada and I have no spec to tell me if it's okay, but I know it don't work.

Btw, 'flat' usually doesn't bother me so much. It's the other stuff...

[derekdarling]

I have heard that early machinists and lathe builders could take a large table and had-scrape it to a couple of thou flat... BY HAND! Over remarkably long distances. These guys were building steam engines and battleships, with hand tools!

Derek in Surrey, BC

[Ed in Tampa]

It is easy to determine if your Mark 5/V table(s) is(are) flat but only if you know what the specification is for "FLAT".

These tables are cast (not milled) and that implies to me that absolute flatness was not one of the manufacturing requirements.

I have used mine for twenty plus years and though it is not "absolutely flat" I have never had a problem that I believe could logically be attributed to the tables flatness or lack there of.

As a side question: Is your work bench flat? Mine is! At least it is "flat enough".

Dusty
I'm not sure I know what your asking or saying here.
First I believe the Shopsmith tables are cast but then the top (work) surface is ground.
I believe a Shopsmith table should be perfectly flat.
I know when I got my 510 upgrade from SS my first main table was not flat (can't remember by how much). I complained to SS and I believe their spec was no more than .005 across the whole table. They replaced my first table. The second was worst than the first. I then got a third. It was within the .005 but still not flat.

End result I was thrilled with Shopsmith's customer service but I was totally cranked off about Shopsmith's lack of quality. I stopped ordering from Shopsmith for over ten years. I then saw the 520 upgrade and I decided to try it. I did and found the whole upgrade to be high quality. I still have warped tables and I they make me mad everytime I have to work around the problem of them being "Slightly" off.

Biggest problem is using the biscuit jointer attachment. If I turn it the wrong direction every biscuit joint is off by about .005 just enough to cause you to see and feel it and have to sand it off. If the turn the attachment 90 degrees using the other side of the table the joints are one hundred percent perfect.

You tell me does .005" make a difference? Probably not for sawing but if you use the SS for Multi purposes that .005 will come back and bite you.

Needless to say this is a real sore point with me. I know Shopsmith has lost thousands of my dollars over the flatness of my 510 upgrade tables.

[dusty]

This sort of discussion is extremely difficult to have "long distance". It is so very easy to miscommunicate. I do believe that your table needs to be reasonably flat and I don't know exactly what that means. I see light under a straight. How much light I don't know but enough that I know I could slip a feeler gauge under the straight edge. Later today, I will quantify that.

I do seem to recall some communication SOMEWHERE I think with Nick that indicated table flatness specification to be <.005". I think there is a thread that discusses this. I'll research later. SWMBO is standing at the door waiting. BYE

[dusty]

I knew this was there and I should have since I participated BUT it clearly indicates that there has been a lot of discussion about table flatness.

Furthermore and more important than maybe anything right now is a caution statement by Nick that the table can be made to be irregular when installing the trunnions on the table.

Read the entire thread. There are several points spread throughout.

[keakap]

I have heard that early machinists and lathe builders could take a large table and had-scrape it to a couple of thou flat... BY HAND! Over remarkably long distances. These guys were building steam engines and battleships, with hand tools!

Derek in Surrey, BC

And I am embarassed to admit that the primary reason for my not building a good workbench all these years is my fear (completely irrational-- I guess I've got plane-o-phobia, or bump-o-phobia {would that be bump-n-grind-o-phobia for a metal table?}), of not being able to produce a quality surface of superior flatitudinousness.
May also essplane why I'm such a stickler for having things I purchase be flat where they should be.

[keakap]

Ed in Tampa, I want to thank you from the bottom of my heart.
For one thing you have reassured me that in at least one aspect of my being I am not a complete delusional lunatic, at least in my own opinion.
For now I know that at least one other Shopsmith owner on earth has had 'table' problems that interfere with his workpieces' quality (I used to have a heck of a time trying to drill perpendicular holes in thick pieces, f.e.)
And I absolutely believe that you acquired your tables from Shopsmith and not EBay or the guy on the street selling stuff out of his staionwagon.

But hey Ed, you say you've got only .005" off? You ever think of selling those babies? Oh, dang, never mind. I wouldn't know what to do with something under 40 thou anaway.

Dusty
I'm not sure I know what your asking or saying here.
First I believe the Shopsmith tables are cast but then the top (work) surface is ground.
I believe a Shopsmith table should be perfectly flat.
I know when I got my 510 upgrade from SS my first main table was not flat (can't remember by how much). I complained to SS and I believe their spec was no more than .005 across the whole table. They replaced my first table. The second was worst than the first. I then got a third. It was within the .005 but still not flat.

End result I was thrilled with Shopsmith's customer service but I was totally cranked off about Shopsmith's lack of quality. I stopped ordering from Shopsmith for over ten years. I then saw the 520 upgrade and I decided to try it. I did and found the whole upgrade to be high quality. I still have warped tables and I they make me mad everytime I have to work around the problem of them being "Slightly" off.

Biggest problem is using the biscuit jointer attachment. If I turn it the wrong direction every biscuit joint is off by about .005 just enough to cause you to see and feel it and have to sand it off. If the turn the attachment 90 degrees using the other side of the table the joints are one hundred percent perfect.

You tell me does .005" make a difference? Probably not for sawing but if you use the SS for Multi purposes that .005 will come back and bite you.

Needless to say this is a real sore point with me. I know Shopsmith has lost thousands of my dollars over the flatness of my 510 upgrade tables.

[keakap]

...some communication SOMEWHERE I think with Nick that indicated table flatness specification to be <.005". ...

Comment, strictly for entertainment value, nothing more:
In a conversation once with SS Support was heard an ear-perking little tid-bit concerning the flatness thing, went something like this: "...but if it's just 1/32 or so, well that's only about 7 thou..."

Beauty, not criterion, is in the eye of the beholder, methinks.

[dusty]

I carefully reread the thread that I linked to in post #16 above and Nick's statement there indicates that the table should be flat to within 010"-012" (two thicknesses of a crisp dollar bill).

I have until now been laboring under the false recollection that he had said .005". He did not.

Actually, a gap equal to two thicknesses of a dollar bill allows some significant light to pass through.