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Using the built in levelling system.

So...... There is sheet metal and there is plate metal. It's kind of two extremes of the same thing.

I don't know if there is a formal definition that decides when flat metal is plate and when it is sheet.

When I think of sheet metal, I think of something I could bend over on itself with my bare hands. When I think of plate, I think of something I couldn't bend unless a brown bear was gunna lick my fur off before he eats me.

My steel lathe stand is not what any normal person would call sheet metal. It is two cabinets made of 1/4" plate welded together. The only sheet metal is on the doors and even that is prolly 1/8 so I don't think you can call that sheet metal either.

Each of the two box sections are bolted through a chip/oil tray into the bed of my lathe. At the bottom, they are lagged into the cement floor on all four corners of both pedastels (8 bolts altogether). These bolts are also attached to the bottom of the pedastels with double nuts so they are easily height adjusted. Using these double nuts, I can adjust the tilt, bend, and twist of my lathe bed. Because of the distance between the floor and the bed, I can easily achieve sub tenths of adjustment in the lathe alignment. However, I have found that the alignment drifts a bit over long periods of time so it takes a while to get it right.
 
toglhot said:
I'm not suggesting anything, just telling what I did for my 280 x600 lathe. I don't have an SM 1440. You do what you like with it.

You clearly are misunderstanding what I've said and what this thread is about. Read the original, first post, look at the lathe, does it look like a new, modern, SM1440, 14" lathe?
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You said in regards to 'sheet metal stands' that "... they make excelent stands on which to place 'light' benchtops. ..." to which i replied that lathes up to 14" in size and ~1800 lbs are on 'sheet metal' bases and have been for decades with no issues and that it all depends on the gauge of the 'sheet metal' (aka sheet steel) and their design that makes the difference. You then went on to state that you wouldnt use one regardless of how well its designed "Well, if you like them, you use them. I don't like them, so I don't use them.".

There is nothing wrong with 'sheet metal' stands on production high accuracy lathes if they are designed and constructed right.
 
Hey @curmudgeon, there is something else I said that might not be clear or might be easily misunderstood.

I suggested that your two mounting bolts might still provide very flexible adjustments through multiple floor bolts under the stand.

If you think about each of your two bolts as an attachment point for a flat flange or pivot plate on your lathe that attaches to a flat plate on the stand which can in turn be tilted forward backward or sideways, you can see how multiple adjustments elsewhere can physically twist or bend your lathe in multiple planes even though there are only two attachments.

Of course, as the overall weight goes down, it becomes harder to do because the lathe is more likely to just go for the ride so to speak.

I hope this additional info helps to explain my earlier thoughts on the two attachments. English sucks sometimes.
 
DPittman said:
FWIW
I believe anything less than 1/4" plate is considered sheet metal (or at least that what the folks around me used to say)
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Just for poops N giggles, I did a little research.

I found your exact reference in other places - 1/4 and above is plate, thinner is sheet.

But I also found another reference that also makes great sense. If it comes in a roll, it is considered sheet metal. If it comes in flat pieces, it is considered plate. No sizes or thickness is referenced.

I still like my susqpower definition.

Interesting stuff!
 
toglhot said:
Lathe stands are best bolted to the floor securely as level as you can get them. Keeping in mind, concrete floor are not the flatest surfaces around, so trying to level a bed lathe to within 0.02mm might be a litte difficult using shims between the concrete floor and the stand, even screw type feet. Metal on metal is another thing, metal is usualy pretty straight, so shimming is reasonably easy, if not quick. That's why I designed the leveling system I use: it is very quick and can be levelled to within 0.02mm on my 280x600 athe, probably better, but that's the best my engineers level can manage.
Click to expand...
If you are using shims on concrete make sure you use anchor bolts to pull the base down to the shim. This compensates for irregularities in the concrete. Match you for accuracy no problem.
 
Susquatch said:
Just for poops N giggles, I did a little research.

I found your exact reference in other places - 1/4 and above is plate, thinner is sheet.

But I also found another reference that also makes great sense. If it comes in a roll, it is considered sheet metal. If it comes in flat pieces, it is considered plate. No sizes or thickness is referenced.

I still like my susqpower definition.

Interesting stuff!
Click to expand...
I've seen 3/8 rolled so is it considered sheet ?:p
 
Degen said:
I've seen 3/8 rolled so is it considered sheet ?:p
Click to expand...

Using the roll definition, yes!

Using the thickness definition, no!

Using the Suspower definition, no. I couldn't bend 3/8 with my bare hands even if a killer whale was licking my fur before dinner.......
 
Susquatch said:
If you think about each of your two bolts as an attachment point for a flat flange or pivot plate on your lathe that attaches to a flat plate on the stand which can in turn be tilted forward backward or sideways, you can see how multiple adjustments elsewhere can physically twist or bend your lathe in multiple planes even though there are only two attachments.
Click to expand...
Exactly! - With only centre-line attachments between bench top and lathe, when making an adjustment between the stand and the floor, there are many other components that will twist or compress before any significant torque is applied to the lathe bed.
Susquatch said:
I also recall a piece of advice from @PeterT who quite correctly pointed out that many smaller lathes are basically set in their ways
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Makes sense to me - with the short bed and narrow mount I think it would be quite the challenge to add/remove twist to the lathe bed.

I need to do some testing to determine how much taper I have and then decide if I should try to reduce it, and then how...

Thanks much
 
curmudgeon said:
! - With only centre-line attachments between bench top and lathe, when making an adjustment between the stand and the floor, there are many other components that will twist or compress before any significant torque is applied to the lathe bed.
Click to expand...

I choose to believe this is a good thing. Gives you lots of options and also reduces sensitivity. Sort of like a fine thread adjustment vs course. But that's just my Glass is half full opinion.

Good idea to measure first and then decide whether or not you care. I think most users wait till it bites them, go crazy trying to figure out what they are doing wrong, finally realize its their lathes alignment, and then make a zillion mistakes trying to fix it because they get some really bad advice on YouTube.
 
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