Building Lathe Bench / Might I Be Overlooking Something ?

[johansen]

I’m admittedly a bit fuzzy on the sono tube shape; are you suggesting the bench top be cylindrical ? I hadn’t really considered that.

Basically you get 90% of the rigidity you want, to hold the lathe bend ends in a fixed fixed condition (that is they are rigidly held in 6 degrees of freedom) for just 5 bags of cement for a 5 foot long lathe. And its a tube so the chips will fall off of it onto the floor.

You will need to support it on something, so you will need another bag of cement to make some feet on the tube, then stack it on some cinder blocks and bolt it all the way through the stack, to the floor, so it doesnt walk on you when turning something out of balance.

The cement will move a bit for the first month, thats about it.

 

[memphisjed]

In theory concrete/epoxy filled tube works, reality is it is better than noting- not as good as a solid chunk of steel. You can rabbit hole different alloys if you really want to...
That said a 1” thick plate or um flat bar with some 1 1/2 xs pipe legs with some bracing (all welded) will be far more rigid and mo-better (tm) than any bolted and stacked structure in 1/4 wall tube.
Rectangle Tube cost more per pound than any other shape, and you want pounds. Sometimes the easiest and cheapest way is just old school real chunks of steel.

 

[RebarRepurposer]

Basically you get 90% of the rigidity you want, to hold the lathe bend ends in a fixed fixed condition (that is they are rigidly held in 6 degrees of freedom) for just 5 bags of cement for a 5 foot long lathe. And its a tube so the chips will fall off of it onto the floor.

You will need to support it on something, so you will need another bag of cement to make some feet on the tube, then stack it on some cinder blocks and bolt it all the way through the stack, to the floor, so it doesnt walk on you when turning something out of balance.

The cement will move a bit for the first month, thats about it.

That’s something to consider. Hey thanks for the suggestion !

 

[Bill D]

Get an old school straight 8 engine block with no heads and bolt it to that.
Bill D

 

[RebarRepurposer]

In theory concrete/epoxy filled tube works, reality is it is better than noting- not as good as a solid chunk of steel. You can rabbit hole different alloys if you really want to...
That said a 1” thick plate or um flat bar with some 1 1/2 xs pipe legs with some bracing (all welded) will be far more rigid and mo-better (tm) than any bolted and stacked structure in 1/4 wall tube.
Rectangle Tube cost more per pound than any other shape, and you want pounds. Sometimes the easiest and cheapest way is just old school real chunks of steel.

I did indeed consider solid steel plate, but in my reading it’s relying on sheer mass to dampen vibrations, rather than material qualities.

From what I’ve read, a tube structure is best for resisting torsion forces (https://physics.stackexchange.com/questions/514821/is-a-square-tube-more-resistant-to-bending-than-a-round-tube#:~:text=Since a round bar doesn't really focus the,round tube will be the same for torsion.)
This is about square tube, specifically, but that’s a hundred-thirty or so bucks more in these dimensions. Rectangle seems like a reasonable compromise. And of course, thicker steel walls (like 3/8”) would be preferable, if not for the higher cost and weight.

Epoxy granite has proven excellent vibration-damping properties (hundreds of web hits, easily searched).

Furthermore, the amount and type of welding proposed (large amounts in very large chunks of steel) is beyond the capacity of my little 80 amp inverter. And I’m just not very good at making my welds look decent.

Given these factors, and a few others mentioned elsewhere, I’m still convinced my proposal is the simplest and most elegant solution within my reach. The internet can drop the steel tube and epoxy off in my driveway, and the rest of the stuff I can pick up on my way to work.

While I certainly wouldn’t turn my nose up at the sort of bench you’ve described, I’d need somebody else to do most of the work, and bring it to my house … and then promise to help me haul it around when the time comes to relocate !

 

[RebarRepurposer]

Get an old school straight 8 engine block with no heads and bolt it to that.
Bill D

I’ve seen some pretty remarkable things being done with old iron engine blocks. Similarly, I actually own a 300-or-so pound block of solid cast iron with a cast-in handle, which served as a counterweight for a shipping dock bay door for a half-century or so. I use it as a heavy base for my pipe vises, which clamp down on the 2 1/2” column for my 5-inch Wilton-clone swiveling bench vise - so I can use it in basically any orientation. It sees more-or-less constant use.

 

[DDoug]

Lot's -O-Words....did you build the %$#@! bench yet ?

Jeesh, get on with it already.
Or go over to the Homeshop forums.

 

[henrya]

Go find a old heavy duty table or desk. Then go buy some 2x4s and frame up a form. Pour the form with concrete. After it cures a bit put it on your found table. Heavy and good and probably under $100.

 

[RebarRepurposer]

Lot's -O-Words....did you build the %$#@! bench yet ?

Jeesh, get on with it already.
Or go over to the Homeshop forums.

Waiting for funding.
Today, in my off moments, I’ve been working on the drill press / treadmill motor upgrade.

 

[RebarRepurposer]

Go find a old heavy duty table or desk. Then go buy some 2x4s and frame up a form. Pour the form with concrete. After it cures a bit put it on your found table. Heavy and good and probably under $100.

Hey thanks for the suggestion - it’s imminently workable. That being said, by this point, I don’t think I’d be satisfied with it, and would eventually just end up building the steel rectangle tube / epoxy granite bench anyway. Bunch of philosophical reasons by now.

 

[EPAIII]

Or just one guy actually. Well, if he isn't approaching 80. I bought my SB in Iowa where the pickings were very sparse. I watched E-Bay for around a year to find one two states away. I made the trip one weekend to pick it up. The seller was nice enough to meet me half way with no extra charge. It came with a welded steel table which I modified to bolt down to a concrete garage floor. So far I have moved it two times. Hopefully I will not need to move it again.

As for the table, I was more worried about leveling the lathe than vibration. Getting it to cut straight and not with a taper seemed to be more important. The welded steel table that I have has a piece of steel channel welded to the top where the lathe sits. I added levelers to the four table legs and brackets to fix them to one and only one spot on the concrete floor. If your table moves even a fraction of an inch on most concrete floors, that will destroy the leveling. I know this from experience. So, no movement after leveling the table. Then, and only then you can proceed to leveling the lathe on the table. That's my experience and I am absolutely sticking to it.

I suspect that Oregon is a lot like Iowa for second hand machine tools. It could take a long time to find one close enough to avoid expensive, cross country shipping. During my year long search I saw many used lathes being sold in California, on the East Coast, and around Detroit. But the shipping would have been more that the price of the machine. It took a while to find one that was in driving distance.

But I do understand the need to work in a budget. And make the best with what I already have. Jumping from $500 to $1000 or more can be a real difficult proposition for some. Good luck.

Oh, and perhaps you may want to look at this BB, it is for home shop guys:

General - The Home Shop Machinist & Machinist's Workshop Magazine's BBS

This forum reserved for general machining discussion. Off topic threads are allowed, but will be closed if they go too far off track or become too numerous. Please add “OT” to the title of any off topic thread. Discussions on religion or politics are not allowed.

bbs.homeshopmachinist.net

I see a southbend 9" lathe for $900 on craigs list in Oregon or one for $600 in Washington.
Folks like SB lathes because they unbolt into a few parts that two guys can carry up or down a basement stairway.
Bill D

 

[plastikdreams]

Lot's -O-Words....did you build the %$#@! bench yet ?

Jeesh, get on with it already.
Or go over to the Homeshop forums.

Relax digger man