140mower
Don
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Shop Inheritance Machining Episode
- Thread starter Tomc938
- Start date
Shop
He's bluffing!
Dabbler
ersatz engineer
I don't know how tiny *your* mill base is, but for all floor-standing mills this is not possible. Bench mills are another thing. I can see great wisdom in bolting down a top-heavy bench mill.
Wow. I understand that in Japan, it is best practice to have anti-vibration feed on all 6 points of contact for a lathe. Yes that is soft feet. Never bolted down. It just isn't done there, which helped me formulate my treatment of my lathes.
A very good point. None of my lathes or the dozens of lathes I've ever used were ever in danger of 'falling down'. When moving lathes, I've see too many scary bad rigging practices the could have potentially tipped the lathe over.
I just cannot help but wade in on the BS**2 story. I might be able to concoct a scenario where it *might* be possible. *if* the bed is made of white cast iron (which it is not), and *if* the crack runs between the headstock and tailstock, (which is possible but not probable), and the hold down bolts are massive, such as 3/4", and the lathe is quite long, and if the concrete subsidence/upthrust is very large, such as several inches, then *maybe* this story is plausible. A lathe bed is not very rigid, as evidenced by the fact we need to make it planar by adjusting - but is *is* very strong. The flexibility of the bed would protect it in many scenarios. The story has the 'feeling' of a "Cautionary Tale" intended to plant an un-erasable image in someone's mind to ensure they do "X"
Sorry but I have infinite BS tokens to throw at that story. I raise you BS to the power of BS
Canadium
Ian
Well it doesn't look like I'm going to convince anybody but my 2 cents worth anyway. I don't think this has anything to do with machines falling over or shattered bits flying around. It has everything to do with relatively thin concrete slab floors and the ground underneath them being unstable. The ground and concrete slabs will expand and contract due to temperature and moisture changes and possibly even due to earthquake activity. I think of expansion joints in roads, sidewalks and concrete driveways and the many cracks in the concrete floor in my garage. I also think of the time I saw a foot high ridge form on my local highway because of frost heaving. If a lathe was anchored to such an unstable base it could easily get twisted along with the shifting concrete base enough to cause serious problems for precision machining. Heck if twist can be induced simply by tightening bolts that hold down the bed then a shifting concrete base could also easily twist a lathe. If a small piece of cast iron like my dividing head body could have been deformed as much as it was then a much bigger piece of CI as in a lathe bed twisting is even more possible. We are talking about a precision lathe. It wouldn't take much to cause a big problem.
I accept every word of that Ian. FWIW, I've seen sidewalks buckle like that from summer heat expansion too. Someplace I have photos. It was downright comical!
But your description and explanation just now take a different twist... LOL! FWIW, I think it would take very little to distort the bed and lose alignment in a precision lathe. I believe that you are absolutely right about that. In point of fact, my own lathe has 8 feet - 4 under the headstock cabinet and 4 under the tailstock cabinet. The lathe is aligned by using these feet to differentially untwist and unbend the bed. It is deliberately designed to work that way. Therefore, it is not a leap of faith at all to believe or accept that moving concrete could do the same and totally mess up the alignment of a precision lathe.
That's why bolting a lathe down to concrete should include adjustable anchors.
I didn't call BS on that part at all. It's the part where the guy you read about claimed that he destroyed his lathe that made me call BS. If he meant it just destroyed the alignment, that's a whole different claim. But I read it as it broke the bed which is what I just cannot imagine. The feet, bolts, stand, and concrete would break long before the bed would.
Your description just now is totally within the realm of possibility. I'd even go as far as to say it's downright likely - in fact even inevitable! That's why precision alignment should be done periodically for those who need it or do it. As I like to say Everything moves - it isn't if, it's only how much. Some prefer to say everything is rubber. But that's a whole nuther discussion.
So ya, I think your discussion just now is absolutely right on. Thanks for clarifying your thoughts on this.
I have in floor radient heat. Not drilling holes into that. Both my lathes, 1500lb and 3500lbs are very stable just sitting on the floor, properly leveled.
Hey, John. Why would you not bolt to concrete?
Sometime I'd love to hear the Japanese rationale Dabbler.
FWIW, mine is not actually bolted down. It sits on 8 vibration isolating pads. But my lathe manufacturer did recommend bolting it down with concrete anchors.
I've read advice both ways, but you are the first I've ever heard mention that the universal approach in Japan is unbolted. Makes me wonder why.
Better get the floor blanket out now Stel....... Cuz I'm gunna guess that's exactly what is coming.... May the floor force be with you...
Canadium
Ian
Well Japan is in a high earth quake prone zone so the unstable base theory would certainly apply. I was searching the net for my original source last night but couldn't find it. In the process tho there were a couple of interesting points I came across. One is that the Monarch company did not recommend anchoring their machines either. The other take away that I had is that it seems to be a very controversial subject. There are many knowledgeable people on both sides of the fence.
I would fully expect that some designs benefit from being screwed down and some don't.
That prolly explains the controversy among experts too.
It's prolly one of those things where everyone is right for a given set of assumptions.
I would be willing to bet that nobody would argue about the value of energy absorbing feet vs nothing. To me, the feet are a no brainer. The jury is out I guess about the extra step of bolting it down. Only a comprehensive vibration analysis could determine that on a given lathe in a given environment over a full range of possible applications.
Dabbler
ersatz engineer
So the Japanese story has some history.
I have a friend, Peter whose garage burnt down. total loss. He was charging RC airplane LiPo batteries using the recommended charger, taking all the mfgr's precautions, but it still happened.
He lost a 16X40 lathe, a 10X50 milling machine, all less than 10 years old, bought new. Total loss was in the hundreds of thousands....
When he got the settlement, he retooled doing gobs of research on what lathe to upgrade to, etc. He chose a Japanese toolmakers lathe, with all the fixings. He thoroughly interrogated the manufacturer about installation, and *they* told him that he had to use vibration dampening feet on the lathe to correctly install it. I was helping him at the time so I saw the emails (this was 10 or 11 years ago). The gist is, that this 3300 lb lathe sits on 8 anti-vibration feet included in the purchase. They had a millwright in Edmonton that would do the installation (for a fee) if Peter wasn't up to the install.
They were very careful about checking that the concrete slab was thick enough, and a lot of other things. Very good customer service for a one-time buy. I think he paid about 27K$ for it. It was a 375 X 1100mm lathe, or thereabouts. Perhaps 400mm, I can't remember. I haven't been to his shop in 5 years, as our interests have diverged.
That's all the information I have, and the people seemed to make an eloquent argument. That doesn't rule out a 'safety tie down' thing where in execgent circumstances the lathe cannot tip over - but in a really bad earthquake, the factory is prolly toast anyway....
I have a friend, Peter whose garage burnt down. total loss. He was charging RC airplane LiPo batteries using the recommended charger, taking all the mfgr's precautions, but it still happened.
He lost a 16X40 lathe, a 10X50 milling machine, all less than 10 years old, bought new. Total loss was in the hundreds of thousands....
When he got the settlement, he retooled doing gobs of research on what lathe to upgrade to, etc. He chose a Japanese toolmakers lathe, with all the fixings. He thoroughly interrogated the manufacturer about installation, and *they* told him that he had to use vibration dampening feet on the lathe to correctly install it. I was helping him at the time so I saw the emails (this was 10 or 11 years ago). The gist is, that this 3300 lb lathe sits on 8 anti-vibration feet included in the purchase. They had a millwright in Edmonton that would do the installation (for a fee) if Peter wasn't up to the install.
They were very careful about checking that the concrete slab was thick enough, and a lot of other things. Very good customer service for a one-time buy. I think he paid about 27K$ for it. It was a 375 X 1100mm lathe, or thereabouts. Perhaps 400mm, I can't remember. I haven't been to his shop in 5 years, as our interests have diverged.
That's all the information I have, and the people seemed to make an eloquent argument. That doesn't rule out a 'safety tie down' thing where in execgent circumstances the lathe cannot tip over - but in a really bad earthquake, the factory is prolly toast anyway....
Good story Dabbler! I can't imagine loosing my whole shop.
Your story explains ONE manufacturer, but I had the impression that you thought ALL Japanese lathes were that way? Is there a bit more to know?
This has been an interesting thread. I think I will come down on the side of...everyone!
My mill will be floating.
My lathe will be on a vibration-dampening mat, and bolted down loosely at the headstock end. So it doesn't tip over. But if the earth moves (Like in Iceland) it won't snap in half.
My mill will be floating.
My lathe will be on a vibration-dampening mat, and bolted down loosely at the headstock end. So it doesn't tip over. But if the earth moves (Like in Iceland) it won't snap in half.
Dabbler
ersatz engineer
It was in the language they used. They went beyond "common practice" (their wording was awkward to me, so I cannot remember it exactly) but it amounted to them saying it was 'best practice' or something like it. Their attitude was surprised when we asked for clarification.
The result is, after 10 years, the lathe is still true, and no further adjustments were needed.
I would love to verify this with a Japanese millwright, but I don't know any!
And that Japanese lathe at app 15"x40" @3300lbs is pretty substantial. My Standard Modern 16x54 weighs 2500lbs.
Former Member
Guest
My first lathe was bolted down, new lathe is on vibration isolating pads. Know what I know now it honestly depends on mass, the higher the less worry of bolting down to eliminate vibration.
Mill the same thing applies with one extra consideration. CNC. Because of the potential rapid large movements of a table, vise and part (lots of mass high up) a mill can be up ended. Here I would recommend a bolt down.
Again on old work horse mills their bases tend to be massive with a very low center of gravity to avoid this even in the days of manual machining let alone CNC.
Mill the same thing applies with one extra consideration. CNC. Because of the potential rapid large movements of a table, vise and part (lots of mass high up) a mill can be up ended. Here I would recommend a bolt down.
Again on old work horse mills their bases tend to be massive with a very low center of gravity to avoid this even in the days of manual machining let alone CNC.