Est. 1998 — 27 years of woodworking knowledge
Floor strength concern
Phil Murray
>While I'm daydreaming about my PM3520A finally arriving, my mind keeps wandering back to a concern I have about all that (700#+) weight on my shop floor. It's two layers of 3/4"OSB over 2x10s, 16" O.C. Should I add more on top (and risk raising the spindle too high)?
Phil
Re: Floor strength concern
Dale Payne
>I found the same floor holds up to my patternmaker's lathe (2000+ lbs.)
What's under the floor?
Ron Sardo
>Can you use floor jacks?
Re:Overengineering
Mark Mandell - Gone Round In Jersey
>Faghedaboudit.
700 - 900 pounds, while heavy to you, is little or no stress on 1-1/2" of flooring plus 10" of joist. The structure spreads the load out over a rather wide area.
If you're concerned about the OSB, just locate your headstock leg contacts on top of a joist.
Mark
drop the 2 for mail
Re:Overengineering
JamieDonaldson
>And how many hound dogs will you kill when the floor gives way?? Don't forget about harmonic vibrations,etc.
Re:Overengineering
JamieDonaldson
>OSB has poor shear strength- I would put a sheet of 3/4 ply AC under the lathe to spread the load.
Re: Dogs Gone
Mark Mandell - Gone Round In Jersey
>Depends on how many are sleeping on the floor under the lathe.
And with the harmonica's vibrations transmitted by the wood beams to the wall plates and studs, they'll spread to the whole structure. Now, if you'd like to argue that that 700 lb lathe's vibrations are gonna bring down the house, be my guest.
On the other hand, better safe than sorry. . .
Phil, go get yourself a passel of lolli jacks for the room underneath, provided that the lower floor's slab-on-grade, then sister up all the joists and place the jacks about every 4' on each joist-set directly under your machine (and them dogs) and for 3 joists in each direction, so you got this steel forest growing down there. Hey, you won't have to worry about how much your blanks add to the total weight or whether you need a bit of dieting. You can also bolt that baby right through the floor (1" bolts ought to handle it), but if the house starts to walk when you spin an unbalanced blank, you're gonna have to consider adding some weight to THAT . . . . .
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Re: Engineering
Mark Mandell - Gone Round In Jersey
>THAT's a good idea
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Re: Floor strength concern
David Chung
>First of all, I would not be concerned about the floor if you have two layers of 3/4" OSB. As far as the floor joists are concerned, it all depends on how far it is between bearing points--how far do the joists span. For 2 x 10's at 16" o.c.: If it is 12 feet or less, you are well within the load tables in the Uniform Building Code. If it is 13-14 feet, then you are getting into nervous category. After 14 feet, you need a structural engineer--I'm only an architect.