subfloor basement

[herb]

Hello,

Currently my shop is in the basement - concrete floor. thinking of moving, new has suitable unfished basement for shop. however floor is wood there is a small crawl space. I have a Powermatic and am concerned about excessive vibrations. Is there a fix for this?

 

[Damon McLaughlin]

Hello,

Currently my shop is in the basement - concrete floor. thinking of moving, new has suitable unfished basement for shop. however floor is wood there is a small crawl space. I have a Powermatic and am concerned about excessive vibrations. Is there a fix for this?

Herb, it may help if you can tell us how the floor is constructed such as what is used for the joists, spacing on center and span as well as what the subfloor material is.

I have a small shed that I converted to my workshop. The joists are 2x4s spaced 16" on center and are on top of several 4x4 pressure treated skids. The floor is 3/4" underlayment grade plywood. I have had a Jet 1640 and a Powermatic 3520c and never had any issues with the floor. Now I have a heavier American Beauty lathe and still, no problems with the floor or vibration even with unbalanced wood. I have since added 1" of high density foam insulation boards and 3/4" tongue and grove plywood on top of the floor to keep my feet warmer, and still no issues with any of my equipment causing problems with the floor.

 

[JeffSmith]

My shop floor is wood - doubled 2 x 12s on 16” centers with 1-1/4 t&g ply over and a 5’ crawlspace under; all insulated. The AB had a problem with largeunbalanced blanks. Solved with jacking up 4x8 beams under the legs.
I had no problems in previous shop on cement. It’s all good now.

 

[herb]

thanks for responses. Can you tell me what you mean by "jacking up 4x8 beams under legs"?

 

[Bob Sheppard]

Hello,

Currently my shop is in the basement - concrete floor. thinking of moving, new has suitable unfished basement for shop. however floor is wood there is a small crawl space. I have a Powermatic and am concerned about excessive vibrations. Is there a fix for this?

Adding another layer of plywood will stiffen up the floor. But if the joists are undersized, it won't be all that effective.

 

[Mike Johnson]

Herb,

You can support the floor that your lathe is on by installing additional supports under the joists in the floor. Depending on the size and weight of the machine will determine how much bracing you need to install under the floor. Steel posts, wood frames, concrete blocks whatever makes the most sense in your installation.

 

[JeffSmith]

thanks for responses. Can you tell me what you mean by "jacking up 4x8 beams under legs"?

Used jack posts (from home depot) in the crawlspace to support two 8’ long 4” x 8” beams positioned under the floor joists and measured to span where the legs are on the floor above. The result is a greatly stabilized floor with no movement at all (the Robust AB configured like mine is very close to half a ton).
Its a pretty simple project if you’ve got a good sized crawlspace. Mine is nearly 5’ so the 4’ post jacks were just about maxed out at one end.

 

[olaf Vogel]

Its likely that each leg of your lathe will centre over one joist and the second leg will be between two joists.
So the load carrying capability is only on a few joists and some bouncy plywood.

If you can't get underneath, then you can run a set 2x6 or 2x8's, perpendicular to the joists, with as many big screws or lag bolts as possible screwed into the joists.
This ties them all together and spreads the load across many joists.

You can always add stiffness but screwing (and gluing) more 2x8's on top, to get the height you want.
Then bolts your lathe's legs onto the 2x8's.

Not quite as good as concrete, but a lot better, for fairly little effort.