Hello all, new turner here. My workshop is in a detached building with a 3/4" plywood floor over a crawlspace. I have a Laguna Revo 1836 on backorder that should be coming in any day now. I originally planned on bolting it down to the joists but after further research I am concerned about vibration and would rather do it right and pour a concrete slab for it to sit on. The frost line here in Cleveland is at about 42" and trying to dig out a good 4' of earth between the joists for a proper footer will mean waiting for a thaw and a whole lot of digging and extra cost for material. Is this all overkill and am I overthinking this when there's an easier option or should I proceed as planned? Thanks.
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Concrete pad
- Thread starter Tyler Kursh
- Start date
Personally I wouldn't worry about it until you get to the point where you'll be turning very off weight blanks. Get some 4x 50lb bags of sand and put some 2x8 lumber between the legs and weight that bad boy down. You'll have plenty to do until summer with your machine not bolted and then, if you still decide you want to, you'll be able to. You'll be learning basic skills just as quickly on a spindle or 2lb bowl as you will with a large platter. Make sure to cut your blanks properly and mount them in a way that they are not off center. You won't have a problem.
Tyler, I would agree with you on the challenges of getting concrete in there, and with Tom about a shelf across the lathe stand with some sand bags. The sand will help greatly with vibration control and machine stability.
If you feel the need to beef up the floor, which I think would be a good idea below this concentrated weight load, if possible in the area below the lathe legs (probably the 2 joists immediately below the stand legs) you could double up those 2 floor joists (full length between the joist bearing points) which would also add significant strength below the lathe, making sure to nail the new joist to the old along the length. As an alternative to adding joists, if your crawl space has building air circulated through it and not exterior air, thus preventing any chance of frozen soil, you may not need to dig 42". You could build pad footings into the soil under the legs of the lathe (min. 8" thick and at least 16"x16" square), and build up a post and beam structure under the floor joists (think post and beam for an exterior deck) below the lathe, again, for weight bearing. If the crawl space is subject to freezing temps, then you may need to dig deeper for frost resistance.
Installing a row of floor joist height solid lumber blocking between/perpendicular to the joists in the area of the lathe will help the joists act as more of a collective system rather than individual joists, adding a bit of strength and maybe some vibration resistance. Lastly, adding another piece of 3/4 plywood on top the floor below the footprint of the lathe (long enough to be secured to the floor joists at the end if the plywood) will help stiffen the floor sheathing at the lathe and create a more firm floor for the lathe. Don't glue it down- you may want to remove it someday.
Vibration (buzz) will be controlled in the floor by the different pieces of additional lumber running in different directions. Bounce in the floor from the added weight will be helped by adding joists or the post/beam system.
Good luck!
If you feel the need to beef up the floor, which I think would be a good idea below this concentrated weight load, if possible in the area below the lathe legs (probably the 2 joists immediately below the stand legs) you could double up those 2 floor joists (full length between the joist bearing points) which would also add significant strength below the lathe, making sure to nail the new joist to the old along the length. As an alternative to adding joists, if your crawl space has building air circulated through it and not exterior air, thus preventing any chance of frozen soil, you may not need to dig 42". You could build pad footings into the soil under the legs of the lathe (min. 8" thick and at least 16"x16" square), and build up a post and beam structure under the floor joists (think post and beam for an exterior deck) below the lathe, again, for weight bearing. If the crawl space is subject to freezing temps, then you may need to dig deeper for frost resistance.
Installing a row of floor joist height solid lumber blocking between/perpendicular to the joists in the area of the lathe will help the joists act as more of a collective system rather than individual joists, adding a bit of strength and maybe some vibration resistance. Lastly, adding another piece of 3/4 plywood on top the floor below the footprint of the lathe (long enough to be secured to the floor joists at the end if the plywood) will help stiffen the floor sheathing at the lathe and create a more firm floor for the lathe. Don't glue it down- you may want to remove it someday.
Vibration (buzz) will be controlled in the floor by the different pieces of additional lumber running in different directions. Bounce in the floor from the added weight will be helped by adding joists or the post/beam system.
Good luck!
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Cut two pieces of 3/4" plywood two inches longer and two inches wider than the lathe. Glue and screw the first piece into the floor joists. Glue and screw the second piece on top of the first piece also into to the floor joists. Use 3" screws. This will spread the load, stiffen the floor and allow you the material to bolt the lathe down.
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Unless your floor undulates when you walk on it, I would take a wait and see approach.
@Paul M. Kaplowitz - plywood reinforcement will likely do the job.
The lathe is hefty at about 600lbs for a medium size machine.
If you bandsaw your blanks it should do well on 14-16” bowls which is about the limit for a medium sized lathe. I do lots if demos and the lathes are almost never leveled ( I do have a few shims in my demo kit but rarely have to use one).
if you find the whole building shakes with an unbalanced piece then you probably want to improve the floor.
4 piers should do the job. A lot less digging and material.
A suggestion - if you rent a 2 man auger get 3 friends to hold on to it while drilling the post holes.
@Paul M. Kaplowitz - plywood reinforcement will likely do the job.
The lathe is hefty at about 600lbs for a medium size machine.
If you bandsaw your blanks it should do well on 14-16” bowls which is about the limit for a medium sized lathe. I do lots if demos and the lathes are almost never leveled ( I do have a few shims in my demo kit but rarely have to use one).
if you find the whole building shakes with an unbalanced piece then you probably want to improve the floor.
4 piers should do the job. A lot less digging and material.
A suggestion - if you rent a 2 man auger get 3 friends to hold on to it while drilling the post holes.
Thank you everyone for your suggestions. I am going to beef up the joists and double up the plywood and will go from there.
No bandsaw yet but I'm saving up for one. Will do my best to round out my blanks some other way before putting them on the lathe.
Really looking forward to diving into the hobby and joining your community here.
No bandsaw yet but I'm saving up for one. Will do my best to round out my blanks some other way before putting them on the lathe.
Really looking forward to diving into the hobby and joining your community here.
Your shop will always be above freezing will it not? If so frost not a factor when you pour a slab. If it is below freezing just use an auger To put in four holes each corner of slab and pour posts below frost line then slab on top with rebar in posts and bent into slab. Like a table with legs that are below frost line.
Agree with everyone else's comments about beefing up the existing floor (joists and/or plywood depending on how much 'bounce' you get walking/bouncing on it now). A much easier route than retrofitting concrete I expect. If you have normal joist spacing and a 3/4" floor I suspect there is some bounce now, and a 600lb lathe might be a bit much without sistering the joists at least and probably adding to the plywood (a sheet or two of ~1" tongue and groove underlayment on top of your plywood after sistering and cross bracing joists would make it pretty stout I would expect).
Regarding bolting down the lathe, I haven't found that necessary. I have a PM3520 which is similar weight to your lathe if yours is 600lb. I have never had it bolted down. Years ago I added an additional 300lb of weight (scrap steel) and did notice some improvement when starting out of round large log cutoffs (~20-30lb?). My lathe sat on concrete, I did some experimenting and measurements and believe that the additional weight would allow me to get up to ~400rpm range vs ~300+ without if I remember correctly, after a few minutes this would be rounded well enough to bring rpms up. Frankly, I seldom put something like that on my lathe and so when I moved I didn't bother moving the scrap steel. For the last 4yrs my lathe has sat on castors (not even locked down) on a concrete floor in my new shop, most of my work is <12" but I've turned up to about 16" balanced blanks without any issues. If I start turning larger logs again I'll lower the castors so they are out of the equation, but from my experience I'm happy to have the lathe readily moveable in my small shop.
Good luck, and have fun dreaming about your new toy
Regarding bolting down the lathe, I haven't found that necessary. I have a PM3520 which is similar weight to your lathe if yours is 600lb. I have never had it bolted down. Years ago I added an additional 300lb of weight (scrap steel) and did notice some improvement when starting out of round large log cutoffs (~20-30lb?). My lathe sat on concrete, I did some experimenting and measurements and believe that the additional weight would allow me to get up to ~400rpm range vs ~300+ without if I remember correctly, after a few minutes this would be rounded well enough to bring rpms up. Frankly, I seldom put something like that on my lathe and so when I moved I didn't bother moving the scrap steel. For the last 4yrs my lathe has sat on castors (not even locked down) on a concrete floor in my new shop, most of my work is <12" but I've turned up to about 16" balanced blanks without any issues. If I start turning larger logs again I'll lower the castors so they are out of the equation, but from my experience I'm happy to have the lathe readily moveable in my small shop.
Good luck, and have fun dreaming about your new toy
For me, a former concrete guy, if you are just wanting pads to support posts to add support to your floor, the frost line is not important since this is not a building structural support. The city sidewalks do not go below frost line, and the big problem with outdoor concrete is freeze thaw cycles, and under the shop/house would be more stable. Under a building, you probably have better insulation than out in the open. You could probably use some of the concrete pavers, I would go for 2 inch thick minimum, and put up posts off of that. Cut a half lap joint on a 4 by 4 post, probably use the bandsaw for that cut, put a piece of tar paper or old comp roofing piece under the post, use a couple of cedar shims to make sure the shelf part of the post is a good tight fit, then screw it to the joist. Some times Jousts are 24 on center, some times 16 on center. Of course 16 is less bouncy. You can also use the posts and set a stringer across the bottoms of a joist or three, again using cedar shims to get a tight fit. When I had my flat work room built, joists 16 on center, and 1 1/8 inch plywood over that. Very sturdy.
robo hippy
robo hippy
For someone just starting, I believe you've done too much research Tyler. Another victim of the internet Bring it into the shop and start turning. Forget about how the lathe sits, you've got a couple years before your skills match the need for a super stable machine.
Tyler, I didn't read how much space is under the floor for you to work with. It would be easy to cut a large section of flooring out to get at your project and then follow the suggestions Reed and the others have made. I would only add that the ground surface is probably soft, so I would dig until it is stable. Then add 3" of gravel, pack, and pour at least a 3" thick x 12" footer for the posts to sit on. Has worked for me many times. Came from Willowick (near Willoughby). Winters were very mild.
I do not agree with you. Why not do it right the first time around? Much easier to learn on a stable lathe than one dancing around the room.
Agreed! Easier to learn, SAFER, better for the building, better for the equipment, and so on. The structure needs to be modified to serve a purpose for which it was never designed or intended to serve. I'm glad to hear that Tyler will at least be beefing up the lumber components of the structure, and is open to further mods if he feels it necessary. But I'd add it is still better to make the structural mods before the load of the lathe is set in place.
As for the structural capability of any concrete to be used, a 2-3" thickness is inadequate for a load bearing pad. For a structural purpose, you will never see anything less than a 6" thick footing in current construction codes (6"x14" diameter, or 6x12x12 square, used for a residential exterior deck with only a very small square foot area of load coming down on it) to prevent cracking of the footing from the load placed upon it.
Build it once, build it right, and get on to the fun stuff.
Tyler, when I owned a Laguna 18-36. I built a box shelf between the legs and put 280# of sand it it. That lathe did not move a 0.001”. If your floor can support the weight I would do the same thing. Itv really made that lathe very stable and reduced vibration even on out of round blanks.
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Tyler, I have a Robust American Beauty in my small shop. The shop is a 12x16 shed with joists 16" on center and 3/4" tongue and groove plywood. Before receiving my lathe I added a layer of 1" foam board insulation (blue boards) topped with another layer of 3/4" plywood. The lathe is bolted down through the floor. I've never had an issue with my floor. I agree with all the others in waiting to see how your current floor works out. I more than likely will be just fine. If anything you can add another layer of 3/4" plywood but make sure your door(s) will still open if they open inwards.
Tyler, I turn in a shop that has wood floor off grade. Prior to my lathe arrival, I pulled the sheet of plywood where the lathe wood sit and poured the two joist cavities with concrete(about 8-10 inches) total and placed j-bolts through floor corresponding with lathe legs. Replaced flooring and bolted lathe down, and have never had any issues.
My shop also has wooden floors - it is new construction, 20'x24' with an office/guest room/loft over half. The floor is doubled joists with 1-1/4" plywood over, the crawl space under is 4 - 5' high on a slope. The joists run perpendicular to the lathe bed. Lathe is a Robust American Beauty - a little over 800# as configured, and sits near mid-span on the joists.
When first set up, turning rough blanks I did get some vibration - more than I was used to having turned on a concrete slab for many years before building the new shop. I placed two 6 x 10" - 8' beams spanning the joists where the legs rest and used jack posts on leveled concrete blocks to support them in place. Solved the problem and was a fairly quick one-man job. Have not considered bolting it down - no need. Been turning on this setup for nearly five years with no problems. I check the jack posts now and again, since the crawl space is used as wood storage I do get down there every now and again.
When first set up, turning rough blanks I did get some vibration - more than I was used to having turned on a concrete slab for many years before building the new shop. I placed two 6 x 10" - 8' beams spanning the joists where the legs rest and used jack posts on leveled concrete blocks to support them in place. Solved the problem and was a fairly quick one-man job. Have not considered bolting it down - no need. Been turning on this setup for nearly five years with no problems. I check the jack posts now and again, since the crawl space is used as wood storage I do get down there every now and again.
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