Mounting, how do I get to where I want to be from where I am now

[Tom]

Here is my current mounting frame for my lister 6/1 - ST5 system:


I originally designed it to mount on logs as skids and it has been working fine for that. I am now ready to construct my cubic yard mounting base and am looking for suggestions to modify this frame for embedding on concrete. I was going to bolt through a 4x6 on end, however hotater has had less than stellar success with the method. I've seen the lag bolts loosen up and break on my mounts too.

I could just put some J bolts into the concrete block and bolt this frame down, but that does not give much surface area in contact with the concrete. Any way I'm looking for some good ideas.

Thanks,

[Doug]

Pour the block as neat and level as possible.

Use long standard grade bolts with washers or steel plates and build a jig to hold them in place above the form before you pour.

Rock lock is another alternative and glue the bolts in place ( product is made for rock bolting but is suitable according to manufacturer )

Place base plate on pad and use steel wedges to square up and level the frame.

Build a second small mold around the base of the bed plate or frame and pour the mortor you mixed.

Dryer the morter the better but it must flow enough to get under th frame or bed plate. After everything sets torque the bolts and watch them for. Check and retorque bolts as required.

Gauge bolts ( sort of a big J bolt but used in railway tract work) will also work and rebar rock bolts are already threaded with large heavy nuts

Make a mixture of 2 parts Fine morter sand and 1 part portland wedge the bed plate about 3/4 to 1 inch above the concrete block

[mike90045]

Ok , so here's my dilemma, I've not purchased my genset yet, but I want the 650 RPM. Only need about 3 or 4 KW (6 HP) All the stuff about balance, and how poorly balanced engines & flywheels have been, with either sand or curry internal and external.  I'd thought of the 10/1 route, with heavier flywheels (internally balanced engine ?) and throttled back to 650 RPM   is this an inherently better balance, or is the chance of it being out of wack, just as great ? It appears my retirement location will not have reliable sun in winter, and I'll likely have to run the generator daily, to top off the batteries.  This will be a lot more runtime and wear on the mount and anchor concrete,  and I'm thinking the better the beginning balance, the better off the long term will be.

  I like the idea of grouting mild J bolts into cast sockets in the slab, I'm concerned that directly into the concrete will loosen/fracture, and hope the grout will be stronger.

open to other bomb proofing suggestions.   I'm also planning on a section of chain link fence inside the gen shed, in case the flywheel comes apart somehow, it should slow the larger chunks somewhat.

[ronmar]

Well you could weld studs into the frame for the engine to set on.  Then weld plate onto the bottom of the channel to box it in and add surface area for the steel-concrete interface.  Then add several holes along the length of the channel(now box tube), not to interfere with engine and generator footprint, to "J" bolt it to the concrete.

Ron    

[MeanListerGreen]

Nice frame Tom.  I have something similiar to that on one of my sets. 

Ron,

I doubt the fence would help any.  It probably would cause the wheel to ricochete.  Personally I think the best place to put the engine is in the ground but thats not very feesable.  I  just make sure that my wheels aren't in the line of fire of anything I care about.  There's no way to tell where they are going to go if they break though.  Theres alot of energy in them.

[Tom]

Thanks Doug,

That sounds like the classic way to do it and the mortar will fill under the channel iron legs.

Ron, I do sort of have studs. See the 4 square holes, they are for 1/2" carriage bolts. I'll just put a nut of them when I mount the frame.

Instead of J bolts I may get 5/8" anchor bolts as they go deeper into the concrete and are designed to have quite a bit of tension on them.

Thanks all!

[Doug]

Just snipits I've hobled together from watching Industrial mechanics mount machine bases and stuff I have read.

Some people say pull the wedges out but I see steel sedges in all the bases at work.

Was looking at the foundation blocks on some 1000 Hp fans a few weeks ago. All cracked because the job wasn't done right ( needed to be bigger ). Vibration monitors continue to trip the units out so I know there will be trouble soon. Cracks in the grout the MCCs sit on, suspect the mix was too wet and probably too much portland.

Asked everyone from engineers to miners with trowls how they build foundation blocks for machines, never got the same answere twice, one constant Mass+Material+Plan+Set up.

I've even seen them grout rail and run trains on it......

Doug

[rpg52]

I put 18"x3/4" j-bolts in concrete, with ~3" pieces of 3" pipe around the j-bolts, then mortared them in.  One thing I found was that the holes in the base of my Listeroid were only 5/8" in diameter.  I would have liked to drill them out to 3/4", but you need carbide drill bits to do that.  I ended up mounting the frame to the j-bolts, then bolting down the 5/8" mounting bolts to a connector.  So far so good, but think running the j-bolts up through the base of the Listeroid would be better.  You can get all sizes of j-bolts from McMaster, up to 24".  Best of luck.
Ray

[LMWatBullRun]

Grout-

Now we get to something I know about.

Typical type 1 portland (or 1/3) shrinks slightly when it cures.  Not much, but a little.

This is why what the pros use for grouting bases is non-shrink grout, which uses a blend of expansive and portland hydraulic cements so that the grout just slightly EXPANDS when it's cured.  This locks everything in tightly.  In the case of bolts in concrete, you will rupture either the bolt or the concrete before you get the thing to pull out, as long as the bolt's not greased.

Demo grout is ALL expansive cements, and will actually crack the concrete it expands so much.  Neat stuff- drill the concrete, mix the grout, pour it in at the end of the day and come back in the morning.  Voila! Broken concrete!  But I digress.

ANother option is to use epoxy grouts.  The trick here is to pick a grout acceptable for a high-vibration application, AND to keep the hole as small as you can and still get the bolt in.  THis minimizes the tendency of the epoxy to creep under vibration  and loosen up over time.  The problem here is that you have to drill the hole in EXACTLY the right spot.  This can be done with jigs and clamps and such, but its a PITA and takes time.  Typically this is used for structural attachments in high strength concrete, where 4000 psi NS grout won't do the job, and epoxy grouts are expensive.  Hilti makes a nice system with drop-in capsules that works very well, but like everything Hilti makes it ain't cheap.

I'd suggest using Non-shrink grout, it's a lot cheaper and entirely acceptable in my experience, plus oversized holes and exact hole placement are not an issue.  You can get it at commercial building supply houses.
As far as bolt size is concerned, I have a supplu of surplus 3/4" bolts and thats what I'll use on my attachments;  I'll place them ahead of time in the concrete, so I don't have to mess around with grouting.