Milling machine in the (wood floored) workshop

My shed is a standard 8 x 16' wooden affair, but has been insulated, powered, lit and guttered with some heavy duty security. It is on a thick concrete pad, with wooden joists on 17" centres topped with planks. If you jump up and down on an area above a joist, it's very solid, but in the middle of each span there is a little movement. I need to ensure that the machines are as rigid without going bananas on it.

I have an ML7 on a welded base - (say, 120kg) whose feet sit awkwardly in the middle of the joist span. I had thought for this to spread the weight using ply or scaffold boards screwed into the floor, across the joists.

Regardless of how that turns out, however - I am hopefully going to get a milling machine (350kg) soon, the feet of which should roughly align to the joist spacing - and I can't really manage shifting around a milling machine on my own in the same way I can with the lathe, so I need to get it pretty right the first time around.

I see there to be two options - strengthen the floor, or create a new one, but I'm not sure which will be just 'good enough':

• Place a sheet of 1" plywood or 38mm scaffold planks beneath the lathe and mill, screwed into the floor and joists, and screw or bolt the machines down into that.
• Cut a hole for a pad in the floor about a 8" bigger than the machine footprint, remove the planks and joists, brace the new ends of the floorboards at the cut, shutter in and pour in concrete to bring it up to floor level.

My only concern with the latter is how permanent it is, and in general I have a few questions about how it would work, i.e.

• Do I want it to bond to the layer below?
• How do I handle damp proofing?
• Should I be thinking about drilling holes into the concrete for fixing studs? I don't know how any of that works....

How seriously should I consider doing this under the lathe also? Clearly the concrete pad method is the most desirable but I'm concerned that should I want to rearrange the workshop in future I'm going to be a little stuck and start running out of floor!

Any thoughts or opinions gladly taken.

Edited By William Ayerst on 03/07/2021 14:43:30

Edited By William Ayerst on 03/07/2021 15:11:20

I had a similar problem when I put my Crusader lathe in the shed.

In the end I had to cut through the floor and poor a concrete base for it.

Good luck.

Jim

1" plywood is extremely strong, and spread across several joists would be plenty. Get a sheet of external type, marine ply is very expensive.

If planning on pouring in a floor then my inclination would be to put down a damp membrane first so that if you ever decide to chisel it away it can be done. If not a thick enough joist then throw in some mesh weld perhaps?

pgk

In my wooden workshop ,I have 2 lathes 2 milling machines and a shaping machine. I cut out the foot print of all the machines and poured concrete through the wooden floor to the concrete pad below. Very easy to do and you end up with a good solid base for the machines to stand on.

Jimmy, I think it sounds drastic but the more I think about the the more reasonable it seems - cheaper, more stable, etc.

With regard to permanance, right now there is shelving along the short wall next to where 'mill' is shown in this diagram, but it seems like the only logical place:

I can't really put the mill opposite the bench or the lathe, as it only leaves about 2' room between them, so it has to go opposite either the drill or the grinder - and I want the grinder away from the other machine tools if possible, so even if I get rid of my bench drill at some point the grinder is likely to end up in that spot, or on a bit of wood chucked under the workbench.

I guess if I make the pad larger than the base, i.e. 3' x 3' - then I have a bit of flexibility in future, but it does peg the machine in that corner "forever"....

A fairly dry screed should be sufficient - not wet concrete - and more easily removed in the future. More easily levelled, too if only a fairly thin layer.

I’m in the process of moving my 2B at the present time. Only a 180 degree turn and about a metre. The Stand will be raised by 150mm to place it at what I think is a better height for me.

Raising or lowering a 2B, while on its wide stand, is not something I would relish, even on a concrete floor.

Edited By not done it yet on 03/07/2021 16:23:15

Put each machine foot on a threaded rod adjuster as big as will fit, lead these through the wood so they rest on the concrete. Have a nut underneath the foot for levelling.

My floor is 22mm chipboard on 25mm polystyrene on 24"sq concrete flags (the original garage floor) Where I have heavy machine feet I've cut a 4" or so square hole in the floor and used solid wood packers down to the flags.

All, do you think it would make sense for the mill to face the door (orange) or into the workshop (yellow)? My expected concrete pad outline is about 3' x 3' - may be shifted inboard depending on not done it yet's answer)

Not done it yet, how tall are you? I'm 5'8"ish and found once I got my ML7 to a good height (41" to the carriage wheel, 44" to the cross slide wheel) it was a revelation - and I guess now is the time to make sure! If you have one may I ask for a bit of cheeky information i.e. the distance from a wall or the rearmost projection to the rear feet, and to the rear of the table when it's as far back as possible?

John H - are you suggesting to use something like a hole cutter through the floor to put the feet down into the pad below and keep the machine raised up onto those rods?

pgk - I guess a 3' x 3' x 4" concrete pad will be plenty stable enough without being bonded to the pad below - I was thinking exactly what you mentioned about potentially being able to be removed in future. What do you mean about mesh weld please?

Old mart - I was leaning heavily towards ply but after reflection - it's more than four times the price of concrete and would be less stable, right?

jimmy b, peter1 - thank you for your anecdotes - all in support.

Edited By William Ayerst on 03/07/2021 17:04:48

Duncan, that's a good point - I hadn't considered using solid wood under the feet!

+1 for cutting a hole in the floor & harcore + concrete on some visquine for damp proof. The last thing you would want is the mill wobbling about.

Steve.

I would use concrete blocks if you already have a concrete base, you can buy singles for £1.66 at B&Q

I wasn't sure about your depth for concrete. If it was only a couple of inches then some sort of reinforcement would be ideal and it’s not a big enough area to warrant rebar. A piece of mesh-weld or even chicken-wire could be used. At 4" I wouldn't bother

pgk

Hm ok - so chicken wire pushed into the void before shoveling in dry screed - that works. It sounds like a good idea to lay out a bit of damp proof polythene or a cut up builder's sack underneath so it can be separate from the main pad?

Also, a global shortage of cement right now. Great.

My Warco Economy Mill /Drill is bolted to an ex industry steel bench, made from angle iron.

Beneath it are drawers, (Well filled ) sliding on angle irons, so there is a lot of weight there.

It stands on a rectangular angle iron frame , intended as a load spreader, on the 3/4 inch ply floor, which stands on 8 x 2 bearers, set on 18 inch centres, on 2 inch paving slabs bedded onto a sand /cement base .

Have never been aware of any lack of rigidity in this set up.

Howard

Angle iron welded together into a frame is used a lot for machine tools

Steel tube up from the concrete and angle iron at the floor level?

Downside is you can never move your machine about

Why not just thicken the whole floor,this would allow future repositioning of the machines. Suggest thicken the whole floor with four sheets of 18mm shutterring ply which is the cheapest ply and thenput down on top four sheets of a better quality 18mm ply to provide a better surface . Dont worry too much about the machines weight 350 kg is nothing in terms of machine tools and easily moved with a crowbar,at one time I had a S7 in an upstairs bedroom,16 inch pitch joist with 20mm t and g floor boards ,no problems with stability or accuracy.

I tried all the options of thickening the floor etc, but it still wobbled around, so I did what John Haine suggested earlier and cut some 3" diameter holes through the floor boards and made some solid steel slugs to sit just proud of the floor and sitting directly onto the concrete beneath, the tops of the steel slugs were counterbored in the centre so my machine jacking feet do not slip off. Also run a bead of sealant around the steel slug.

I have never had any more trouble.

Phil

I’ve got a VMC simply screwed down to my wooden shed floor and haven’t experienced any problems with it so far.