Centre of gravity and tipping for a stand

[sjalloq]

Hi all,

I'm in the process of building a stand for my recently aquired Fobco Star bench drill. I decided to build a frame out of softwood so that I could fit one of the Bisley cabinets in that i've purchased recently. I've made the frame out of 45mm square timber that is domino'd together. However, the unit is currently 950x370x470mm (HxWxD) and I want to put some adjustable feet on it to level it but am concerned about stability.

The Fobco is pretty heavy so once it's on top of the still to be fitted MDF top and bolted down, I think it will take a fair bit to knock it over. But I thought I'd get a second opinion or two. Perhaps I could mount the adjustable feet on legs that extend the width of the base but I'm not sure how to do this cleanly. Any thoughts? Or will it be okay as it is?

Cheers.

 

[mtr1]

I think once you fill the cabinet it should be fine, but if you are worried once you get the drill on top and if it feels top heavy, I think it would it be possible to mount the casters/levellers out from the side thus widening the cabinet. I have done something similar to my Boxford, only I tapered the cabinet, thin at the top to fit the stand, and perhaps 75 mm wider either side, seems to be okay after six years, though I don't move it much only to sweep the floor.

Could you get some steel angle iron bolted to the bottom perhaps and mount the casters/levellers to that?

 

[dzj]

Keep heavier stuff in lower drawers. If all fails, you can always bolt it to the floor.

 

[mindthatwhatouch]

Some steel plate or concrete inside the wooden frame below the metal cabinet?

 

[mseries]

So long as the CoG falls within the footprint of the base your machine will not topple over. Drills are not likely to move side to side or back to front in use, you push down which doesn't cause the CoG to move. Is it likely that the machine will get knocked while you do other things ? I share your concern though, I made a stand for mine recently, I splayed the legs front and back but not sideways, it's fine, absolutely fine. My legs are much chunkier than yours but that's not the point, strong enough is strong enough, the physics are the same. I'd say try it and if it's not satisfactory then add some feet. I'd make a small low profile frame which is as wide as you want and screw the stand on top. Essentially just two strips running east-west attached at the front and back of you stand. At the end of each string add a smaller foot. Maybe make it as wide as the stand is deep so the new footprint is square. It won't spoil the look much.

 

[RobCee]

It should be ok like it is as long as you don't plan on moving it around on the stand. Mine is on an A-Frame stand with wheels and is a bit wobbly, although not unmanageably so. My A-Frames are splayed sideways, rather than front to back, so it's instability is mainly when I move it back and forth. For reference, I spayed the legs by around 10 degrees.

 

[sjalloq]

OK, thanks all. I'm going to try and get some L-brackets to that I can mount the leveling feet I have on the sides. I'll see how this feels once I have the drill in place.

 

[dean0866]

I have the exact same cabinet with my drill stand mounted on top. Mine doesn't have the additional structure/frame work you've added but is perfectly stable whilst using the drill even with the addition of a small base and castors that I added to enable it to be moved around easily. Admittedly, my stand drill is one of those el cheapo's you get from the likes of Pee & pooh and isn't particularly heavy.

 

[sjalloq]

You can mount your drill directly on the Bisley? Mine is so wobbly it wouldn't be usable. It is a seconds unit though so perhaps the knock to the side panel has weakened it somewhat.

 

[dean0866]

Sort of, I put a thick piece of chipboard between the drill stand and the top of the unit and built the sides up a little (3 or 4 inches) on the the base trolley, which seems to help. To be honest, it isn't 'empire state building' solid but perfectly usable as is. I do forget to shut the draws when drilling and end up with draws full of sawdust, but that's another issue!

 

[xy mosian]

How about a short safety chain to the wall behind? Just to be sure.
xy

 

[sjalloq]

I don't think I'm too worried about it tipping forward as the base is longer in that dimension. I've done some searching and what I think I want to try is a set of these: http://www.rutlands.co.uk/sp+hardware-k ... akota+dkt3

If it still doesn't feel sturdy enough then I'll add some legs that widen the stance.

 

[WoodMangler]

I lowered the centre of gravity on both my woodwork bench and my lathe bench by making the bottom shelf hollow and filling it with builder's ballast. If you line the cavity with plastic and screw on the top panel of the bottom shelf, it's easy to remove if you move house or whatever. Serependitiously, I found it damps down vibration to a certain extent, too.