Mobile Bases: Why always two fixed/two swivel?

Why aren't there any 4 swivel caster mobile bases out in the market place? All the ones I have seen have 2 fixed and 2 swivel. For very heavy equipment, this becomes a limiting factor, since you have to move your machine back and forth if you go in the direction not supported by the swivel. I remember having to steer my 8" jointer flush with a back wall, just as you would do it trying to parallel park a car in a tight spot.

I know swivel casters are more expensive than fixed ones, but I would gladly pay the difference for the convenience. Or is there any safety (tipping risk) or physics considerations (can't move it in a straight line because all wheels just swivel around) that make them not recommended?

Just wondering.... :rolleyes:

My only guess is,to stop the cart/base from going sideways (very much like Ikea shopping carts which drives me nuts),other than that ,I don't get it either,I have a small shop with a cracked floor,imagine going 7-8 times over the bumps back and forth so I can put a heavy jointer against the wall.

I just realized,another reason other than the higher cost of swivel casters,you will need 4 locking levers instead of 2.I would still pay the difference to get a comfortable mobile base .

My Sawstop base has 4 swivels, and it is very well appreciated. To answer the question, the shopping cart comes to mind also.... LOL. I would much rather have 4 swivels than 2. I put 4 on my lathe, but everything else has only 2 and that is rather annoying, back and forth, back and forth to manuever into exactly where you want it. Oh sorry, you already know that..... Yeah, I don't get it either. At least they should offer an option to buy 4 or 2.

I built a cart for my 20 planer and 8 inch jointer. 4 X 4 construction with 1/2 laps and 4 casters with brakes. Planer was a PITA to move tipping the scales @ 900 lbs try rocking it to get all the wheels pointed in one direction. even then it would crab walk on ya. Made a handle to drag it that did work either.

The best I have seen was the mobility accessories that are offered by Luguna, MM, Felder etc. Jacks one side up with a Johnson bar the other side has fixed wheels. Beachside Hank (may have gotten his handle wrong) posted one he made for a lunch box planer convertible. I think he had a rigid OS mounted on the other side.

Ha, my first thought was those darn Ikea shopping carts too! I was just there the other day and it was such a PITA to keep the cart moving forward in a straight line. haha

I think of it this way: if you have unlimited space, 2 swivel/2 fixed caster bases are far easier to maneuver. Like with a shopping cart, you steer by pulling one arm toward your body and/or pushing the other away from your body while pushing the cart forward. The two fixed casters, which are nearest to you, won't allow that end of the cart to roll sideways (or swivel), allowing the opposing force you're creating to translate into steering the front of the cart.

With 4 swivel casters, when you try to apply that lateral movement to steer it, the casters nearest to you will swivel. They don't allow you to apply the opposing force that makes the thing steer.

However, when you're limited on space, you may have no choice but to go with 4 swivel casters... because you may not have enough room to maneuver the cart otherwise (i.e., parallel park a machine vs just rolling it into its place).

So if I had a massive shop, I'd go with 2 swivel/2 fixed every time. If not, 4 swivels is a fair compromise, but it will be hard on your "core" because you'll need to rotate your torso while you push in order to steer the thing.

you'd need to have the kind of casters that lock both roll and swivel to get a solid base. I'm pretty sure that even with that, the base when fully locked, would not be as stable. There is always some play.

And, I agree that 4 swivels would make rolling pretty difficult. Having 2 wheels in a fixed direction actually improves rolling stability.

The johnson bar approach provides more stability to the machine though it does require more space and you have to get the bar,move the tool and put the bar back. I use this for a shear/brake that weights about 450lbs. However, I find myself not moving it very much because it takes a bit more time and I am impatient. Easier to jack up one of the other tools and move it.

I have 2 drywall carts that I use for plywood, one has 2 swivel wheels, the other has 4.The one with just 2 swivel wheels drives me crazy, I would have never bought it if I knew ahead of time how hard it would be to maneuver around the shop with it.

I build my own mobile bases, all with four swivels. The worst factory mobile base was on the 25/50 SuperMax, all four straight line casters. Try locating that in the average space deprived shop.

Quote:

---

Originally Posted by Augusto Orosco

Why aren't there any 4 swivel caster mobile bases out in the market place? All the ones I have seen have 2 fixed and 2 swivel.
Just wondering.... :rolleyes:

---

Lack of directional stability with heavy loads.

The best mobile bases are the semi-live skid designs with a tow bar.

You see them on European machinery a lot.

I make all my bases that way............Rod.

Quote:

---

Originally Posted by Bill McNiel

I build my own mobile bases, all with four swivels. The worst factory mobile base was on the 25/50 SuperMax, all four straight line casters. Try locating that in the average space deprived shop.

---

Now that is stupid!

Quote:

---

Originally Posted by Rod Sheridan

Lack of directional stability with heavy loads.

The best mobile bases are the semi-live skid designs with a tow bar.

You see them on European machinery a lot.

I make all my bases that way............Rod.

---

My drywall carts have 4 swivel wheels and one that has a lock that you can lock straight or at 90% and they hold 2000 lbs

I have a few machines on 4 swivels, Great Lakes casters, a performax 22/44 on dual locking swivels, most machines are two fixed/2 swivels. The 4 way swivels are easier to park but much harder to move, it's a bit like ice skating with a dancing bear, doesn't always follow you or go where you wanted exactly, you have coax them as much as lead them. My planer is on 4 swivels, those are way over capacitated, so it's more of a semi mobile approach, doesn't have to move far. I can see a purpose for both types. That euro Johnson bar set up is maybe my least favorite method, we have that on a BS at work....it's not for the faint of heart lifting a #600 BS with a class II lever and dragging over a slippery smooth but often less than perfectly clean concrete floor. It's like parallel parking a dump truck with a hockey stick.

In my limited experience, four swivel caters are OK on light things; like under 100lbs. I replaced the "rear" swivels with fixed casters on more than one heavy object. Four swivels on a 450lb machine would lack control in my hands and end up banging into things while I struggle to direct it to where it is going (love the ice skating with a dancing bear analogy :D). I agree that for initial placement in difficult situations, four swivels allow diagonal movement. When I am guiding my drum sander between my jointer and planer I am trying to avoid diagonal movement and don't want to have to do that via my muscles. For small lateral adjustment I use a pry bar but, these situations do not come into play when I am moving a machine from a stored location into an operating position. I am lucky to have enough room (although not a lot of room) so that I only need to move machines a few feet to place them in the operating position. Different strokes.

Quote:

---

Originally Posted by glenn bradley

. Different strokes.

---

I guess, that's what I was getting at. I see uses for both, but seems to me that that if you want to buy a mobile base, your only option is two fixed/two swivel. So, I was wondering if I was the only one who would be interested in such a thing, and there is no demand for it. I can certainly see the "ice skating with a polar bear" issue, though; but that's probably less important (I think) when you want the base not to move the machine long distance, but simply to pull it away from the wall a little so you have better clearances.

It's quite interesting to hear all your experiences, though!

Two reasons, from my shop situation.

1: I have a 37" Woodmaster drum sander that I shove perpendicular against a wall. When I need it, I pull it out about 4', then shove it back in. It is 1000 pounds or so, and I would never get it in and out straight with four swivels.

2: I have a couple of carts that I use to bring wood and other stuff from the driveway to the shop...100' or so. There are various slight slopes on the concrete for drainage. The four wheel swivel cart is constantly trying to go downhill, and I end up chasing it rather than just pushing it, like I do with the two wheel swivel cart. I almost tipped my top heavy Shopsmith (4 swivels), moving it from the driveway to the shop.

On the other hand, super tight access is possible with four swivels, and sometimes desired.

Your mileage may vary,
Rick P