Do urethane caster wheels deform over time under load

On Tue, 09 Mar 2010 20:28:39 -0600, the infamous Ignoramus17831 scrawled the following:

I doubt it, but you can ask them easily enough:

I installed pinkish-red bushings for the leaf springs on my F-150 which didn't deform at all. Good schtuff, Maynard.

-- There is no such thing as limits to growth, because there are no limits to the human capacity for intelligence, imagination, and wonder. -- Ronald Reagan

On Wed, 10 Mar 2010 07:59:51 -0600, the infamous Ignoramus5886 scrawled the following:

And ensure a level of within 1/4".

-- There is no such thing as limits to growth, because there are no limits to the human capacity for intelligence, imagination, and wonder. -- Ronald Reagan

They all flat spot to a degree. How much all depends on the durometer of the caster, the load, the temperature, and time... I've seen the tires deform so badly they crack and fall off, and now you have a cast iron caster.

Several solutions out there, pick one. The easiest would be to use the urethane casters on a sub-frame, and put crank-down landing jacks or levelling screw jacks or floor locks or leveling mount "Bun Feet" (pick one) at the four corners to take most of the load off the casters when parked.

The casters might flat-spot a bit if they have a little weight left on them, but it won't be a huge divot. I'd research air bearings if you've got a big chunk of plate steel - leave it under the tool permanently and have screw-down leveling feet, when you need to move it just hook up the air chuck. I know it will work, but there must be finer points to it.

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Unless you provide an alternate support for it when it is in use, you are in for some excitement. With servo motors, you will find that a rapid move in the X or Y axis will cause a corresponding move of the base of the mill -- related to the mass of the main body of the mill, vs that of the table, vise, and workpiece on it.

At first, the speed of a rapid move can scare you.

If you were using the older stepper motor version, it can't go fast enough to do much of this, but servos are *fast*.

If you put them there (I would suggest 4x4s, since 2x4s on edge would be likely to topple if the motion of the tables was perpedicular to the 2" dimension.

I really don't know about that. Hopefully, someone else will know about the dark red compound.

Good Luck, DoN.

Amen!

There is one reason for leveling the mill. The flow of coolant back to the reservoir can be quite sensitive to leveling.

Enjoy, DoN.

Makes me wonder what life as a machinist was like on the big WWII ships. I worked on one that was converted to a crab processing plant in Dutch Harbor, AK. It had a complete machine shop and I was told they could make damn near any part they'd need as long as they had the stock. This ship was permanently docked but it'd still list depending on how the loads were stowed down below. I have to assume it wouldn't be level underway. Well, perhaps akin to a broken clock being right twice a day anyway.

Newb