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Mike Amick
10-01-2012, 11:21 PM
I am building a caster cart to set my Cincinnati mill on. Its pretty heavy #2500.

I want to be able to wind the casters up ... so that the mill will set totally on
the ground .. then wind the casters down .. when I want to move it.

I am using some pretty thick steel channel. And the casters are beasts. I'm not
real sure I am going about it right .. as far as the up down part goes ... here is
a mock layout. I will be using 2 of these tied to together front and rear.

Maybe ? ... no ?

.

http://www.mikeamick.com/misc/cart_layout_notes.jpg

armedandsafe
10-01-2012, 11:46 PM
At ~625 pounds per caster, it looks sturdy enough. Does that lift bolt go through the floor plate of the caster? That looks to be the weak point. The metal of the caster plate will be supporting all the weight on the washer between the bolt head and the plate.

Pops

LKeithR
10-01-2012, 11:46 PM
I think you're on the right track. Only thing I would do is make a plate that bolts to the caster and weld the stud to it. This eliminates any heat on the caster itself and also makes it easy to replace one if you ever need to. I might be inclined to go to a bit larger bolt--I'm guessing that the ones in the pic are about 3/4"...

Mike Amick
10-01-2012, 11:58 PM
cool thanks ...

I should have put a pop can in the pic for scale ... the bolts are 1 1/8th
I agree .. about the plate .. the bolt will be welded to a plate that will be bolted to the top
of the caster ... and I even thru the bolt in the lathe .. and flattened the top for good
surface contact for the weld.

914Wilhelm
10-02-2012, 12:02 AM
I'd plate the sides of the double uprights as the form a rectangle rather than a triangle and may be prone to racking which will ultimately lead to wrecking. How will the casters swing up and down?

cameron
10-02-2012, 12:44 AM
I'm probably mis-reading this, but it looks as if you will be turning the castor as you turn the bolt. If so, as you've shown it, it seems the castor will hit the upright. And if you're using the castors to do the jacking, it's going to be hard to turn the bolt as the wheel contact patch will be describing a circle on the floor.

Just ignore this if I've got it all wrong.

Arcane
10-02-2012, 12:56 AM
Maybe you could hinge the caster to the upright so that when you crank down on the bolt, the base is raised off the ground when the caster top is level.

Mike Amick
10-02-2012, 12:58 AM
914 .. this is realllllly heavy duty stuff ... and I don't know what racking is .. is that like twisting
or something like that ?>

Cameron .. I have taken care that the bolt (centerline) will be far enough from the upright
so the caster doesn't hit it. But you are probably right about it being hard to turn the bolt.
I don't think the whole caster will turn .. I believe just the pivot plate on top will (I think) but
that is probably my biggest worry.

I haven't done any drilling or welding yet .. in case a really good idea comes up to lower and
lift the caster.

The Artful Bodger
10-02-2012, 01:01 AM
I suggest rather than retracting the casters how about a bolt that you can screw down to lift the entire machine so that the casters have no weight on them? These bolts would also serve for levelling the machine.

John

RussZHC
10-02-2012, 01:16 AM
Going with Artful on this...have seen lots of designs where the bolt/screw raises or lowers machine to load or unload the caster, don't know that I can recall seeing a design where in effect the caster itself is involved in the raise/lower.
There have been a few similar bases here before, not sure what to suggest as a search item...

Mr Fixit
10-02-2012, 01:21 AM
I think Artful Bodger has a good idea. Get some of that 1"1/8 in longer length and put it through the 2 uprights as jacks and levelers when it is in position. Racking is the sideways movement of ths cradle so the gussets suggested should be welded on the sides of the uprights this will help stop it from racking.

Mr fixit for the family
Chris

Mike Amick
10-02-2012, 02:28 AM
One thing I should have mentioned. One reason I am doing this is to lower the mill as much
as I can. Right now I have it on a reinforced pallet and the table is like upper chest high. I
really wanted to have the mill sitting flat on this channel to lower it. Because of this .. I may add
adj feet for leveling ... but .. I don't want to use them for caster positioning.

I may have think about that idea of hinging a plate with caster on it ... then .. swiveling the plate
up and down.

chipmaker4130
10-02-2012, 03:30 AM
I strongly advise against hinging the plate. I've use identical casters (mine are 8" wheels) and although they will hold a lot of weight, the weak link is the center rivit on the swivel bearing. There is already a pulling load on that rivit due to the angle of the castering arm, and if you 'swing' the mounting plate that angle becomes more acute with a corresponding increase in tension. The rivet head or the plate will likely deform and fail, at the least releasing the bearing balls, at worst breaking completely. I know the rivit looks massive, but the material is soft.

With regard to height, 'landing gear' as suggested above is still the best solution. If you mount the casters high (outrigger style) so that the machine support is only a half-inch or so above the floor, you're only gaining a half-inch more than your proposed design and a much stronger and simpler mechanism.

Mike Amick
10-02-2012, 04:16 AM
Ok .. you just talked me out of hinging or anything else that adds more angle to the casters
already built in angle. I see exactly what you mean. If I had a nice shop floor I wouldn't
mind having my cart glide a 1/2" off of the floor ... but .. I have a couple of diff slabs that have
settled and have "lips" .. that require much more clearance than that to get across the shop.

I just have to think outside the box a little here. You guys really are helping the think tank
process here though. Its like having a bunch of old heads sitting around a table saying ...
" nope .. can't do that .. here's why .. think of another way .. " .. lol

Boostinjdm
10-02-2012, 04:23 AM
I'm still trying to figure out why a 2500 lb machine needs to be easy to move.

Mike Amick
10-02-2012, 05:14 AM
Hey .. Boostinjdm .. where the mill is in my shop .. If it was sitting flat on the floor and I had to
move it .. even to just get behind it .. it would be reallly hard. Not enough room to get a gantry or
hoist above it ... can't even roll it on bars ... the damn bottom isn't flat. Can't get the cherry picker
centered over it to lift it right... its just ugly. Being on the pallet is nice for the ease of moving using
the pallet jack.

I am actually starting to think that my original plan is just going to work fine. This caster is built
twice as strong as it needs to be .. the swivel pin/rivet will not get any more pressure put on it
than it would under normal usage. the caster place will be bolted to a thick metal plate with a
great big bolt welded to the place. The massive nut will be overly welded to the plate
since ... I concider IT to be wink linkl

EVguru
10-02-2012, 05:32 AM
It looks like it has resiliant tyres. If the weight is resting on them then they'll flat spot and you'll lose the ability to move the machine easily.

BigJohnT
10-02-2012, 08:09 AM
Any kind of non-metalic wheels will suck. I added leveling feet to my Samson lathe and it raised it up past my comfort zone so I just built a wood platform with my anti fatigue mat on top to raise me up... sure was easy to build.

How often do you plan on moving the mill? I have a hydraulic toe jack that I lift equipment with to put on rollers to move them and it is a life saver.

John

winchman
10-02-2012, 09:01 AM
I did a similar thing when I put casters under our Doringer. It's not as heavy as your mill, so my casters weren't as big.

I found that the channel flexes at the edge of the machine. I welded a triangular gusset over each caster, and put a padded plate on the vertical edge of the gusset closest to the machine base. That transfers the bending load back to the machine base, and the channel no longer flexes. You could probably eliminate the second vertical channel if you did that with your design.

http://img.photobucket.com/albums/1003/winchman/MiscellaneousSeptember232012on_zpsf438855c.jpg

SteveF
10-02-2012, 09:43 AM
914 .. this is realllllly heavy duty stuff ... and I don't know what racking is .. is that like twisting or something like that ?>



Racking is when you build a square and move the top either right or left. The vertical sides will remain parallel to each other and will move right or left with the top. So, the only thing that keeps a square from racking and collapsing under load is the strength of the four corners, which may not be enough. That's why, for example, on shelf units with no back, diagonals are installed to add strength and prevent the shelf unit from racking.

Steve

rmuell01
10-02-2012, 10:48 AM
Leveling the mill on a long bar will be a problem. I might consider an option that uses a trailer jack process on our corners. It could be configured to either raise/lower the wheels while still having only four points to level.