I have been building mobile machine bases for my garage machines (angle
iron frame with 2 swivel, 2 fixed casters attached to bottom). I've
been welding the casters directly to the bottom of the frame, which
naturally prevents me from easily removing them. I am looking for a
"better" way to fasten the casters. How do you attach casters to the
bottom of your tables/machine bases? Thanks. John

I have built several pieces of equipment with casters in the past years
and have always cut out 4 pieces of steel plate, what ever thickness
was available, the same size as the caster plates. Then drilled
mounting holes for the casters. I set the welded frame on the garage
floor, put the plates in position under the legs and tack weld them in
place. This way I am sure the plates are in position and are square
with the frame. At some point, I also round off the corners of the
plates for safety!

Finally I finish welding the plates to the frame and then paint the
whole unit. When complete, I bolt on the casters. Works for me, anyway.

Paul

I bolt each pair of casters between two downward-facing angle iron
rails so they are attached and supported at all 4 corners, then connect
the two assemblies with either angle or wooden planks. Generally the
wheels clear the angle if it is attached to the short sides of the
caster plate.

The angle iron is reuseable if the casters need to be swapped for
larger ones.

For lighter machines I put plywood between the casters and a welded
angle-iron frame.

On really light machines like my table saw the casters are on a narrow
hinged plate that can be kicked under the base to move it or swung out
to let the saw rest solidly on the floor.

Jim Wilkins

"John" wrote in message
oups.com...
I have been building mobile machine bases for my garage machines (angle
iron frame with 2 swivel, 2 fixed casters attached to bottom). I've
been welding the casters directly to the bottom of the frame, which
naturally prevents me from easily removing them. I am looking for a
"better" way to fasten the casters. How do you attach casters to the
bottom of your tables/machine bases? Thanks. John


There are square steel plates of various sizes available at wrought iron
supply stores. From 2x2 up to 6x6, I believe. They are 3/16 and 1/4 thick.
You will have to drill holes to match your casters, but you won't have to
spend any time fabricating. And the price is right. And they are usable
for many other things, too.

Check with your steel supplier. Maybe they have rems that could be bought
very cheaply.

Steve

John wrote:

I have been building mobile machine bases for my garage machines (angle
iron frame with 2 swivel, 2 fixed casters attached to bottom). I've
been welding the casters directly to the bottom of the frame, which
naturally prevents me from easily removing them. I am looking for a
"better" way to fasten the casters. How do you attach casters to the
bottom of your tables/machine bases? Thanks. John


I prefab caster plates which match the ones on the casters, both size and bolt
pattern (I shear/punch them on the ironworker) and then weld them on, clean the
weld and finish the plates with the frame (galvanize, paint, whatever) and as a
last step bolt on the casters. See e.g.:
http://tinyisland.com/images/splate2.jpg

On semi-portable machines I also mount wheels on the side, so they barely clear
the floor, and put a handle on the other side so you pick up the handle and then
the wheels engage and you can roll your machine but when you put it down it's
solid.

GWE

On Tue, 21 Jun 2005 11:44:14 -0700, Grant Erwin
wrote:

John wrote:

I have been building mobile machine bases for my garage machines (angle
iron frame with 2 swivel, 2 fixed casters attached to bottom). I've
been welding the casters directly to the bottom of the frame, which
naturally prevents me from easily removing them. I am looking for a
"better" way to fasten the casters. How do you attach casters to the
bottom of your tables/machine bases? Thanks. John


I prefab caster plates which match the ones on the casters, both size and bolt
pattern (I shear/punch them on the ironworker) and then weld them on, clean the
weld and finish the plates with the frame (galvanize, paint, whatever) and as a
last step bolt on the casters. See e.g.:
http://tinyisland.com/images/splate2.jpg

On semi-portable machines I also mount wheels on the side, so they barely clear
the floor, and put a handle on the other side so you pick up the handle and then
the wheels engage and you can roll your machine but when you put it down it's
solid.

GWE

I do what Grant said. just bandsaw a piece of plate to caster plate
dimensions, drill and tap, then weld them on. Usually, I mount them
flush with the bottom frame with all bolt holes inside the frame, as
otherwise they're ankle biters.

Pete Keillor

Gunner wrote:

I weld a rectangular plate in each corner, then drill and tap for
capscrews to hold the casters in place.

That must be how they do things in the California oil fields. Up here I find it
easier to drill the holes in the caster plates *before* I weld them on. :-)

GWE

On Wed, 22 Jun 2005 13:46:35 -0700, Grant Erwin
wrote:

Gunner wrote:

I weld a rectangular plate in each corner, then drill and tap for
capscrews to hold the casters in place.

That must be how they do things in the California oil fields. Up here I find it
easier to drill the holes in the caster plates *before* I weld them on. :-)

GWE


I did that once. And it was a pain in the ass. Now I simply weld em
on, turn the dolley upside down where the weight helps hold things in
place, line up the casters so the through hole doesnt interfer with
anything and hit it 4 time.

Differnt strokes for different folk I guess.


Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

I weld them on. How often do you expect to be removing them? It
doesn't take that much bead to secure them and it's more-or-less easily
ground off if you EVER need to remove them. I like things simple.

Bob

In my experience as I upgrade my machines, I tend to remake my machine
bases and reuse my casters as bigger and better machines find their
home to my shop.

And to complicate the discussion, I tend to use WOOD as the base
material..especially plywood that resists splitting with its different
plys.

Plywood scrap is much more plentiful for me to scourge and is
FREE...metal is neither. Considering all the machines I have, I would
have a small fortune in the bases if I had gone metal. As it is, I
spend the money on GOOD casters that are readily recycled when the next
machine arrives.

I have a number of machines (500-1000 lbs) on double layered bases of
3/4" plywood (1.5" total) with 3" casters rated for the load. These
casters are bolted to the wooden base. These bases have not given me
any problems and many times are recycled themselves when more machines
are added to my zoo...err I mean my shop. Only my Bridgeport (2500 lbs.
) is on a metal machine base that has 8" casters but rides 2" off the
ground. That machine base cost several hundreds of dollars and many
hours to manufacture but makes moving the mill across the shop or
across the country a simple matter.

I would recommend the same size of casters in your bases. The uniform
height off the floor allows one to use that space for extra
storage...and what shop doesn't need more storage space.

TMT

"Too_Many_Tools" writes:

Plywood scrap is much more plentiful for me to scourge and is
FREE...metal is neither. Considering all the machines I have, I would
have a small fortune in the bases if I had gone metal. As it is, I
spend the money on GOOD casters that are readily recycled when the next
machine arrives.

Are the load ratings on cheap casters generally accurate, or is
there something else to look for?

What I'm really asking is, can I buy them locally if I pay
attention to the load ratings, or do I have to go to mail order
to get "good" ones? (the local stores only stock "cheap", but
they do have a variety of load ratings)

A former employer got ahold of some cheap casters once, and they
were a PITA (the wheels were OK, but the frames slowly collapsed
so they wouldn't swivel properly). I don't know if he paid
attention to the load rating or not, but ever since I've wondered
if there's something else to look for.

Also, do you have to de-rate them for impact loads if they're
running over cracks in a concrete floor? That might have been
part of our problem...

I try to buy stuff locally to support the local stores....mail order
does me no good when I need something NOW.

When I design anything, I try to allow for the stresses and strains
that I normally wouldn't think of. Since I am not doing this for
production, I can allow for more money for a better caster.

Years ago when I lived in the upper Midwest I bought my last quantity
of casters from the two places that I found carrying decent casters
(Faultless brand) were Menards and TSC (Tractor Supply Corp.). I went
with 3" steel as a compromise of size versus height versus cost. Lowes,
Home Depot and several discount places carried cheaper and poorer
quality casters. The load limit on the casters I bought were double
(400 lbs) what the others were. Keep in mind that suppliers change and
you need to verify that what you use is rated for the weight it will
carry. Assuming four casters rated at 400 lbs., I consider placing a
machine of 800 lbs. on a plywood deck (2 layers of 3/4" plywood of
approximtely 30" x 30") with these casters bolted on to be a good cheap
compromise. If you go for a longer base or a heavier load, I would
recommend going with a suitable metal frame or use more than four
casters on a wood base to carry the load.

On machine bases, you should try to have as large a wheel as possible
to allow the base to roll easily over floor imperfections, cracks,
debris, etc. At the same time, you want to try to maintain as low a
profile for the base as possible...raising the CG of a machine tool
makes for a dangerous situation and raising the overall working height
of the working area can result in awkward or dangerous situations.

For derating, I usually try to have the caster rated double the weight
I will have mounted. Keep in mind that the "rating" is a general one
that is based on static loads. When you start rolling a caster, it is
subjected to more than the weight of the machine as it travels across
the floor. I also note that the fasteners you use should be of decent
quality also...nothing like having a caster falling off at the wrong
time to make life interesting. I have seen more than one caster sheared
off as it hit a floor crack. Just one more reason not to raise the
height of the machine anymore than necessary.

For my Bridgeport machine base, I had a heck of a time finding casters
that could be derated properly. Based on that effort, I can tell you
that most mobile Bridgeport bases you see have under rated casters on
them.

One other point I will mention. Many machine tools assume that they
will be supported along the entire base of the machine. I have had
several machines where someone has attached casters by bolting or
welding them on. Since now the machine is being supported only by those
points of contacts, the machine will suffer excess vibration,
misalignment and in one case, the cabinet began to collapse. The lesson
learned is that the machine needs to be supported at all points where
it would normally rest on the floor....slapping a set of casters on a
machine and thinking you are done is far from the truth.

TMT