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Thread: Rolling stand for Bridgeport
11-03-2011, 07:25 AM #1
Rolling stand for Bridgeport
I have a small shop at home with limited floorspace. Most of my tools and equipment are on casters. I recently acquired a Bridgeport milling machine, and I'd like to put a rolling frame under it. I have four 5" swivel casters rated at 1000# each. I was thinking of making a frame out of 4"x1/2" angle iron and attaching the casters on the four outside corners with 6"x9"x1/2" steel plates mounted on gussets and welded to the angle iron. The plates would protrude 6" from the angle iron, but have to be 9" wide to allow the caster to swivel freely. I'm looking for about 1" floor clearance. I know that the mill weighs around 2000#, and the milling vise and material being milled would add a couple hundred more. There's also an old coolant tank and pump inside the machine that's not operational. I don't have an engineering background, so I'm kinda fluing by the seat of my pants. Do you think that 4"x1/2" angle iron will be stiff enough, or will flexing be a problem? The flexing could come from both directions, the weight of the machine on the base, and the leverage of the plates on the corners of the frame. Thanks for any input you could provide.
11-03-2011, 07:47 AM #2
I dont think that will work well , even locking casters will move a bit, the machines torque and vibration will be amplified. A way I have done this is to attach blocks to the bottom of the machine, either 4 x 4 wood or 4 inch steel channel and then you can easily move the mill around with a pallet jack. works well and the extra height is a plus in my opinion.
11-03-2011, 10:17 AM #3
What about jack screws instead of locking casters? They will also allow you to level your machine.
As to your flexing- well that depends on how much material, and more importantly how it's configured.
That would not be my first choice of materials, but if the price is right....
11-03-2011, 10:20 AM #4
The machine is presently sitting on a pallet covered with a sheet of 3/4" plywood. This makes it hard for someone of my stature to reach the switch easily. Although I think that your suggestion has merit, I can get around the vibration issue by putting small screw jacks on each corner with steel plates on the floor which will take part of the load off the casters. They'll also help level the machine. What I'm really wondering about is if my seat of the pants design will be rigid enough not to flex. Thanks
11-03-2011, 10:34 AM #5
We have a bridgeport on two 4-4 blocks in the shop right now because it's not at it's final resting place. The blocks are wide enough to squeeze a narrow pallet jack through and don't stick out past the machines footprint so no trip hazard. To get past the 4" height increase we made a 4" expanded steel/square tubing deck to stand on in front of the machine. I usually kick it out of the way unless I'm taping alot or something else where my hands are working with the uppen portion of the machine more.
Even once we get all our equipment on the floor, it'll still be handy to have a deck like this.
11-03-2011, 10:44 AM #6
I've used some pretty solid pallets for machines that are better kept mobile. They work fine but a good solid one in particular doesn't help keep the controls within reach.
What I have seen people try, and would be the approach I would take, is to make a low slung cradle for the machine and to have the casters on some kind of a crank or screw. The idea is that the casters only hit the floor when you are moving the machine. When the machine is being used it sits on the cradle which in turn sits on the floor. If the cradle is done right you are basically just sitting the machine on a few steel plates, not that much different from having nothing under the machine.
I don't think I would trust 1000lb casters all that much with a 2000lb machine resting on them *constantly* and vibrating and moving around when it is in use. I sure wouldn't want to be running a bridgeport standing an inch in the air on locked casters. That sounds like a toe muncher.
Another nice feature of having the casters retract is that you can lift the machine just enough to clear the path you are rolling across.
11-03-2011, 11:08 AM #7
Casters under a Bridgeport can't work any worse than the ones I have under my shaper -- although they do work rather poorly.
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11-03-2011, 11:15 AM #8
Try to do a a search for this on this forum. I distinctly remember a gentleman that made a rather slick caster arrangement for his B-port. He used jack screws to support it off the casters when he got it into position. I think he also came up with his own wheel caster design. It looked quite stout and sturdy. Let me know if you can't find it, as I think I saved the pics.
11-03-2011, 11:29 AM #9
I also remember that there was a thread on this topic, but I searched for it last weekend and wasn't able to find it. If you could post the photos, I'd appreciate it.
11-03-2011, 11:46 AM #10
You may try making one similar to a Saw Stop cabinet saw that uses a bottle jack to raise the machine off the ground for moving, when being used just lower the jack and the machine frame sits on the ground. Its a really slick setup.
11-03-2011, 12:34 PM #11
This isn't the one I was thinking of, but looks good. I wasn't able to find the one I was thinking of, it may be on the home puter. Go down in the thread and he has more detail on it.
11-03-2011, 01:43 PM #12
04-11-2012, 12:12 PM #13
Here are a couple photos of the completed stand. There are bolts on each corner that can be threaded down onto steel plates on the floor, which takes the load off the casters once the machine is in position. They are also used to level the machine.
04-11-2012, 07:02 PM #14
Just a suggestion on the jack screws that they have feet (even if loose pieces of flat bar) and not be the flat end of the bolt. Roughly 1" dia min, 1-1/2" dia better (or square). The bare bolt end will dig into the concrete.
04-11-2012, 07:41 PM #15
You could bolt a turret mill to a wall, hang it from a wire, ect and run it reliably (more or less) having regard for drippy coolant and other minutia. It's a rigid machine not dependent on a foundation or external support to maintain its alignments. All forces generated in the machine circulate through its structure and therefore except for motor start torque and operator wrenching there is nothing to move the mahcine in norlam operation.
Thus there's no reason not to mount knee mill of most any size on casters of movement and portability are necessary. Most solve the problem by raising the machine a few inchec for fork lift access. In a small shop without a forklift sturdy casters are the best solution.
I prefer hard phenolic casters in chip generating areas in the shop. Elastomeric (rubber and urethane) wheels pick up and imbed chips and eventually fall apart. Hard phenolic won't damage concrete nor will it pick up chips yet it rolls freely.
All this is moot because it looks like PeteDE has made a dandy castered cart for his turret mill. It's low slung so he won't need elevator shoes to run it and if the casters are cared for and the floor kept clean they won't load up with chips. I see jack screws for leveling and tighter coupling to the floor which is good. It';s awkward to have the mill move around when you're tightening bolts and a level machine is always handy come set-up time
04-12-2012, 04:29 AM #16
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07-10-2012, 12:58 PM #17
I have been thinking about building a bunch of these carts for guys that do not have the equipment to build it themselves. The design will be very similar to the one that PeteDE put pictures on here of. The only difference is mine will have 4 Phenolic casters on it. The problem with only having 2 casters is, you have to pull it out away from where ever it is sitting and jockey it all around just to move it 2 inches to the left or right. If I use a true heavy weight phenolic machine caster, not like the ones pictured, they will be able to move very easily just a little bit in any direction without normal caster binding when you have some of the wheels turned one way and some turned a different direction. The bolts on the corners to take the weight off of the wheels will be very similar though. I don't use these on my mill, I have no need to move it, but I have the equipment and the knowledge to build these quite easily if there is enough of a demand. So, who would be interested in buying one if I build them ? Let me know please. You can either post in here or send me a PM. Thanks, Geoff
Last edited by GeoffD; 07-10-2012 at 04:18 PM.
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07-11-2012, 02:50 AM #18
As usual there is very little new under the sun. I responded to the same question on rec.crafts.metalworking in January of 2003. I included pictures of a caster frame that I had built, and somehow they ended up in the mwdropbox. I didn't put them there. These are the links:
It is amazing how similar PeteDE's design is to mine. I guess the problem dictates the solution. The following are a few comments on my dolly. The jack screws are 1" in diameter with swivel pads. When raised on these jack screws the machine is rock solid. I didn't want chips to become lodged between the frame and the mill so I bondoed the gap between them. This has proven to be a very good thing to do. It makes cleanup a breeze. I would never put swivel casters on all four corners. I have found that doing so makes it very difficult to steer a heavy piece of equipment such as this. The little clevis pin on the front of the frame is for attaching a T-handle that I use to move the machine. I found that using the handle is much easier than pushing and pulling on the machine itself.
I like the pallet jack idea, but where I have my machine, it is inaccessible to a pallet jack.
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07-11-2012, 04:50 AM #19
you can install mine with a crow bar
the angle iron frame setup means a 6 inch lift and drop straight down from over head
07-11-2012, 08:13 AM #20
A number of the heavy machines in my shop are on wheels. Have not yet put the mill up, but if I do, it will be similar to what I have done with an Onsrud pin router ("similar" shape machine, albeit only about 1/2 the weight of the mill). I took a long piece of 4 x 6 x 1/2" angle with the 4" up, and spanned the bolt holes at the front of the base, + another 10" or so sticking out past each side to put the casters under. There are spacers as necessary between the steel and the machine base at the bolt holes; with a couple 5/8" bolts in the original base holes holding it all together. This way the base "hangs" down from the steel, and only adds about 3/4" - 1" height to the machine. Though I am one who would be happy to have the table higher on the mill.
Then at the back of the machine, I welded and machined a wide heavy bracket that bolts right onto the column with holes drilled and tapped into the casting, with a base sticking back from that for a single caster.
Wide stance of wheels at front under the table area where they are never in the way of operator, combined with tricycle arrangement makes a very stable platform. I use wood blocks and wedges when in use to prevent movement of the pin router, would probably do same for mill. Or add jack screws.