Proper size square tube for a mill dolly/stand

[danlb]

First the background;
I have a small knee mill that I will want to move a few times. I have to clear room so that I can move things to clear room to move things before I can put the mill in it's final spot.

It's an old (1978) Taiwan model with an 8x30 table. It weighs around 1100 pounds as near as I can tell. It stands 5 foot tall.

The base is hollow cast iron. It measures 20 wide by 28 deep and has a 1 inch flange around the bottom. There are 1/2 inch bolt holes in all four corners. The cast iron is 1/2 inch thick.

I have taken some elementary classes in welding. I can stick two pieces of steel together with a wire feed welder.

Now the project;
I want to build a simple dolly to move it with. When It's in place I can use feet in the bolt holes to level it.

I was thinking that I could build a mobile base. I have some 500 LB steel casters to hold it up (two swivel, two fixed). It would be similar in concept to the "Shop Fox Super HD Mobile Base" sold by woodcraft ( http://www.woodcraft.com/product.aspx?ProductID=816491&FamilyID=2026 )

I can't quite figure out the math for determining the proper metal for the frame. Angle iron or box tubing? How thick? Mild steel should work, I think. I think i want to support it around the entire perimeter.

My guess is that 1 inch square tube with 1/8 thick walls should support it.

The basic design is as shown in the jpeg below. The black is the frame, blue is the mill base, red are the holes for the feet, grey are the casters.

http://www.tanj.com/mill/mill_cart.jpg


Any help?

Thanks

Dan

[danlb]

I spend too much time thinking... :)

Am I better off just buying the Shop Fox base, even though the mill will come close to (or exceed) the max weight rating of the base?

I'd also be able to figure it out for myself if someone can explain how you figure the weight bearing ability of a bar when the weight is supported on the bottom flange and thus spread over 90 square inches and not just at one end or the other.

Thanks

Dan

[shawnspeed]

I would be hesitant to put a mill on a cart like you drew..the casters should be outboard of the machinery base as mills are a little top heavy...this means canterleavering the caster mounting plates outboard of the frame. two suggestions, one , roll it on 3/4 or 1" black pipe, works good is easy , and cheap. 2 do a search of this site , or possibly the PM site for mooving pads, If I remember correct , someone made a air pad out of plywood with a canvas/cloth skirt that was powered by a shop vac to float a brigeport into a room they couldnt get a dolly into, they sell a system like that but it is a bit pricy...I usually move my B'port with a pinch bar. If you still decide to build a dolly 2x2x3/8 angle should be goodwhen in doubt , over engineer it...Shawn

[dan s]

I agree...


If you still decide to build a dolly 2x2x3/8 angle should be good when in doubt , over engineer it...

[danlb]

Thanks for the moving pad suggestion. That had not occurred to me.

The black pipe rollers were considered, but since the base is hollow that would concentrate the weight on a few small points. I do not yet understand the mechanical stresses that might or might not make that a problem for cast iron. I was cautioned about using caution when using a prybar to raise it because of the posibility that it would crack/chip the edge.

I should put together a real drawing. That was just a rough sketch. I am planning put the wheels outboard, possibly hinged with a jack screw to force them down when needed.

Thanks for the materials advice too. 2x2 x 3/8. Check. That will be one solid dolly :)


Dan

[rmack898]

Just want to throw this out there because it works for me. I wanted to keep all of my stuff mobile so that when you need to do a quick re-arrange to bring that big whateveritis in the shop, it doesn't take all day. I started out building frames for equipment and adding heavy casters.

If you're only talking about 1 or 2 machines its no big deal, but we all know big things just find their way to the shop. After a while those heavy duty casters and the material to build frames can get expensive.

My solution was an inexpensive pallet jack. One stick of rectangular tube is enough to make 3" feet for an awful lot of machines and equipment and the pallet jack will make moving just about anything in the shop a safe and painless one-man operation.

[dan s]

My solution was an inexpensive pallet jack. One stick of rectangular tube is enough to make 3" feet for an awful lot of machines and equipment and the pallet jack will make moving just about anything in the shop a safe and painless one-man operation.

That's what I did to get my mill home. I got the jack(4400 lbs) at Menards for $200 I didn't have time to make a steel pallet, so I made this beast (2x4's & 4x4's) in a little under 2 hours. The jack is really going to come in handy when I start to refurbish the mill in the spring.
http://img369.imageshack.us/img369/8715/pallet300x225iz6.jpg (http://imageshack.us)
http://img369.imageshack.us/my.php?image=pallet300x225iz6.jpg

[rode2rouen]

The black pipe rollers were considered, but since the base is hollow that would concentrate the weight on a few small points. I do not yet understand the mechanical stresses that might or might not make that a problem for cast iron. I was cautioned about using caution when using a prybar to raise it because of the posibility that it would crack/chip the edge.




Here's some pics of my Index 645 move. It was done solo (all my friends were "busy"). The black pipe rollers worked like a champ. Base thickness was around 5/8" to 3/4". Took about 45 minutes.

I'm not a pro rigger. Hey, you gotta do what you gotta do.
http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index01.jpg

On the pipes, ready to roll.
http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index02.jpg

Not even sweatin'.
http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index03.jpg

Starting the left turn.
http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index04.jpg

More to follow.


Rex

[rode2rouen]

These next pics show the "drive it in, back it out" move so the mill would be oriented correctly near the back wall. Due to the amount of stuff in the garage (3 motorcycles, my racing go kart and boxes of ??, I was moving all that out to where the mill had been.

http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index05.jpg

http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index06.jpg

http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index07.jpg

http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index08.jpg


Rex

[danlb]

You make that look so easy Rex.

The pallet jack's a good idea. I just need a place to store one. :) That takes me back to moving the mill so I can move the..... well, you know. That will not stop me from getting one.

My ulterior motive is that I want to get more experience with welding. This should be a low risk project if I keep it low to the ground.

Dan

[rode2rouen]

Moving nicely to it's final resting spot.
http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index10.jpg

http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index11.jpg

The strips of rubber truck mudflap are to prevent movement while I square it to the wall.
http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index12.jpg

The mighty 645 sitting on it's high-tech, anti-vibe mounts (4 Czech hockey pucks from a local sporting goods store $.99ea.).
http://i721.photobucket.com/albums/ww216/bjorn_toulouse/index13.jpg


Rex

[danlb]

Well done move there. How long does it take to move it that way? 30 minutes?

Dan

[piniongear]

You make that look so easy Rex.

The pallet jack's a good idea. I just need a place to store one. :) That takes me back to moving the mill so I can move the..... well, you know. That will not stop me from getting one.

My ulterior motive is that I want to get more experience with welding. This should be a low risk project if I keep it low to the ground.

Dan A mill is too top heavy to use any kind of dolly under it unless the wheels are wide apart, and that increases the 'footprint' of the machine.
Here is what I did with my Bridgeport, which I have to move from time to time. Since you already have a pallet jack, this is what you can do...........

http://i12.photobucket.com/albums/a214/piniongear/Bridgeport%20Milling%20Machine%20Photos/FinalRestingPlace-1.jpg

The pallet jack stores right under the milling machine. When I need to move it a couple of pumps on the jack handle and away it goes.

http://i12.photobucket.com/albums/a214/piniongear/Bridgeport%20Milling%20Machine%20Photos/BridgeportSupports.jpg

All that I used was 2 pieces of 3 inch by 4 inch by 3/8 inch thick wall tubing. Each piece (front and back) is bolted to the mill base with 5/8 x 6 inch bolts. I have 1/2 inch leveler bolts in the bottom and each sits on a steel pad to prevent it from chewing up the concrete floor. I cannot think of anything that is simpler than this and provides storage for the jack at the same time....in a 'ready to use' location. That is why I did it............pg

[rode2rouen]

Well done move there. How long does it take to move it that way? 30 minutes?




Dan, it took about 40 minutes, what with picture takin' and stuff movin'. If it had been a straight shot from point A to point B, maybe 15 minutes.

piniongear, you're a pretty tricky guy! Nice solution!



Rex

[apd855]

I second the pallet jack. This is my arrangement. 2x2x1/8 square.




http://i478.photobucket.com/albums/rr148/apd855/DSCN1403.jpg

http://i478.photobucket.com/albums/rr148/apd855/DSCN1404.jpg

http://i478.photobucket.com/albums/rr148/apd855/DSCN1405.jpg