Milling Machine base

[Megar arc 5040dd]

I figured this was probably a more appropriate place for this. The rest of the discussion about this mill is here https://canadianhobbymetalworkers.com/threads/new-to-me-zx45-milling-machine.7314/ this will just be about the actual project of building a base for the mill.

So 2 problems needed solving 1) the roller base that is came with was a little wobbly since it was just a regular roller base for tools with 2 pieces of 3/4" plywood holding all the weight at the 4 corners. And 2) and probably the most important problem the mill was just way to low to use unless I was sitting on a mechanics stool. I am 6'2 with back issues having to bend that much makes using the mill not enjoyable so it needs to be raised up.



This was the base the way it came when I bought it.


The plan was to remove the plywood and replace it with some 4"x4"x.125" tube I have had laying around for about 15 years. Then add some levelling feet to the tubes on the sides right by the casters.


Got the frame all welded up. The welds on top and bottom were ground flush to it can sit flat on the mobile base and the cabinet can sit flat on the tube. The cabinet will then be welded to the tube at the end to make the cabinet and base one solid structure.


Then snag I hit the first and hopefully only snag. Its still way to short deep down I had a feeling 4" wasn't going to be enough but I wanted to use up the tubing.

More in next post.

 

[Megar arc 5040dd]

New plan I will bake another tubing frame about 6" wider than this one and put it on the mobile base, since it can easily be made wider, then stack the first tubing frame on top. making a stepped pyramid. Then I will weld them all together. once I am happy then the mobile base will be welded all together and those stupid clamping bolts can be gotten rid of. They are going to be in the way of the levelling feet anyway.

After a lot of measuring the height of things in the shop I think that 44" table height will be good. Any higher and I will have to find a new way to lift it. 4 more inches will max out the chain falls lifting room.



More to come once I get the next frame built.

 

[Susquatch]

New plan I will bake another tubing frame about 6" wider than this one and put it on the mobile base, since it can easily be made wider, then stack the first tubing frame on top. making a stepped pyramid.

I have only one comment. Don't confuse strength with rigidity.

1. Your new base has to be strong enough to hold the weight of your mill and stop things from falling over.

2. But mills also benefit from significant rigidity - resistance to flexing and vibrating due to cutting forces and loads.

Both goals are important and both require attention for the best results.

 

[Megar arc 5040dd]

There is one factor that I failed to mention. I have to take weight into consideration. The way my shop is built the floor is wood. It is 2 layers of 3/4" plywood sitting on 2x6 joists spaced 12" on center. The joist run the 16' width of the shop supported at both end with a beam in the middle. so each joist essentially has a span of 8 feet either side of center of the shop. the mill sits in the center above the beam. But with a lot of weight the floor gets a little springy i guess you could say. Long story short its not as ridged as a cement garage floor.

I had thought about filling the tubing with sand but I was concerned about the added weight, I am already pushing the scales at about 1000lbs as far as I can figure out, as well as I don't have any sand so would have to buy find some.

I am open to all suggestions on improving rigidity or just a better way of doing it. So far it is all materials I already have so I am not out anything by starting over with a new idea.

 

[Dabbler]

If your position for the mill lands the wheels between joists, you have a vulnerability.

The longer the wheel is between the joists, the more the wood floor will relax. If that part of the plywood has a void, it can result in fracture. Very low possibility of a hole all the way through. And your base is very low, so it wont break through far.

Your leveling feet have a smaller footprint than your caster ( or so it looks). You can help by putting the leveling feet onto steel discs, perhaps 3" in diameter...

I also have a shop fox base for my 12" table saw. It is the one 'rated' for 1000 lbs. It has double wheels on the same axle.. My table saw is under 400 lbs, and it didn't hold up very well. It is now disassembled in the corner waiting for metal recycling. (so there's that).

(gosh I'm sounding a lot more negative than I mean to...)

The larger the diameter the wheel, the more the contact area... But you might be better off using the heavy steel base as your mobile base. By putting larger non rotating wheels in the back of the unit the whole affair will roll easier with the inevitable flexing of the floor. You can reattach the swivel casters to the outboard sides at the front of your 4x4s Leveling jacks can be 1/2" ready rod, pushing onto steel discs, or better yet a 2X2 angle iron to bridge the width between joists.

Sorry for redesigning your base, but I've had casters go through 3/4 ply before.

 

[Megar arc 5040dd]

If your position for the mill lands the wheels between joists, you have a vulnerability.

The longer the wheel is between the joists, the more the wood floor will relax. If that part of the plywood has a void, it can result in fracture. Very low possibility of a hole all the way through. And your base is very low, so it wont break through far.

Your leveling feet have a smaller footprint than your caster ( or so it looks). You can help by putting the leveling feet onto steel discs, perhaps 3" in diameter...

I also have a shop fox base for my 12" table saw. It is the one 'rated' for 1000 lbs. It has double wheels on the same axle.. My table saw is under 400 lbs, and it didn't hold up very well. It is now disassembled in the corner waiting for metal recycling. (so there's that).

(gosh I'm sounding a lot more negative than I mean to...)

The larger the diameter the wheel, the more the contact area... But you might be better off using the heavy steel base as your mobile base. By putting larger non rotating wheels in the back of the unit the whole affair will roll easier with the inevitable flexing of the floor. You can reattach the swivel casters to the outboard sides at the front of your 4x4s Leveling jacks can be 1/2" ready rod, pushing onto steel discs, or better yet a 2X2 angle iron to bridge the width between joists.

Sorry for redesigning your base, but I've had casters go through 3/4 ply before.

The 2x2 angle is a really good idea to span the distance between joist. The plywood floor is 2 layers so 1 1/2" total thickness and only 12 form center to center of the joist. I am adding 4 leveling feet to the square tubing that will use 1/2" or 3/4" threaded rod right beside each caster. I was going to have it come down to 3" or 4" diameter disks but I like the idea of the angle Iron spanning the length of it. It should sit across at least 3 joists no matter what. Sadly I didn't have the forethought when building the shop to mark out where the joist were. That would be handy to know. My yard slopes and the one end is 13" from the ground to the bottom of the joist. I have added more supports between the beams on that end of the shop because in all my infinite wisdom I put all the machining and welding stuff on that end of the shop and the wood working stuff on the other end so the tablesaw could be in line with the door. I have some pictures of the underside of the shop from when I was bracing up the end of the shop if anyone wants me to post them.

 

[Dabbler]

I stand corrected - 2 thicknesses of 3/4 ply is very much harder to flex and penetrate than one!!

I'm far less concerned about the plywood relaxing.

 

[Megar arc 5040dd]

I stand corrected - 2 thicknesses of 3/4 ply is very much harder to flex and penetrate than one!!

I'm far less concerned about the plywood relaxing.

1000 lbs is still a lot of weight even on 1 1/2" of plywood so anything I can do to spread the weight out helps.