Need Help!- RF BenchTop Colume Mill/Drill Post Headaches

[skip20]

Pictures would be good on these great ideas.
Will be changing from 460 stepper to 39V servo in the near furture.
Skip20

[BrendaEM]

You could add a second column almost a foot behind the main column, to keep the main column from turning.

I would think that a length of drill rod, 1/2 to 3/4 inch drill rod, gliding on some drill bushings could make a fairly tight sliding situation. Brackets could be made that would be bolted on the back of the machine.

The challenge would be to make a bracket that holds the rod on the top and bottom, while the head/spindle rides in the middle of the rod. The bracket would probably have to be triangulated to make to strong against the head's tendency to rotate about the Z-axis.

The rod would have to be quite parallel with the big round column. I would think that the spindle/head would have to be ran up and down a few times to ensure this before it's final attachment.

The drill bushings are nice because they are hardened, but using flat blocks would over-constrain the head less, with a lower chance of binding it. Some kind of slotted adjustability, like milling slotted slotted screw holes in the blocks would allow them to have drift adjustability, so you can take the slack out. You would want enough contact area to take the wear, so you won't have to keep adjusting it.

It would seem that the longer the brackets are from the column centerline, the less rotational/angular slop there would be.

You might be able to figure out a way to cap-bolt the whole thing together.

[ZipSnipe]

one of our members slotted an HF round column model but I don't remember who it was. But that seemed like it worked best.

[skip20]

Using 1/8" angle, I mounted 2 roller bearing to fit the rack.
Then mounted to the top & bottom of the head.
NO LEFT OR RIGHT MOVEMENT OF HEAD.
Also have the rack bolted top & bottom & pinned in 3 places to prevent side movement.
Haven't tried it under a heavy cut as yet, but hope this fixes the headache!
Included pictures show the chain drive Power Lift I built for it a few years ago, this works great & works on AC.
You can also see the 2.5 HP DC motor I mount.
Last picture shows most of the mill.
It was CNC over 7 years ago with 460 stepper X&Y & 150 stepper on Z.
Also have a power feed on X & can still use it manual.

[BrendaEM]

Skip 20, What an elegant solution : )

[acondit]

Skip,

I second BrendaEM's comment. An elegant solution.

You could still tighten the column/head bolts to avoid movement and loosen them to raise or lower the head. I would only add a little time to the raising or lowering of the head and provide some peace of mind.

Alan

[skip20]

I do still tighten the 2 head bolt, however I changed to 2 grade 2 nuts & bolts with Grade 8.
I had to use a mig welder to add to the size of the head on the bolts to match the recess foe the head. Had to reuse the stock washers due to size but used Grade 8 nut.
I loosen the 2 bolt & boy the motor makes it easy to raise or lower the head, then tighten the bolts.
No more play in the head assy. now.