Milling Machine Counterbalance Upgrade

[ri702bill 7,275]

Seems that this was the weekend for Milling Machines! I finally finished my sprocket & roller chain counterbalance. This is on top of a large tabletop milling machine where there is no movable knee to raise and lower the table; instead the head itself travels up and down on dovetails of the fixed column - total travel is about 12 inches. I wanted to make it easier to lift the head - it has an acme leadscrew and nut. The counterweight is a cut down actual elevator weight, now weighs 41 pounds. Had the room to add an Oilcup with an extension tube over the leadscrew  - used a 1/4" brass twisted tube brush as a wick to slow the exit of the oil. The proof is in the before and after torque numbers  this device cut the force to lift by 2/3rds - from 60 inch pounds to now 20 inch pounds - the down torque was cut by half, from 10 inch pounds to 5 inch pounds. Added the two clear Lexan angles this morning to keep the chain free of debris.

Bill

Edited November 1, 2021 by ri702bill

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I'm impressed!! Thats pretty ingenious .... and  -- for dang sure a big help. 

 

I had an "Induma"?? (not sure If I remember the spelling) made in Italy? Anyhoo, the crank to raise the table took 2 turns to raise what the Bridgeports etc took. Trying to raise the table more than a couple inches would have you gasping for breath...... The handle did come off like other mills, so I rigged up and old Milwaukee 1/2" hand drill and adapted a way to stick the drill on and pull the trigger..... that really turned out well. Was main reason that when I got the Enco mill, I quickly put a power feed on the knee, along with the other 2 on table.

[ri702bill 7,275]

Thanks. I have added a power feed only on the X axis because I still have a handwheel on the right end. No such choice on the Y and Z, each has only 1 handwheel each.

Bill

[echris 1,425]

That is freakin' beautiful, simple, mechanical solution.

My old neighbor taught me a few years ago about saving the old lead sash weights from windows to use as a drill press table counter weight.

This video is kinda funny. With the PO's repair on the drill press table (you'll see it in the video), I didn't think I could easily one-hand it even with the counter-weight, since it tends to bind on the column.

While recording the video one-handed, I accidentally found the exact correct spot to lift the table so it wouldn't bind.

Result: Counter weight project exceeds expectations!
Profit.
 

 

[ri702bill 7,275]

Thanks - I was going to use coated wire rope (cable) and grooved pulleys, but the #40 roller chain and idler sprockets were only a few bucks more - no fiddling around with thimbles and cable clamps. And I already had 2 of those Elevator weights.

There is a company named Tormach that sells top of the line small Machine Tools - this type of system is built into their Milling Machine from the factory.

Bill

Edited November 13, 2021 by ri702bill