Setup - Round Deux
Due to some rattling/noise issues Matt graciously arranged to ship a new mill head. Finally got time to play Tetris in the shop (move equipment to move more equipment to maneuver crane without crashing into the garage door opener).
I liked the idea of a mill head removal post. Seemed like the best compromise to get the head off and on while ensuring proper alignment using the table.
You use a 3/4 collet to secure the head.
The head is back heavy with this solution but the post is robust (slotted/welded and heavy gauge steel). Seemed fine to me. I'll definitely use this solution when rebuilding or doing invasive repairs - will build a fixture to hold at normal human height. H&M Machine Repair supplied the post (and a wealth of instructional videos on YouTube).
Part of the weekend project was replacing the leveling shims with leveling feet. Shims work but we found that we were tripoding even though we were level (didn't notice at the time). Leveling 4 points can be tricky with heavy stuff. Leveling a lathe requires voodoo I imagine. Our garage floor is really sloped - shims were a pain.
Strongly recommend planning heavy lifts beforehand...the potential for serious injury is very real. We got some wheel chocks for the casters which worked out very well.
The design of the foundation helped a lot. We did a prior lift to store the new mill head on a table in order to put the old one back into the shipping crate. The hole in the wall is the result (less than 400 lbs and the crane got away from us). These knee mills are front heavy (as I suspect all mills are) so a lift will usually involve some lateral loads. Plan for that and make sure whatever you are using to lift has enough headroom for some lateral loading. No joke with 3k lbs.
Found this to be an excellent way to lift a J-head. 6 foot strap double wrapped. We're a little vertically challenged in our shop (I can move the crane up 6" but then we're dodging light fixtures and as of yet don't have the bottle jack mod to actually lift the I-beam). So we needed all the headroom we could get. This worked really well...very secure and balanced.
Mounting the new one. The installation post makes this really easy with a mill table's precise movements.
Did one more lift to install the leveling feet. Cribbed H&W's design with some 1x3" steel bar.
Measure, cut, bore, thread.
Finished product with leveling feet attached.
Leveling feet with cantilevers installed. Super stable and easy to level. Looking forward to many years of service in our metal fab business.
Note: new head is running much more smoothly, spindle action up/down is smoother, pdf engagement is better. The TV heads are convenient and the design is robust and simple. The variable pully design does introduce some noise and vibration into the mix just to set expectations. I think a TS and VFD is a better solution if you have the technical ability and patience to handle the install.
