Tree Vertical Mill 2-UVR
December 20, 2006 - Just under a year ago I bought a Mid-sized Harbor Freight Mill. I liked it but recently found a 60's era Tree mill with DRO that was in fabulous condition for a price that I could not resist. Now I have to figure out how to squeeze it into my garage.
OK, got it home with no trouble.
Backed up to the driveway.
Put an anchor in the garage floor.
Here's my son providing the muscle.
Here's my Dad adding more weight... err uhh. I mean supervising.
in the garage on rollers...
Done! wasn't nearly as hard as I thought it would be.....
The mill uses "Z" collets instead of the R8 type like Bridgeport and all the Bridgeport Clones. When I got the mill, the guy I got it from gave me what he called "a full set of collets" and assured me "you can buy them all over the place". Well I've should have checked each one, I really only got two that were usable - a 3/8" and 3/4". The rest were all odd sizes like Letter sizes and such. Of course the first thing I needed to machine required a 1/2". I checked around on the internet and found a couple of places to get them but I needed it quick so... I made one.
1/8" collet on the left that I got with the machine, 1/2" on the right that I made using cold rolled steel. Took about an hour.
Worked Perfect!
One of the first projects for the mill was to machine a small fixture to be utilized for testing a plastic part. Kind of like a nest.
August, 2007
I decided to add CNC capabilities to the Tree Mill. It took awhile to evaluate the mill to see how feasible this project was going to be but it looks like it's doable so, here I go.
The plan is to replace the X and Y axis acme screws with Ball Screws, which requires a total redesign of the table end castings to accommodate the new screw and the angular contact bearings required to remove all the backlash. When I got the mill, the backlash was a surprisingly small .005 inches. Excellent for a hand-cranked mill (especially one that has been in use for 40+ years) but that's still too much for good quality CNC machining.
I purchased new ball screws and nuts from HIWIN, that were made to be replacements for a Bridgeport mill. They were the closest I could find to the Tree's. I found angular contact bearings from VXB.com and with all that in-hand, I was able to design end castings that will make them all work.
This is the casting I'll be replacing:
Here;s a CAD rendering of what it will look like:
Here's the pattern I made for the end castings. I'm casting them from A356 aluminum.
Here's the result:
Machined and ready to install - the other side has a deep pocket machined ready to receive the angular contact bearing needed to remove any play between the new ball screw and the table. The part was sand blasted with aluminum oxide, treated with Alodine and coated with clear acrylic.
