Tree 2UVR-C head rebuild

[nc5a]

This is a followup to the Tree ram repair post in Jan 2021. I tried to attach the link to that post but couldn't get it to work.

The initial plan for the head was to retrieve the spring clip I dropped in the spindle housing, install new belts and change oil in the gear box. But that wasn't in the master plan as you will see. The **** hit the fan (so to speak) when I pulled the cover off the gear box and discover the spindle nut was damaged and loose and machining a nice groove in the gear box cover. Also the driven cogged sheave appeared to be setting proud of the mating surface for the gear box cover and was therefore doing some machining of it's own in the cover.

spindle nut

under side of gear box cover


So I decided to bite the bullet and do a complete rebuild and repair. After all I already had a couple grand in repairing the ram Tee slot and worm wheel.

Photos of the head before cleaning and repairing.
looking into the gear box

parts and pieces



More to follow.

[nc5a]

Parts cleaned and layed out for inspection.

cracked discovered in the yoke mount.

close tolerance bushing to to keep the bore and counter bore clean during welding process.

bushing installed and prepared for welding.

welding done, yeah it's ugly but when cleaned up the repair was solid.

[Fasturn]

Love it !! TREE.. best knee mill ever. Made alot of money on one of those. Owned a lot of Bridgeports, but this mill was solid and accurate. Congrats !

BTW. NC5A... is that Ham Radio? 73'

[nc5a]

All the radius Tee nuts in the yoke needed to be hand lapped to allow smooth nodding of the spindle housing.



All new parts were ordered, bearings including spindle bearings (upper and lower), seals, gaskets, thrust washers, belts, keys, spacers, gear box oil level sight glass and new nuts, bolts and screws where needed. When the parts arrived it appeared one of the thrust washers had been up graded to a thrust bearing. This is when the trouble began.
new thrust bearing

old thrust washer

tower with the bushing in it is where the thrust washer rides which has a constant spring loaded thrust on it.

[nc5a]

So right away there was machining to be done because the thrust bearing was considerably thicker than the thrust washer. To make matters worse my other mill a K&T 2H didn't have enough clearance between the table and the head for me to machine for the thrust bearing. So I had to do it by hand with a battery powered drill, specially ground wood spade bit silvered soldered to a guide bushing. The following photos will give you the idea of what I did and how I did it. When the smoke cleared I took off .006" more than I wanted to but not too bad for a hand controlled milling operation.



Before machining

After machining


More later I have to catch a flight back to Alaska.

[nc5a]

Love it !! TREE.. best knee mill ever. Made alot of money on one of those. Owned a lot of Bridgeports, but this mill was solid and accurate. Congrats !

BTW. NC5A... is that Ham Radio? 73'

NC5A is the model number to my first patented product.

[mattthemuppet]

that piloted spade bit is a very clever fix. Finish looks really good too! I made a piloted reamer out of O1 once that worked really well, but that was on alu, not CI.

sounds like alot of work but you should be good to go for several more years once you're done

[nc5a]

that piloted spade bit is a very clever fix. Finish looks really good too! I made a piloted reamer out of O1 once that worked really well, but that was on alu, not CI.

sounds like alot of work but you should be good to go for several more years once you're done

The Tree gear box housing is aluminum allowing the piloted spade bit to machine the tower with relative ease.

[nc5a]

In addition to machining for the new thrust bearing it was necessary to deepen the counter bore for the seal or trim the seal. I elected to trim the seal.

I had this lap laying around from a previous job that was the correct size so I slid the seal on and applied pressure with a piece of EMT, ran the lathe in reverse and trimmed the seal with a narrow cutoff tool.


trimmed seal in the foreground

[mattthemuppet]

gotya, that does make life a bit easier. Cool to see all the different solutions to the problems you're finding.

[Doozer]

nc5a -
You do great work.
I would love to find a decent Tree mill.
I will keep some of your repair techniques in my mind.
Thanks.
--Doozer

[nc5a]

nc5a -
You do great work.
I would love to find a decent Tree mill.
I will keep some of your repair techniques in my mind.
Thanks.
--Doozer

Thanks Doozer,

Speaking of Tree mills. I spent the last 12 days in Cleveland OH and while there I checked out a Tree with the hope of buying and reselling it in Alaska. I didn't buy it because of price but if I lived in the lower 48 states and been able to get the price down a bit I would have. It was in pretty good condition, a little head noise probably generated from belts, pulleys, keys/keyways or bushing wear. I didn't pickup on any clearly identifiable gear or bearing noise. There is some rust on the ways but in the rust free area the factory scraping is well defined. There's a couple pin hole marks in the table but otherwise pretty clean. I didn't run the power feed because I had no way to clean the rust off or verify motor rotation (the rotation window was too dark to see through).

[nc5a]

All bearings including new spindle bearings are installed and ready for reassembly of the gear box.
The T-handle wrench is holding the 2 spring loaded bronze shifting forks down so the hold down bracket can be installed.

hold down bracket installed.

another angle looking into the gear box

Gearbox assembled and ready for the cover

Gearbox cover and driven pulley and belt in place

[nc5a]

Now for the unique Tree spindle drive arrangement. Tree uses a drive hub with 4 square wheels held in place with eccentric pins and secured in place with spring clips. The square drive wheels slide up and down a splined shaft which turns the spindle. The eccentric pins allow the square wheels to be moved toward and away from the splined shaft thus allowing excessive backlash to be removed. The spindle can also be adjusted to reduce runout with careful adjustment of the square wheels.
bottom of the drive hub


Drive hub engaged with the spindle spline. Parallels allow one last check before gearbox and drive hub are seated on the spindle housing.

Square wheels

Head back on the ram. The ram is sticking out so far for easier access and hoist limits.

[nc5a]

Another view of the bottom of the gearbox

Notice the burrs on the gear teeth. The third time I took the head apart because of excessive noise. I deburred each tooth of each gear then blended the previous wear pattern of each tooth on each gear with 600 grit paper followed by a 800 grit stone. The idea was to provide a fresh surface for the gears to lap themselves in. It appeared to work quite well because the longer I ran the mill the quieter it became. It's not as quiet as some of the new Bridgeport clones I've been around but it's not too bad for a mid 70's vintage machine. Especially one that started it's life in a Boeing machine shop.
lapped and polished gear

One of the gears prior to deburring and polishing.

Lapped and polished


It was very time consuming but worth it.