[IJ.]

I've just picked up my new big Mill for CNC retrofitting and can offer this advice, Step back and think about it there is a way!

My driveway is too narrow for a truck and even if they could get one in there my garage is too low to allow a lift arm in!

I had them remove the head at the warehouse and load it into the back of my Ute (pickup for the US)
The rest went on my Trailer and off I went home.

My Mill is 1000 Kgs (2200 Lbs) I backed it into the garage and used a chain hoist to get it on the floor and then moved the Ute forward to another chain hoist and removed the head and lowered it to a garage creeper (thing you lay on to work under cars)

I wheeled the head to the main body and placed a 1" thick sheet of wood against the main body then used the chain hoist over the body to slide the head up and then over the body.

Once it was reunited I lifted one end and placed a sheet of 1/8 stainless under the body then used a long bar as a lever and slid it into position.

My point here is if you stop and think about it you'll find a way and above all else think safety, I did all this on my own 3 weeks after a minor surgery and besides it being a 30c degree day I breezed it in.

A guy that taught me about cars when I was a kid used to like the quote I think by Archimedes
"Give me a lever and a place to stand and I will move the world"

[Swede]

This project looks and sounds very cool. Thanks for sharing. Your retrofit plan sounds well thought-out.

Couple of questions: Your servos sound quite powerful... have you considered direct drive for the X and Y? The Z, given its mass, may require a geared motion with ultimately slower rapids than the X and Y, but with ballscrews you may be able to go direct and really get it moving. I suggest this as a means to really eliminate backlash, takeup, or other evil issues that come even with timing belts.

Second, what brand/grade of ballscrews are you going to go with? Is there room in the base, or will you have to mill out some CI?

One last thought - the ways are pretty and look to be ground. Have you thought about flaking them for oil retention? That would be easy to do, and probably fun to boot, with a $8 hand scraper.

Please keep the pics coming! Thanks again.

[JEFFY]

Quick question, fast screws and servos but what kinda of spindle speed does it have?

[IJ.]

Originally posted by JEFFY
Quick question, fast screws and servos but what kinda of spindle speed does it have?

If it's identical to the one we get here in Austrlia it's 95>1600 Rpm.

[SJ781]

Swede
I've thought of driving the screws directly but the software is not fast enough. I've changed from 500cpr encoder to 625cpr to get a resolution of .0001 which at 250ipm will require 42,000pps from the software it's max is 45,00pps. Also by running the servos at 2:1 It will help with acceleration which is where a lot of time is lost anyways. The ball screws are 1" precision ground preloaded nut .0005pf lead error. I just could not bring myself to go with .004pf lead error screws no specific brand just watching ebay and waiting and hoping. I have the y axis on hand the x is on it's way and still have not found a z axis ball screw. There is plenty of room for the z axis the y is a little tight I have to lower the screw for the ball nut to clear the housing and the x is going to be really close. I plan on putting rubber bellows over all the ball screws to keep the chips on coolant off of them. Since I'm buying off of ebay I have to check them when I get them just in case. To eliminate the slack in the timing belt drives I will put the encoders on the lead screw. I do plan on tweeking in the ways a little and checking them for squareness, especially the column since it is a bolt on item.

JEFFY
The max spindle speed for now is 1960rpms. Later I plan on adding a pwm dc motor and hope to acheive 5000+rpms May have to look into new spindle bearings and the gear head components. The thing runs nice and smoothe at 1960rpms so hopefully that won't change as the rpms go up.

Here is a pic of the underside of the base. I cleaned up the casting to allow for rellocation of the screw. The original had no support on the rear of the screw. The pic is of the rear of the casting. This is where the lead screw will attach and the servo will connect to the screw at this end. The screw will be supported on the other end as well but will not go through out the front of the machine. From the outside of the machine the y axis drive will not be seen at all. There will be a cover over the hole where the old screw used to protrude. It will be strictly cnc no manual work at all.

[SJ781]

Just finished one of the Y-axis bearing blocks. This one will contain two angular contact roller bearings for axial support on the lead screw. I built it on my round column cnc, it's slow but gets the job done.

[TyRex]

nice machining job!

[rvan]

I finally got my Mill, I purchased a the RongFu 45 which is the same model as the Enco, but it has a bit better travel and quality. I plan to use it just as a manual mill.

What a ***** it was to get that thing down into my basement. It took me a while to figure out how to dissemble it so I could carry it down into my basement. The column has to weight close to 300 pounds. The problem is that its difficult to find places to grip the parts to carry them, and everything is coated with packing grease.

Right now I have all of the parts in the basement. I need to construct a temporary crane to reassemble the mill.

[SJ781]

Well I finally got back to work on my project. I got the cabinet painted today and the base casting sitting on it. The cabinet draines to the center and it has 2 1-1/2" pipe nipples welded in for draines. The coolant tank and controls will all be located inside the cabinet. The coolant tank will be removable for filling and cleaning. It's not the best job but it was free. The place that built it let one of the new guys weld it and he got a little carried away. It left a few waves in the sheet metal. The owner said he would be glad to scrap it and build another one correctly but I figured it was good enough for what I'm doing. So he let me have it for free...Woohooo.. I tried to pay for the material but he would'nt let me told me to not let anyone know who built it. The frame was built out of 1-1/2 square tubing and then sheet metal was added to close it in.

[CNCPlastic]

This is my Lathemaster version of the dovetale mill, another knock-off of the Rong-fu 45. I finished mine a while back and its working great.

Some replies to some of the posts in this thread...

1. I would advise against switching from forward to reverse while the spindal is turning or at the very least check your china instructions over very carefully. I can switch it back and forth too, did in high gear, then someone told me the gears are not hardened and if I kept doing that I was apt to have a gear box blowout. I looked over my instructions and it stated in there clearly not to change directions while the spindle was turning. Just thought I'd pass that along. They do make models for tapping and they are advertised as such.

2. The head weighs about 220lbs without the motor, its the heaviest part, if you are working alone plan on using an engine hoist to reassemble. I attempted to lift mine once...I litterally heard something go crunch in my back and used the hoist thereafter. lol Two guys could probably lift it back on but then someone has to get the nuts on and tighten them up. I bought an engine hoist at the local auto parts store, you can get a nice one now for only about $200. I picked my mill up at the freight terminal and yanked it out of my truck with the hoist. Broke it down and used it in the basement to reassemble.

3. I moved mine to the basement, not difficult at all once you break it down in peices. Use a hand truck, I got one at Sears for only $20. Strap the head to the hand truck, its oddly balanced and you don't want it flipping off the hand truck on the way down.

4. If you plan to run flood coolant build a really big base table. Once the table starts moving with all that cnc gear hanging off it and some shavings get wrapped around the end mill and fling coolant all over hell you will be glad you did...I didn't! lol The footprint to contain flying coolant is pretty big. Hold on...I just measured mine which is too dang small, I would say once you get all the cnc gear hanging off it, 5 feet wide and 42 inches deep and a good 2 feet high.

5. The lathemaster head floats on a big round plug from the factory, that fits through the Z slide and bolts to the screw mounting block e.g. so the head/plug/screw mounting block float in the Z slide, e.g. its not bolted to the slide. This results in about .020 slop on my mill, thats fine for a manual mill since you will lock it in place but for cnc its not acceptable, no sense using a ballscrew on Z just to end up with .020 of backlash. IndustrialHobbies designed a fix for this which will bolt the head solid to the slide and eliminate this. I'm tearing my mill down in a week or so to send the parts off to them for the machining.

6. Plan on lapping the Z column, so far I have not heard of one that is true enough out of the crate. Mine is tight at the top and tight at the bottom, and thus when adjusted so it doesn't bind its too loose in the middle and pitches forward. The table was super right out of the crate but Z...I don't think they paid much attention since they figure people will leave it loose and crank the gib bolts down tight when machining in manual mode.

7. Consider building some spacers to extend your Y travel. Mine came with barely 7 inches of Y, I added 3 more inches for a total of 10, about 9.5 is usable since with cnc you need a little margin of safety if you are zooming the table around in rapids.

8. Dump the cheap china on/off forward/reverse switches, mine were toy like. I replaced them with some nice switches I purchased at Grainger.

9. That head/motor/slide combo is very heavy. I have a 1200 ounce stepper on top now via direct drive but I'm going to switch to a servo, you can lose steps trying to move that mass too fast or stop it too fast even with a stepper that large. I had to tune it to a reasonable acceleration and top speed to ensure that I don't lose steps. I have servos on x and y and they work super.

10. Last suggestion, Home Depot has a simply awesome workbench for the mill PC, a steel bench with two big shelves and two big drawers with roller bearing slides and a keyed lock, a nearly 2 inch thick hardwood laminated top (not hardboard, real wood), its about 50 inches long, all that PLUS big 4 inch casters. This has worked out very well, I can move the whole thing in close when doing setups and just roll it back a safe distance when running a part. For $99 there is just nothing better anywhere near that price. They dont always have them on display, the store near me did not, I purchased 4 of these.

Here's the mill part way through the cnc conversion


Here it is in action, thats a 10 inch rotary table if that gives it any scale, these mills are brutes! You can see the hoops I'm jumping through trying to contain the coolant, I drape half a shower curtain liner across the front. It doesn't look pretty but the floor is dry now. lol A larger table is in the works when I tear the mill down.