# Ferro brand 10" X 50" mill brought back to life.



## John Conroy (Sep 8, 2018)

Since it's a cold rainy day I thought I would re-do my old post about the re-furbishing of my mill. The original post was deleted after the great Photobucket debacle.

I had been looking for a bigger milling machine than my current PM932PDF and finally ran across a “Ferro” branded Taiwanese Bridgeportclone locally. I borrowed and tilt deck car trailer on just about the coldest day of winter (February of 2015) and brought it home with the help of my friend Darcy. It was a challenge getting this 2500 lb machine loaded and unloaded but we got it done. This is the only picture I took that day, I just plain forgot to take any others as I was stressed and cold.





It was in a pretty neglected state so a complete teardown ofthe table, cross-slide and knee was required. There was no crank handle for theknee so I made up this 9 spline adapter that can be turned with a 15/16” wrenchor a ½” square drive on a drill.


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## John Conroy (Sep 8, 2018)

I wanted it to be easily moveable so I welded up a base using 2” square tubing with ¼” wall. I welded ¾” nuts on the corners to mount wheels.









I made it in 2 pieces to make it easy to install without having to remove the wood blocks the machine was sitting on. I used 9/16”threaded rod to bolt the machine to the base. I had to make some tapered spacers to match the angle of the rounded top of the machine’s bolt holes.


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## John Conroy (Sep 8, 2018)

I tried using the same wheels I use to move my lathe and thePM932 mill but they proved to be not strong enough, the bearing outer races split due to the weight of the machine. It weighs about twice as much as the other machines. Even after I machined some steel tires to protect the outer races. I came up with a solution for this which I will detail later. The ball bearing wheels lasted long enough to get it into a good working position.


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## John Conroy (Sep 8, 2018)

Since the motor is 3 phase I bought a cheap Chinese Hyanyang VFD to convert the 240 volt single phase power in my garage to 220 volt 3phase. I completely gutted the electrical box on the machine and went to work using the crappy instructions that came with the VFD as well as a lot of research done on the internet. I mounted the existing electrical box on a swingarm and re-enforced the bottom sheet metal with a piece of ¼” by 2” steel.



















I removed the digital display from the VFD and mounted it in the door of the box and used 2 latching switches, 1 momentary switch and a 10,000 ohm linear potentiometer to provide the functions I wanted. It has 1 switch for ON/OFF, another for FORWARD/REVERSE the momentary switch is for JOG and the pot is for the variable speed. I kept the maximum frequency for the motor to 60HZ as the mill has a variable speed head. It wound up looking like this when I was done with it and it works great.


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## John Conroy (Sep 8, 2018)

If you are familiar with VFD set up, here are the settings Iused. I chose not to run the motor at more than 60hz.





Next I moved on to the table, cross-slide and knee. I used my engine crane to remove these heavy parts and found that the bevel drive to lift the knee was completely full of chips. I still can’t believe it worked like this, and pretty smoothly too!





Here are some pics of the process I used to remove the knee.


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## John Conroy (Sep 8, 2018)

I used engine shampoo and a pressure washer to clean out all the mess inside the knee.






All the parts were in good shape with only cleaning and new bearings for the bevel drive shaft required. I cleaned out and re-used the bearing on top of the knee jack and installed a plexiglass shield to keep the chips off the bevel drive area in the future. I reinstalled the knee and adjusted the gib. I used lots of high pressure moly-grease on the bevel drive gears.


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## John Conroy (Sep 8, 2018)

More to come later.


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## John Conroy (Sep 8, 2018)

The Y axis lead screw and bronze nuts were completely worn out. I found out later that many Taiwanese mills use this same weird size threaded shaft for the screw. It is 32mm diameter but has 5 TPI acme threads, not the metric trapezoidal thread you would expect on metric sized shaft. The nuts are available for a reasonable price but not the screw. I wound up buying a 3 foot length of 1.25” acme threaded shaft locally and ordering 2 left hand thread nuts from Roton Industries, who were, by the way, great to deal with. The nuts were not the correct dimensions on the OD but were the correct 1.25”left hand acme thread to fit the shaft I bought. Since 32mm = 1.259” this seemed a good way to convert the shaft to a standard size. When the new nuts came I machined them to fit the mill’s feed nut bracket. I then machined the new screw shaft to match the original shaft’s dimensions and milled the keyway slots. I bought new RH thread 32mm nuts for the X axis from Supra Machine Tools on eBay. They were nearly a straight drop in part with only the bolt holes pacing needing to be modified.


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## John Conroy (Sep 8, 2018)




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## John Conroy (Sep 8, 2018)

Polishing the threads.





Test fitting.


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## John Conroy (Sep 8, 2018)

Cutting keyways.





























Original shaft and new one.


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## John Conroy (Sep 8, 2018)

New bearings.





Shaft installed and backlash adjusted. Works perfectly!













To be continued.

John


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## Dabbler (Sep 8, 2018)

very nice rebuild - a lot of work very well done!


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## Tom O (Sep 8, 2018)

Well done!


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## John Conroy (Sep 8, 2018)

Thanks guys, I'm considering a complete tear down for a re-paint this winter.


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## David Henry (Sep 8, 2018)

Thank you so much for posting these great pictures. I enjoyed looking at your handy work.


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## RobinHood (Sep 8, 2018)

Excellent job!


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## Chipper5783 (Sep 8, 2018)

Very nice work.  Thank you for sharing the photo progress.  David


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## PeterT (Sep 9, 2018)

Wow John. When you see the pics laid out in start to finish manner, its evident how much TLC effort you put into the mill. And now you have an awesome machine. Thanks for posting.

Re the legacy chips buildup over the lead screw / nut area, did you get the impression there was supposed to be some sort of cover that was missing. Or maybe a certain job setup where they migrated down? Could a guy even have a peekaboo in there once in a while by retracting the table & removing a cover, or does it require a more extensive table removal like the point you were at?


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## John Conroy (Sep 9, 2018)

There is a kind of layered cover over the bevel gears you can see in the last pic. I guess some chips get by it and over 30 years of use with no maintenance they build up. You can look up into that area from underneath the knee with a mirror or by removing the knee lead screw. When I had the leadscrew out to intstall the power feed there were no chips there so my plexiglass shield is working as I've been using the mill for 3 years like that.


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## John Conroy (Sep 9, 2018)

To carry on with the repairs, I found that 1 of the 4 bolts that holds the head to the ram was broken off. They are 1/2" by 7" with square heads so I had to order them from the bolt supply place. I used my Vertex super spacer and a 7/8" rod in a collet to move the head away from the ram. I put a small piece of plywood on the table in the center hole of the super spacer chuck and put the 7/8" rod in the chuck with the rod projecting all the way to the bottom and resting on the plywood on the table and tightened the chuck. I put a 7/8" collet in the spindle and raised the knee so the rod entered the collet and tightened it up. With the spindle all the way to the top of its travel and the spindle clamp tight I loosened the 3 remaining bolts holding the head to the spindle and raised the knee slightly to release the pressure on the bolts. Then I used the Y axis to move the table outward and bring the head away from the ram. The table has a 800lb weight capacity and the super spacer and the head weigh about 500 combined so I wasn't too worried about damaging anything.. I slid in the new bolts and cleaned and lubed the worm gear that allow tilting the head side to side and the reversed the process. Once I was started the head was away from the ram for about 15 minutes.

OK I was a little nervous as you can see I slid some wood blocking under the head but it really didn't do anything as the set up was very solid without it.





































I used some hardened washers from big block Chevy head bolts opened up to 1/2" from 7/16" and long nuts to engage all the thread on the 7" bolts. I smeared lots of moly grease on the worm gears.









Then I loosened the chuck on the super spacer and lowered the knee, all done!


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## John Conroy (Sep 9, 2018)

The m5 screw in the end of the power down feed direction change shaft was broken off and the little pull handle was missing. I drilled a 1/8" hole in the center of the screw and then found that my smallest easy out was broken so I used a #1 Robertson screw driver bit and tapped it into the hole and the screw turned out easily. I chased the thread with a tap and made up a new handle. With the handle pushed inward the power down feed goes down and with it pulled outward the feed goes up. The hand wheel was missing too.

















New handle installed.


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## John Conroy (Sep 9, 2018)

As I said earlier I wound making a heavy duty set of wheels to move this beast around. Some 2" square tubing with 1 side removed. Some solid steel wheels with 2" OD and 1" ID and axles with 1/2" nuts on the ends. These thing will not bend! A good coating of moly grease and the machine rolls pretty easily on them.













To move it into it's final resting place I jacked up 1 side at a time and thread the wheels onto the 3/4" threaded rod I have for leveling. I use a floor jack with the axle cradle removed to do the lifting. When the machine was out in the middle of the shop I lifted the front first then the rear but after I rolled it back to the wall I lifted 1 side then the other to remove the wheels.









I had to move the Ferro out of the way so I could get my small PM932 mill out of the way.













I just turn the wheels in the direction I want to go and use a long pry bar against the floor and bottom of the stand to get it rolling.













I used machined cups under the threaded rod for a solid foot for leveling and then added hockey pucks under those for vibration dampening.


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## John Conroy (Sep 9, 2018)

I added a quill travel DRO starting with using epoxy to bond a threaded boss to the quill stop piece that travels with the quill. I used the existing hole you can see in the first pic and machined a boss to fit in the hole and used some blocks and an angle plate to get it square and let it set overnight. I also picked up a 4” hand wheel and drilled a hole for a pin to match the one on the face of the power down feed flange. I had to turn a little off the OD of the hand wheel to clear the scale and I knurled the OD while it was in the lathe.





















I made the mounting bracket from a length of 2.5” aluminum tube and got the scale at KMS tools. The quill has 5” travel so I bought a 6” scale.


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## John Conroy (Sep 9, 2018)

I made some stainless sheet metal grilles for the head to replace the broken plastic ones.









A little too shiny for this old girl but they will get dirty soon enough.


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## John Conroy (Sep 9, 2018)

After using the mill for a year or so I decided I like it enough to invest in a 3 axis DRO. I bought a Sinpo brand on ebay and it has been trouble free and accurate for a reasonable cost.













I won't bore you with all the details of installing the scales but it was an all day job to get them square to the travel of all 3 axis within .002". Lots of drilling and tapping and making custom brackets.


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## John Conroy (Sep 9, 2018)

I installed some way covers to keep the swarf out of the works. eBay purchases.


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## John Conroy (Sep 9, 2018)

And the latest update is the z axis power feed to help with my bum shoulder.


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## PeterT (Sep 11, 2018)

John, I read through your power knee lift pictorial again.
Is it safe to say all of these units will require drilling cross hole through shaft for the drive gear (roll pin)?
Any reason to think brand X might be different than brand Y - ie. you buy a different unit in the future & the hole no longer lines up? Or that can be accommodated by different shims?
Does the power drive in any way prevent ability to re-set the dial to a new reference position?


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## PeterT (Sep 11, 2018)

I noticed you use the limit switches on power X travel. I am a bad boy & mine is hanging behind the mill. I use my homemade 2-position hard stop quite often & I don't want to give that up. I guess the downside is I cannot invoke power feed & then go answer the phone  Have you figured out a way to integrate or are your limit switches triggering accurately enough that you trust them to stop consistently? Seems to me when I tested this it was kind of spongy +/- too much for my liking.


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## John Conroy (Sep 12, 2018)

The kit comes with an extension for the existing z axis shaft. It threads onto the existing shaft that has 34" 16tpi threads. According to Matt at Precision Matthew's most of the Taiwanese mills use the same threads and this kit will fit them. He asked me to check my mills thread size before ordering. I'm pretty sure the kits are all very similar no matter the brand. The only part that would wear would be the bronze gear and its keyed to the shaft, not pinned so it could be easily replaced.

I never use the limit switches and i never thought of making a hard stop in place of them. Great idea! Now I've got another project.


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## Dabbler (Sep 12, 2018)

Be careful that you hard stop doesn't jam the drive. The gears are vulnerable to stripping if jammed while the servo is still turning!


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## John Conroy (Sep 12, 2018)

I would only use a hard stop while hand feeding, for sure.


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