# RF 30/31 Milling machine rebuild



## Investigator

First, let me say thanks to basically everyone on this site.  This really has been the best site I've found.  With that in mind, I thought my meager accomplishment might help someone else.  Mods, if this is the wrong place, feel free to move it to the right one.

Some months back I bought a round column milling machine sight unseen from an online ad.  The basic story on it was that the guy selling it had gotten it as partial payment for some work he did.  he had never actually used the machine.  So, I got a good deal on the initial price.  Here it is after we loaded it in my truck for the drive home:






And after unloading it in my fathers shop (he had more room than I did to work on it):











As you can see, the name plate is missing.   I'm not 100% sure who made it, but I have a pretty strong suspicion who.  The machine was dusty, with a very light coating of rust on the table.  Motor was wired for 110VAC single phase.  

Since I didn't know what kind of shape it was really in, and it needed a good cleaning, I decided I would be money ahead if I went ahead and rebuilt/clean/repainted it.  My main worry was the bearings and spindle.  

So, everything came apart for cleaning.  The paint was flaking off and looked to be crazing especially above the hand wheel on the right side.  The primer under it looked like to be a sickly teal/turquoise color.  I decided to strip the paint completely and start over.  You can see on the column base, it looks like a solid piece although I knew it was not. Looks like they used a lot of filler to make it smooth:





The disassembly begins ....................


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## Investigator

I carefully took everything apart.  the spindle was the most concerning dissasemble since I had never done it.  But I found some tips from other threads on this site:
Canuck75 thread replaceing quill bearings
Mikeys spindle bearing replacement thread
Mikeys drive sleeve bearing replacements

The above are where I found the information to pull my spindle.  After getting the motor and spindle off the head, it was just a matter of cranking the head up until I could use an engine hoist to pull the head housing off.

The table was pretty easy to get off and apart, especially after ready this:  Rick Sparber- moving a mill drill

Then, its just a matter of taking the column off the base.  
	

		
			
		

		
	





The column is heavy, don't let it fall on your foot. The bearing section of the column looked dirty.  I cleaned it with purple power and then wrapped it in shop towels soaked in Evapo Rust. 
	

		
			
		

		
	





	

		
			
		

		
	
 After a day or so, I took the towels off and rinsed it. It had some black marks on it, but nothing you could feel.  All the (very light) rust that was on it was gone.

The base of the column was painted and had lots of body filler material on it.  It all got cleaned off.  The base also had lots of filler.  Here you can see how thick it was where it met with the column:








It was very soft, and came off with a wire brush easily. 

For stripping paint, I used Aircraft Remover.  It ate through the paint really fast.  I used latex gloves, and ended up getting some chemical resistant gloves at Harbor Freight.  I recommend the thicker gloves.

When I was researching this mill and planning the rebuild, I read in a few places about stiffening the mill with epoxy-granite.  For those who don't know, folks mix crushed granite and sand with epoxy and let it harden.  Supposedly this is better than just using concrete because the epoxy mix doesn't shrink like concrete does.  I'm not sure if it works or not.  But, I already had the machine apart...........
I decided to fill the base with the epoxy granite while I had it in pieces.  I had read, from some who had done this, that filling the base reduced flex more than filling the column.

So, up next Epoxy fill......................


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## Investigator

The epoxy-granite fill.   From what I have read, there may not be a more divisive modification to a mill/drill.  It seems people fall into one of two camps...."It's silly and can't help anything", or "It's the greatest improvement to get rid of vibration and add stiffness in the history of ever".  I really don't know which is right or wrong.  My thinking was that

I was in a good position to do it since I already had the machine torn down. 
It wasn't too terribly expensive to add to the overall cost of the rebuild
I was reasonably sure it wouldn't hurt any thing
Here is a good place to read up on this, and honestly this link was the reason I decided to do it: CNC Cookbook epoxy granite filling a mill/drill

Before doing the epoxy, the base was stripped and repainted.
	

		
			
		

		
	





	

		
			
		

		
	
  I decided to update the color from greenish blue to off white.

As far as cost, I bought a 2 part epoxy, one gallon of part A and one gallon of part B.  I used about 3/4 of each gallon on this.  The mix proportion was 50/50.  For filler I used play sand, almost an entire 50 pound bag.  Several places on the web will speak of various ratios of sizes of aggregates.  Do some research if you want to try this.  I found one site that basically said for filler that anything was fine.  I mixed in small batches and poured in sections.  I used as much sand added to the mixed epoxy as I could mix with an electric drill and metal paint stirrer.















I used plastic pipe over all the mounting holes.  My thinking was that if I was off on the alignment, I could drill through the hole and clean the inside edges of the plastic much easier than if it were metal tubing.

The base had to cure for over 24 hours.  the epoxy's chemical reaction generated heat.  the shop was cooled with a window unit AC, the base of the mill was over 20* F higher temp than the room or other material in it.


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## Investigator

I'm telling the story a bit out of order.  The epoxy fill was actually one of the last things I did before reassembly.  Let me back up and talk about repainting.....

My color selection was based on 

what I could get in a spray can
what I liked that fit No. 1
I originally went to Tractor Supply and got some of the Majik brand spray paint.  I used an almond/off white color since that seemed to be the current factory color of the RF-31 I found on line.  I painted the head first.  It was cleaned, stripped, and very warm from sitting in the sun.  After spraying, I let it sit for about an hour before bringing it back in the shop.  It wasn't completely dry after the initial hour.  Outside temps were 80*F plus.  After sitting all night in the shop, it was till tacky.  I was trying to do a 'pin stripe' on it just for kicks.  Pulling the painters tape off removed the paint. 




 I stripped it again and started over. 

This time I used Rustoleum Industrial spray 
	

		
			
		

		
	





	

		
			
		

		
	
 Very happy with this paint.  Dried to touch in less than 20 minutes, dry enough to handle tape the next day, probably within a few hours although I didn't re-tape until the next day.

As I said, I wanted a pin stripe look.  So I painted the almond then taped for a stripe.  Within that area, I used some cheap letter and number stickers from Wal-Mart and marked it.  I really don't know if this machine is an RF30 or an RF31 but I don't really care either.  I'm not trying to sell it, and I will fully admit what I have done to anyone if I ever decide to sell it.













The base got a similar paint and stripe, although with no letters.  The column base was painted also:





I would not hesitate to recommend the Rustoleum brand industrial paints.


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## Investigator

Oh yeah, the tables were also stripped and painted:






When i reassembled the base to the column, you can tell why they used so much filler













I replaced the column to base bolts with Grade 8 bolts.  Interestingly, at least to me, they were not metric.  They were 5/8 as I recall.


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## kvt

*Investigator* I a watching this with interest.   I am supposed to be picking up a RF30 next weekend.  it is coming with all kinds of items   D40 kurt, Albrech 0 5/16 chuck,   Collet sets, end mills etc    Problem is that it has all been sitting in a shed for several years not even looked at.   Thus I do have some rust to clean up where there was not enough oil etc on things.    Lucky The old man that had it had kept the table covered and so little rust on it but the top of the vice has some.    Brought some of the stuff home and have it in evapo rust and others in Vinegar now.   Will see how it goes.  
LIke your paint but will prob go back with more original color or something to match my lathes.   
Keep it coming so I know what I'm doing.


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## Investigator

The biggest issue, at least in my mind, was the spindle and bearings.  With some very much appreciated help from Mikey, I ordered some new bearings.
Did it need new bearings?  Honestly I don't know.  I really have no idea what kind of shape the bearings were in.  I didn't even test the run out on them to see if they needed replacing.  I made the decision to replace the bearings because I could get permanently sealed bearings and never have to worry about re-greasing them. Also, new bearings could be had with very high accuracy, there was almost no chance that the new bearings would not be better than the existing bearings.

My bearings were the same as Mikeys.  I could have ordered cheaper bearings but I went with German made FAG bearings.  I could not find them anywhere but 123bearing.com  They are located in France.  The bearings were expensive, I paid almost $200 for bearings and shipping.  I could find other bearings that would fit at other places, including Ebay for much cheaper.  But I chose the higher quality higher accuracy FAG's. 

One note on ordering from 123bearing.  Because it is an out of country order, I had to call my bank and authorize charges to France.  It wasn't that hard, but was kind of a pain in the backside.  But it all worked and they sent me a free ink pen, I have found that it will right in French and English. So I have that going for me (which is nice).

The bearings that came out were tapered roller bearings




	

		
			
		

		
	
  Honestly, they were likely fine.  But now I have no worries or doubts about them.

If you read the linked threads you can see that Mikey and Canuck75 had different assembly orders for the threaded retaining nuts on top of the spindle.

My assembly came apart in the same order Mikeys did, which is the same order shown on the parts diagram.  With that said, I put it back together like Canuck75.  I believe the tabbed washer is meant to hold both of the nuts.  I put on a nut, then the washer then the last nut and bent the washer in place over both nuts:






Other than that small difference, I did everything as Mikey outlined in his thread linked above.

EDITED TO ADD:

I forgot to show how I screwed up.  When pressing the bearings out of the spindle, I got ahead of myself and did not remove the retaining cup from the bottom of the assembly.  Mine was some type of pot metal.  I say was, because I thoroughly broke it.





This brought up a bit of a problem, since I wasn't completely sure who the manufacturer was of this machine.  I looked at several comparable Mill/Drills on the Grizzly Tools site.  Some had parts available, some didn't.  I found one that matched the one I had at least in appearance and ordered that part from Grizzly.  The part I got from them was plastic not metal, but it threaded right on just like it was made for it.


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## Investigator

I replaced the belts on top.  I used the green link belt.  Not sure if it is better or worse than the red link belt, but it was a lil cheaper.  the original belts had taken a set and were pretty stiff.

The switch was re-installed and re-wired as original





The down feed spring was actually pretty easy.  It is just a coil spring that you tighten once it is on the machine.













While I was working on the machine, I asked my father to build a stand.  I wanted drawers for storage and he delivered.  I used a 2x3 foot aluminum drip pan from the auto parts store on top of the stand to catch any swarf or liquids.  I painted to drive enclosure just to  make it all new looking and I added a 4" vise.














Overall very happy so far.  

Thanks for following along.  I'll try to answer any questions, or help anyone with a similar project.  

And again, thanks to the many folks here who helped me get this far.

Scott


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## Investigator

Forgot to say....

Before tear down, the table was stiff and hard to move.  That was part of the reason I decided to rebuild.  When I got in the thrust bearings were stiff and gummed up with lots of dried grease/oil .  
	

		
			
		

		
	






I just used some acetone and a rag to clean them and it came right off.  I reused the originals and the table moves smooth now.

I also have a set of IGaging EZ-View DROs I plan to add in the near future.  After using the machine a few time I can tell I will really like DROs


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## Dave Paine

Very good work on the rebuild and very good documentation.  The mills looks like it will now give you good service for years to come.   Interesting thread.  I can imagine the long time for the work.   Well done.


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## mikey

Nice job, Scott! 

Did you happen to also change the drive sleeve bearings?

Emco still had new spindles a few years back. The RF-30/31 should have the same one. Cost was $135.00 when I bought mine and I wish I had ordered two and kept one as a back up. In any case, MSC might have one if you need one someday.

I also wanted to suggest you run your mill at about 1500-1800 rpm for about a half hour and check to be sure the bearing temps remain below 100 degrees F. If it goes higher then adjust preload.


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## Billh50

Nice Job...really like that bench. Is it all metal ?


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## Investigator

mikey said:


> Nice job, Scott!
> 
> Did you happen to also change the drive sleeve bearings?
> 
> Emco still had new spindles a few years back. The RF-30/31 should have the same one. Cost was $135.00 when I bought mine and I wish I had ordered two and kept one as a back up. In any case, MSC might have one if you need one someday.
> 
> I also wanted to suggest you run your mill at about 1500-1800 rpm for about a half hour and check to be sure the bearing temps remain below 100 degrees F. If it goes higher then adjust preload.




Yes, I forgot to mention that.  I did replace the drive sleeve bearings, they were easy and I found them easily on line.  I think they were fairly inexpensive too.

This project has been done for a couple months, just now getting around to writing it up.  I ran the mill on the lowest speed for 10-15 minutes watching temps at top and bottom of quill.  Then I ran it around 2000rpm (not sure of exact speed) for about 15 minutes just to make sure while I checked temps. It was all good.


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## Investigator

Billh50 said:


> Nice Job...really like that bench. Is it all metal ?



The bench that the mill is on? or the one in the background?

I assume you mean the one the mill is on.  Actually it is all wood.  heavy built with a 2x4 framework and supports for the top, plywood 'outer skin' as it were.  I painted it with hammered finish paint to give it a metal look.  I actually chose the bench color before I painted the mill, so I added a matching stripe to make it look like a pair.

My dad and brother kind of laughed at the color.  My thought was most everything I have in the shop is kind of drab in color, grey lathe, white walls, grey floors, off white base cabinets on bench. 

[insert Bob Ross voice/   
 I just wanted some happy little colors in the shop\]


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## Billh50

I thought is was wood but was not sure.


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## kvt

Thanks for the additional inforation.   when I pick mine up this weekend and start looking into it I will be checking these things out.


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## paws-fixit-shop

Thank you for this writeup.  I just brought home what I think is an RF-30 (no name plate, top cover is gone). It needs a going through, so your pics and instructions will be very helpful.


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## Joe Sukenick

Investigator said:


> Forgot to say....
> 
> Before tear down, the table was stiff and hard to move.  That was part of the reason I decided to rebuild.  When I got in the thrust bearings were stiff and gummed up with lots of dried grease/oil .
> 
> 
> 
> 
> 
> 
> 
> 
> 
> View attachment 248952
> 
> 
> I just used some acetone and a rag to clean them and it came right off.  I reused the originals and the table moves smooth now.
> 
> I also have a set of IGaging EZ-View DROs I plan to add in the near future.  After using the machine a few time I can tell I will really like DROs


Hi Investigator, I am REALLY late to this party and have a question on the effect of stiffening the base of your mill. I have an older Tiawanese model mill and surface finishes leave a bit to be desired with the vibration. Using about 5 lb. of pressure on the head with by finger I get 3 or 4 thou. of  head "nod". Do you see any appreciable difference in the mill with surface finish? Did you also stiffen the column of the mill or was it not needed?


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## Investigator

Joe Sukenick said:


> Hi Investigator, I am REALLY late to this party and have a question on the effect of stiffening the base of your mill. I have an older Tiawanese model mill and surface finishes leave a bit to be desired with the vibration. Using about 5 lb. of pressure on the head with by finger I get 3 or 4 thou. of  head "nod". Do you see any appreciable difference in the mill with surface finish? Did you also stiffen the column of the mill or was it not needed?



Well, I'm not sure how to answer your question. This is the first milling machine of any type I have ever owned or used. I did not use it before the rebuild and putting the epoxy granite in the base, so I have no frame of reference for what it 'used to do'. I also did not put any in the column.

Having said that, I will say that I have used a large (6") fly cutter on steel and get a very nice finish.  When I was contemplating doing this I read all I could find on the web about epoxy granite, especially about using it to stiffen these bench type mills.  I do remember reading that someone did a test and found much more improvement from filling the base and leaving the column alone than they did from filling the column.  

In my case, I already had it torn down and it really didn't take much extra time to fill the base. Also I reasoned that there was almost a 100% chance that it wouldn't make it any worse, and I had read that it would make it better so.........

Not sure if that answers your question or not.  I will say finally that I'm glad I did it.

Scott


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