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Tips For Owners Of Rong Fu Rf-20, Rf-25, Rf-30, Rf-31 Mill/drills

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Which model Rong Fu mill/dril or clone do you own?


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KenS

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#1
Many of us hobbyists can neither afford or have space/power for a Bridgeport or even an RF-45 square column mill. Often we have to settle for one of the Rong Fu or RF clones -- RF-20, RF-25, RF-30 or Rf-31-- round column mill/driils.

I have both an HF mini-mill and and RF-31 (Taiwan made). And while the mini-mil is a nice for small parts, the RF-31 is in an entirely different league. The mill weighs well in excess of 400 pounds and you need an engine hoist or crane to move it. However, on craigslist you can often pick up a Rong Fu for just a little more cost than a mini-mill. I saw a nice RF-31 the other day for $375 including vise.

At any rate, being round columns, the Rong Fu's are notorious for losing tram whenever the head is moved up and down the round column. The R8 drawbar can also be a little annoying.

Searching for ways to improve my RF-31, I came across the following YouTube machining channel belonging to a video creator whose handle is "Cuppa Joe."

This is a link to Cuppa Joe's machining site with Rong Fu Mill/Drill information.

This ingenious machinist has developed a novel -- and relatively inexpensive -- way to fix the tram problem, and has made several other modifications to his RF-31 that have transformed it into a real workhorse.

As a joke he calls his videos about his improvements to his RF-31 either "Wrong Fu" or "Wrong Fu." This may have hurt hits to his site when those titles are bypassed by Google searches.

Just today in response to a backchannel email exchange I have been having with him, Joe released this overview video showing his many modifications.

I encourage any of you Rong Fu mill-drill owners, or prospective owners, to take a few minutes to visit Joe's YouTube site. I'm sure you'll find it worthwhile.
 

Hawkeye

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#2
Bookmarked it. Thanks.
 

hman

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#3
Back in November, 2014, CannonFodder started a thread about a device for quickly setting a vise square on a mill table.
http://www.hobby-machinist.com/threads/tool-for-quickly-setting-up-your-vice-on-the-mill.28527/
He added a steel plate to the front of his column for a reference surface.

I did something a bit different. I kludge-mounted an angle grinder in my mill vise, with a hold-down to keep it from popping out. I advanced it to just kiss the column surface, then ran the table back and forth [thank goodness for power feed!], advancing it just a bit each pass. This gave me a concave surface known to be parallel to the X axis.
kkHPIM3664.jpg
I then re-mounted the grinder and cut a second groove a bit higher. The final result was a nice ridge, against which I could set the quick tram.
kHPIM3665.jpg
 

hman

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#4
The RF-30 and its cousins sometimes have an issue with the vertical motion handles interfering with a workpiece, vise, or other object on the table. I solved this by making a new crank handle, whose end is sized to just slip into the threaded holes of the spider. I pressed on an aluminum collar that has some 8mmx8mm magnets pressed into it. The magnets keep the arm in place even if I crank the spindle all the way down and release it to "fly" back to the top. But it's easy enough to remove and/or reposition in a different hole. Just for fun, I used a file to flatten the areas around the holes, though that may not be necessary. Those magnets hold very well!
kHPIM3153.jpg kHPIM3154.jpg
PS - Yup. I've posted this before. But I thought it would go well in this particular thread.
 

davidh

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#5
vertical motion handles, sheesh, i can't count how many times i have smashed my face or head into those damm things. thats a great solution.
 

GreatOldOne

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#7
I've just completed several of Joe's mods on my own rf25. They've worked out really well, and with minimal setup I've got the head clocked at 0.02mm (which I believe is a little under a thou) when indicating the quill. :)

Mill4.jpg

Mill1.jpg

Mill2.jpg

Mill3.jpg

I've also pinched his captive drawbar mod, added an LED IKEA milling light ala Doubleboost, and cobbled together a TouchDRO system.
 

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KenS

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#8
Thanks so much for sharing -- especially the photos. Here are a few questions:

1. What is the diameter of the shaft and radial bearing? And are the shaft and bearing Thomson? Can you give us an idea of the cost?

2. How did you attach the blue angle iron that holds the bearing support block to the rear of the mill?

3. Any chance we can get a few photos showing the back of the mill with the blue angle iron?

4. What type of scales did you use for your TouchDRO. Have you been happy with the results?

Glad you're enjoying your mods!
 

dave_r_1

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#9
Very unusual to mount the mill to the ceiling...I guess it makes it easier to see, with the swarf falling away from the work...Flustered
 

GreatOldOne

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#10
Very unusual to mount the mill to the ceiling...I guess it makes it easier to see, with the swarf falling away from the work...Flustered
What the fudge??? dunno what happened there - they look fine on my iPad / iPhone, but not in a PC browser... Must be the exif / image data. Hang on. I'm turning the gravity back on. :)
 

GreatOldOne

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#11
Thanks so much for sharing -- especially the photos. Here are a few questions:

1. What is the diameter of the shaft and radial bearing? And are the shaft and bearing Thomson? Can you give us an idea of the cost?

2. How did you attach the blue angle iron that holds the bearing support block to the rear of the mill?

3. Any chance we can get a few photos showing the back of the mill with the blue angle iron?

4. What type of scales did you use for your TouchDRO. Have you been happy with the results?

Glad you're enjoying your mods!
1. It's 25mm diameter precision ground linear shaft, with a matching 25mm linear bearing in an aluminium pillow block. They're not Thompson branded - I'm in the UK, and wouldn't know where to get it from. I got what I used from an outfit called Zapp Automation:

http://www.zappautomation.co.uk/mec...ound-rail-385/sfc25-precision-round-rail.html
http://www.zappautomation.co.uk/sma25uu-linear-bearing-with-housing.html

I used 600mm of the round rail, so with tax and shipping it cost me £52. I'm sure similar parts could be sourced in the States for similar or lower cost.

2. & 3.
The blue angle iron is something I saved from the scrap pile when they replaced the lifts at work. It already had some slots and holes drilled / cut into it, and I reused these. The slots went toward the head casting, and the holes went toward the aluminium block the bearing was mounted on.

mill_angle_close.jpg

mill_angle_bolts.jpg

mill_angle_bearing_fix.jpg

M10 bolts where used with washers - the bolt heads on the casting where turned down so as not to interfere with the motor mounting plate. The head and bearing block was drilled and tapped appropriately (M10 x1.5). The slots allowed it to self align once everything was assembled, and then they where tightened up.

4. I've used iGauging style scales that are available in the UK from http://www.arceurotrade.co.uk. I believe you can get them from various sources in the US. Yes, I'm very happy with it - once I'd moved from the MSP430 based interface to the Arduino based one, and used the custom sketch that is available from a guy called Rysiu M on the Touch DRO forums. I found that the MSP version a pain in the ass to upgrade when new firmware was published, as there's no Mac based firmware flasher available from Texas Instruments - that and I could never get the tach to work on it. Moving to an arduino based one allowed my to update the sketches without jumping through hoops, and the tach works. I was so impressed with it I built a second one for my lathe, and built another two for a friend.
 

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rick9345

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#12
Quite feat turning a drill press into a mini mill.;)
 

KenS

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#13
1. It's 25mm diameter precision ground linear shaft, with a matching 25mm linear bearing in an aluminium pillow block...
Thanks so much for the additional information. This will be very valuable when I do the mods on my mill/drill.
 

atlas ten

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#14
Lots of good info here. I don't have much to add. I do like to keep a little pressure on the quill lock while feeding to stop any backlash from happening.
Jack

Sent from my SGH-I337M using Tapatalk
 

hrc118

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#15
Awesome work!!!
 

rbottos

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#16
the taiwanese manufactured mill drills are very capable machines. Mine is my old mill replaced with a pm pm25v mill.
It was complete with sony dro's , kurt swivel vise, vertex 6" super spacer, align power feed, tooling , ETC. Actually made an extension for the pm 25mv mill to raise it 9 inches on the rong fu rf-30. It is too heavy for me to handle the components any more.
 

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Silverbullet

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#17
Cuppa Joe , was one of the first YouTube videos I ever watched. In fact he was starting his side bar build then. He added about a hundred pounds of plate on top. He stuck with it too.
 

KenS

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#18
As the OP in this thread, I have just become aware of a Rong Fu Mill/Drill stabilization alternative now under development in Australia.

The project evolves in the following three threads, with the actual True-Line 88 product revealed in the fourth.

Rong Fu RF-30 Protoype Stabilizer -- Part 1....

Rong Fu RF-30 Protoype Stabilizer -- Part 2...

Rong Fu RF-30 Protoype Stabilizer -- Part 3...


And the soon-to-be-released True-Line 88...

I have no financial interest in this, and am only interested in the concept as an RF-30 owner.

It will be interesting to hear your comments.
 
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mikey

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#19
Very interesting idea. It looks like the rear handle for the down feed needs to be removed. I would be interested in this for my RF-31, especially if they can show us how repeatable/accurate the positioning is. This device, like others of similar ilk, removes the one big disadvantage to a round column mill.

Thanks for bringing it to our attention, Ken.
 

Silverbullet

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#20
May not hold exact zero but I bet its close . If you mills trammed in and isn't off it should be within a few thou max.
 

stioc

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#21
That's a great idea. I was thinking of making something similar except with a round bar stock and linear bearings but this looks even simpler and better. However, I so rarely have to raise or lower the head mid-operation ever since I converted to TTS collet system and a consistent sized set of tooling that I just haven't felt the need to build anything like that in a while. Although, if it's reasonably priced I'll spring for one just for the flexibility and ease should the need arises.
 

Swissmat

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#22
hey guys, it's been a while since there was some activity re. RF-20s .. I have a lead on one that claims limited hours and includes some basic tooling, nothing to write home about .. asking price is 1000.- CAD (roughly 770 US$ or 1000 Australian$) .. 850 for mill and 150 for tools ..

Are you guys happy with your RF-20s? Is it worth to hold out for an RF-30 or 31? Is there a big difference? Would you pay 850.- for it?

Hope to hear from someone! thanks
 

Hawkeye

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#23
I had an RF-25. It was pretty good, but got all rusted up after a house fire.The available replacement was an RF-30. I find it to be a LOT stiffer than the RF-25. If it's an option, it might be worth a bit of a wait.

$ 850 is about 1/2 what I paid for a new RF-30.
 

Swissmat

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#24
Thanks for the info .. half eh? does't seem like that good a deal anymore for a very old and smaller machine ... where did you buy your RF-30?
 

Hawkeye

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#25
They had it on sale at KMS Tools. Good timing.

Side note: I took the RF-25 to the scrappers, minus the motor and stand. I got $13.20 for it.
 

Norseman C.B.

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#26
This is at the top of my mod. list for my new to me Taiwan built HF -RF30 now that it is up and running................
 

Swissmat

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#27
They had it on sale at KMS Tools. Good timing.

Side note: I took the RF-25 to the scrappers, minus the motor and stand. I got $13.20 for it.
thanks, I stepped away from the purchase ... I'll wait for a better deal ;)
 

Hidyn

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#28
Right now I can get a new RF-30 with stand for $2450 Canadian (Or something different) or a used one with a stand for $1400 Canadian. I don't know what freight would cost.
Edit: No shipping, there's one local

Both come with a little bit of tooling, but not much.

I've been grinding my teeth over it for a little while.
 

pontiac428

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#29
Right now I can get a new RF-30 with stand for $2450 Canadian (Or something different) or a used one with a stand for $1400 Canadian. I don't know what freight would cost.
Edit: No shipping, there's one local

Both come with a little bit of tooling, but not much.

I've been grinding my teeth over it for a little while.
Buy the used one, and use the savings for getting tooling or accessories. Regardless if you buy these machines new or used, they still need cleaning and adjusting, so nothing gained there.
 

dpb

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#30
My RF-30 has no obvious means of braking the spindle while tightening or loosening the drawbar. What am I missing?
 
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