Thinking of joining the RF-30 club, but I got some questions...

[ARC-170]

I'm finding that my LMS 3990 is a little small for some of what I make. So, I took a look and I saw an RF-30 sale on CL (made in around 1991) for $1,000 (machine only, no tooling or vise). There are a few others for a little more (up to $1600) and they come up for sale from time to time. In spite of the round column issues, I'm drawn to this machine.

1. Seems a bit high for just the machine only. I looked at these before so I looked at my old thread and seems this should be below $1K, maybe in the $800 range. Thoughts?
2. What should I look for as far as wear, red flags, etc?
3. Is the overall depth (front to back) 42-1/2"? If so, I'll need a bigger bench.
4. A search gave weights in the range of 500-660 lbs. I've got 4x4's spaced about 48" apart supporting a steel frame that has a 1-1/4" thick plywood top with a 16 Ga steel cover. This is bolted to the wall of the garage. Is this enough support? I suppose it's moot if I have to move it to a bigger table, but I'd build the new one the same way unless it needs to be stronger.

 

[mikey]

1. Costs vary with location and availability. I agree that $1K sounds a bit high for a 1991 machine but if it is in good condition and fully functional then that's fair. If the mill in the pics is the one you're discussing then it looks to be in fairly good shape.

2. These things are fairly bulletproof. Make sure everything works, including the fine downfeed. That black know in the middle of the downfeed handle with the three spokes engages the fine downfeed. Lightly snug that knob and turn the round wheel in front of the feed and that should lower the quill with fine control. Make sure the fine downfeed disengages fully when you loosen the black knob. Lower the quill all the way down and look for rub marks on the quill; if you see any, walk away. The machining on these mills is actually quite good and the quill should move freely in the bore; marks mean major issues. Otherwise, just make sure nothing is cracked or not functional.

3. Yeah, mine is a bit over 42" from the back of the motor to the Y-axis handle.

4. No idea what your bench looks like so I can't tell you if it will work. Just know that you must be able to access the bottom of the machine in order to lube and adjust the backlash on the Y-axis leadscrew nut. I think it is better to weld up a stand with that in mind and perhaps include a chip pan under the mill. This mill is a lot bigger and heavier than you might think a benchtop mill really is.

5. The unasked question on how to get the price down. Take a dial test indicator and stand with you and lower the quill. Also bring a metric wrench or socket set and loosen and remove the belt to the main pulley up front. Put the tip of the DTI inside the spindle taper and turn the front pulley by hand and check the run out of the spindle. Ideally, you want to see under 0.0002" TIR. I can almost guarantee you that if the spindle bearings are stock, run out will exceed this. Then lower the quill a little bit and push and pull on the bottom of the spindle. If the indicator shows a lot of run out (like in the 0.002-0.003" range or more) then the drive sleeve bearings are worn and need replacement. You may be able to get the seller to lower his price if run out seems excessive. Tell him that the entire quill and spindle assembly has to come apart in order to do a bearing change, plus you have to source the bearings. Hopefully he'll come down a few hundred; that would bring the mill into the range it should be in - $700-800.

 

[addertooth]

I would pay very close attention to the condition of the Dovetails. So many of these RF-30 machines were put in small shops, and were placed next to the welding/grinding station. I was looking at one which had been in a car garage, and it had heavy corrosion and deep scoring on the dovetails. This was due to the mill getting welding splatter and grinding dust land on the dovetails. It was a genuine Rong-Fu, which came from the factory with the hand-scraped surfaces. The poor environment had obliterated any signs of the once beautiful hand scraped dovetails.

Virtually anything can be repaired or replaced on any mill (gears, bearings, handles, etc), but once your dovetails are scored, worn, swayback, you are out of luck

I would suggest you read up on the many inventive methods people use to Tram mills which have a round column. Get very familiar with the process, and decide if you can live with your preferred process. When you change your height (Z-Axis), you will need to Tram the Mill to get it back to true. I have seen a large jig (home made), which relies upon ground rods and bearings to keep the alignment true when raising and lowering the head; that is also an option. Overall, most people who have one of these mills find them very capable.

 

[WCraig]

The pictures seem to show that the owner has rewired to permit normal and reverse rotation but the cover on the motor is missing. To me, that is a red flag and I'd check the wiring very carefully. Well, honestly, I pretty much always assume that the previous owner was a yahoo!

Re price, if you waive around $800 or $900 in cash, the seller may change their mind. Or not. When I'm selling, I have an asking price and a number in my head that I'm willing to accept.

Craig

 

[ARC-170]

Thanks everyone!
Mike, I usually take a few measuring devices with me, so thanks for letting me know what to measure.
Addertooth, thanks for the tip about the ways. I'm familiar with the "losing the x and y" issue with this machine. It's the price I have to pay to get the next size up, I think.
WCraig: I thought the open electrical box was a concern as well. The seller is "firm" on the price, but waving money around usually helps, and I think the same as you: they always have a price in mind.

 

[ARC-170]

What about this one. It's a Smithy BX-288. Looks like a Rong Fu clone and it appears to have a tilting head. A local machine shop has it for sale for $850. It has what appears to be a motorized X feed. Probably well-used, though. And that motor looks like it might be 220 or even 440, or 3-phase.

 

[DavidR8]

Interesting machine. I think that's the equivalent of an RF-40; same basic idea except gear driven and tilting head as you say.

Gear Head Bench Type Milling Drilling Machine - RF-40 - RongFu

Gear Head Bench Type Milling Drilling Machine - RF-40

www.rongfu.com

The tag says 110v so unless the motor has been replaced I’d say it’s still 110v.
It looks pretty rough but could just need a serious cleaning. Could be the better deal to be honest.


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[pontiac428]

I would avoid the round column with the geared head. Even the dovetail column gear head is a compromise. High part count plus inexpensive construction equals a tool that won't age well.

Like Mikey said, the RF30 mills are pretty bulletproof. They're simple to work on and simple to improve. Many of their shortcomings can be addressed with modifications and detail-oriented adjustments.

The ways on mine were flaked at the factory. It has lived a pretty good life between my Dad's shop and mine, but I still have surface rust. Until I learned how to dial the movement and rigidity into my work technique, I was thinking of selling it off. Once I got smart, I started to really like it. I installed DRO, power feed, überfett pinch bolts, and new way lock knobs. Every part that mates to another part has room for optimal alignment, allowing for fine tuning and adjustment. My tram from the factory is perfect, so I got comfortable pushing the kind of tools that a 2 hp mill should be able to push and getting good results. I gotta say, the round column mill does not get the credit it deserves.

Finding your datum after a head height change should be childsplay, and I do not understand why people complain about it. I consider it a non-issue. People have come up with a variety of thoughtful mechanisms for dealing with that if it becomes an issue.

The mill weighs as much as a complete small block Chevy. If you can set one of those on your bench, then it's strong enough. If that idea makes you cringe, you might need more bench. Lumber is okay, but I'd want my 4x4 posts spaced at the corners of the mill base rather than too far out.

 

[DavidR8]

@pontiac428's advice is sage. In honesty I looked at an RF40 before I bought my RF30 clone and couldn't deal with the gear noise.

 

[mattthemuppet2]

although lots of great work has been and is still being done on round column mills, if you can keep looking and wait for either a dovetail column bench mill or a small knee mill I would do that. I've had to deal with the re-zeroing of the work from a round column type "mill" and the constant work arounds with short/ long drills, this that and the other and really don't miss them. Keep saving and keep looking and I think you'll end up with a far better mill. You also know already that tooling up a mill, even if you already have a smaller one, is going to be a chunk of change, so keep that in mind when you're looking too.