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A sloppy RF-45 mill/drill

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I bought a RF-45 that had been CNCed , and I put it back to manual use. After milling some slots of a motor mount, I'm getting little tired of the drama. The combination of a powerful motor and a gearhead exposes the center wear on the X-axis . No belts to slip. I've adjusted the gib so it's tight, almost too tight at the ends. I bought it used with a lathe for good deal. Since this is not a Bridgeport, I won't end up with a $20,000 machine, even if I get it perfect. Nor could I afford the tooling to arrive at that point. Nor am I looking for perfection, it's a used mill/drill for heaven's sake .I'm a retired miilwright, on a budget, but not unhandy. So my question , what tools can get away with and where to find them. I have a cheap BusyBee (Canadian Grizzly) granite 12x18 surfaceplate used for layout and a couple of babbit bearing scrapers.
 

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#3
What do you mean by 'center wear'. Could it be the leadscrew + anti-backlash nut combination in the middle range of travel or some dimensional issue relating to the table or...? Dumb question but has the original manual lead screw been re-installed or you have the cnc ballscrew assembly in there?
 
#4
The RF-45 or it's clones are pretty much ideal for space limited garages .The RF-45 is fair bit more substantial than the clones. Even a 8x30 baby Grizzly bridgeport is over $7000 Canadian landed. Yes, I would have loved a Excello, but any used machine would have involved a much greater rebuild and cost twice as much to start with. I even know where a Richmond #4 with an optional head is. They are an excellent British milling machine. It fills his garage and he can't unload it.

Speaking of rebuild, when I got it, the X-axis screw wasn't even fixed at one end, no dials on either x or y, and there was a hole in the top of the column which to me suggested CNC. Hey, he was a cabinetmaker not a machinist. When I pulled the table , I found all the adjustment was taken up on the nuts. I 'll have to at least replace the nuts, may be the screws as well. But with all that backlash, I don't think that's my problem.
 
#5
I owned a Taiwan made '97 RF-45 until just recently, so am somewhat familiar with the machine. There are some issues that, lets just say come with the price point. I would say running wise they all are not exactly quiet & you wont plough a 1/2" end mill through steel at full depth. That should not come as any surprise though. But in terms of overall accuracy, column squareness, table X&Y movement, dovetail fit, gib adjustability... I had no issues there. It was actually a very accurate machine. The current version of this is like this PM. So if that does not meet the 'decent' criteria, next step up is a baby Bridgeport for about 2X the cost depending on country of origon. There really isn't much in between, new at least.
https://www.precisionmatthews.com/shop/pm-833t/

It sounds maybe yours got molested somewhere between CNC conversion or re-assembly. Or maybe was a Chinese version of an RF-45 which have been known to be a bit more problematic even when new. But I'm still confused as to what is your specific problem. If you are saying the gibs feel tight, but only on the ends, that kind of infers dovetail wear or warpage in the middle section. So with the table off, how do the surfaces look & how does the geometry measure? Can you twist or displace the table in the middle travel & measure with DTI but not on the ends? Are all the components that hold the screw, end bearing castings all tight? Is the leadscrew straight or bowed slightly?

If you have the OEM lead screw & bronze nut, both are in good shape & grub screw acting against the nut's slit has been properly adjusted, you should have minimal backlash & the table should move silky smooth. Mine still had about 0.005" backlash with plenty of use. And it would repeat to within a thou over most any travel against DRO. The anti-backlash adjustment is a bit hokey but also no different that 99% of Asian mills & lathes out there. OTOH if the nut threads are buggered or lead screw warped... something has to be wrong in order to exhibit problems, so its a bit of detective work unfortunately.
 

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#7
Mine is Taiwanese '01, that I've had for 4 years. It and the DF1224g lathe ($1750)were one of my first purchases after retirement. We had one at work that was only ever abused as a drill press., we never had any endmills after the first batch. But I was impressed enough with it to pickup a used one. The local ones are labeled Advance, house brand for Thomas Skinner. When I needed parts I went to them ,but they didn't handle them anymore but had contact at Rong Fu. So dropped over the line and got parts from Grizzly. They fit but weren't nearly as nice. And yes ,one of the gears are nosier than the others.

I have over .020 " backlash all the way along, I can't see a brass nut wearing the lead screw that much. But the nuts have no adjustment left,. They are kinda simple aren't they. I'm not looking for perfection, or even good, just acceptable . I was milling slots for a electric motor base, I was hogging them out with a 3/8" 2 flute slot drill with .020 depth cut. On a motor base I didn't need precision ,just adjustability. Enough with the drama queen, time to fix.
 
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