• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

New to me RF 45 ..... In the shop

Gearhead88

Gearhead88

Ultra Member
I have this RF45 that's been here since the summer .

It's 3 phase , 2 hp , gear drive .
It came with a digital readout & a power feed , both of those are working now .
I have not powered up the machine yet because , I'm on the fence & un decided on how I'm going to tackle that problem .
This thing was grubby !!!! , it was put away covered in slime and stored for several years , un - loved , I spent a solid day cleaning it and getting it on the stand.
It was dropped off here , and there it sits .
I will be , at some point , getting it powered up , I'm kinda poor lately , I don't work anymore , coming up on a year since retiring ( yay ) .
I'm not real keen on having a VFD , instead , thinking about a phase convertor and just running it with the gear selections that are available.

Thought's ?? Suggestions ?
Trying to keep the cost of powering this thing ....... some what reasonable .

IMG_5413.JPG


IMG_5414.JPG
 
Last edited:
A cheap VFD can be had for less than 200 bucks easy peasy. Many of us have them with no problems.
A good VFD is more money but also a better product.
Unless your have the knowledge and parts and pieces to build your own rotary phase converter, I think a cheap VFD will be hard to beat in terms of affordably powering your mill.
 
We had a phase convertor for many years. It was just a 3phase motor we spun up with a pull rope, then put the single phase power to it. This is the idler motor set up. That motor has to be at least a 1/3 bigger then any equipments motor that will be run off it. Worked well, there were no capacitors in the set up or anything else, though none of the machines were ever worked that hard. Some say it's kind of a dirty 3 phase produced. But hey, worked for us.
A vfd will give you the option of near indeffenent variable speeds with a cleaner power.
Others will step in on this subject, I am sure. As has also been said, a "cheaper overseas" vfd may work better on a mill then a lathe.
If you have a spare 3 hp. motor sitting about, that maybe a cheaper answer. If not, the vfd maybe the cheaper way to go.
You will get lots of ways to do it/spend money very soon! I too am making up my mind on possibly 2 vfd's over the next while. Lot of posts about it in the forum.
 
Congrats
The Rong Fu 45s have a wider column than their clones . I haven' found the need for VFD on my 240 single phase, there is wide enough range of gears. . BTW I like the tilt table. They could use a power down feed for boring, but that's later internal gear driven option. A cordless drill adapter on the down feed is what most guys resort to.
 
I'm aware of the advantages that come with a VFD , I have seen plenty of posts about this .

I'm a little weak in the electrical skills/ knowledge department .

Not to be a negative Norman but ........ I'd like to know what the down side is , as in , features I'm not going to like or need .

If I had to choose between simplicity and complexity and having to constantly fiddle with stuff , I'm going to almost always go with simplicity .
 
Gearhead88 said:
I'm aware of the advantages that come with a VFD , I have seen plenty of posts about this .

I'm a little weak in the electrical skills/ knowledge department .

Not to be a negative Norman but ........ I'd like to know what the down side is , as in , features I'm not going to like or need .

If I had to choose between simplicity and complexity and having to constantly fiddle with stuff , I'm going to almost always go with simplicity .
Click to expand...
I converted my RF30 to 3-phase and it was easy. I bought an electrical box, a single pole, double throw switch for direction control and a 10K potentiometer for speed control.
Programming the VFD was pretty easy and I guarantee you we can help you get this running. Once running there is no fiddling. Turn the knob to adjust speed, flip the switch for forward/off/reverse. I can think of zero downsides.
 
Last edited:
Luddite opinion. A VFD is nice, but doesn’t really provide consistent power output. A VFD 2HP motor at rated 1750 rpm canproduce 100% of rated torque. Run the VFD at 1/2 speed (30 Hz), it produces 1/2 the rpm at the same torque, but only produces 1HP. HP = RPM x TORQUE / 5252.

But if you use a set of gears to reduce rpm, if you halve the rpm you double the torque. Same HP to the cutter. A geared head makes 100% of the motor HP available at all spindle rpm settings.

Personally, I am willing to put up with having to stop the spindle to make speed changes using a geared head. A geared head gains the sheer grunt power available in a low-speed geared cutting operation like running a large face mill.

IMG_0048.jpeg
 
whydontu said:
Luddite opinion. A VFD is nice, but doesn’t really provide consistent power output. A VFD 2HP motor at rated 1750 rpm canproduce 100% of rated torque. Run the VFD at 1/2 speed (30 Hz), it produces 1/2 the rpm at the same torque, but only produces 1HP. HP = RPM x TORQUE / 5252.

But if you use a set of gears to reduce rpm, if you halve the rpm you double the torque. Same HP to the cutter. A geared head makes 100% of the motor HP available at all spindle rpm settings.

Personally, I am willing to put up with having to stop the spindle to make speed changes using a geared head. A geared head gains the sheer grunt power available in a low-speed geared cutting operation like running a large face mill.

View attachment 56656
Click to expand...
Right this is a gear head mill. Ignore everything I said. Pulley/belt changes are a total pain in the behind which is why I went 3-phase.
 
Another vote for using a VFD. They work well. Biggest advantage of a VFD compared to a phase converter (rotary) is the VFD is silent. If you get a good one there are many adjustments you can make to tweak things. Basic set up of a VFD is really easy. I have a lathe that uses a VFD. I use it as a single speed motor to shift the wear around to the various gears. My mill uses a VFD in a variable speed mode.
 
I'm not so sure about VFDs being easy .I'm hoping I may get my Hitachi WJ200 running before 2025 . I bought it in 2014 . The electrics on my used DF1224g lathe were toast when I got it. A cheap toggle switch turned the motor on !
 
For this application the VFD is about as basic as it gets. Power wires in, motor wires out, start stop on the VFD panel, no worse than wiring a switch. You can do more if you want or not after that.
Remote on off button (still pretty simple wiring and low voltage), adjust the speed (frequency) via a knob or buttons on the front of the device or don't and only use the gearbox to select speeds.

I used a VFD on my RF45 variant - kept the gearbox and used the vfd to adjust speed. Pick the gearbox setting for the approximate speed and twiddle the vfd freq to get it just right (i.e. you go up or down from 40 to 80-hz to adjust speed) Same on the lathe. Don't worry about torque / hp graphs - you're either in the green (enough power) or you're not and being a manual machine you'll know when that is. By using the gearbox you get all the torque multiplication it provides, and by staying close to nominal speed you get most of your power out of the motor even if you do reduce speed a bit. A full 2hp on a manual mill, that is a fairly hefty cut.
 
whydontu said:
Luddite opinion. A VFD is nice, but doesn’t really provide consistent power output. A VFD 2HP motor at rated 1750 rpm canproduce 100% of rated torque. Run the VFD at 1/2 speed (30 Hz), it produces 1/2 the rpm at the same torque, but only produces 1HP. HP = RPM x TORQUE / 5252.

But if you use a set of gears to reduce rpm, if you halve the rpm you double the torque. Same HP to the cutter. A geared head makes 100% of the motor HP available at all spindle rpm settings.

Personally, I am willing to put up with having to stop the spindle to make speed changes using a geared head. A geared head gains the sheer grunt power available in a low-speed geared cutting operation like running a large face mil
Click to expand...
When I converted my rf45 to 3 phase, I opted for a 3600rpm motor - for this very reason.
More inform or pictures if you guys want!

My vote is for the 150$ vfd - No brainer!
 
Downwindtracker2 said:
I'm not so sure about VFDs being easy .I'm hoping I may get my Hitachi WJ200 running before 2025 . I bought it in 2014 . The electrics on my used DF1224g lathe were toast when I got it. A cheap toggle switch turned the motor on !
Click to expand...
I bought a used Harrison M300 lathe. The motor was unusable to me as it was 480 volts. I replaced the motor with a more common 240? volt one. Using a VFD really simplified the wiring. I used the original switches but eliminated all of the relays.
 
whydontu said:
Luddite opinion. A VFD is nice, but doesn’t really provide consistent power output. A VFD 2HP motor at rated 1750 rpm canproduce 100% of rated torque. Run the VFD at 1/2 speed (30 Hz), it produces 1/2 the rpm at the same torque, but only produces 1HP. HP = RPM x TORQUE / 5252.
Click to expand...

I'd like to try one more time to explain why this HP thing doesn't matter.

Imagine an endmill cutting the side off of a piece of barstock, and picture the force it takes to rip a chip (chunk of steel) off with each endmill blade. This force is a torque (ft-lbs of torque force). It takes x ftlbs of force to cut a given size piece of steel off with a flute. It doesn't really matter how slow you go, the same force is required for a given size of chip. So constant torque is a good thing.

What HP does is change the rate of chip removal. So if you need to cut bigger chips at lower speeds to maintain a constant rate of material removal, you need constant HP.

But nobody needs that. We don't increase the depth of cut when we slow down. We keep it the same or perhaps even smaller. If the chips are the same size but removed at a lower rate, you just need constant torque. You don't need constant HP.

It can be argued that a production environment needs maximum throughput. So they want to maintain constant rate of material removal. In this case, you need constant HP.

whydontu said:
But if you use a set of gears to reduce rpm, if you halve the rpm you double the torque. Same HP to the cutter. A geared head makes 100% of the motor HP available at all spindle rpm settings.
Click to expand...

Yes, absolutely correct. But as explained above, it isn't really necessary in a hobbiest setting.

Think of torque as the size of each chip, and think of HP as the size of the pile of chips (the number of chips produced per unit time).

Back to the OP @Gearhead88 - A VFD together with a working set of gears will give you the best of both worlds exactly as others have described.
 
I know yours has a House of Tools sticker on, mine had a Thomas Skinner , but the new price of the genuine Rong Fu 45 is pretty high. In the States, in USD of course, Penn State, a discounter,has it listed as $4,995 but out of stock and MSC was well over $7000 but in stock.. As you work on it, keep that in mind.
 
You must log in or register to reply here.
Back
Top