Belt Drive Spindle Possible?

[Bird_E]

Does anyone know if the rf45 clone Square column mill can be converted to a belt drive setup?

I would think, for milling alum and such that more spindle speed would be nice, and with all those gears in head for power and speed changes this will limit how fast you can turn the spindle. I would imagine a 2 HP vfd belt drive to the spindle would allow much higher spindle speeds. I have mill on order, so I haven't seen the insides yet. But does anyone know if this is possible with minimal work?
Thanks!
Bob

[NC Cams]

You really need to figure out the loads you'll be running and the speeds you'll be running at and do the load calcs with the belt sizes you plan to run.

Once you know this and run the numbers via the power tranamission formulae, you'll be able to determine the viability of the project.

Most industrial belt drive catalogs and/or handbooks provide the formulae and shock load assumptions needed to determine belt sizes and projected belt life.

2hp at 1750 rpm has a much different torque factor than a 2hp motor at 3500 rpm and TORQUE is what is going to create the forces that you'll have to deal with.

HP= torque x rpm/5252 and torgue is expressed in ft-lb

Multipy torue by shock factor to provide for the inevitable oops and/or a factor of safety.

[ChrisJ]

It is my understanding that Aaron at IH had successfully converted one of his mills to belt drive. I believe he changed the spindle out to a #30 at the same time.

Chris

[Brian Kidd]

Originally Posted by ChrisJ It is my understanding that Aaron at IH had successfully converted one of his mills to belt drive. I believe he changed the spindle out to a #30 at the same time. Chris

Yeah at one time when I was talking to him he did do this and he was thinking about setting it up as an option for the conversion.

B.Kidd

[IndHobby]

Yes, you can convert it to belt drive. It does take some machining, a few custom made components, and some minor head adjustments, but it does work and it does go fast.

We will be offering it as a listed modification in a couple months along with prices. It's not something we're going to give away simply because it took some time to figure our.

We will probally sell it in a few ways:

Instructions and plans.
Instructrions/plans and major pieces machined.
We do everything.

Of course the farther down the list you go the more it costs, but I'm guessing prices will be pretty reasonable.

[Bird_E]

If I may ask a couple of more questions:
When converted to belt drive, what kind of spindle speeds are we talking about? Also, do you feel any capability of the machine is lost when converted to a belt drive?

And I completely understand your need to post only "General" information.
Thanks again!
Bob

[phil burman]

Seems kinda strange to buy an RF45 (read geared head mill) then convert it to beltdrive, bypassing the gear box. That's a significant portion of the total cost of the machine sitting there redundant. Or have I missed something.


Regards
Phil

[Bird_E]

To me the biggesst asset of the machine is it's mass and rigidity for a desktop Mill. However, if you want to use small cutters and get good finishes on aluminium A higher speed spindle would be nice, the gear box doesn't lend it's self to running at high speed. For that reason I believe belt drive would give you more opportunity for higher speeds.
Bob

[phil burman]

Exactly Bob.

If you want or need much above 2,000 rpm then a geared head is not going to make it. Look at a high end BP type, 60 to 4,000 + rpm. They have VFD with belts to change ranges. But then a BP doesn’t have a column in the way to restrict the design of the pulley system. You can easily get high-end speed with a compact pulley arrangement but for low speed pulleys need diameter in order to handle the additional torque, assuming you want to use all the available horsepower. Square column mills don’t have the space. That’s why there are no square column belt drives out there, at least not without a variable speed motor. The next significant step in the evolution of the square column bed mill is going to be a drive system that gives both high and low speed capability. This might be a hybrid using a VFD with pulley drive for high end speed and gear drive for low speed torque.

Regards
Phil

Originally Posted by Bird_E To me the biggesst asset of the machine is it's mass and rigidity for a desktop Mill. However, if you want to use small cutters and get good finishes on aluminium A higher speed spindle would be nice, the gear box doesn't lend it's self to running at high speed. For that reason I believe belt drive would give you more opportunity for higher speeds. Bob

[TPPJR]

Originally Posted by phil burman Exactly Bob. If you want or need much above 2,000 rpm then a geared head is not going to make it. Look at a high end BP type, 60 to 4,000 + rpm. They have VFD with belts to change ranges. But then a BP doesn’t have a column in the way to restrict the design of the pulley system. You can easily get high-end speed with a compact pulley arrangement but for low speed pulleys need diameter in order to handle the additional torque, assuming you want to use all the available horsepower. Square column mills don’t have the space. That’s why there are no square column belt drives out there, at least not without a variable speed motor. The next significant step in the evolution of the square column bed mill is going to be a drive system that gives both high and low speed capability. This might be a hybrid using a VFD with pulley drive for high end speed and gear drive for low speed torque. Regards Phil

True 2 speed RF-45's do 3k out of the box. But the gear box is noisy for me and I am fighting high running temps when running full speed for over an hour. I got the mill for the square column not the gear box. I wish it was belt drive and my look into converting it in the future.

Thomas

[phil burman]

Hi Thomas,

What 2 speed RF-45 are you referring to

Best Regards
Phil

Originally Posted by TPPJR True 2 speed RF-45's do 3k out of the box. Thomas

[TPPJR]

Originally Posted by phil burman Hi Thomas, What 2 speed RF-45 are you referring to Best Regards Phil

Phil,

As far as I know Roung-Fu only makes one two speed RF-45 gear head.

Thomas