Rick

[georgeseal]

Please tell us how the new belt drive is going

Am wanting to purchase same but still hesitant.

I built the one in HSM or PM and it works alot better than the plastic gears.


George from Conyers Ga.

 

[Cedge]

George
Go for it!!! No regrets at all here.

Steve

 

[rake60]

I love it too!
It's much quieter than the gear drive.

Those noisy gears were doing more than just making noise.
The finishes with the smooth running belt drive are much better.

Rick

 

[BobWarfield]

I intend to convert my Industrial Hobbies mill to a belt drive at some point. I also want to build a new spindle that's capable of a lot more rpm's.

The standard IH spindle is fine for steel, but max rpms are 1600 rpm, which is really too slow for aluminum. Ideally, I'd like to be able to hit 10,000 rpm at the high end, which would be sweet for aluminum, while still keeping a low end of 100 rpm. The problem, of course, is that the speed range there is huge. It's much more than a VFD can make up for.

So, I've been researching various possibilities for a little transmission for the belt drive. I figure a hi/lo range will be adequate based on my calculations. I could just wimp out and use step pulleys, but there are more elegant solutions. I've been researching the vari-drive style pulleys, which are one possibility. I would like need to build one.

Lately, I discovered what I think is a neater approach. While nosing around the web, I discovered a complete set of manuals for the Fadal 4020 VMC, including maintenance manuals with exploded parts diagrams and pictures of how to take things apart. Kewl!

I got to looking at how their belt drive works, and it's pretty darned simple. Basically, they have a step pulley arrangement with 2 steps on 2:1 pulleys for both the motor and spindle. This gives a range of 4:1 between the two ranges, which would be about right for aluminum verus steel cutting. The way the Fadal works is to have 2 belts and air-operated idlers. To engage a range you release the air on the existing range and apply air to the desired range, which engages the idler and tensions the belt. The belt not in use just sits there. They're counting on it to "spring open" a bit and not get tangled in the works.

Anyway, it sure is simple. The idlers look like over sized roller-tipped rockers for you car enthusiasts:

I'm thinking such a thing might not be that hard to build. For a smaller Sieg mill, you might even choose to use roller rockers if you find some used ones on eBay, and operate them with a lever rather than an air cylinder.

For those interested in my mill spindle rants, here is the page on my site: http://www.thewarfields.com/cnccookbook/CCMillBeltDrive.html

It's not real high on the priority list, but I'll eventually get to it.

Best,

BW

 

[Cedge]

Rick
I too felt like there was some improvement in finish as well, but discounted it as possibly being my imagination. I guess I'll have to give the upgrade proper credit, now that the same opinion is shared by more than just me. I not going back to the gear drive, of that I'm quite certain.

Steve