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fatboy55
12-28-2008, 11:39 PM
Hello Everyone,

http://www.5bears.com/vfd.htm What do you think of this idea being applied to the IH mill?

FS

fatboy55
12-28-2008, 11:41 PM
http://www.5bears.com/vfd01.htm This is a better link. Could we put in a belt drive vfd 2hp setup like this?

BobWarfield
12-29-2008, 01:54 AM
The belt conversion is the hard part and 5Bears isn't converting--his mill came that way from the factory. He's just adding a vfd.

It's a good article about how to add a vfd, but it'll take a lot more to get to a belt drive. Cruiser did a belt drive conversion. Look around for his thread.

Best,

BW

Cruiser
12-29-2008, 02:17 AM
The IH mill's gear box is much more substantial than that little drill press belt drive. If your going to change to belt drive there must be an advantage involved ! What i saw from that link is a joke ! Do i laugh now ?

Mike Nash
12-29-2008, 08:36 AM
The IH mill's gear box is much more substantial than that little drill press belt drive. If your going to change to belt drive there must be an advantage involved ! What i saw from that link is a joke ! Do i laugh now ?

That's funny. That looks suspiciously like my Enco 9x42 knee mill. Substantially heavier than my IH mill and quiet to boot.

fatboy55
12-29-2008, 10:00 AM
So if this mill is heaver and uses the same 2 hp is it really hard to put some pulleys on the motor shaft and on the spindle? Other than the existing pulley's that he changed out shouldn't it be pretty much the same opperation? No idlers, no case mods. He's using close to a 1 to 1 gearing so there should be room inside the IH case for some small 1 to 1's.

FS

BobWarfield
12-29-2008, 01:39 PM
So if this mill is heaver and uses the same 2 hp is it really hard to put some pulleys on the motor shaft and on the spindle? Other than the existing pulley's that he changed out shouldn't it be pretty much the same opperation? No idlers, no case mods. He's using close to a 1 to 1 gearing so there should be room inside the IH case for some small 1 to 1's.

FS

You're describing essentially what Cruiser did. LIke I said, check out his post. Not sure why he's a bit snarky up above, but I'm sure he meant it in jest.

You'll want to think very carefully about the gear ratio. The problem is there is a huge gulf between the needs for steel and other hard metals and aluminum or other soft materials. The latter wants a lot of rpm while the former wants less.

Without some form of transmission, you're relying on your VFD to deliver lots of torque over a very wide speed range. At the very least, you'll want a little more expensive VFD to do this--a sensorless vector drive. A true servo drive would be even better at the low end.

I've made some notes about buildling a belt driven spindle on my web site, though I haven't done anything about it yet:

http://www.cnccookbook.com/CCMillBeltDrive.html

Hopefully you'll find some of the information there helpful.

Another issue you will face converting the current mill head is that at some point you are without a mill. When I get ready to make a belt drive, I will probably look at creating a head from scratch for that reason, though it would be really cool to build one that fits right inside the existing head.

Cheers,

BW

fatboy55
12-29-2008, 03:12 PM
Hey Bob,

All good points but I find that I do pretty much everything on the same speed on the IH. High speed gear 2, thats 960 rpm. I'll go slower for using center drills but I find that handles almost everything else.

Your 4 to 1 speed ratio on your blog with a 1 to 1 pulley setup and a 1750 rpm motor might handle all my stuff.

FS

BobWarfield
12-29-2008, 03:27 PM
FS, trust me, you will want more speeds!

You might look into a feeds and speeds calculator. Lots of them available. I use MEPro from Michael Rainey and like it.

Cheers,

BW

fatboy55
12-29-2008, 03:40 PM
[QUOTE=BobWarfield;544860]FS, trust me, you will want more speeds!

I do, I know your very knowledgeable but I've had the machine for a few years and only used the top gear once. My end mills last a very long time and the work comes out nice, steel and alum.

I'm manual, not cnc.

But, you do know what your talking about so how about a 3000 rpm 3 phase motor and your fancy wide ratio vfd with a 1 to 1 gear set?

FS

fatboy55
01-01-2009, 09:48 PM
So no one wants to discuss belt drives if it only covers the speeds that come from the factory?

Maybe asking for 30 to 10,000 rpm from a vfd and the IH mill is a bit unrealistic.

I find the stock range of speeds very useful. Trying to replace that range might be much more practical. That linked belt would help in making the distance between pulleys less critical.

I get the feeling many of you don't think its even worth discussion.

FS

Cruiser
01-01-2009, 11:39 PM
There are many factors involved with a belted pulley system. One is the distance between the pulleys or center to center measure. It has an impact on the belt in many ways and yes a toothed belt as i used is more forgiving. The IH box and center to center was very limiting and I wanted to range above 5,000 rpm. I managed to get 6,028 rpm if i remember correct. In doing so i also had to cut a section out of the back of the box on column side for wheel clearance, and that was for the smaller of the two wheels. My final ratio I don't recall but it is in archives if you want to search for it. I believe it was somewhere like 1 to 1.739 and at 6,000 I run 1/4" quality carbide end mills for quite a while before they go away. Usually they go away from the bug in system which I only find in the mirror ! I found some very good information from several sources along with belts and wheels, then went to the local McGuire bearings and finished sorting out the issues and ordered parts. They talked me easily out of my original belt choice and what i ended up with works quite well for me. The short coming of it all is that the vfd has a minimum of 10% duty and I try to stay about 20% which gives me a minimum rpm for practical use of 1200 rpm and i must stay moderate in loading tool. I could do better if i bought a new vfd that would give me full power at reduced rpm but i don't have the funds for that or the immediate need. Some have Brought up using multi belted sheaves, but confines limit the types of belts further. Also the prospect of a planetary gear set but design confines again are limiting. I could build a new gear box from scratch and work it out so i had best of all the worlds but the best bet so far would be the vfd improvement over my hitachi L200 which works good so far. I could have gone to a heavy "V" belt and had an easier time for the size constraints, but I'd still need to have adjust ability for belt tension probably being an idler. I still have an idler pulley but it does not produce tension per-say but just takes out the belt rattle that would be highly detrimental without it. And just a simple idler took 3 designs before i got one to last more than a couple of days. If you would like me to design one for you I could do so but I'd charge enough to make up for all the homework already done ! Any more information that I can help you with here. Better yet search out "Belt drive" and see if pics and info are still there. I know Bob has some of my pics on his website, but all my pics are lost from a major puter crash thanks to a frickin trojan off of the you tube site and thank you very much whoever you are for that one !

BobWarfield
01-02-2009, 12:07 PM
A couple points FS.

First, many people might not be interested in belt drive for the exact same range the head already has. What would you gain? Quieter operation?

That's an awful lot of work to go to for a few decibels. I couldn't justify it myself unless I get more top end speed.

But this is your spindle. If you want to reduce the noise, then go for it and don't let anyone throw you off that plan. You'll learn a lot if nothing else.

Second, if you go looking for spindle info, you'll find pretty quickly a lot have talked about it, but very very few have actually done a new spindle setup like Cruiser. It's not an easy thing to just throw together. Some who got pretty far have still not yet gotten to a workable solution that they're actually using either. So there probably aren't a lot of experienced spindle builders for you to have a conversation with.

And lastly, if you start looking at "how to do it right" in the area of bearings, experimentation gets expensive.

I hope you go for it. It'll be interesting to watch another spindle build.

Cheers,

BW

Cruiser
01-02-2009, 12:49 PM
http://www.cnczone.com/forums/showthread.php?t=35961
This is the link to my original postings while i built the system and all the pertinent info is there for study. It looks like the pics are intact too.

fatboy55
01-02-2009, 01:48 PM
Hey Bob and Cruiser,

Thanks for the info. All I want is a quiet machine. I have it outside and I work mainly at night on it. If it lost that gear noise I could work later into the night. Also I like the idea of the vfd for speed changes instead of gears. I love the vari speed on my lathe.

So there's two things I would get with a belt drive other than extra speed.

If someone else had done it I would probably too but I just don't have the time to figure it out all on my own. I love the machine but I do hate the noise.

FS