[ksanalytical]

With any luck my IH geared head will be history in the very near future. It's been problematic since day 1. Apparently the Chinese guy who ran the press which installed bearings on the gear shafts didn't notice when one shaft diameter was WAY out of tolerance and just crammed the bearing on anyway. The inner race was likely split from the day is first arrived at my shop. The bearing blew up and spun in the head for who knows how long. With all the comments about noise, I just assumed this was normal. So the first head rebuild came with a new, oversized bearing pocket in the head as well as the normal clean out.

I also took that opportunity to replace the spindle bearings at which point I found an enormous amount of metal crud inside the quill, waiting to fall into the lower bearing. Removing it required a long shaft grander and more than a little time as no amount of brushing in the parts washer was getting it all. At the time, I picked up a grease seal and bored out the threads at the bottom of the quill too. Installing the seal without turning the spindle nose down didn't seem to cause much trouble, but then again, I don't use this machine much.

It's been about a year of very infrequent usage and a constant oil leak which I finally decided was intolerable. During a small part project, it was like the machine was bleeding all over it during machining. Gear ol from the head and also some kind of thick black greasy stuff from around the spindle nose. The Kluber spindle grease is white so I assumed it must be burning up in there or something. It turns out that the oil from the head had washed all my expensive grease right out of the bearings.

The oil seal at the top of the spindle was easy enough to find and replace, but sweeping the head with a magnet brought out a bunch of metal... again.... All gears come back out, I clean it all up again, reassemble and within a few seconds, I'm already seeing metal bits floating past the site glass. Putting a magnet over it grabs them pretty good even through the plastic. So I add a few more magnets and start looking at a belt drive conversion. That's another story.

While it's apart I took the opportunity to grind down the spindle nose to the spec 2.0625" for the oil seal and replace the seal itself. I also ground the outer surface of the quill as I'm planning a clamp-on aux spindle and wanted a good perpendicular surface to mount to.

Reassembling the whole thing goes like normal, but running it up, it's getting much hotter than usual. After less than one minute at 3400 rpm, coolant splashed onto the spindle nose boils instantly. Like an overheated skillet.

I spent the day jacking with preload settings, running in at lower rpms. Nothing works. Finally, out of desperation, I pulled the oil seal to be sure it wasn't the cause of the heat. Lo and behold, the spindle nose is still uncomfortable, but no where near the "boiling" temperature as before.

The next step will be AG bearings and belt drive, but I'm not sure what do do about the seal. I know Cruiser has been down this road and seems happy, perhaps someone can chime in and tell me what I'm doing wrong (plus any advice on the AG swap) as the new drive will top out around 9K if I can make the spindle take it.

It's been a frustrating weekend and I just had to vent.

Ken

[arizonavideo]

Run a over sized seal that barely touches or even has slight amount of clearance. I made one on the router table that fit the cap nicely.

It is really not to hold grease but to keep the crud out. After you go to a belt you wont need all that gear oil in the head and the whole head runs way, way cooler and wont drip on you either. The spindle grease stays put for the most part.

A belt drive is really the way to go I'm working on a few myself.

[ame=http://www.youtube.com/watch?v=s3weHXFRtHw]2speed-change.MP4 - YouTube[/ame]

They have been taking longer than I planed on with spring break, taxes and the kids getting sick.

[duwayne.]

Very nice! Are you making kits?

Hopefully I will be able to get mine to run as quite as williamsmoto's does. He has the gear box like mine, but with the VFD from Tommy. So he's running 3,600 RPM and you wouldn't even know it. I was over to his house a few weeks back and he demo'd his machine and I was just amazed as to how quite and smooth running his gear driven head was.

If I can't get mine to run like his, then it's belt drive time.:cheers:

[jetflatline]

no kidding, these kits sound like a shortcut to me.

[arizonavideo]

Their will be kits.

I have stock for 5 or 6 now and will keep them going for a while.

I will start a new thread in the benchtop section and perhaps a few post in the IH topic.

[jetflatline]

What timing -- I have my head apart and a shiny new 3hp VFD motor sitting next to it.

[duwayne.]

Hi jetflatline

Sorry to take this off topic for a second.
I sent you a PM the other day. Not sure if you got it.

[Mark Housel]

What timing -- I have my head apart and a shiny new 3hp VFD motor sitting next to it.

Coincidentally the IH CNC mill that I purchased via this forum came with a VFD motor and VFD that was to be installed.

So, how much would you want for a complete belt drive kit?

[jetflatline]

duwayne, sorry, I thought I responded, caught up now.

[Mark Housel]

Their will be kits.

I have stock for 5 or 6 now and will keep them going for a while.

I will start a new thread in the benchtop section and perhaps a few post in the IH topic.

Any updates on the availability of this belt drive system?

Thanks

[arizonavideo]

I'm still working on them but it just takes longer than I planed with taxes, kids ,vacations and things. The cut off saw broke for the fifth time yesterday.

I do have 14 pulleys ruffed and mostly ready for final grooving.

I'm not really selling them now mainly because I don't have them ready to go.

I will be doing a thread in the benchtop section and perhaps one here when I have inventory to sell.

I think all the first 5 are sold so I should have 2 more to display in the thread.

I need to try to streamline the process to get the man hours down some.

I hope to get some more out the door in the next two weeks.

Thanks
Dave

[Mark Housel]

Thank you Dave. email inbound

[Cruiser]

The key to a cool running seal is the surface finish at the contact area. I know you said you "Ground" it, but, as a machinist I know that a ground finish can still be in the 36rms finish range with a course stone and still need a buff with some emery cloth. I turned mine to size +.0015" then run a strip of 220 grit on the area till it got a little shiny, then I went to 320 and held it in place till it shined pretty. This brought the surface finish into the low teens for rms. The seal is still going to make some heat and this is expected. It will break in and mellow out with a little time. Mine still gets warm to the touch, holds oil for bottom bearing, and I run a coolant manifold on quill end that cools it during cutting process. Don't worry so much about the heat and pay more attention to if it loosens up and allows you to shake tool holder with hand. This is an indication of needing more preload. And also it must of course run silent, which is a tell for bearing condition. For a grease run spindle, the heat will liquify the grease and cause it to puddle ontop of the seal, but if you were generous enough with the grease it will still be in contact with the bearing and it will pick up and continue to circulate the grease.
Your design for the drive is very nice and looks quite functional. But, I would have targeted a lower bottom ratio and a higher top ratio, I run top speed near 6g but would have liked to get it up higher. and my gear change takes an hour but my low gear would be nicer if it went lots lower for large tool turning torque in steel.
All in all I like what you have done, it looks good !

[arizonavideo]

Low RPM is where you get slippage so I tried to keep the pulleys as large as possible.

The low speed is 2.5" and 6". Their is room to make the 2.5" 2" with no changes which will happen some day if I have to re cut a pulley.

I do have three 7"x3 pieces of stock that will be made into a three speed unit which will have a lower low and a higher high, just for fun...

The batch of pulleys above do have a higher top speed. 5.5"to 2.5"=2.2 to1 or 3850 RPM at 60 HZ. This gives 6,400 RPM at 100 HZ with a 1750 motor.

I may do a higher RPM set just to see how a 1/2" cutter really does at full power at 8K. My drip /blower system is working well so I can keep things cool now.

[RustedOut]

Low RPM is where you get slippage so I tried to keep the pulleys as large as possible.

Why is that? Not getting my pea brain wrapped around that. Is there a difference in cutters you use in that low speed range or run bigger bites or something along those lines? Are you able to get good tension on the belt?

I know in the pulleys I'm going to turn soon I'll be cutting for 10 rib belts and I've kept the smaller diameter pulley at 3" to give the belt plenty to grip to. I'm hoping for the best when it all finally comes together.

Bob

[arizonavideo]

The belts specifications I found don't give torque numbers but HP ratings.

At 4000 RPM a 10 groove will transfer (I forget the exact #) like 40 HP but at 100 RPM it was around 2 HP for a 4" pulley.

I have not had any real slippage problems but if its going to slip it will be with a big drill and slow speeds. I don't see slippage being much of a problem but I also wanted to have good coverage in the middle of the power range as much milling is done at 1K or 2K in Steel and 2k and 4k in Aluminum.

[arizonavideo]

Perhaps I missed something, you said

"I would have targeted a lower bottom ratio and a higher top ratio"

And then you say you going to use a 3" small pulley for low range. To have a lower low speed you would need something like a 7" or greater large pulley for low gear.

Were you saying that you were thinking of a higher speed low gear?

[RustedOut]

Perhaps I missed something, you said

"I would have targeted a lower bottom ratio and a higher top ratio"

If this is a reply to me, Don said that, I didn't. I have a target that's yet to be proven.

And then you say you going to use a 3" small pulley for low range. To have a lower low speed you would need something like a 7" or greater large pulley for low gear.

Were you saying that you were thinking of a higher speed low gear?

I mentioned the 3" small pulley as that's what I have in mind. My planned drive ratio will be 1.8:1 and .5555:1 (not sure that's how to represent the ratios correctly), a 3" and a 5.4" pulley used for high and low speeds, then the inverter motor and vfd handling the rest. I'm not planning on moving the motor to tension the belts, so I need room for the tensioners and that limits me some in the pulley choices.

I don't use big drill bits on my mill, mostly going only to about 1/2" and doing the rest with cutters or boring bars. And I've yet to tap with it, but I'd like to have something other than hand tapping. That may move to to the drill press though. So the real low end below about 300 rpm isn't a concern right now. The little cutters that need the real slow speeds below that like keyway cutters and saws should be ok with the bottom end of the combined pieces as there's no hogging going on with them. At least to my way of thinking.

I was at a friends last night and he has the small round column mill like the RF31 and noticed the head cover is just like IH mills, so these belt drive conversions should fit them as well. That should expand the market for anyone wanting to put conversion kits out there. I'm not one of those, just saying. Of course it would have to be tried to ensure the fitment.

Bob

[jetflatline]

Multiply by 2.2 -- so a 3400rpm motor will yield a 7400 cutting speed?

[arizonavideo]

To Bob

I already found out that the real Roung Fu has a different bolt pattern for the top plate. I make a new one to fit but I was not able to check the fit myself so I'm still not firm on the fit for the real R-F mills. I think their is at least three different makers so I'm sure I will find out soon enough.

I do most all the tapping on the mill but I did buy a small tapping head. The VFD is out of reach so reversing is hard right now. I really need to move it within reach. For bigger taps I'm back to hand but I'm running a single speed internal belt drive right now so I'm missing low gear.

I did a short video of the single speed.

[ame=http://www.youtube.com/watch?v=4dmfP5i2syQ&list=UUOtPHVL6Qi-LuJp17ASrBww&index=3&feature=plcp]Single speed internal belt driive RF-45 LM-45 .MP4 - YouTube[/ame]

So far no one has requested the single speed so it may be the only one. I like it but a 4HP motor might have been better for low end torque.