[rwskinner]

I just bought a VH-5C and going thru cleaning it up and checking it out.
I ran into a few small problems, most likely from sitting but a little oil in the lines and cycling the collet back and forth has it opening and closing okay now.

What I did notice, the front of the 5C spindle nose (not the collet) moves 0.010" when opening and closing the collet.
Is this normal? Seem it would be hell on repeatability when changing parts.

Is there an adjustment to adjust the thrust so it doesn't move as much?


I know there is a small section in the maintenance manual regarding rotary's but, in the past, I remember seeing a VH-5C Manual available but I haven't had any luck finding it again. Anyone have an electronic version available?

Thanks,
Richard

[rwskinner]

Ah, it's not that simple, when turning by hand it's all gritty feeling and has real tight spots. Being that it has all that end play and the axial movement and feels gritty it has more serious issues.
I see a rebuild in my future.

[rodney247]

First off those Fadal VH-5c's are not easy to rebuild Lot of work. Probably 20 different o-rings. But you need to ge to the lock -nut behind the disk-brake. So you have to take the whole back of the rotary apart. and your going to use the disk brake to tighten that lock-nut. ON the bottom of the rotary there is a plug remove that to get to the capscrew to loosen the Lock-nut. Do not strip this capscrew or you will be up you know what creek. LOL

[rwskinner]

Thanks, I got it all apart last night. It's full of rust and the cone bearing that sets the end play is trashed pretty bad from rust. Looks like a very wet air source!
The hardest part is getting all the pistons out. When it's corroded and there aren't any surfaces to pull on.
I figured out the two plugs, one is a lock screw in the end cap hidden behind a hex plug, and the other is on the bottom to get to the locking nut.

Total rebuild in order....

Richard

[rodney247]

Glad you got it apart they are tricky. And hope you get it working. If you need a 5c rotary replacement for your Fadal go here. https://www.indexdesignscnc.com/4th-axis-5c-indexers both Air or Manual collets.

[rwskinner]

I'm going back together with it.

Not that I'm doing this way, because mine is totally apart already, but if a person had to make small adjustments to the end play, they could take care of adjustments without total disassembly.

As mentioned, there is a 1/8" NPT plug in the bottom of the VH5C casting. When this pipe plug is removed, it provides access to the clamp screw for the adjusting nut. You would slowly rotate the spindle until your hex key wrench drops into the screw head. Loosen the screw a few turns so the adjusting nut can turn.

Now, you need to hold that adjusting nut so you can turn the spindle and tighten up the bearing preload. To do this, you can apply air pressure to the brake fitting (one closest the center). Since the brake disc is bolted to the adjusting nut, this will hold the nut steady and allows you to slowly turn the spindle. Turn a little at a time and get your end play where you want it. Afterwards, turn the brake off and align the clamp screw again, and tighten.

Double check the end play and don't forget to apply sealant to the 1/8" pipe plug and reinstall in the bottom of the casting.

Hopefully you don't ever have to do this, but stuff happens.

Richard

PS. I didn't get any pictures of it coming apart, but I'm trying to take some while it's going together. Hard to do with greasy paws!

AND to add, if you have more than 2 or 3 thou of end play, you may have more serious issues going, like I did.

[rwskinner]

I noticed the worm gear adjustments in the Rotary Maintenance section don't seem to be for the VH-5C and are more geared towards the VH-65. Since the pivot points and cam plates are totally different, I don't think the instructions apply properly.

Are the worm backlash setting instructions available for the VH-5C?

If not, would it be best to set both sides equally at the max clearance, then slowly adjust each side up until the desired backlash is found? I mean, that's probably how I'd do it anyway unless the instructions said something specifically different.

Richard

[rwskinner]

It's back together with all new o-rings and bearings. Sounds great and is nice and tight. Spins great with no more grit. I have to post some pictures of the bearings. I hadn't seen any this bad in a very long time!

People, make sure your air is nice and dry because there is no place for water and stuff to drain out of these 4th axis's. I'm not sure if it makes sense to add a lubricator set really low or not. I know it shouldn't hurt all the air valves, but oil down the drawbar and in the spindle may be an issue?

Okay, the rebuild is a slight PIA ! Hardest part, is getting it apart. The second hardest part, is adjusting the worm gear back and forth to keep it level and get the right amount of backlash without any binding. Not really hard, but time consuming to do it right, and it's a little tight in some sections for measuring.

Brake is working good, the end play is good, and the backlash is good. Tomorrow, setting up the amp and tuning the amp.

Richard

[rwskinner]

Nice looking rotary's you all have there!