Head lift/drop crank stuck on Rong Fu RF-20. Any ideas?

[Speedly]

Hello! As mentioned, I have a Rong Fu RF-20 mill, and the crank that raises and lowers the entire head is jammed. I found the old manual with the exploded drawing, but it doesn't give me a lot of information other than pointing out the crank connects to the "worm shaft" (part 5-59 in the manual). Not a lot of help... I know what a worm gear is, but it isn't a lot of help in actually fixing it. If it helps, some pictures are posted below. An interesting symptom is that I can turn the handle a half turn or so, and the shaft itself runs in and out, but jams again before actually moving the head.

The only thing I found is the video above, which appears to be similar to the one I have... but not exactly. I also have concerns that when I open it up, the head might fall, creating a potentially dangerous situation for both the machine, and for myself. This person doesn't support theirs, but I want to check with people who know better than I do. Also, the one in the video doesn't have that side panel that I do.

The head is currently unable to move up or down, so setting some kind of blocks below it isn't an option.

So, my question. Is supporting the head necessary to do this fix? How do I go about checking and fixing this?

Please advise. Thank you!

As mentioned below, reposted up here for visibility:

Admittedly, I posted this without actually going out to the shop to check. Mine has no "panel" like shown in the video. The head is DEFINITELY not at the top limit - it has nearly six inches of travel left before topping out.

Back to square one - exploded view isn't really helpful. Can anyone guide me as to how to go about checking this safely?

Pictures below. Let me know if other angles might help!

 

[mmcmdl]

When in doubt , take the safe way out .

 

[Speedly]

I mean, yes, but the issue is that I don't have a means of supporting the head safely (that I know of). I could throw a ratchet strap over one of the exposed pieces of wood in the ceiling of my garage, but I don't know it's actually safe to do so.

This is why I'm seeing if it's necessary at all!

 

[matthewsx]

Yes, you can crib the head up from the table. If you have exposed floor joists above they should be strong enough too.

John

 

[Speedly]

Ok, new issue. Admittedly, I posted this without actually going out to the shop to check. Mine has no "panel" like shown in the video. The head is DEFINITELY not at the top limit - it has nearly six inches of travel left before topping out.

Back to square one - exploded view isn't really helpful. Can anyone guide me as to how to go about checking this safely?

 

[matthewsx]

Safety is relative.

But, if you put cribbing almost up to your spindle the head can only drop that far. If you have joists above you can put some upward pressure on it, otherwise you could use a jack.

Shoot some pictures and post them here, will get better advice if we can see exactly what the problem is.

John

 

[mmcmdl]

Wrap a strap around the head and hang it from an above joist . Use a chain fall or come along if neccesary . Tear into it . If it falls , it can't go far . If it doesn't , you wasted 2 minutes . Without pics what can we tell you ? You know , I wouldn't take anyone's advise on whether to crib it up or not . This is up to you , your machine and your body parts . If you're not sure , just do it .

 

[mickri]

Your mill is like mine. First take everything off of the top of the head. This will allow you to see inside to see what the problem is. You will most likely have to take the head off the column to fix it. Be very, very careful. The head even with the motor off will be very heavy.

 

[RJSakowski]

I have an RF30 clone so there may be differences. The two bolts shown int the second picture lock the head to the column. If they are tight, the head can't move. If you remove the column cap, the rack should be free to move up and down with the crank. If it doesn't move, your problem is with the associated gearing. If it moves freely, the head is locked to the column. If the head is frozen to the column, loosening the two bolts in picture #2, you will not be able to rotate the head on the column. In order to repair the gearing, it will be necessary to lift the head off the column using a hoist. Loosen the two bolts and remove the top cap. You should then be able to lift head and rack off the column.

 

[David2011]

Is this mill new to you and stuck from the beginning or was it working and then it got stuck?

Can you rotate the head right/left if the locking nuts are loosened? If so, refer to mickri’s post. He said the same things that I was going to. If not, try to determine why it won’t rotate first.

You will probably have to take the rack (geared strip) off at the same time as the head. A come-along or chainfall hoist is IMO safer than a ratchet strap. You can get either inexpensively at Harbor Freight along with a real lifting strap. With this much weight it’s worth spending a little to be safe.