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The Rohm chuck saga...

clarnibass

Aluminum
Joined
Dec 23, 2015
I'm trying to decide whether to return this chuck or not. I'll try to make it short...

I bought this Rohm keyless chuck a couple of months ago. It had a problem that a couple of spots in the its range were very resistant, almost like getting stuck, with some force necessary to "climb" over. I gave it back to the store to check.
It took a very long time but eventually they told me it was dry grease from standing for a while. They oiled it and brought it back to me.

I'm trying it the problem is definitely solved, there are no hard spots throughout the range. However I suspect it might be too resistant in general. It is very even and smooth, but feels a bit like a bearing with thick grease.
My theory is the oil broke down the grease and spread it pretty evenly, so there are no hard areas, but instead a relatively thick grease throughout (grease + dry grease + oil combined and spread evenly).

I can return the chuck but it's a hassle. I can have it replaced but who knows if the new one would be better. I can return it and get an Albrecht chuck from a different store.
Both the Rohm dealer and Albrecht dealer are pretty far from me so I can order and they bring them to me, I can't go there and try them to see what they are like.

I'll emphasize that it is very smooth and even, question is whether it's too resistant compared with what it should be. I know it's hard to tell how resistant it is from a video, I tried to slide my finger and also release quickly to give an impression of what it is like as best as I can.
I don't have any other keyless chuck to compare with, but I have two keyed Rohm chucks and in comparison, when opening/closing them by hand, they definitely much less resistant (like a bearing with no grease) and if I sort "spin" them with my finger, they rotate a little bit after before stopping. The keyless chuck doesn't rotate any more then moment I don't touch it and it takes quite a bit of force to rotate that way. The comparison might be irrelevant since they are keyed chucks...

Thanks

 
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Agree with MichaelP that is is probably by Design. I have three which behave the same. I took one apart to clean and oil and there was no change.
 
I was under the impression that you were not supposed to lubricate these, or at least not where the inner parts of the shells contact the jaws.
 
Never used a Rohm but I’ve used several Albrechts, an LFA, and a few knock offs. Unlike keyless hand drill chucks and keyed chucks I’ve never had a keyless mill chuck that would just spin freely, including after a full teardown and cleaning.

The LFA was a bit gritty and occasionally spun on a drill, but the other were all smooth, though with resistance as you noted.
 
Unlike keyless hand drill chucks and keyed chucks I’ve never had a keyless mill chuck that would just spin freely, including after a full teardown and cleaning.
Thanks. I don't really expect it to spin like some other chucks, but I was assuming (maybe wrongly) or at least hoping I could open and close it by rolling my finger over it. You can just see in the video how even with a little bit of pressure my finger or palm sometimes slide over the knurled ring. I like to do that to get close to the dill size and only then grip it. I guess some resistance is normal, but I'm trying to determine whether this is normal or if it's more resistant than it should be.
 
No lubrication? Why not?
I don't design them. I'm just reporting what I thought I had read or been told. Something about internal wedge angles, coefficients of frictions, and self-locking. I.e., if you get lube in the wrong places, the chuck won't hold.
 
No lubrication? Why not? I thought keyless chucks just used a finer thread than the keyed ones.

He is right, sort of. Lubricant in the "thread" area that moves the jaws is fine, what is not supposed to get any lubrication is the area where the taper inside the rotating shell touches the taper on the outside part of the jaws. As sfriedberg noted, doing that can make the chuck loosen on its own. That area needs to stay dry to lock the chuck better.

All of my Albrecht chucks are pretty smooth moving but have a decent bit of resistance to turning with nothing in the chuck. I can't easily rapidly spin them between two fingers like I do with a mic when rapidly opening and closing, for instance. So I'd say it's normal to this type of chuck.
 
Lubricant in the "thread" area that moves the jaws is fine, what is not supposed to get any lubrication is the area where the taper inside the rotating shell touches the taper on the outside part of the jaws.
Albrecht:
“Put a lot of grease (water and heat resistant) on the balls, only a little grease on the guides. Take care not to put grease on the thread between spindle 2 and body 4. These surfaces have to be clean and dry in order to secure the function of the chuck.”
 
Albrecht:
“Put a lot of grease (water and heat resistant) on the balls, only a little grease on the guides. Take care not to put grease on the thread between spindle 2 and body 4. These surfaces have to be clean and dry in order to secure the function of the chuck.”

Good call. I was going by memory, got those backwards - had been a few years since my last rebuild. It says little grease on the guides, but from my experience that should be a very very small amount of oil from a q-tip at max. I gave one a small dab of grease there on each jaw once and it didn't hold worth a darn until I cleaned it out.
 
I have been given keyless chucks by people who say they don't hold anymore.
Lacquer thinner bath usually fixes them.

-D
 








 
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