Sherline Chucks

[D.C.Clark]

Hello All,

Back in 2008, I conducted a pretty extensive test of the holding power of Sherline 3 Jaw Chucks. The attached have been in the files of the Sherline Yahoo Group. I'm posting them here as a follow on to the current thread on chucks.


Best regards,

David Clark in Southern Maryland, USA

 

[itsme_Bernie]

Wow! What a great test!
I look forward to reading your results!
So far very interesting read...


Bernie

 

[D.C.Clark]

Wow! What a great test!
I look forward to reading your results!


Bernie

Thanks very much, Bernie. But the report contains the results, that's all I got.

The conclusion is that the suspect chuck I received from another member performed dramatically worse than either of mine -- so badly as to be practically useless. I still can't say with certainty why that was. I do think I demonstrated the fact.

Recently a new thread came up on Sherline Yahoo raising the question whether as many users were experiencing holding problems with chucks purchased in the ensuing 5 years. This was never determined, it would be interesting to conduct a follow up poll.

Anecdotally, can't remember seeing any new complaints posted since I published the report. It had been a pretty hot topic over the previous years. Whether this means anything -- whether Sherline found and fixed a problem -- I can't say. I never heard from them on this.

I visited the Sherline plant in Vista, California some time prior to publishing my report. When I introduced myself, they apparently knew me from my forum posts, ("Oh, You're David Clark!"). I believe that Sherline has a policy of reading, but not participating in various online forums. They could not have been more friendly and forthcoming -- gave me a great extensive tour of the place, showed me anything and everything I wished to see about their processes. I remain a dedicated, devoted, and enthusiastic user and advocate of Sherline Products.

DC

 

[cazclocker]

I downloaded both of the .pdf files... thanks for the very useful info. One question - you state that you lube your chucks with PTFE dry lube. Is there a reason you use that? I ask because I use Mobil-1, and it seems to work well. Should I be using what you use?

 

[D.C.Clark]

I downloaded both of the .pdf files... thanks for the very useful info. One question - you state that you lube your chucks with PTFE dry lube. Is there a reason you use that? I ask because I use Mobil-1, and it seems to work well. Should I be using what you use?

I like both PTFE grease and dry lube. My general rule is to use dry anyplace I'm concerned about chips sticking and grease everywhere else. I also use Mobil-1 where oil is preferable to grease: ease of application, for example. Those 3 are about all I use on anything. I also recommend frequent disassembly and cleaning, whatever is used.

DC

 

[sinebar]

Hi,
I'm just a new guy on the forum and I'm catching up on the threads of interest to me, but if anybody is still reading this thread, I thought I'd throw in my 2 cents.
First, I must say to D.C. that your tests are very impressive and I am glad that there are guys like you out there that take on projects like that benefit of all the rest of us. One thing that your test doesn't mention is the dynamic effects of RPM on work holding power. I never considered it myself until I read about it or may have watched a video just a couple of days ago. I tried to find the exact source of the information I found, but could only locate the following, taken from page 23-15 of the Tool and Manufacturing Engineers Handbook by The Society of Manufacturing Engineers: "Chucks are generally guaranteed to maintain from 50-75% of their rated gripping force at maximum speed."
The point being: as RPM increases, jaw holding power decreases due to centrifugal force. Granted, the jaws of a Sherline chuck don't have much mass, but maybe, another factor could be too much spindle speed that could be causing work to fly out of chucks.
Please accept this just as added information only intended to generate more thought on the subject.

If I find exactly what it was that I read or watched, I'll post a link to it.

jj