What’s the best way of telling a poster he’s wrong?

[nigel jones 5Participant @nigeljones5]

One of the first things we were taught at university (studying biochemistry) was just because something is written and explained in a text book doesn't mean that it is factually correct. Now this came as a complete shock to me as we were taught at school to research and reply. It is in a book, backed up mostly by supporting data and as such surely must be correct – alas no. This in effect makes telling people they are wrong, in my opinion, quite difficult at times. All one can do is relate to personal experience or reference your source. Many years ago on this very forum I recommended to a chap asking about regulators to pop to screwfix and buy a ball valve and install that as they are cheap and very reliable. A boffin from the petrochemical industry who clearly knew his stuff utterly shot my suggestion down stating that it was not designed for this application and would never work. I have been using them in boilers for years with complete reliability and success but he wouldn't have any of it. I think the moral here is to not tell someone they are wrong unless you actually know they are wrong. By doing this, even if it offends them you are ultimately doing them a favor, that is assuming they take the blindest bit of notice!

[Martin KyteParticipant @martinkyte99762]

How do you find out the correctness of something? "do the dammed experiment"

regards Martin

[John ShepherdParticipant @johnshepherd38883]

Oh dear! A perfectly reasonable opening post and we drift on to debates about rotten fish and tightening chucks.

Now that has made my mind up about not contributing in future.

[mark costello 1Participant @markcostello1]

Can We quietly tell You,You are wrong about not contributing in the future.

[Neil WyattModerator @neilwyatt]

Well Arthur Jacob's patent doesn't say use multiple holes

"The first key that is shown is formed of an indented spindle 15, having a handle 16 and a gear 17. Then the end 18 of this key is inserted into a socket 14, the teeth of the gear will mesh with the rack-teeth on the edge of the sleeve, and when the key thus placed is turned the meshing of the teeth imparts a rotary movement to the sleeve and nut and causes the desired opening or closing of the tool-holding jaws. 7"

(Scanning errors corrected with no change to meaning).

[oldveloParticipant @oldvelo]

Hi Neil

Well Arthur Jacob's patent doesn't say use multiple holes

"The first key that is shown is formed of an indented spindle 15, having a handle 16 and a gear 17. Then the end 18 of this key is inserted into a socket 14, the teeth of the gear will mesh with the rack-teeth on the edge of the sleeve, and when the key thus placed is turned the meshing of the teeth imparts a rotary movement to the sleeve and nut and causes the desired opening or closing of the tool-holding jaws. 7"

Yes this is correct for opening and closing jaws but say nowt about tightening on a drill shank could have omitted the other two holes for clarity and saved on machining costs why have three when one would suffice.

Eric

[Neil WyattModerator @neilwyatt]

Posted by oldvelo on 25/01/2017 20:33:37:

Hi Neil

why have three when one would suffice.

Balance and convenience?

If it was for security of tightening two would probably be adequate and four would be belt and braces. Three always suggests balance to me.

Rumour has it that ball raced Jacobs chucks definitely don't need multiple hole tightening, but they still have three holes?

It's an interesting issue and I should leave it to the correct thread.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Since Neil seems rather coy about disclosing references:

**LINK**

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=709014A&KC=A&FT=D&ND=&date=19020916&DB=&locale=

and

**LINK**

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=911012A&KC=A&FT=D&ND=&date=19090126&DB=&locale=

and

**LINK**

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=1123541A&KC=A&FT=D&ND=&date=19150105&DB=&locale=

may be of interest.

MichaelG.

[Sam Longley 1Participant @samlongley1]

Posted by Neil Wyatt on 25/01/2017 20:49:37:

Posted by oldvelo on 25/01/2017 20:33:37:

Hi Neil

why have three when one would suffice.

Balance and convenience?

If it was for security of tightening two would probably be adequate and four would be belt and braces. Three always suggests balance to me.

Rumour has it that ball raced Jacobs chucks definitely don't need multiple hole tightening, but they still have three holes?

It's an interesting issue and I should leave it to the correct thread.

Neil

My theory for three holes is this

Lots of drills have a turned down shank to half inch. If the jacobs chuck had one hole & a workshop was using lots of these drills the teeth of the chuck could become strained & I have seen chucks with snapped teeth. With 3 holes the law of averages suggests that over time the teeth get used fairly evenly.

Which has nothing to do with why one would need to use the 3 holes each time one tightened the chuck but would extend wear on the teeth themselves

[DodParticipant @dod]

I'm saying nothing as i have opinions on anything and everything, nobody seems to agree with me ( even in the wide world outside this forum ) so I read the forum and learn and adopt and adapt what I read and quietly get on with my life.

P.S. I have read all this thread, some good stuff in it and some dubious stuff (my opinion) and probably some of it downright wrong so I leave it up to yourselves to decide whats what and keep it to yourselves, unless I have got something wrong.

[Roger Williams 2Participant @rogerwilliams2]

+ 1 Sam Longley 1 . Wait for the flak……

[doubletopParticipant @doubletop]

Re this Jacobs 3 hole business, a lengthy discussion over an uncorroborated statement. It’s not April yet, so is it a wind up?

Pete

[HopperParticipant @hopper]

Last time I was told to use all three holes it had something to do with international travel…

[mark costello 1Participant @markcostello1]

Wonder if it would help to use 2 keys at the same time? I'll get Me coat while putting on a helmet!

[oldveloParticipant @oldvelo]

Posted by mark costello 1 on 26/01/2017 17:02:59:

Wonder if it would help to use 2 keys at the same time? I'll get Me coat while putting on a helmet!

Sure you are two thirds there grab a buddy and another key then you have it right

Eric

[HacksawParticipant @hacksaw]

You know when you drill a large hole in thin sheet , fairly too fast, and it shakes about a bit…? And the hole's triangular? Well, I think that's got something to do with the 3 holes not tightened the same , making it unbalanced.

[Sam Longley 1Participant @samlongley1]

deleted

Edited By Sam Longley 1 on 26/01/2017 22:24:06

[Michael GilliganParticipant @michaelgilligan61133]

In the spirit of the title of this thread … May I ask whether the thread about tightening Jacobs drill chucks has been abandonned ?

MichaelG.

.

http://www.model-engineer.co.uk/forums/postings.asp?th=124179

Edited By Michael Gilligan on 26/01/2017 22:26:36

[John Stevenson 1Participant @johnstevenson1]

I feel this thread has run it's time out.

Move on lads, nothing to see.

[not done it yetParticipant @notdoneityet]

Yes, mods

Time to stick a lock on it.

[Author]

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