# Square Stock in a 3 Jaw



## rake60 (Sep 15, 2007)

When I first read about turning square stock in a 3 jaw I doubted it's 
safety or even the sanity of such a set up.
None the less I had to try it to see if it would work.
It's just a matter of trapping two side between jaws then shimming the 
third jaw to bring the open side to the same run out as the trapped sides.









I this case a small piece of 1/8" steel rod brought it to within .005"
It felt surprisingly solid.  Cuts of .050" depth didn't effect it stability at all.




If your 4 jaw is available by all means use it!  But, it is possible to get by
with the 3 jaw if the need arrives.  

As I've said before,  If it doesn't look and feel safe to *YOU*, don't use it!

Rick


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## mklotz (Sep 15, 2007)

Rick, I'm sorry, but you can't pay me enough to even think about trying that.


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## rake60 (Sep 15, 2007)

Those were my thoughts as well Marv.
Then after seeing it again in Edward G Warren's "Home Made Steam 
Engines Volume 2"   I had to a least try it.

Rick


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## Bogstandard (Sep 16, 2007)

Hi Rick,
And you thought my turbine was scary.
If it needs to be done safely, make up a split bush, most probably more accurate as well.
But it does show what lengths people will go to to get the job done.

John


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## Cedge (Sep 16, 2007)

I think I'll have to second Marv on this one.  Not something I'd get out of the electric chair to give it a go....LOL.  I've seen what even a small piece of metal can do when loaded up with kinetic energy. I'd not want a chunk of metal to be the last thing I saw before entering the pearly gates....(grin) 

Four Jaw, mandrel  or Face plate.... but all points are going to be securely trapped before I turn on the machine here. 

Steve


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## Bogstandard (Sep 16, 2007)

I put a post on here about buying a 4 jaw self centreing chuck, just for this sort of situation, in fact I very rarely use my three jaw now, except when I need to turn a bit of large hex (over 1"), under that I use my collet chuck.

John


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## wareagle (Sep 20, 2007)

This doesn't look to be a good set up to me (again, an uneducated hack machinist).  It won't be done in my shop, as I don't have the guts to even try it.  Thanks for sharing, though!

It does bring up a point, however, and that is if you have the proper tools/equipment to do something the correct way, then why would someone risk harm to his work, equipment, or self in order to save a few minutes?  _BTW Rake, I am not aiming this at you by any stretch, so please don't take it that way._  It only takes a few minutes to do it right, and sometimes years to heal from saving that minute or two.

Usually when I tear up something, or get myself hurt, it is because I am trying to "hurry" something along by taking a risky short cut, and I usually pay for it in time, money, and sometimes pain.  This applies to machining as well as many other things!  If there is something that doesn't quite look right, or is questionable, then I stop and make the appropriate corrections to whatever needs attention, and then proceed.  And even then, things still screw up from time to time.

The other thing to keep sight on is that we (the hobby machinist) are not _usually_ doing production type work, so in my opinion, time is the one thing that we really do have working in our favor.  Use a little extra to keep everything safe and keep everything serviceable!

Rake, you are right in that one should only do what he/she is comfortable with.  Thanks again for sharing this.

Descent from soap box. This probably belongs in the safety forum, anyway. :roll:


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## lugnut (Sep 20, 2007)

Wareagle and John, one of the things that all of us want-a-be machinists need is some one to take the time like you two did and tell us what is safe and what's not.  We all thank and praise you for that.  I'll just speak for my self, not knowing anything about what can happen if  a improperly chucked chunk of mystery metal does not stay where I put it.  
I'm totally stupid on the subject, but when you guys see or read of what some of us are doing and you find it wrong or unsafe please tell us!
Nuf said
Mel


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## compound driver (Sep 20, 2007)

HI
Just as an add on your loading the jaws in the wrong way. If you look at how the jaws are clamping the work the load on the two direct jaws is wrong and possible doing damage to the scroll and the jaw slot.
I have seen this done and by people that should know better and in a factory graded ISO9000. please avoid this its both dangerous and possibly costly to the machine and your wallet.

Cheers Kevin


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