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Gallery, Projects and General => How to's => Topic started by: ieezitin on January 22, 2014, 01:27:19 PM

Title: Machine small work unobstructed
Post by: ieezitin on January 22, 2014, 01:27:19 PM
Hello everyone,

I have had a need lately for modifying screws, fasteners, small round stock items with no real length to them, the three and four jaw chucks I own are around the 6” size and the jaws are quite deep, this interferes with work holding for example: if I needed to machine the threaded end of a hex-head bolt the head would be the piece being held in the chuck jaws and this would be unstable to machine.

A solution is to make a set of tool makers mini jaws, they clamp on to the regular jaws of the chuck so they expand and contract as normal. Here they are mounted on my 6” chuck

(http://i721.photobucket.com/albums/ww212/ieezitin/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS6_zps704895be.jpg) (http://s721.photobucket.com/user/ieezitin/media/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS6_zps704895be.jpg.html)


Sets of these can be made to fit your 4-jaw or 3 jaw chucks skies the limit really.


Here you see a up close shot of a 8=32 brass knurled head thumb tack screw being held tight with the head positioned flush to the jaw face giving a nice perpendicular hold to the piece.


 (http://i721.photobucket.com/albums/ww212/ieezitin/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS3_zps5d5f8392.jpg) (http://s721.photobucket.com/user/ieezitin/media/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS3_zps5d5f8392.jpg.html)



Here on this shot you can really see the advantage of this set up, the head has the clearance  through the jaw length to be seated so the opposite end can be machined, you can even draw it up to the inside step to use as a depth stop, or place a depth stop from inside the chuck because now the jaws are opened.

(http://i721.photobucket.com/albums/ww212/ieezitin/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS1_zps33cc9288.jpg) (http://s721.photobucket.com/user/ieezitin/media/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS1_zps33cc9288.jpg.html)



Here you can see what work space you have, I believe the length of this screw is about 1-1/8 long


(http://i721.photobucket.com/albums/ww212/ieezitin/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS4_zps4b2844c7.jpg) (http://s721.photobucket.com/user/ieezitin/media/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS4_zps4b2844c7.jpg.html)




I decided on this set of mini jaws I wanted a 1/8 Diameter hole put through, I did this by drilling a pilot hole then reaming the hole out to size, (the jaws were fully closed on the chuck and there was no hole in new set of mini jaws to begin with) I am only going to use this set for Ό-20 and below size screws and this diameter is a nice comfortable fit for these size screws.


(http://i721.photobucket.com/albums/ww212/ieezitin/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS2_zps53605849.jpg) (http://s721.photobucket.com/user/ieezitin/media/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS2_zps53605849.jpg.html)




(http://i721.photobucket.com/albums/ww212/ieezitin/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS5_zps1eb8063b.jpg) (http://s721.photobucket.com/user/ieezitin/media/Machine%20shop/LATHE%20MINI%20JAWS/MINILATHEJAWS5_zps1eb8063b.jpg.html)



NOTES…………

These are made from stainless steel but any material can be used. If made out of carbon I would suggest hardening them.

Making these is self-evident.

while facing on the jaws to thickness I noted the jaw number and stamped each jaw the same for future location in use.

If a larger radius is needed on mini jaw surface, tighten all three mini jaws down to chuck jaws securely, open the chuck so a 1” diameter washer can be fitted behind the mini jaws and located on the original chuck jaws and tighten up the chuck, now the chuck is tight and the mini jaws are in an open position, with a boring bar bore very softly in taking the edge off and produce a wide round profile on jaw tips.

To install the jaws for the first time, place mini jaws on chuck jaws, slightly tighten up to locate all three, with a mallet while at the same time as turning the jaws apply a slight tap to locate jaws into place the jaws now have been self-centered.

Now seat the side grub-screws leaving the top screw till last, once all three screws are set take a facing cut, then unscrew one side screw on each jaw, then reverse the jaws and tighten up the side screw you just relived, take another facing cut, the jaws are now seated.

punch stamp the jaw number on each.
 
Removal is release one side screw (the same on each jaw) then release the top screw and take off, install is just a reverse, colouring the grub screw would it easier to remember what one has be released.

Hope you all enjoy.

Anthony.


Title: Re: Machine small work unobstructed
Post by: awemawson on January 22, 2014, 01:41:50 PM
 :thumbup: :thumbup: Very neat  :thumbup: :thumbup:

Title: Re: Machine small work unobstructed
Post by: mfletch on January 22, 2014, 01:55:39 PM
I like them thanks
Title: Re: Machine small work unobstructed
Post by: Meldonmech on January 22, 2014, 02:01:38 PM


                 A well thought out solution.

                                                              Cheers  David
Title: Re: Machine small work unobstructed
Post by: Brass_Machine on January 22, 2014, 02:01:45 PM
Nice!  :thumbup:
Title: Re: Machine small work unobstructed
Post by: krv3000 on January 22, 2014, 02:17:43 PM
well dun
Title: Re: Machine small work unobstructed
Post by: Stilldrillin on January 22, 2014, 03:09:09 PM
WOW! I like those jaw adaptors.  :bugeye:

Well done Anthony!  :clap: :clap:

David D
Title: Re: Machine small work unobstructed
Post by: micktoon on January 22, 2014, 04:15:12 PM
A simple idea but looks really useful, Top class photos and post too :thumbup:
  Cheers Mick
Title: Re: Machine small work unobstructed
Post by: AussieJimG on January 26, 2014, 11:29:17 PM
A very useful idea Anthony, and well described.

You mention using paint to identify the grubscrew that is loosened; could that grubscrew be replaced with another capscrew?

I can also see a use for soft jaws of brass and aluminium.

Jim
Title: Re: Machine small work unobstructed
Post by: mechman48 on January 29, 2014, 03:55:35 AM

Here's a set I made from your idea, thanks, as you can see made mine from hex bar, gives me the resource to use all 6 corners.. within limits of course.

Title: Re: Machine small work unobstructed
Post by: ieezitin on January 29, 2014, 07:03:20 PM
Nice one George..... you will have years of use from them...

i see from your picture your an oil man?  mee too.

Anthony..
Title: Re: Machine small work unobstructed
Post by: macbrat on February 06, 2014, 11:22:01 AM
Interesting chuck adaptation and excellent photos. Has given me food for thought for special chuck applications – thank you. Avoids spending money on commercial chuck products.

I never throw away good chucks from broken electric drills. They can serve a similar purpose of holding small items without obstruction. Unlike your masterpiece Anthony, ordinary chucks have a very limited capacity for holding screw heads inside the chuck.

Just remember that if held by the outer (knurled) sleeve, it could be less accurately concentric, and a high cutting force could possibly unwind the jaws of the smaller chuck.
I tried moderate cuts on a 3/8th mild steel work-piece with no problem with the chuck unwinding (Fig. 1). Smaller stock certainly no problem (Fig. 2)

 So, if it has a shaft of some sort attached to the main body, use that. If the shaft has a morse taper that you have no use for, machine it parallel.

Brian
Title: Re: Machine small work unobstructed
Post by: Meldonmech on February 06, 2014, 12:31:06 PM
Hi Brian

                  When clicked on, your pics only show a portion of the original. Your pics need re sizing before posting, see details in GALLERY --  Photo re sizing by - Divided he ad. It is quite easy and most newbies need to do it when joining the forum.

                                         Good Luck       

                                                           Cheers  David
Title: Re: Machine small work unobstructed
Post by: mechman48 on February 07, 2014, 05:39:22 AM
Neat idea Brian, as always ;simple is best   :clap:

ieezitin; was an oil man, now retired, don't miss the chopper flights especially in winter  :(

George
Title: Re: Machine small work unobstructed
Post by: macbrat on February 08, 2014, 11:22:45 AM
Hi David

I've just posted an article headed 'centre marking . . ' in which I have been very pleased to follow your advice and link to the resizing app. Excellent. Is there any way one can review a post to include attachments before posting? Also, how long do postings allow modifications before that option disappears?
Title: Re: Machine small work unobstructed
Post by: dsquire on February 08, 2014, 03:51:22 PM
Hi David

I've just posted an article headed 'centre marking . . ' in which I have been very pleased to follow your advice and link to the resizing app. Excellent. Is there any way one can review a post to include attachments before posting? Also, how long do postings allow modifications before that option disappears?

macbrat

When you preview a post before posting, any attachments made to it do not show up. Once the post is posted then it shows up in the post. There is a short time (a day or so) that you can edit the post. If you can no longer edit the post get a hold of one of the Moderators and we will help you edit it.  :D :D

Cheers  :beer:

Don
Title: Re: Machine small work unobstructed
Post by: macbrat on February 09, 2014, 09:43:03 AM
Thanks for the info Don.

Regards

Brian
Title: Re: Machine small work unobstructed
Post by: superc on April 07, 2014, 03:48:59 PM
Very good idea.
Title: Re: Machine small work unobstructed
Post by: aRM on August 15, 2015, 11:05:56 AM

Here's a set I made from your idea, thanks, as you can see made mine from hex bar, gives me the resource to use all 6 corners.. within limits of course.

El-BRILLIANTE  !!!
Nudder  one  we  have  to make
The last in round  turned  out  poorly
This in HEX  is  ingenious, to say the least
aRM
Title: Re: Machine small work unobstructed
Post by: Ross on October 25, 2015, 12:06:50 PM
Love that design, Brill idea
Title: Re: Machine small work unobstructed
Post by: wongster on March 16, 2017, 01:31:30 AM
Sorry to ask my questions in an old thread.  I'm looking for solution(s) to hold not so square stocks in my 4-jaw scroll chuck (or called automatic chuck by the manufacturer of my lathe) when I remember this thread. I reckoned that I only need to make 2 pieces; one for each opposing jaw.

Now my super newbie questions:
1) how do I size up the stock to use as the jaw, ID and OD?
2) what would be the angle of the faces if I'm to make one for each of the 4 jaws? 90-degree? Does it matter if making only for the 2 opposing jaws?
3) I would like to make the jaws a little taller to provide better hold for facing and drilling through.  Will that cause the part held in this manner unstable?

Thank you for any help.
Wongster
Title: Re: Machine small work unobstructed
Post by: philf on March 16, 2017, 05:31:05 AM
Hi Wongster,

To arrive at the correct OD and ID I think you'll have to draw out your chuck jaws and draw the new jaw around that.

On a 4-jaw you would only need 2 jaws and wouldn't need to angle the ends. You could use square or rectangular bar.

I wouldn't extend the jaws above the original jaws - it would, as you say, be unstable.

I made some for my 3-jaw but I also have a self centering 4-jaw and will have a go at making a pair for that. Machining soft jaws on a 3-jaw to clamp a diameter isn't that straightforward as you can't easily measure a diameter when there isn't a diametrically opposite jaw. This is easy with 2 or 4 jaws.

Phil.
Title: Re: Machine small work unobstructed
Post by: Biggles on March 16, 2017, 03:29:55 PM
A very good idea and something I can use for some jobs.  :clap: