Author Topic: Machine small work unobstructed  (Read 49859 times)

Offline ieezitin

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Machine small work unobstructed
« 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




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.


 



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.





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







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.











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.


If you cant fix it, get another hobby.

Offline awemawson

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Re: Machine small work unobstructed
« Reply #1 on: January 22, 2014, 01:41:50 PM »
 :thumbup: :thumbup: Very neat  :thumbup: :thumbup:

Andrew Mawson
East Sussex

Offline mfletch

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Re: Machine small work unobstructed
« Reply #2 on: January 22, 2014, 01:55:39 PM »
I like them thanks

Offline Meldonmech

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Re: Machine small work unobstructed
« Reply #3 on: January 22, 2014, 02:01:38 PM »


                 A well thought out solution.

                                                              Cheers  David

Offline Brass_Machine

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Re: Machine small work unobstructed
« Reply #4 on: January 22, 2014, 02:01:45 PM »
Nice!  :thumbup:
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline krv3000

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Re: Machine small work unobstructed
« Reply #5 on: January 22, 2014, 02:17:43 PM »
well dun

Offline Stilldrillin

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Re: Machine small work unobstructed
« Reply #6 on: January 22, 2014, 03:09:09 PM »
WOW! I like those jaw adaptors.  :bugeye:

Well done Anthony!  :clap: :clap:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline micktoon

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Re: Machine small work unobstructed
« Reply #7 on: January 22, 2014, 04:15:12 PM »
A simple idea but looks really useful, Top class photos and post too :thumbup:
  Cheers Mick

Offline AussieJimG

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Re: Machine small work unobstructed
« Reply #8 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

Offline mechman48

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Re: Machine small work unobstructed
« Reply #9 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.

George.


Always look on the bright side of life, & remember.. KISS..' Keep It Simple Stupid'

Offline ieezitin

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Re: Machine small work unobstructed
« Reply #10 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..
If you cant fix it, get another hobby.

Offline macbrat

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Re: Machine small work unobstructed
« Reply #11 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

Offline Meldonmech

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Re: Machine small work unobstructed
« Reply #12 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

Offline mechman48

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Re: Machine small work unobstructed
« Reply #13 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
George.


Always look on the bright side of life, & remember.. KISS..' Keep It Simple Stupid'

Offline macbrat

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Re: Machine small work unobstructed
« Reply #14 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?

Offline dsquire

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Re: Machine small work unobstructed
« Reply #15 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
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Never let it rest,
'til your good is better,
and your better best

Offline macbrat

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Re: Machine small work unobstructed
« Reply #16 on: February 09, 2014, 09:43:03 AM »
Thanks for the info Don.

Regards

Brian

Offline superc

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Re: Machine small work unobstructed
« Reply #17 on: April 07, 2014, 03:48:59 PM »
Very good idea.

Offline aRM

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Re: Machine small work unobstructed
« Reply #18 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

Offline Ross

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Re: Machine small work unobstructed
« Reply #19 on: October 25, 2015, 12:06:50 PM »
Love that design, Brill idea

Offline wongster

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Re: Machine small work unobstructed
« Reply #20 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

Offline philf

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Re: Machine small work unobstructed
« Reply #21 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.
Phil Fern
Location: Marple, Cheshire

Offline Biggles

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Re: Machine small work unobstructed
« Reply #22 on: March 16, 2017, 03:29:55 PM »
A very good idea and something I can use for some jobs.  :clap:

Offline fatal-exception

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Re: Machine small work unobstructed
« Reply #23 on: April 18, 2017, 03:35:07 PM »
Thanks for the idea. I'm not a fan of holding hex socket head cap screws by the head OD, but seem to have to do it often. This will eliminate those problems.  :headbang:

I also like the drill chuck in the lathe chuck idea. I just found a box of old drill chucks while cleaning out my dads garage this weekend. Some are very old and look to be good quality. My new Bison 6" chuck wont hold anything under 1/16", so this will come in handy for the odd part.

Paul