Free 173 Best Homemade Tools eBook:  
Remove advertisements
Results 1 to 10 of 10

Thread: Dial Indicator Adjustable Arm Extension for Unimat Lathe

  1. #1
    Paul Jones's Avatar
    Join Date
    May 2014
    Location
    Yorba Linda, California
    Posts
    1,132
    Thanks
    4,838
    Thanked 1,208 Times in 596 Posts

    Paul Jones's Tools

    Dial Indicator Adjustable Arm Extension for Unimat Lathe

    Space is limited for using a dial indicator (DI) on my small 3” swing Unimat lathe for 4-jaw chuck setups. Most of the lathe is made from non-magnetic parts and also has very little room to attach a magnetic base where there are ferrous metal parts. Using a boring tool holder in the QCTP (quick change tool post) works but this requires changing the cutting tool holders and possibly resetting the previous tool position (see photo below).

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-holding-dial-indicator-adjustable-arm-qctp-tool-holder.jpg

    My solution uses a separate adjustable arm extension and attachment bracket for a small Noga adjustable arm DI holder with an 8 mm clamping rod. The adjustable arm extension is made from ½” square 6061-T6 aluminum and 12L14 steel rod materials.

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-unimat-lathe-dial-indicator-adjustable-arm-extension.jpg

    The Dial Indicator Adjustable Arm Extension parts were created using the milling head to the 3” swing Unimat lathe, a 7” swing mini lathe dedicated to collet work and a 12” swing geared-head lathe. These are the parts for the Dial Indicator Adjustable Arm Extension.

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-parts-dial-indicator-adjustable-arm-extension.jpg

    I designed the riser blocks for supporting the Unimat SL lathe on a small cabinet. The riser blocks include several pairs of 6-32 threaded holes along the block sides and ends for “future” attachments to the lathe. I am already using one pair of threaded holes behind the headstock to hold the detent arm support to the dividing plate (see http://www.homemadetools.net/indexin...nimat-sl-lathe). Using a similar method, I added support brackets to the headstock and tailstock riser blocks and still have plenty of pairs of threaded holes for other uses.

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-unimat-di-bracket-attached-headstock-riser-block.jpg

    The aluminum rod extension made in two parts is ½” square and 4.5” long with a 8 mm rod clamping end and a shorter piece 2.5" long for allowing side-to-side adjustments. The clamping end has a 8 mm by 2” deep hole that is externally threaded ½ X 20 and with four 1.1” long jaws formed from the slots. There is a knurled 12L14 steel collar internally threaded and with a internal tapered end to compress the four jaws. The 8 mm rod of the Noga adjustable arm DI holder fits into end with the four compression jaws and is clamped in place with a internally threaded collar. Note: before finally assembly, an 8 mm dia. drill was used to "cleaned up" the 8 mm by 2" deep hole after partially threading on the knurled steel collar (not yet to full compression) to ensure an exact fit for the Noga 8 mm support rod.

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-machining-6061-t6-aluminum-rod-into-extension-arm.jpg

    The four slots forming the jaws were cut with a 0.045" thick abrasive cut-off wheel and Dremel tool while the aluminum arm extension was held in the lathe using a 4-jaw chuck. In this operation, my 12” swing lathe could have use the lathe dividing head designed by Christophe Mineau (see [Metal lathe] Indexing plate and cranck) but I substituted a Starrett combination square protractor level and soft jaw adjustable clamps to do the dividing. When I was a teenager in the early 1960’s, I taught myself the basics of machining by reading many used books for the 1930’s and 1940’s about machining. I think the use of levels was far more prevalent than we see today and is often overlooked. I checked my protractor level work with a 0.0005”/foot master precision level (and previously used to level the lathe) and it is very accurate.

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-part-slitting-setup-using-level-4-jaw-chuck-dial-indicators.jpg

    Lately on HMT there seems to be a theme of showing Dremel tool uses and below is another photo of a Dremel tool at work. It is cutting the slots for the clamping jaws with a 0.045” X 1.5” reinforced abrasive cutoff wheel. The abrasive wheel easily cuts through the aluminum but is partially consumed in the process and the dial indicator measuring the carriage travel is no longer valid for determining where to stop the cut. In this case a visual stop and don’t rely on depth stops or dial indicators whenever the diameter of the abrasive wheel is diminishing. Also, the lathe was protected from the cutoff wheel grit using paper towels and bulletin board magnets.

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-cutting-fourth-slot-di-adjustable-clamp-extension.jpg

    FYI - The Dial Indicator Adjustable Arm Extension is attached to the risers blocks I previously created for the Unimat lathe. At the time I anticipated adding more accessories to the lathe. I added pairs of 6-32 threaded holes to accommodate these future accessories. See the photos below. I plan to post more article about other special purpose parts that will be attached to the Unimat riser block including a power feed attachment.

    Photo below shoes the pre-threaded 1" square lathe riser block for attaching lathe accessories.


    Dial Indicator Adjustable Arm Extension for Unimat Lathe-6-32-threaded-holes-riser-blocks-future-attachments.jpg

    Photo below shows the mounting bracket for the adjustable arm extension attached via 6-32 socket cap screws to the riser block.

    Click image for larger version. 

Name:	Unimat DI bracket attached to headstock riser block.jpg 
Views:	955 
Size:	79.8 KB 
ID:	10039

    Thank you for looking,

    Paul Jones
    Last edited by Paul Jones; 02-02-2018 at 07:30 AM.

  2. The Following 9 Users Say Thank You to Paul Jones For This Useful Post:

    C-Bag (04-17-2016), Catfish (04-18-2016), Christophe Mineau (04-19-2016), jjr2001 (09-01-2016), Jon (04-18-2016), mklotz (10-17-2016), PJs (04-18-2016), rossbotics (04-19-2016), scoopydo (04-18-2016)

  3. #2
    MetalDesigner's Avatar
    Join Date
    Sep 2013
    Location
    Las Vegas ~ @MetalDesigner Twitter
    Posts
    95
    Thanks
    45
    Thanked 157 Times in 61 Posts

    MetalDesigner's Tools
    Well Done!! Great Project ... The parts are like artwork!!

    CHEERS!!

  4. The Following User Says Thank You to MetalDesigner For This Useful Post:

    Paul Jones (04-17-2016)

  5. #3
    Paul Jones's Avatar
    Join Date
    May 2014
    Location
    Yorba Linda, California
    Posts
    1,132
    Thanks
    4,838
    Thanked 1,208 Times in 596 Posts

    Paul Jones's Tools
    MetalDesigner,

    Thank you. I think I have the lathes so well adjusted and finely tuned that the finishing cuts no longer need any further polishing or improvement. What you see is the actual machined surfaces.

    Thanks, Paul

  6. The Following User Says Thank You to Paul Jones For This Useful Post:

    PJs (04-18-2016)

  7. #4
    bstanga's Avatar
    Join Date
    Sep 2015
    Posts
    78
    Thanks
    0
    Thanked 133 Times in 49 Posts

    bstanga's Tools
    Outstanding work Paul!

  8. The Following User Says Thank You to bstanga For This Useful Post:

    Paul Jones (04-18-2016)

  9. #5
    Content Editor DIYer's Avatar
    Join Date
    Aug 2013
    Posts
    3,087
    Thanks
    333
    Thanked 635 Times in 576 Posts


    Thanks Paul Jones! We've added your Dial Indicator Adjustable Arm Extension to our Lathe Accessories category,
    as well as to your builder page: Paul Jones's Homemade Tools. Your receipt:




  10. #6
    Christophe Mineau's Avatar
    Join Date
    Jul 2014
    Location
    France, Brittany !
    Posts
    682
    Thanks
    401
    Thanked 994 Times in 373 Posts

    Christophe Mineau's Tools
    Great, I like the way you take time to explain things Paul, and your finishing level is really impressive. I wish I could reach the same ... And I like the way you did the collar chuck, especially with the Dremel wheel, I would have done the same, I also find the Dremel on the lathe very useful.
    For the protractor level I also totally agree, and we could add that if possibly more accuracy was needed, it is always possible to put a straight edge on top of the chuck jaws and check with the level at the extremity of the straight edge, but obviously not necessary for your application.

    May I ask a question, except for the beauty of it, why didn't you use a simple set screw for attaching the arm of the DI instead of the collect chuck ?
    Thanks,
    Christophe
    Cheers !
    Christophe
    ________________________________________________________________
    Visit my Website : http://www.labellenote.fr/
    Facebook : La Belle Note
    All my personal works, unless explicitly specified, are released under
    Creative Commons BY-NC-SA license.

  11. The Following User Says Thank You to Christophe Mineau For This Useful Post:

    PJs (04-19-2016)

  12. #7
    Paul Jones's Avatar
    Join Date
    May 2014
    Location
    Yorba Linda, California
    Posts
    1,132
    Thanks
    4,838
    Thanked 1,208 Times in 596 Posts

    Paul Jones's Tools
    Christophe,

    Thank you and an excellent question about the use of a set screw. I originally wanted to use a cap head screw and offset the 8 mm hole closer to one edge of the 1/2" square shaft so there would be room to tap threads. In all the modifications to the Unimat, I have standardize on 8-32 cap head screws and M6X1 cap head screws for tightening parts to allow for only two sizes Allen wrenches. The size differences allow picking up the correct wrench the first time.

    The real reason I used the collet chuck is because it will be used in some of my future projects and I just wanted to see how to make one. There is one step in the chuck fabrication I thought might be a problem but I found a work-around. The 1/2" shaft is pre-drill to 8 mm x 2" deep (sorry about the mix of measurement systems but I am use to working in both systems) but there is some inward compression after slotting for the compression fingers (chuck jaws).

    However, after partially threading on the knurled steel collar there is slight (a few thousands) of inward compression on the four jaws before reaching the internal taper-end used locking the 8 mm shaft. At this point the 8 mm shaft of the Noga DI holder won't slide in. I made a 0.375" thick washer as a spacer that temporarily prevents the knurled collar from threading all the way and reaching its point of compressing the four jaws. I then re-drill the 8 mm hole (or use a spiral fluted reamer), removed the spacer, threaded the knurled collar back on but not fully tightened. The 8 mm shaft slides in freely until the knurled collar is tightened to full compression and locks the shaft.

    I hope this makes sense. Shown below are photos of this final operation using the temporary spacer to prevent the knurled collar from closing down completely on the chuck jaws.

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-closeup-temporary-spacer-drilling-final-8-mm-hole-id.jpg

    Cleaning up the chuck with an 8 mm drill to ensure a sliding fit to the Noga 8 mm shaft

    Dial Indicator Adjustable Arm Extension for Unimat Lathe-drilling-chuck-opening-final-8-mm-id-note-temporary-spacer.jpg

    Thank you for the question.

    Paul
    Last edited by Paul Jones; 04-21-2016 at 08:54 AM. Reason: Added photos showing the chuck jaws clean-up operation

  13. The Following User Says Thank You to Paul Jones For This Useful Post:

    PJs (04-19-2016)

  14. #8
    PJs
    PJs is offline
    PJs's Avatar
    Join Date
    Sep 2014
    Location
    Northern CA
    Posts
    1,098
    Thanks
    5,364
    Thanked 779 Times in 499 Posts

    PJs's Tools
    Thanks Paul and Christophe (good question). Had the same thoughts but really get trying to "make a collet chuck". A skill set and technique that is handy for all kinds of projects. Standardizing wrenches is way smart thinking IMHO. It's a pain to have 5 different ones at hand while on a project.

    Thank you Paul for the overall build with the detail on the collet build and the nuances to it! ~PJ
    ‘‘Always do right. This will gratify some people and astonish the rest.’’
    Mark Twain

  15. #9
    rossbotics rossbotics's Avatar
    Join Date
    Dec 2013
    Location
    Florida
    Posts
    511
    Thanks
    628
    Thanked 929 Times in 258 Posts

    rossbotics's Tools
    Hey Paul
    Great looking work and write up as well, that's a cool little setup you got there, nice work on the parts you made, they look outstanding, If you make a mistake now it's your fault ! LOL

    Cheers
    Doug
    Comments are always welcome
    Doug



    Tool Plans for Sale by rossbotics




  16. The Following User Says Thank You to rossbotics For This Useful Post:

    Paul Jones (04-19-2016)

  17. #10
    Paul Jones's Avatar
    Join Date
    May 2014
    Location
    Yorba Linda, California
    Posts
    1,132
    Thanks
    4,838
    Thanked 1,208 Times in 596 Posts

    Paul Jones's Tools
    Thanks Doug,

    The thing about mistakes when working on your own tool projects is these can become additional features (or not ).

    Last night, I weighed the "cool little setup" and discovered it added some weight in the last year with all the new tooling and attached parts. What you see in the first and second photos (lathe, milling head and cabinet full of tooling) now weighs 60.5 lbs. I would have never guessed the weight.

    Thank you,

    Paul


    Post your reply!
    Join 33,912 of us and get our 173 Must Read Homemade Tools eBook free.



    173 Must Read Homemade Tools
    Last edited by Paul Jones; 04-19-2016 at 10:18 PM.

  18. The Following User Says Thank You to Paul Jones For This Useful Post:

    PJs (04-20-2016)

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •