Free 50 Best Homemade Tools eBook:  
Remove advertisements
Page 2 of 2 FirstFirst 1 2
Results 11 to 16 of 16
  1. #11
    mklotz mklotz's Avatar
    Join Date
    Aug 2015
    Location
    LA, CA, USA
    Posts
    1,315
    Thanks
    84
    Thanked 2,362 Times in 845 Posts
    Quote Originally Posted by jjr2001 View Post
    Thanks for all the great info guys. I see that TM51 had a link where they are putting a large 3 or 4 jaw chuck on the tail stock.
    Marv's solution is eye opening....Why did I not think of that....Pull out only the part that you need and then extend the blank
    and continue keeping the part close to the collet or chuck.....I will try that method....

    So far it is little piece of steel 2 and hobbiest 0.....Tomorrow I will try again.

    I think my lathe tool bits were too dull. Sharpened all of them today and we should have a part by tomorrow night..

    Cheers, JR

    Oh, the model I am working on is Gerry's Beam engine. I posted a few of the parts completed so far here:
    Gerry's Beam Engine

    The interesting part I am working on is the shaft for the steam chest valve.
    Here's another approach to add to your list of ways to attack this job...

    It's called a traveling steady. For large work this is a frame that is attached to the carriage and carries two adjustable arms that are set to keep the work from deflecting away from the tool. If you type "travelling steady" into Google Images, you'll get lots of pictures showing what they look like and how they are deployed in use.

    The idea is that the travelling steady, as its name implies, travels with the tool, unlike the more common fixed steady which remains stationary. This means that the support of the work is always close to where the tool is cutting.

    The conventional travelling steady is way too large and cumbersome to be used for tiny model engine work. Nevertheless, the idea is a good one and model engineers have come up with many variants that better suit their purposes.

    One of these is a piece of stock with a hole the size of the parent stock drilled through it. This is clamped to the left side of the lathe tool with the stock to be cut passing through the hole. With the stock supported right next to where the cutting action is taking place deflection is vastly reduced.

    Of course, this simple version has a major drawback. If you want to take a second pass on your cut, the hole in the steady will be too big. So this version is really only good for a cut that can be completed in one pass. Often, on tiny engine parts, this is possible.

    When it isn't possible, tiny adjustable fingers [Sometimes a single adjustable finger with a birdmouth "V" groove is used.] are added to the steady so it can mimic the action of its bigger brother with the difference that it is attached to the tool or toolpost rather than the carriage. A Google search of the various fora that support model engine building will probably produce some designs (but it's probably more fun to design your own).

    Keep this idea in your mental tool idea repository. Even if you don't need it at the moment, it may come in handy in the future.
    ---
    Regards, Marv


    Home Shop Freeware
    http://www.myvirtualnetwork.com/mklotz

  2. The Following User Says Thank You to mklotz For This Useful Post:

    jjr2001 (05-08-2017)

  3. #12
    metric_taper's Avatar
    Join Date
    Mar 2017
    Location
    Marion, Iowa
    Posts
    112
    Thanks
    41
    Thanked 40 Times in 28 Posts
    duplicate message, somethings .......
    Last edited by metric_taper; 05-08-2017 at 09:51 AM. Reason: duplicate

  4. #13
    jjr2001's Avatar
    Join Date
    Jun 2016
    Posts
    568
    Thanks
    736
    Thanked 951 Times in 350 Posts
    Quote Originally Posted by metric_taper View Post
    I'm curious how good the runout of the 3 jaw drill chuck is?

    I like the idea of the 3 bearings that will average out the radial play to near zero, as well support the cantilever forces from the 3 jaw chuck.
    Well my assembly runs just a bit better than .001" . However after trying 4 small chucks (3 jacobs ) I was able to get the total runout to about .003". These economy chucks are not so great.

    The jacobs chucks are the lower quality designed for small hand drills and such. So I ordered a 7BA and that hopefully will be much better. The worst one had .008" runout with a dowel pin in the jaws.
    Last edited by jjr2001; 05-08-2017 at 10:36 AM.

  5. #14
    jjr2001's Avatar
    Join Date
    Jun 2016
    Posts
    568
    Thanks
    736
    Thanked 951 Times in 350 Posts

    Made a good part

    Well I do have a traveling steady but it is a bit large but I guess I could have tried it....I have pictures of a "micro traveling steady" that is on my build list.

    The thing is that what Marv said, "Shafts with turned down sections on the ends of the parent stock can be turned without benefit of TS support by feeding just a small bit of the parent out of the collet, turning it to size, then feeding a bit more out, turning, etc." was the answer I needed.

    I used a 4 jaw chuck and just re-centered the square stock after each new stick out.
    Thanks again Marv. Your process worked very well and I now have my stem for the steam chest. Yippie.

    Here are a few pics with the two pieces of "practice metal" and one good part.

    Cheers, JR
    Attached Thumbnails Attached Thumbnails Revolving Tail Stock Chuck or Rotating Tail Stock Chuck-2.jpg   Revolving Tail Stock Chuck or Rotating Tail Stock Chuck-3.jpg   Revolving Tail Stock Chuck or Rotating Tail Stock Chuck-4.jpg   Revolving Tail Stock Chuck or Rotating Tail Stock Chuck-5.jpg   Revolving Tail Stock Chuck or Rotating Tail Stock Chuck-6.jpg  


  6. The Following User Says Thank You to jjr2001 For This Useful Post:

    Paul Jones (05-09-2017)

  7. #15
    mklotz mklotz's Avatar
    Join Date
    Aug 2015
    Location
    LA, CA, USA
    Posts
    1,315
    Thanks
    84
    Thanked 2,362 Times in 845 Posts
    I'm very pleased it worked for you. Be sure to favor us with some stills and video of the engine after it's completed. It looks like it will be a real winner.
    ---
    Regards, Marv


    Home Shop Freeware
    http://www.myvirtualnetwork.com/mklotz

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

    jjr2001 (05-08-2017)

  9. #16
    Content Editor DIYer's Avatar
    Join Date
    Aug 2013
    Posts
    3,072
    Thanks
    306
    Thanked 603 Times in 545 Posts


    Thanks jjr2001! We've added your Rotating Tail Stock Chuck to our Machining category,
    as well as to your builder page: jjr2001's Homemade Tools. Your receipt:





    Post your reply!
    Join 33,912 of us and get our 50 Must Read Homemade Tools eBook free.



    50 Must Read Homemade Tools

  10. The Following User Says Thank You to DIYer For This Useful Post:

    jjr2001 (05-09-2017)

Thread Information

Users Browsing this Thread

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

Tags for this Thread

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
  •