Announcement

Collapse
No announcement yet.

thru boring a 6" chuck for direct bolting to rotary table

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Hey that's some helpful math to aid my layout. or scare me off my present plan. I may have to drill and tap - which is fine too. .654 from the jaw centerline - I dont see how that can work with jaws that have to be close to an inch. I need .125 clearance and .1875 (half of bore) so .312 from edge of jaw. .812 from center. So I'm thinking I can go the edge but it sounds too tight.


    Originally posted by old mart View Post
    When I wanted to mount 3 jaw scroll and 4 jaw independent on a 4 tee slot RT, the four jaw just needed front mount holes, bolts and tee nuts. The three jaw problem was solved by mounting the front mount chuck using tapped holes directly into the RT. I should have removed the top to examine it properly, as one of the holes happened to intercept a lubrication drilling which I had not noticed. So a second set of holes were drilled in full thickness metal. Before tightening the three jaw, I gently clamp the jaws onto a MT2 arbor fitted in the centre of the RT. That centralises the chuck and the screws can be tightened. It might be possible to find a position for 4 threaded holes in the top of a 3 slot RT to mount a 4 jaw independent directly. If the threaded holes are no closer than 1/8" from a tee slot, it would be feasible.
    Drilling the chuck with three holes will result in 2 of them being 15 degrees from the centreline of 2 of the jaws. The further out the holes are drilled results in that 15 degrees being a larger measurement. If the holes in the chuck are drilled on the 5" diameter, 2 of the holes will be 0.654" from the jaw centreline. That may be enough with a 6" chuck.

    Comment


    • #17
      Wow loved watching this video link, that guy is just too cool. I'm planning to center the table and lock in on the spindle. As far as then mounting the 4 jaw I dont have the foggiest clue. I've never gone down this road. really lookiing forward to having the ability to grab work this way. I'm also ordering a MT3 draw bar style blank so I can mount a small 3 jaw for round stuff and 5C collets.

      Thanks on 1/64 over. Makes sense.

      Sorry but I'm not understanding what butting 3 cap screws in a 4 jaw means... coming in from bottom?

      the Insane step drilling was bc I read about semi steel and thought it might be pretty hard. my science was bad on the sizing I guess. Doozer has been talking me out of my tree on this matter ;-)





      Originally posted by The Metal Butcher View Post
      I wrote this before the rest of the discussion but got sidetracked, so I'm gonna post it anyway as is:

      You might find this video useful: https://www.youtube.com/watch?v=MGCBrhsUVu0

      At any rate, it's not that critical. Especially if you're going to bump it in anyway. In fact, I would go 1/64th over. Working overly-tight when there is no reason for it does nobody any favors. I guess since it's a 4 jaw it doesn't matter if the body runs out, whereas it does on a 3 jaw.

      PS, have you checked butting 3 caps screws in a 4 jaw? 4 and 3 don't generally jive, but maybe you can fit them in.

      Lastly, what's with the insane step drilling? 3/8" is a pilot drill in cast iron. Hell, 5/8" is a pilot drill in cast iron unless your tools are small. 3/16" just means a lot more chip clearing and chances for wander.

      Comment


      • #18
        Ive been thinking about how to do this - so thanks. I can center the table, it's really clear conceptually. But the chuck and these mounting bores are tough. I have a lathe - I think you are saying turn a double ended allignment pin that is a tight fit to both RoTab and Chuck center bore? They make Mt3 machinable blanks up to 1.5" diameter, might not be quite enough for chuck so I can turn a delrin sleeve. But am I reading you right? cause that makes the whole set up wicked clean if so.



        Originally posted by Bented View Post
        Drill the mounting holes with substantial clearance, .010" per side minimum, these holes do not align the chuck to the center of rotation.

        If you do not have a lathe mill a pilot that fits the thru hole of the table in place flip it over then mill a diameter that tightly fits the chuck bore, this will center the chuck whilst the bolts merely hold it down.

        Comment


        • #19
          Originally posted by Bill White View Post
          Ive been thinking about how to do this - so thanks. I can center the table, it's really clear conceptually. But the chuck and these mounting bores are tough. I have a lathe - I think you are saying turn a double ended allignment pin that is a tight fit to both RoTab and Chuck center bore? They make Mt3 machinable blanks up to 1.5" diameter, might not be quite enough for chuck so I can turn a delrin sleeve. But am I reading you right? cause that makes the whole set up wicked clean if so.




          Exactly, many rotary tables have straight pilot bores rather then tapers.

          Comment

          Working...
          X