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  • 3t-
    replied
    Thanks, I appreciate the info.

    Leave a comment:


  • jugs
    replied
    [quote=3t-]I have one of these http://www.jtsmach.com/jtswebshop/MillingTools/M033.asp
    that came in a box of lathe tooling and chucks. I have it set aside to use in my turret lathe.

    Can this also be used in a Bridgeport type mill in place of a standard boring head to machine a boss?[/quote]

    Yes ... but make sure everything is locked down tight before you start cutting, or things could start flying about , once the cut is on, it's self centering.

    john

    Leave a comment:


  • Rif
    replied
    Hello,

    Yes, it can. I am using an almost identical one to machine a boss. It works a lot faster than a boring head would.

    Regards,

    Brian


    Originally posted by 3t-
    I have one of these http://www.jtsmach.com/jtswebshop/MillingTools/M033.asp
    that came in a box of lathe tooling and chucks. I have it set aside to use in my turret lathe.

    Can this also be used in a Bridgeport type mill in place of a standard boring head to machine a boss?

    Leave a comment:


  • J. R. Williams
    replied
    Hollow Mills

    Try (Geneseemfg.com) as they make a line of adjustable hollow mills. I have a set of four and have the smaller one loaned out. The cutter blades are carbide tipped and reasonable in price. The set just finished a 3K part run in brass. They save several operations and were used on a small Hardinge CNC.
    JRW

    Leave a comment:


  • 3t-
    replied
    So just to clarify

    I have one of these http://www.jtsmach.com/jtswebshop/MillingTools/M033.asp
    that came in a box of lathe tooling and chucks. I have it set aside to use in my turret lathe.

    Can this also be used in a Bridgeport type mill in place of a standard boring head to machine a boss?

    Leave a comment:


  • Rif
    replied
    Originally posted by jkopel
    @Rif
    Take a look at the last image in this thread on PM
    http://www.practicalmachinist.com/vb...collet-192877/
    Looks a LOT like what you are trying to accomplish.

    Hello,

    Thanks for posting that link. I bought a pot collet and tried to machine it out to do the 5/8" square brass off-center on the lathe. But, I wasn't very successful with the square hole. Making up a master collet and using inserts is a great idea and a money saver given the price of those collets.

    Regards,

    Brian

    Leave a comment:


  • jkopel
    replied
    pot chuck

    @Rif
    Take a look at the last image in this thread on PM
    http://www.practicalmachinist.com/vb...collet-192877/
    Looks a LOT like what you are trying to accomplish.

    Leave a comment:


  • DATo
    replied
    OK Rif , I got ya. A picture is worth a thousand words *LOL* I thought you were only interested in creating something that would look like an o ring groove.

    Leave a comment:


  • Rif
    replied
    Hello,

    What I am doing is using a hollow mill to create a 0.150 long boss that is 3/8" in diameter on a piece of brass. Then I use that boss to hold the brass in a 3/8" 5c collet on a lathe. On the lathe, I then turn down the other end to 3/8". Check out the picture about 1/4 the way down this page: http://www.reprap.org/wiki/J_Head_Nozzle

    Basically, I am doing off-center turning and I am using this method as a fast way to setup the piece in the lathe as opposed to fiddling with a 4-jaw chuck. The end that I cut with the hollow mill eventually becomes the tip of an extrusion nozzle that is used in a 3d printer.

    I checked out that machine you have a link to. I don't think I could fit it in my basement.

    Regards,

    Brian


    Originally posted by DATo
    I'm not really sure I understand what you're trying to do but you might consider grinding a broken or dull end mill to the shape of a lathe parting tool making sure to have a square bottom and then using the boring head and offsetting it such that the inside sweep of the tool generates the diameter of the boss. The process is called "trepanning".

    EDIT: Check this out http://www.youtube.com/watch?v=Rvk8RKFVXwA

    You'd be doing this in the mill of course with only one cutting edge if you use the single point tool method described in my post.

    Leave a comment:


  • DATo
    replied
    I'm not really sure I understand what you're trying to do but you might consider grinding a broken or dull end mill to the shape of a lathe parting tool making sure to have a square bottom and then using the boring head and offsetting it such that the inside sweep of the tool generates the diameter of the boss. The process is called "trepanning".

    EDIT: Check this out http://www.youtube.com/watch?v=Rvk8RKFVXwA

    You'd be doing this in the mill of course with only one cutting edge if you use the single point tool method described in my post.
    Last edited by DATo; 05-28-2011, 08:39 PM.

    Leave a comment:


  • jugs
    replied
    Originally posted by Arthur.Marks
    PixMan,
    Old, old, old type: http://www.brown-sharpe.com/102103.php
    Typical HSS type: http://www.jtsmach.com/jtswebshop/MillingTools/M033.asp
    New indexable type: http://www.sommatool.com/catalog/cut...hollowmill.asp

    They're for turret lathe work. Rapid removal of stock.

    Hollow mills ???
    We know them as tangential box tools.

    A hollow mill is like a Rota-broach.

    But a broach is a shaped hardened rod, pushed through a hole to make a shaped hole / keyway/ splines / internal gears .......

    Then we have
    Taps you can't hit or get water from, Right hand tools cutting on left & Left hand tools cutting on right,
    No wonder no one knows what we're talking about (including us )

    john

    Leave a comment:


  • Rif
    replied
    Originally posted by Toolguy
    Rif-
    Why not use a 5/8 square collet with a stop and a vertical collet fixture in the mill? You could cut your bars to finish length to begin with, then simply do each end in the mill with a stop for the quill to come down against. That would go very quickly, especially with an air collet fixture. The cutting edges are held very securely and the hollow mill does not fly apart when rotating.
    Hello,

    I just wanted to add an update and thank you for this advice.

    I was using a vise and, due to the small size of the brass at only about 1.125 long, I was scrapping a few pieces here and there as they wouldn't always stay in the vise properly. This was even after I tightened it up really tight.

    So, I remembered your advice and tried it. Using a 5c collet fixture, with a 5/8" square collet, worked great. There was no more scrap. Even the hand cranking on the horizontal mill wasn't bad at all.

    Here is a link to what I have been making: http://www.reprap.org/wiki/J_Head_Nozzle

    Thanks!

    Brian

    Leave a comment:


  • Rich Carlstedt
    replied
    Rotabroach comes to mind

    http://www.hougen.com/cutters/rotabroach_advantage.html

    Leave a comment:


  • Rif
    replied
    Originally posted by Toolguy
    Rif-
    Why not use a 5/8 square collet with a stop and a vertical collet fixture in the mill? You could cut your bars to finish length to begin with, then simply do each end in the mill with a stop for the quill to come down against. That would go very quickly, especially with an air collet fixture. The cutting edges are held very securely and the hollow mill does not fly apart when rotating.

    That would work nicely. There is only one problem. (Which I didn't mention and you wouldn't have known.) My biggest mill is a Hardinge TM horizontal. (My other mill is a Sherline 2000....let's not go there. )

    Some day I would really like to get a mill, with a quill.

    On the other hand, I do have two collet fixtures and would just have to get a square 5/8" 5c collet. (No air collet fixture; but, that would be cool.)

    I'll certainly keep the 5c collet idea in mind. I was thinking about using a vice and a vice stop.

    Best Regards,

    Brian


    I

    Leave a comment:


  • Toolguy
    replied
    Hollow mill

    Rif-
    Why not use a 5/8 square collet with a stop and a vertical collet fixture in the mill? You could cut your bars to finish length to begin with, then simply do each end in the mill with a stop for the quill to come down against. That would go very quickly, especially with an air collet fixture. The cutting edges are held very securely and the hollow mill does not fly apart when rotating.

    Leave a comment:

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