80% milling question

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  • John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,731
    Socialist State of Maryland
    I have been reading about making lowers and most posts talk about the jigs being made so you can use a router instead of a drill press or mill. I have a mill and I am wondering if I can still complete the lower with the current jigs or do I have to go out and buy a router.

    Thanks,
     

    MigraineMan

    Ultimate Member
    Jun 9, 2011
    19,109
    Frederick County
    There's nothing magical about jigs - they just make the process easy. There are plenty of dimensioned drawings available, and you just need to take your time and confirm your measurements. A DRO makes it easier, but you can count turns and read distances off the handwheel graduations (was done that way for a loooonng time.)

    Probably the most difficult element is getting a good reference from the front takedown pin location (everyone seems to use that as a datum.) You can insert a piece of drill rod, a metal dowel pin, or a close-fitting drill bit and use an edge-finder to pick up the edge, then offset back to the center. Slightly fussy, but works well.
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,731
    Socialist State of Maryland
    There's nothing magical about jigs - they just make the process easy. There are plenty of dimensioned drawings available, and you just need to take your time and confirm your measurements. A DRO makes it easier, but you can count turns and read distances off the handwheel graduations (was done that way for a loooonng time.)

    Probably the most difficult element is getting a good reference from the front takedown pin location (everyone seems to use that as a datum.) You can insert a piece of drill rod, a metal dowel pin, or a close-fitting drill bit and use an edge-finder to pick up the edge, then offset back to the center. Slightly fussy, but works well.

    Since you appear to be a machinist, you know how set up time eats up your time. Since I am now retired, I am willing to buy something rather than taking the time to make it. My time is more important since I don't have as much left as I used to. :lol:
     

    Boom Boom

    Hold my beer. Watch this.
    Jul 16, 2010
    16,834
    Carroll
    Research thoroughly before making an impulse buy. Don't buy based on low price. Lots of crap jigs for sale.
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,731
    Socialist State of Maryland
    Not trying to crap on your thread OP.......I had just never thought about a full milled 80% on a press[/QUOTE said:
    I never thought of doing it with a router. In my experience, routers were used for making molding and furniture in my younger years. :rolleyes:

    Since I didn't know about the router business, I always planned to use my milling machine to do it and ass u med, that all the jigs were for milling machines or drill presses.

    Ah well, live and learn. :lol:
     

    StantonCree

    Watch your beer
    Jan 23, 2011
    23,932
    I never thought of doing it with a router. In my experience, routers were used for making molding and furniture in my younger years. :rolleyes:

    Since I didn't know about the router business, I always planned to use my milling machine to do it and ass u med, that all the jigs were for milling machines or drill presses.

    Ah well, live and learn. :lol:

    I have no doubt you’ll do a decent job but I feel like that kids drill press lower was like a big hunk of poop metal

    Also I misspoke I meant to say never saw one being done on a mill....not thought.....damn bourbon and yelling child :)
     

    Sticky

    Beware of Dog
    MDS Supporter
    Mar 16, 2013
    4,501
    AA Co
    That will likely work fine for doing an 80 lower on a mill. I have done many and you really need the side plates to be able to hold the part accurately and locate the holes. The top plate on my jig is used to mate the side plates and also has inserts (at least mine does) to guide the milling. I did the majority of mine on a Bridgeport with DRO, so I didn't use the milling guides, just worked off a print and they all came out fine.

    I would much rather use a decent mill than a router, but then, I'm not much of a router... :lol2:
     

    Ranchero50

    Ultimate Member
    Dec 15, 2012
    5,411
    Hagerstown MD
    Since you appear to be a machinist, you know how set up time eats up your time. Since I am now retired, I am willing to buy something rather than taking the time to make it. My time is more important since I don't have as much left as I used to. :lol:

    With a decent CNC mill setup is 90% of the work. For pocket milling my program references off the center of the front pin hole for the X axis and center of the part on the Y axis. Then use a 1/4" carbide end mill with a 1.375" stick out. For the pin holes and safety, reference both the X and Y axis off the center of the front pin. .156" drill bit for the pin holes and 1/4" EM for the safety bore. Takes an hour or so to setup and complete one lower. I use a vise and sweep across the surfaces to get true setups. None of the lowers I've done were completely square. I think I do .050" depth cuts in the pocket so it's just a bunch of passes that take some time.







    So far no drama finishing them.
     

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