80% lowers, etc...

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    fabsroman

    Ultimate Member
    Mar 14, 2009
    36,005
    Winfield/Taylorsville in Carroll
    Chriss613 said:
    How tight are they when attached with an upper? Is there any any play?
    Click to expand...

    How tight they are when mated to an upper will have virtually nothing to do with the completion of the 80% lower. Those dimensions are already in the upper when it is shipped. Now, if you are really worried about how tight they are when attached, and you know how to drill a hole and tap it, you could order some of these:

    http://www.tacticalinc.com/upper-receiver-tensioning-screw-for-ar15-receiver-p-1130.html

    When installed properly, they look like #8 in the description of this:

    http://www.tacticalinc.com/t15™-ar15-lower-receiver-with-stba™-installed-p-1162.html
     
    Bolts Rock

    Bolts Rock

    Living in Free America!
    Apr 8, 2012
    6,123
    Northern Alabama
    FlatsFlite said:
    Nope, aluminum blanks. If your speed is right it cuts like butter. The only issue is the end mill wants to creep out. I used a small laminate router, I learned on the first one to check my depth every half pass. That was the only problem.

    It's actually super easy, just go slow. An easy hand will feel a problem before it develops.
    Click to expand...

    It creeps out of the collet because of the flute geometry, mills tend to be up cut and it pulls the bit into the work, this can cause the bit to pull out of the collet. When that happens really fast it can fling the bit at incredible force. Down cut bits on the other hand can throw the router out of the work and that's not a whole lot of fun either. Ask me how I know.

    As for why the upcut flute bits creep out of the collet it is caused by improper collet size and/or type. Routers have crappy collets, especially small routers that have a faux collet cut into the motor shaft. Even the Porter Cable type collets don't have that good a grip, especially on slick carbide shanks. I would never put a carbide bit with upcut flutes in a cheap router collet integral with the motor shaft; I'd use HSS instead because it's a little rougher and the collet grips it better.
     
    boatbod

    boatbod

    Ultimate Member
    Nov 30, 2007
    3,833
    Talbot Co
    Bolts Rock said:
    As for why the upcut flute bits creep out of the collet it is caused by improper collet size and/or type. Routers have crappy collets, especially small routers that have a faux collet cut into the motor shaft. Even the Porter Cable type collets don't have that good a grip, especially on slick carbide shanks. I would never put a carbide bit with upcut flutes in a cheap router collet integral with the motor shaft; I'd use HSS instead because it's a little rougher and the collet grips it better.
    Click to expand...

    Glad it's not just me this happens to. I had an endmill creep out of it's collet (in a manual mill) far enough that it trashed the part being machined. Very frustrating!
     
    85MikeTPI

    85MikeTPI

    Ultimate Member
    Jul 19, 2014
    2,744
    Ceciltucky
    To continue the concerns after building:

    So has anyone had to deal with a LEO concerning a completed 80% lower?

    What would a town or county officer know or deal with you having an unserialized rifle if pulled over or in an accident on the way to/from the range?

    How would you deal with LE and insurance if a completed lower was stolen from your house?

    Do you have to retain any documents concerning the purchase date of the 80% and/or completion date for future issues like those above or other?
     
    Bolts Rock

    Bolts Rock

    Living in Free America!
    Apr 8, 2012
    6,123
    Northern Alabama
    boatbod said:
    Glad it's not just me this happens to. I had an endmill creep out of it's collet (in a manual mill) far enough that it trashed the part being machined. Very frustrating!
    Click to expand...

    Yep, I learned a long time ago that shallow cuts are best with them and check the depth every pass. Trashed a beautiful piece of walnut I was routing a barrel channel in for a muzzle loader.
     
    lsw

    lsw

    לא לדרוך עליי
    Sep 2, 2013
    1,975
    FlatsFlite said:
    Nope, aluminum blanks. If your speed is right it cuts like butter. The only issue is the end mill wants to creep out. I used a small laminate router, I learned on the first one to check my depth every half pass. That was the only problem.

    It's actually super easy, just go slow. An easy hand will feel a problem before it develops.
    Click to expand...

    What about using an actual carbide straight-flute router bit? It should be able to cut aluminum easily and the straight flutes wouldn't tend to pull it out of the collet like the spiral end mill flutes.
     
    Bolts Rock

    Bolts Rock

    Living in Free America!
    Apr 8, 2012
    6,123
    Northern Alabama
    lsw said:
    What about using an actual carbide straight-flute router bit? It should be able to cut aluminum easily and the straight flutes wouldn't tend to pull it out of the collet like the spiral end mill flutes.
    Click to expand...

    Poor chip clearance and less smooth cut. Bit geometry means something.
     
    FlatsFlite

    FlatsFlite

    Active Member
    Aug 6, 2012
    691
    King George, VA
    lsw said:
    What about using an actual carbide straight-flute router bit? It should be able to cut aluminum easily and the straight flutes wouldn't tend to pull it out of the collet like the spiral end mill flutes.
    Click to expand...

    I defer to Bolt's response, as I don't know squat about machining. Modulus did the thinking for me. I just followed the directions to the letter and it was nearly flawless.
     
    jcbvh

    jcbvh

    Active Member
    Dec 30, 2012
    995
    Louisiana Cajun Country
    85MikeTPI said:
    To continue the concerns after building:

    So has anyone had to deal with a LEO concerning a completed 80% lower?

    What would a town or county officer know or deal with you having an unserialized rifle if pulled over or in an accident on the way to/from the range?

    How would you deal with LE and insurance if a completed lower was stolen from your house?

    Do you have to retain any documents concerning the purchase date of the 80% and/or completion date for future issues like those above or other?
    Click to expand...

    I would put some form of identification on it. Although its not required, the ATF suggests you do it just in case it gets stolen.

    Besides, it avoids any issue with trying to explain the law to the police or whomever.
     
    B

    buckshotu2

    Member
    Sep 30, 2013
    54
    I suppose one can't be too safe when creating your own custom rifle from a paperweight. I would probably also stamp something to identify it as yours..... I haven't yet built a 80% lower myself, but seems like sound advice from those above....
     
    DutchV

    DutchV

    Ultimate Member
    Jul 8, 2012
    4,738
    You don't have to go overboard with markings. Just enough to be unique. Initials, city, state, serial number. Or even a made-up manufacturer name. You're not trying to do anything fraudulent, so if you want a DeWalt lower, go for it.
     
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