B||ade
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« on: November 01, 2009, 06:03:54 AM » |
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Can someone help me decipher some of the information on the AR blueprint? IF this were an electrical/electronic schematic I could read it in my sleep. But there is a lot of info on the mechanical drawing that I either can not find or do not understand. I've searched the web over and the only information I could find was on ordering books or enrolling in college courses and I do not have the time for that right now.
My goal is to be able to machine one of my lowers from the print without having to use the jigs. here is a list of the areas I am having problems with;
I can find the dimension for the width of the pocket, and the overall length but I can not find the dimension for the length of the trigger and hammer pocket from the front to where the pocket for the safety lever starts. Ok, I think I found this one, deduct .491 from 2.560
Another thing is I need to brush up on math... the radius of the pocket corners is shown as .218. If I remember correctly the figure the diameter of the end mill to use for this you just double the radius which would come out to .436 so a 7/16 mill would be the correct one?
What is the width of the pocket for rear lock pin?
It appears that measurements all originate at the centerline of the front pivot hole, is this correct and would it be considered the "Datum point"
Lastly, I'm having trouble figuring out where to start the slot for the trigger. Am I missing it on the print?
Thanks for the help guys.
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lifeofahero
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« Reply #1 on: November 01, 2009, 01:53:43 PM » |
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Yep, 7/16 endmill gives the correct radius. I think the width of the rear take down pin lug is .500" Check out Ch. 10 of the Ray-Vin Tutorial. That should help with the trigger slot. http://arlower.ray-vin.com/ar15/ |
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« Last Edit: November 01, 2009, 01:55:45 PM by lifeofahero »
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goober
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« Reply #2 on: November 01, 2009, 08:02:46 PM » |
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as lifeofahero said, the Ray-Vin tut will help a lot.
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B||ade
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« Reply #3 on: November 02, 2009, 08:23:45 AM » |
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Thanks for the link to the Ray-Vin tutorial, How did I miss that? Anyway that is great piece of work and has answered all my questions. This is just what I needed to get the most out of my new DRO setup.
I do have one more question though now, I noticed in the tut that he mentions "touching off' quite a bit and uses a piece of paper between the mill bit and the parts surface. What is the point of the paper, is it just to keep from marking the part with the cutting blades of the bit?
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goober
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« Reply #4 on: November 02, 2009, 09:14:57 AM » |
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Thanks for the link to the Ray-Vin tutorial, How did I miss that?
yeah... its everywhere  http://www.cncguns.com/forum/index.php?topic=1258.0http://www.cncguns.com/forum/index.php?topic=1204.0http://www.cncguns.com/forum/index.php?topic=651.0http://www.cncguns.com/forum/index.php?topic=967.0http://www.cncguns.com/forum/index.php?topic=1253.0http://www.cncguns.com/forum/index.php?topic=809.0http://www.cncguns.com/forum/index.php?topic=821.0http://www.cncguns.com/forum/index.php?topic=969.0http://www.cncguns.com/forum/index.php?topic=1356.0http://www.cncguns.com/forum/index.php?topic=1229.0etc...  Anyway that is great piece of work and has answered all my questions. This is just what I needed to get the most out of my new DRO setup.
I do have one more question though now, I noticed in the tut that he mentions "touching off' quite a bit and uses a piece of paper between the mill bit and the parts surface. What is the point of the paper, is it just to keep from marking the part with the cutting blades of the bit?
its a common practice. keeps from marking the part &/or digging in, meaning you aren't at the Z of the surface any more, makes it so you don't have to back off, etc. |
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« Last Edit: November 02, 2009, 03:49:09 PM by goober »
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lifeofahero
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« Reply #5 on: November 02, 2009, 04:10:57 PM » |
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+1 what goober said.
Usually the thickness of a piece of paper is .003" and once you touch off on the paper, you can adjust the dials or dro to be negative 2-3 thousandths. This way you are precisely cutting from the given surface.
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guneng
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« Reply #6 on: November 02, 2009, 09:23:41 PM » |
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very true .002 to .005 use your mics or verniers . Make them snug and slide the paper through it is the best way to clean them. The same for you surface plate. Wipe it down with Windex and paper towel. When it drys wipe it with a clean pieces of printer paper in a figure 8 pattern until the paper stays white. It will feel smoother then a babies @$#*^
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IOWOLF
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« Reply #7 on: November 05, 2009, 12:39:18 PM » |
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Originally it was Cigarette paper(.001 ) and tolerances were .005 on a lot of things. If you Find a pack of papers in a Kennedy, chances are The machinist is NOT 420 friendly.  |
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ironlung
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« Reply #8 on: November 06, 2009, 08:25:15 AM » |
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Originally it was Cigarette paper(.001 ) and tolerances were .005 on a lot of things. If you Find a pack of papers in a Kennedy, chances are The machinist is NOT 420 friendly. Some tools have more than one use...  |
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goober
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« Reply #9 on: November 06, 2009, 09:52:27 AM » |
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Originally it was Cigarette paper(.001 ) and tolerances were .005 on a lot of things. If you Find a pack of papers in a Kennedy, chances are The machinist is NOT 420 friendly. Some tools have more than one use... says the guy w/ the nick "ironlung"  |
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