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Posted: 12/13/2008 8:37:22 PM EDT
| Is there a screw-type solution for mating a 604 upper that's not counter-sunk to an NDS-601, a la Colt's SP1? I have a 604 upper that I'm thinking about building on a 601 when they come back in stock but I'm not sure how they would go together. I might just wait it out and get an XM, but I love those slabsides.... |
I think one of these would work
yes, I know it's not a screw type 
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Why not have your upper countersunk/rebated??? Then you can get one of the cool pins to hold it together... 
But I admit I'm getting somewhat anal about authenticity...My rebated & pinned (with the ball & spring pins) uppers have all the mag fence milled off...  did you ad the "+"?
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It's probably a DPMS. Just sell it and get one of ours I'll add the + +1 sell what you have and buy what you want to build, if you don't do it now you eventually will.. Say Mike, any front pins yet, been waiting since middle of september for mine. got my receiver but no pin.. ordered both at the same time... |
Well, it's got a CM forge mark so doubt it's a DPMS.  I don't think I could sel it for enough to get one of yours.... although I am pretty tempted! But you know I plan on getting two or more 601s, so isn't that enough for you profiteering capitalists?? 
It doesn't have to be a screw-type solution, just has to work. I would consider having it rebated if someone could suggest a reputable (and affordable) person to do it. If they want $100 for it, I might as well buy a new one from NDS! I'm surprised there isn't a Colt SP1-ish screw for mating a small-hole upper to a small-hole lower. |
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Quoted:I would consider having it rebated if someone could suggest a reputable (and affordable) person to do it.
Any competent machinist can do it...the hangup is that by my measurements, the rebate/countersink is .325" OD and .090" deep...that .325" is an oddball size...(I measured a USGI Colt upper)... 
I'm not sure how important that size is...maybe someone here who has done it can comment...
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Quoted:I would consider having it rebated if someone could suggest a reputable (and affordable) person to do it.
Any competent machinist can do it...the hangup is that by my measurements, the rebate/countersink is .325" OD and .090" deep...that .325" is an oddball size...(I measured a USGI Colt upper)...
I'm not sure how important that size is...maybe someone here who has done it can comment...
I am no authority, but I would imagine that the minimum tolerance of the counterbore diameter is critical and the maximum tolerance is more lax. As long as the detent ball has enough room and is not depressed when the pin is fully seated. Counterbore depth probably has a tight tolerance as well. Too deep and the pin can possibly back out a little bit, too shallow and it won't fully seat. |
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Well, I just picked up a screw-type pivot pin on the EE that is described as being .250". Hopefully it works. I wanted to build an SP1 carbine look-alike, anyway.  I think you're going to find that set up looks like a standard pivot pin on the side without the screw. It's meant to butt up against the mag fence on receivers that weren't drilled for a captive type pin |
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I am no authority, but I would imagine that the minimum tolerance of the counterbore diameter is critical and the maximum tolerance is more lax...Counterbore depth probably has a tight tolerance as well. Too deep and the pin can possibly back out a little bit, too shallow and it won't fully seat. Yes...but...when the pin is installed, the diameter becomes the depth...and the depth becomes the width...
...You'd best buy that pin on the EE...
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did you ad the "+"? No...Haven't figured out how to do it yet... 
Defiant1 - Just get one of HeatNBeat's front pins now, and use the NDS pin for a spare when it comes in...
If you're enterprising, you could mask off the + on the lower, and apply some epoxy resin or something similar and apply the +. Once the resin cures, you should have a little cross on the lower. ~Augee |
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If you want to spend the postage you can send it to me, I'll set it up in the mill and do the counterbore por nada. Just consider it a "pay it forward" and pass the favor along. HeatNBeat - Do you have a miniature boring bar??? I'm curious as to how you can bore holes/reliefs that small...
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If you want to spend the postage you can send it to me, I'll set it up in the mill and do the counterbore por nada. Just consider it a "pay it forward" and pass the favor along. HeatNBeat - Do you have a miniature boring bar??? I'm curious as to how you can bore holes/reliefs that small... Um, my shadetree ass can do it on a drillpress... 
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Cool!...Where did you get the .325" end mill??? Well if you're a good shade tree with tools, a .312 end mill with paper folded beside the collet works. Or.. .375 that's been sharpened a few times. Or.. a drill bit with a pilot ground on the end to make a counterbore. Or.... if you're really shade tree like Beel a flat ended drill bit and real slow feed would work. Come on; it's only aluminum, not like it's made out of Unobtanium or something!
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Or.... if you're really shade tree like Beel a flat ended drill bit and real slow feed would work. Come on; it's only aluminum, not like it's made out of Unobtanium or something!
I suspect the drill bit is what he's thinking of...21/64" [.328"] would be close enough...ground flat at the end... 
But Travers has a double-ended 21/64" end mill for $16.46... 
I was hoping you had a source for miniature boring bars (adjustable)...
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Or.... if you're really shade tree like Beel a flat ended drill bit and real slow feed would work. Come on; it's only aluminum, not like it's made out of Unobtanium or something!
I suspect the drill bit is what he's thinking of...21/64" [.328"] would be close enough...ground flat at the end...
But Travers has a double-ended 21/64" end mill for $16.46...
I was hoping you had a source for miniature boring bars (adjustable)...
McMaster-Carr Part Number: 3050A53 $13.01 Each
Type: Square End Square-End End Mill Type: General Purpose End Mill Material: High-Speed Steel Coating: Uncoated Number of Flutes: Four Flute Single or Double End: Double End Style: Noncenter Cutting Mill Diameter: 21/64" Mill Diameter Tolerance: +.001", -.000" Shank Diameter: 3/8" Length of Cut: 3/4" Overall Length: 3-1/2" Helix Angle: 30° |
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I was hoping you had a source for miniature boring bars (adjustable)...
What would stop you from making an adapter bushing to mount a small boring bar in a boring head? Assuming you don't have a miniature boring head. ( boy oh boy that would be a nice thing to have! Hey Santa.......) |
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If you want to spend the postage you can send it to me, I'll set it up in the mill and do the counterbore por nada. Just consider it a "pay it forward" and pass the favor along. That's a Hell of a deal from a damn generous guy. DO IT! and pick up some parts from him while you're at it! +50 for Heatnbeat |
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What would stop you from making an adapter bushing to mount a small boring bar in a boring head? Assuming you don't have a miniature boring head. ( boy oh boy that would be a nice thing to have! Hey Santa.......) No, I don't have any boring head (for my mill)...Wish I did...Couldn't find one in Travers catalog...I have MacMaster's Brooklyn phone book here somewhere...I'll take a look...
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