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Old September 15, 2019, 03:30   #1
Orion the Hunter
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Not So Golden Triangle....

Ok...Looks like I panned out a Nugget of Fools Gold within the Golden Triangle (story of my life):

I am in the process of (trying) to time an Indian Barrel to a Imbel Inch Upper.

For Starters....When I first threaded it up, it was way overtimed...

After acquiring some shims on hand. I have been trying different sizes and discovered that a .025 + .010 lands me right in within the notorious "Golden Triangle".

With that in mind, I figured, "Wouldn't it be better to have just (1) Shim, instead of (2)? Fortunately, I had a Shim that was larger than .035, so I shaved off a little bit at a time...until I landed it perfectly within the "Golden Triangle".

I was super stoked (since this is my first Shim-Sham-Attempt) and figured "what could possibly go wrong? I clamped everything in the vice...ready to rock...

I hand tightened the Upper until it landed snug in the "Golden Triangle" and then installed a cheater expecting the last twist to need some leverage.

WRONG.....

I bet I barely 40 - 50lbs until it reached 12:00 Top Dead Center....

Lesson Learned...."When Using Shims, the Golden Triangle Theory obviously doesn't apply....

Million Dollar Question:

So, what is the secret to get the freaking thing right? Obviously having the Notch on the Barrel aligned to the notorious "Golden Triangle" (10:00 O'Clock)...does not work for shims.....

So then....Where is a good position to have it land so it torques to 120lbs etc?

9 O'clock? 8 O'clock? Any suggestions out there regarding where the "SHIM GOLDEN TRIANGLE" is located??????????????????????????????

Last edited by Orion the Hunter; September 15, 2019 at 04:20.
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Old September 15, 2019, 06:48   #2
The Chief
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Sometimes OEM breeching washers have more 'give' to them, whereas the steel in some custom washers can be a bit harder and give less. I've had this issue. The 'golden triangle does hold sway, in my experience, with the OEM washers with the numbers stamped on them, but sometimes some trial-and-error must be dome... best of luck!
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Old September 15, 2019, 09:31   #3
hkshooter
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What Chief said plus, if you had to shave a larger shim, did you get it perfectly flat? If there's a high spot or two that can give you the impression of timing perfectly but when you crank on the torque the high spot gives easily long before the rest of the shim will start to add resistance. The shaving, be it the receiver face, the barrel shoulder, or a breeching washer, need to be done as flat as possible so there isn't a false timing issue.

And it just came to mind, watch that the washer or shim stays centered during the torquing of the barrel. Sometimes they will shift or smear off center and you hand guard ring won't fit.
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Old September 16, 2019, 04:50   #4
Orion the Hunter
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WECSOG Shim Shave...

What I did...

Was set my Belt Sander (fine) on slow auto-mode and clamped it upside down in the vice and (with gloves on) held it flat and altered it from side to side.

According to my rudementary calculations, when I stacked on a .025 + .010 it came in just over the Golden Triangle, which lead me to believe that my goal was ~.036 to .038

I kept alternating back and forth...shave a little..test..shave..test until it landed spot on the Golden Triangle.

However...

When I attached the Torque Wrench..as mentioned...it is way undertorque'd.

Finally, I Mic'd it out to see how far off I am: It appears to fall anywhere from .0365 to .040.

Next plan of attack it to order a couple more larger Shims and try it again I suppose. This time, I will be sure to stop way before the Golden Triangle and Mic it out to see if there is Highs and Lows..maybe I can use some emery cloth to level that out?

PS: Good point on centering the Shim. I did center it on the barrel "Just Because it was there" but it never dawned on me that it would foul up the HG situation...! That would have sucked big time!
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Old September 16, 2019, 07:06   #5
Grahamneall
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James.

Since you talking about 0.010" thou or so tolerance, you might try to 'stone' the final finish after the sand belt grinding .

Try to find some machinist 'blue' (actually, cold gun blue may work ?) and providing your stone is flat (true), the blue will show you the 'Low' spots on the shim after each stoning.

Just keep applying the blue and stone it, until all the blue is gone after stoning.

Graham.
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Old September 18, 2019, 05:42   #6
Orion the Hunter
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Stoning Is Next...

I never thought about trying a Sharpening Stone...

I have ordered a couple more larger Shims to give it another try. I think this time I will try shaving with a stone vs Belt Sander (although it may take a month of Sundayís).

Thanks and Good ideas everyone, I will keep ya posted....
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