Yes I did before the first shot. Part of my "pre-checks" at home.Originally Posted by BillSWPA
Yes I did before the first shot. Part of my "pre-checks" at home.
My friend who did it for years has explained to me many times that making parts to fifty millionths requires that temperature and barometric pressure be controlled in the lab just to measure them with sufficient precision. Very few machines have the inherent precision required to achieve such numbers.
Move the decimal one place to the right, and it's a lot more doable, but still subject to all the issues you mention and many more. Remember that "tooling," in this situation, includes every moving part in the system, from the fixturing to the cutter itself to the bearings and the ball screws on the actuators.
Don't want to jump on your case, but after years of being part of the management of a business that machined a lot of parts, the phrase "CNC has made it impossible to produce an out-of-spec part" kinda sets me off. CNC is a wonderful tool, but I feel a need to help people understand there are sooooo many ways to make parts not-to-print, and so much effort required to get it right and operate "in control," consistently.
On the other hand, the last two brand-new revolvers (one S&W and one Ruger) I've bought have ended up being sent home due to dimensional issues that were apparent to me just by looking, which means stuff was off by a lot more than half a thou.
So... this made me take a closer look at my relatively new M69, and the barrel is clocked, ever so slightly, but this causes the lines on the top of the barrel to not line up with the lines on the top strap, and more importantly, the detent ball is not centered in it's detent.
I believe the barrel is screwed in with a special mandrel, is the sleeve just sandwiched between? Can it be moved just by turning? Is this how you plan to fix your 617?
Olong, no offense taken - just because a machine can do something doesn't mean that's the result. Maybe I should have said more consistency, and can allow for less tolerance stacking.
We were dealing with jet engine shrouds, and had .003 to .005 play for most dimensions on finished parts. We had issues like no other after lunch (temp changes), the fixtures weren't designed properly, hastaloy vs S7 wearing, and hiring the cheapest labor possible all played into a big mess. The company thought that six sigma would fix everything (it doesn't), but wouldn't change anything in their processes.
Again though, craftsmen (in this case, machinist and tool/die) that gave a damn would have fixed their issues. But they also would have had to pay 3x the labor costs (while having very little problems with their parts, but hey).
Last edited by jeep45238; 12-02-2016 at 05:16 PM.
my 686 has a canted barrel, and I've debated sending it in to get it fixed. the rear sight is cranked all the way to it's limit to correct the POA/POI error.
and thinking about it, maybe it's a 6" issue?
here's my data points:
my 686 is 6". it's got a canted barrel.
my 617 is 4". it's dead on.
a friend of mine has same but different...
his 686 is 4" and is dead on.
his 617 is 6" and it's canted.
Mr. Kelley's 617 is also a 6", and it's canted.
I could be totally wrong though.
The "fix" is pretty straight forward. Barrel vise, and a frame wrench. Rotate barrel to suit. Over the many years of playing with our beloved ballistic toys, I have collected lots of tools and some knowledge in using them.
Thanks for your feedback. Over the years I have become, as I might say, a little more "bold" and I can fabricate things that will adequately support and grab things. I have also developed a feeling that many things that are perceived to be complex and precise are really not that complicated. I have also evolved to the point that I am not so risk adverse when it comes to making things right on my own, and if they end up NOT right, well, it is my fault...
Emboldened by your verification of my suspicion I will sally forth and concoct something to adequately support the frame and grab the shroud and umph it to where it needs to be.
Now, about the hole in the side of the frame...
Ive seen barrels not indexed correctly back into the 80s. When I wanted to by a 629, the one in the case was clocked a little. I asked if they had more in back, the guy brought 6 or 8 out, I found the best one and bought it.
The unpinned barrels are pretty danged tight, at least the earlier versions Ive messed with. Without adequate support you can twist the frame. The frame blocks Brownells sells work.
Last edited by Malamute; 12-02-2016 at 08:26 PM.
I am gonna just stick a broom handle through the frame and crank on it. I'm KIDINGGGGGG, I'm KIDINGGGGGG !!!
Here is the part that has a burr under my saddle:
I read another thread where S&W called this "they get them as close as they can". In fairness it shoots just fine, and yes I could make some waves and get a shipping tag, but these are the two piece barrels and the external shroud should just be able to spin. Anyway, at some point I will try it, right now I am busy doing the grip chop on my M&P and painting my house, this may be a round tuit project for a bit.
"Close as they can get them while highly inebriated" seems more like it. That is truly abysmal. I hope you get it fixed.
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