Shouldn't a dovetail be square?

BullOnParade

BullOnParade

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In a machining sense, I mean, that's what I thought ...

Backstory:
A couple of weeks ago, I picked up a chiappa mare's leg. My goal for this rifle is a handy little brush gun while building trails and general work around a piece of land my wife and I just bought. With that in mind, I want to mount a red dot.

So I took the barrel into work, measured up the dovetail on the shadowgraph, and milled up a Picatinny rail to replace the rear sight. I mounted everything tonight, and theres a glaring angular gap where the rail meets the octagonal barel and an ever so noticeable cant to the left.

Now, to me, there's something off about the dovetail slot. But this is my first time actually machining something to fit one. Am I missing something?

I'll post some pictures tomorrow if there's interest.
 
Not sure about dovetails and guns but in carpentry the sides angle out (or in depending on which piece) this the name dovetail.
Mortice and tenon joints on the other hand are square.
 
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I believe that he understands that the dovetail is angled, I think that when he speaks of "square" he is referring to the dovetail being machined at 90 degrees to the slide which is in fact how it should be cut.
 
JW15s by Norinco often suffer from the same misalignment... set err up in the mill by eye... Likely the issue; cutting corners, not following "standard" work or operating procedure. Fulfilling orders come before quality control (old industrial adage: "it's better to ship #### than to short ship"; warranty claims may cost less than missed shipment penalties... or they just don't give a crap.
 
LOL I appreciate that a dovetail is angled in from the base and not 90 degree angles.

I'll get some pics up tomorrow probably. I'm not encouraged by the issues I've found, especially in the mare's leg manufacturer who's often considered the highest quality. But like I said, it's a platform that appeals to me, so I aim to make it right. I just figured I'd get to spend more time making custom and specialty parts opposed to fixing bad factory work.
 
BullOnParade said:
LOL I appreciate that a dovetail is angled in from the base and not 90 degree angles.

I'll get some pics up tomorrow probably. I'm not encouraged by the issues I've found, especially in the mare's leg manufacturer who's often considered the highest quality. But like I said, it's a platform that appeals to me, so I aim to make it right. I just figured I'd get to spend more time making custom and specialty parts opposed to fixing bad factory work.
Click to expand...

At no point in time has Chiappa ever been considered a high quality gun manufacturer. I think rather the opposite in fact
 
I would put a filler in the dovetail, and make a base that saddles the octagon barrel. I would then drill and tap the filler and attach the sight base with a screw. This way the base would be indexed to the barrel, and the dovetail would be irrelevant.
 
Yes, dovetails are supposed to be tapered, but the centrelines of the dovetail are also supposed to be perpendicular to the bore.
 
Because the dovetail is tapered from right to left, as described previously, your male dovetail, which is square to the picatinny, may tend to be pulled down tighter on the left side. I can understand the desire to avoid altering the rifle if it is avoidable but, in this case, you should have probably set the rifle up in the mill and indicated the dovetail. If it was not square, you could then make a truing cut then fit you rail to this, now oversized, dovetail. As it is, you can only console yourself with the knowledge that your work was correct; their's was not. :)
 
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