Looking for why these two pieces might not fit...

[OTmachine]

I usually cut my thread relief larger than required and have pretty much always relied on plug gages to verify fit. YMMV

Die sinker rifflers?

 

[WobblyHand]

I usually cut my thread relief larger than required and have pretty much always relied on plug gages to verify fit. YMMV

Die sinker rifflers?

How do you use a plug gauge in a groove? A ~ 2mm wide groove? Or do you have a different design/application? This confuses me, please explain. I thought a plug gauge was just a precision pin. I'd need something like an inside micrometer with 1.5mm wide probes to measure the groove, if there is such a thing. Pretty sure it would be unaffordable...

The OD of the part is only 10mm, the ID is 7mm, and the groove is 10mm deep inside the 7mm bore. There's not much room to begin with to go wild with depth.

Die sinker riffler files seem to be similar to "riffler files". I saw a set of Grobet files listed for $499.99 at Penn Tool! Think I'll try a 7mm bore brush first!

 

[OTmachine]

Sorry, I meant for the threads. Have not followed your post all of the way. For I.D. grooves I use a set of modified spring calipers to get size, measuring them with a OD mic. Gotten pretty good with them over the years and can usually get within .001”.
I have bought a lot of rifflers at second hand stores for cheap.

 

[sdelivery]

What's a ruffling file? I tried to look it up, but found nothing. Found riffling, but not ruffling. Riffling files look like what you meant, I can see how they could be helpful. There seems to be quite a few to choose from! Could go broke assembling a set...

Yes,I meant Riffling but Auto incorrect new better than me so.....

 

[WobblyHand]

Well this is almost done. Not quite to print, but close. I couldn't make myself machine the narrow section to 10mm, for fear of break through, so it is 10.5mm. And I didn't put in a chamfer like I wanted to. I haven't ground that tool yet. I did knock off all the burrs, so it isn't too bad. Besides, that whole section will be covered by the shroud and won't be visible. The only thing I need to do is to drill a couple of holes in the flange and make another spanner wrench so I can tighten it. I'll blue it. Hmm, need to check it will seat properly, might have to relieve the area by the flange.

 

[sdelivery]

Nice job