Stripped a heli-coil trying to fix a 1970s Mamiya - old school vs new inserts

I was working on a Mamiya RB67 body last week where the tripod mount threads were totally gone. I was about to tap it for a standard heli-coil like I usually do, but then a buddy who does a lot of vintage stuff told me to try a time-sert instead. Man, what a difference. The time-sert went in way smoother, held tighter, and I didn't have to worry about the threads pulling out under heavy lens weight. The heli-coil I tried on another body last month spun out after a few test fits - total headache. Anyone else swear by one insert type over the other for softer aluminum bodies?

3 comments

3 Comments

viola_ward29d ago

Honestly, @mark_mitchell hit the nail on the head. Time-serts are overkill for newer stuff, but on those old soft aluminum bodies from the 70s, they're the only thing that really grabs. I've seen too many heli-coils spin out on Mamiya and old Hasselblad gear. The time-sert's solid wall design just bites into the soft metal way better, no chance of it walking out. Plus, you don't have to slather Loctite on it and pray it holds. But real talk, have you ever had to drill out a time-sert after installing it wrong? I hear that's a nightmare compared to a heli-coil. Curious if that's actually true or just old-timer talk. I'd rather not find out the hard way.

mark_mitchell29d ago

Yeah I heard that time-serts are basically overkill for most stuff but when you're dealing with old soft aluminum they're the only thing that really bites in there. A buddy of mine stripped out a helicoil on a Nikon F2 body doing the same thing and he said the timesert was night and day different. I've never used one myself but after hearing that story I'd probably go with the insert that doesn't spin out on the first test fit.

joel_butler29d ago

Heli-coil spun out after a few test fits" - exactly why I always hit the hole with Loctite first even on new inserts.