Spiral shank re-stem
Posted: Sat Mar 13, 2021 7:57 pm
You guys have seen enough re-stems on this repair board to last awhile (which is why I haven't posted many lately), but this project has several educational tidbits buried in it.
The root problem in this case was a nearly 7-inch long 80-gram pipe with a long, flattened shank that presented very little shank face, a .250" tenon to allow that shank design, and Italy's finest Crumble-Matic garbage acrylic having been allowed within a hundred miles of it.
Here is the critter:
Eye-catching doesn't begin to describe the famous design. Amazing, isn't it?
.
The issue with the original stem can be seen here. The tenon didn't even have the dignity to snap off, it disintegrated.
.
This next pic shows you what to avoid---any molded blank or cylindrical section of that glassy stuff with the tall, shallow, rectangular slot. See the square edges? Run
Notice also how the material around the slot has chipped away from mere pipecleaner wire. Finally, look closely and you can also see radial cracks in the roof of the slot from tooth pressure. If the tenon hadn't quit, the bite zone soon would have.
.
So, what was the fix? A new stem, of course, but what about the .25" tenon on a 7-inch, 80-gram pipe problem?
Sleeving with stainless to reinforce was one option, the other was to use the same material Iron Man's helmet is made from: Mike Butera's proprietary super-duper mondo stem stuff. It's blacker, much stronger, and somewhat lighter than even the best of the readily avalable varieties. I chose option #2 to keep things simple.
(Why the company that produces Mike's stem material doesn't sell it generally is because it's absurdly difficult to cut and shape, plus it's impossible to bend without using special techniques. It's an absolute royal pain in the ass except when a design or application must have what it does best, in other words.)
Here's a chunk of it:
The root problem in this case was a nearly 7-inch long 80-gram pipe with a long, flattened shank that presented very little shank face, a .250" tenon to allow that shank design, and Italy's finest Crumble-Matic garbage acrylic having been allowed within a hundred miles of it.
Here is the critter:
Eye-catching doesn't begin to describe the famous design. Amazing, isn't it?
.
The issue with the original stem can be seen here. The tenon didn't even have the dignity to snap off, it disintegrated.
.
This next pic shows you what to avoid---any molded blank or cylindrical section of that glassy stuff with the tall, shallow, rectangular slot. See the square edges? Run
Notice also how the material around the slot has chipped away from mere pipecleaner wire. Finally, look closely and you can also see radial cracks in the roof of the slot from tooth pressure. If the tenon hadn't quit, the bite zone soon would have..
So, what was the fix? A new stem, of course, but what about the .25" tenon on a 7-inch, 80-gram pipe problem?
Sleeving with stainless to reinforce was one option, the other was to use the same material Iron Man's helmet is made from: Mike Butera's proprietary super-duper mondo stem stuff. It's blacker, much stronger, and somewhat lighter than even the best of the readily avalable varieties. I chose option #2 to keep things simple.
(Why the company that produces Mike's stem material doesn't sell it generally is because it's absurdly difficult to cut and shape, plus it's impossible to bend without using special techniques. It's an absolute royal pain in the ass except when a design or application must have what it does best, in other words.)
Here's a chunk of it: