Thickest, stuckest seat post
11-21-21, 03:49 PM
#51
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Join Date: Feb 2020
Location: Little Rock, AR
Posts: 273
Bikes: (2) 1980 Schwinn Voyageur 11.8 All Chrome, 1985 Schwinn Peloton, 1987 Schwinn Tempo, 1987 Schwinn Prelude, 1988 Schwinn Premis, 1987 Trek 520,, 1985 Schwinn Voyageur, 1985 Schwinn LeTour Luxe, 1989 Schwinn Voyageur, 2011 Specialized Roubaix
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Originally Posted by dddd
Lessons from this removal might include firstly to go slow, check progress often (probing the slot with a sharpened, bent-tip spoke to gauge progress, as the sharp point will glide across steel but "snag" on aluminum).
The cut(s) went too far up, so the teeth contacted the seat tube opening where resulting excessive contact pressure resulted in the blade's teeth cutting into steel). Keeping the working edge of the blade tilted slightly away from the edge of the seat tube opening is important.
There is no need to slot the post any higher than the bottom of the slot in the seat tube, since, above that point, no compressive bonding of the corrosion can occur.
No need to pry open the clamping ears either, for the same reason, and best not to. I would not bother with trying too hard to get any penetrant down in there, at least not beyond using a few thermal cycles. Safer to add penetrant to the ever-growing slot in the post.
A single cut slot is all that is ever needed to release the compressive bond, but the slot does have to be continuous and down to bare steel, from the bottom of the seat tube's clamping slot down to the end of the post (hence, the need to periodically probe the slot being cut into the soft-metal post).
My basic reciprocating saw sells for just over $20 and is a useful tool to have. Blades are a few bux each at any hardware store, and specialty blades are available even at Walmart for pruning live tree limbs, cutting nail-studded wood or for cutting steel. I find that the wood/metal combination blades cut through aluminum well, and that the few teeth near the tip end up doing all of the work since I keep the blade tilted slightly away from the edge of the seat tube opening. I have at times resorted to sharpening the leading teeth of a well-used blade, using a Dremel grinding/cutting disc (being very careful to under-cut and to not shatter the wafer-thin disc).
The blade's teeth will not cut into steel unless contact pressure is applied up near the seat tube opening, thus concentrating the pressure (just don't use a diamond-crusted blade).
The cut(s) went too far up, so the teeth contacted the seat tube opening where resulting excessive contact pressure resulted in the blade's teeth cutting into steel). Keeping the working edge of the blade tilted slightly away from the edge of the seat tube opening is important.
There is no need to slot the post any higher than the bottom of the slot in the seat tube, since, above that point, no compressive bonding of the corrosion can occur.
No need to pry open the clamping ears either, for the same reason, and best not to. I would not bother with trying too hard to get any penetrant down in there, at least not beyond using a few thermal cycles. Safer to add penetrant to the ever-growing slot in the post.
A single cut slot is all that is ever needed to release the compressive bond, but the slot does have to be continuous and down to bare steel, from the bottom of the seat tube's clamping slot down to the end of the post (hence, the need to periodically probe the slot being cut into the soft-metal post).
My basic reciprocating saw sells for just over $20 and is a useful tool to have. Blades are a few bux each at any hardware store, and specialty blades are available even at Walmart for pruning live tree limbs, cutting nail-studded wood or for cutting steel. I find that the wood/metal combination blades cut through aluminum well, and that the few teeth near the tip end up doing all of the work since I keep the blade tilted slightly away from the edge of the seat tube opening. I have at times resorted to sharpening the leading teeth of a well-used blade, using a Dremel grinding/cutting disc (being very careful to under-cut and to not shatter the wafer-thin disc).
The blade's teeth will not cut into steel unless contact pressure is applied up near the seat tube opening, thus concentrating the pressure (just don't use a diamond-crusted blade).
This one is not all lost, ended up with a nice 600 Tri-Color Groupset and wheelset with tri color hubs for about $80 with new tires. I may put the framset in the for sale section for peanuts and maybe someone can use it or at least the fork...
