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PostPosted: Thu Aug 01, 2013 8:12 pm 
Retro Guru
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Joined: Wed Sep 21, 2011 9:29 pm
Posts: 1770
Location: yorkshireland
velomaniac wrote:
Thats just a hacksaw blade clamped by screws into a piece of alloy rod. So simple yet not thought of until now. Genius !!!!!!!!!!!!!!

Mind you, I suspect splitting the rod or cutting a groove acurately down its length without a decent bench power saw would be even more difficult than removing the post without this tool. Maybe replace rod with a couple of strips of alloy flat plate to make it easier.

Still genius though :D


You could make a home version quite easily with bits n bobs from a hardware shop, this one lives in a commercial workshop so was designed to survive the end of the world.


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PostPosted: Fri Aug 02, 2013 12:36 am 
retrobike rider
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Joined: Thu Apr 17, 2008 1:24 am
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Location: Manchester
Presumably you could use a round length of aluminium tubing, cut a thin slot in it and drill and tap for grub screws to hold it in place?
Maybe use a jib to press against the blade rather than the grub screws.


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PostPosted: Fri Aug 02, 2013 9:35 am 
Old School Grand Master
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Joined: Mon Jun 14, 2010 9:06 pm
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Location: Herts UK
a DIY cheap version would be two peices of flat steel clamped together to hold the blade.


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PostPosted: Tue Aug 13, 2013 4:32 am 
Old School Grand Master

Joined: Sun Oct 21, 2007 2:33 am
Posts: 5487
Location: WI, USA
And you think that "1/10th of a millimeter" stress riser you created (which is actually closer to .3 or .4mm deep) is no cause for concern?

12 years in bicycle retail and repair in very busy shops that sold over 1,000 bikes a year and repaired thousands more each year. Another 40 years as a hobbiest with another 700 bikes through the home basement shop and never once have I not been able to remove a seat post with the best tool....common sense.


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PostPosted: Tue Aug 13, 2013 5:25 am 
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Quote:
And you think that "1/10th of a millimeter" stress riser you created (which is actually closer to .3 or .4mm deep) is no cause for concern?


I wondered about that. Also, is this an aluminium frame? Some steel frames are only about 0.4mm thick at the thinnest part of the butting, so you'd have to be really careful further down the seat tube away from the seat clamp/collar portion of the tube or you'd risk going right through.


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PostPosted: Tue Aug 13, 2013 12:14 pm 
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Location: The land of Lea & Perrins
gm1230126 wrote:
And you think that "1/10th of a millimeter" stress riser you created (which is actually closer to .3 or .4mm deep) is no cause for concern?

12 years in bicycle retail and repair in very busy shops that sold over 1,000 bikes a year and repaired thousands more each year. Another 40 years as a hobbiest with another 700 bikes through the home basement shop and never once have I not been able to remove a seat post with the best tool....common sense.


Personally (and if all other reasonable options/methods had been exhausted), I'd much prefer to have something like that done rather than render a frame unusable through a stuck seatpost.


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PostPosted: Tue Aug 13, 2013 12:32 pm 
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Joined: Tue Feb 23, 2010 1:56 pm
Posts: 1032
Location: West Yorkshire
Given the labour cost of a shop removing a stuck seatpost and the resultant damage, it would have to be a reasonably expensive frame to be worth rescuing I would have thought.

There again I've never neglected even my lowliest of bikes enough to end up with a stuck seatpost.

There again I'm a road bike rider so perhaps it's much less of a problem.

Mark.


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PostPosted: Tue Aug 13, 2013 2:27 pm 
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Posts: 1770
Location: yorkshireland
gm1230126 wrote:
And you think that "1/10th of a millimeter" stress riser you created (which is actually closer to .3 or .4mm deep) is no cause for concern?

12 years in bicycle retail and repair in very busy shops that sold over 1,000 bikes a year and repaired thousands more each year. Another 40 years as a hobbiest with another 700 bikes through the home basement shop and never once have I not been able to remove a seat post with the best tool....common sense.


The mark barely registers as more than a polished mark once you feel about 5mm into the frame, due to the line being so straight it looks like a savage cut but it is really nothing of the sort.
Without wanting to look like I am sticking my chest out here I am intrigued as to what your perfect method of removal is. This came in to me after the customer had already wrenched the head of the seatpost off in a vice, as you can see the gallons of releasing agent that he had soaking in the seat tube for a week before this made no difference whatsoever. Even when this post was cut right through it still had sufficient salt corrosion to have to grip the top and hammer it out. An ultra light cnc'd pin such as this is not sufficiently strong to have an aluminium bar welded on to it and be twisted loose, it would just tear like a piece of orange peel. As it is aluminium on aluminium it cant be melted out with caustic soda. I have used a loctite product in the past which freezes the tubes but results have been mixed, In a commercial workshop it makes no sense to try and ream out the post as it is extremely labour heavy and unless the post is clamped into a jig there is no guarantees that it will cut straight. This little device makes the job far more cost effective to the customer who is paying an hourly rate for the job. I must add that I have never once had a seized post in one of my personal frames, this one lives in the pennines which has savage winters and heavily salted roads.
I would love to hear any other useful tips on the subject if there is something I am missing that eases the burden of this unenviable job I am all ears :D


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