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  1. #1
    seņor member seaneee's Avatar
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    Taking a 26.0 seatpost down to 25.6

    Is it possible? I know that you can take 22.2 stems down to 20.0 with emery paper, but am I thinking crazy about using emery paper to take a 26.0 seatpost to 25.6?

    I can find the run of the mill kalloy for now, but the post is for a 1970's Paris Sport track bike and I would love to put either a simplex or stronglight seatpost on it.

  2. #2
    Senior Member Grand Bois's Avatar
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    I've taken a seatpost down that much. I used a power sander, but it could be done by hand.

  3. #3
    stringbreaker stringbreaker's Avatar
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    Take it to a machine shop and have them turn it down on a lathe or if you know someone that works in a shop maybe they can do it for you. It should be relatively inexpensive it you go to a small shop and then you can be sure its going to be exactly the right diameter and it will be straight. My two cents

  4. #4
    Senior Member Grand Bois's Avatar
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    This is the SR Laprade post that I sanded down and repolished.

    The flutes got a tiny bit narrower.

    I used a Porter Cable Quarter sheet sander.


  5. #5
    biked well well biked's Avatar
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    I agree with Dirtdrop, it could be done by hand. I've hand sanded a seatpost down .2mm, it took maybe 5-10 minutes. Figure twice that much for .4mm. As far as precision, you just check it every so often, and stop when it fits into the seat tube.

  6. #6
    Senior Member Grand Bois's Avatar
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    It's just like sanding a stem to fit a French steerer, but you have to repolish the part you've sanded. Just start using a finer grit when you get close. Sanding aluminum is just like sanding very hard wood except that you'll have black hands before you finish. I wear a dust mask. I don't know how harmful aluminum particles are, but I don't want them in my lungs.

  7. #7
    Newbie cyberbiker's Avatar
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    A safer and better solution might be to search the net for "25.6 seatpost". You'll find 25.6x350mm seatposts manufactured by Promax in black and silver for $10-$12 and 25.4x350mm in silver by Kalloy Uno for $16-$20. There are numerous listings from eBay, Amazon and mailorder.

  8. #8
    Senior Member Grand Bois's Avatar
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    Quote Originally Posted by cyberbiker View Post
    A safer and better solution might be to search the net for "25.6 seatpost". You'll find 25.6x350mm seatposts manufactured by Promax in black and silver for $10-$12 and 25.4x350mm in silver by Kalloy Uno for $16-$20. There are numerous listings from eBay, Amazon and mailorder.
    He was looking for that post seven months ago! He clearly stated that he didn't want to put a cheap POS post on his classic track bike.

    I bought a vintage 25.4 SR post on eBay last week, but I was searching for a long time. The smaller sizes are hard to find.

  9. #9
    iab
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    Senior Member iab's Avatar
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    I paid $20 for the local machine shop to turn down a 26.4 to a 26.2, still cheaper than buying a 26.2 outright.

  10. #10
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    seat post sanding

    I did this the other night! I took an old 26.8mm post to use in my retro 26.4mm seat tube.I placed teh bare post (cradle parts off) on a solid work table with the post head hanging off table edge, I rolled the post with R hand as left hand sanded with coarse emery carefully and uniformly as possible, taht way my hand work didnt run out any more than .1 mm, using digital calipers is a must BTW.
    I even used a broad, fine steel file to take down the bulk of the work, then emery, and left a little room for finish sanding with fine emery. For .4mm, your looking at about .015 thousands sanding. do it carefully, and you wont end up undersize, or with an uneven surface .
    Also, mark the part that is out of frame, that way you wont add more work tahn you need to do.

  11. #11
    Excursionist
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    I've done this - hard work, but quite doable. Be careful - aluminium dust is not only bad to inhale, it's explosively combustible!

  12. #12
    Senior Member RobbieTunes's Avatar
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    6 beers should do it.
    Robbie ♪♫♪...☻
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  13. #13
    rhm
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    multimodal commuter rhm's Avatar
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    Quote Originally Posted by RobbieTunes View Post
    6 beers should do it.
    Drano works better! For the seat post I mean. Drink the beer, dunk the seat post in Drano.

  14. #14
    sultan of schwinn EjustE's Avatar
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    The fastest and least expensive way to accomplish this would be to post an ad in the ISO/for Trade forum here.
    -E

    still stuck in the '80s; '70s were good as well, but i severely dislike tubulars.
    I tri...

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