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Technical & Reference Section => Tech and Restoration => Topic started by: deeman on April 01, 2015, 04:24 PM
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I have an ACS Stoker stem which I would like to perform the potts mod on just as I had bitd. I am having trouble finding a suitable bolt....First of all all the bolts I have tried are too thick to go through the hole in the stem cap, this is not a problem as I can drill it. Secondly, the wedge is kind of a unique shape and looks too thin to get a thicker bolt through as it is contoured on the inside. Is it a case of I just need to find a genuine ACS hollow bolt? or is there another solution Has anyone else had similar bother? or have any advice? I definitely cant remember how my dad did it bitd!! :idiot2: :idiot2:
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Got any pics of the wedgey bit cocker? diameter of stem hole would be handy too :)
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Just sell me the stem :whistle:
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This may work..
http://bmxmuseum.com/forsale/150715
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Got any pics of the wedgey bit cocker? diameter of stem hole would be handy too :)
Away working tonight, will take some pics / measurements tomorrow. the hole is nearly big enough for the 2 bolts I have but they are too thick for the wedge if that makes sense? :daumenhoch:
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This may work..
http://bmxmuseum.com/forsale/150715
Thanks dude, I saw that but just looks like a generic bolt and wedge like the 2 I have! :daumenhoch:
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Just sell me the stem :whistle:
I have an interested party already but it may be for sale if I can't sort out a potts bolt solution for it ! keep you posted Nick :daumenhoch:
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find a local engineering firm to drill your top . measure your bolt pitch and retap your wedge to make your bolt fit. take 10 mins in the machine shop .
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(http://i1089.photobucket.com/albums/i349/deeman37/P8050145_zps8d8jljab.jpg) (http://s1089.photobucket.com/user/deeman37/media/P8050145_zps8d8jljab.jpg.html)
(http://i1089.photobucket.com/albums/i349/deeman37/P8050146_zpsllhw5hwi.jpg) (http://s1089.photobucket.com/user/deeman37/media/P8050146_zpsllhw5hwi.jpg.html)
(http://i1089.photobucket.com/albums/i349/deeman37/P8050147_zpsvx4xqpos.jpg) (http://s1089.photobucket.com/user/deeman37/media/P8050147_zpsvx4xqpos.jpg.html)
here are a few pics of the bolts n wedge Clint :daumenhoch:
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HmmmI see what you mean about the groove in the wedge. Would be a bit of a fiddle to bore out that groove but probably the easiest option if you can't find the right bolt.
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What about one of these :daumenhoch:
http://www.ebay.co.uk/itm/NOS-Odyssey-Hollow-Bolt-Old-School-BMX-Stem-Bolt-Potts-Mod-For-BMX-Bikes-/191340630083?pt=LH_DefaultDomain_3&hash=item2c8cca5043
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What about one of these :daumenhoch:
http://www.ebay.co.uk/itm/NOS-Odyssey-Hollow-Bolt-Old-School-BMX-Stem-Bolt-Potts-Mod-For-BMX-Bikes-/191340630083?pt=LH_DefaultDomain_3&hash=item2c8cca5043
Thanks man I saw those but it won't help me just like the 2 generic bolts I have...the wedge is all wrong for the stem :daumenhoch: :daumenhoch:
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HmmmI see what you mean about the groove in the wedge. Would be a bit of a fiddle to bore out that groove but probably the easiest option if you can't find the right bolt.
Do you fancy undertaking the job if I lined your palm with silver?? it's beyond my tools and facilities! :idiot2:
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Always happy to help out if I can mate :daumenhoch:
Might be worth considering if a local engineer can turn down a bolt to the right diameter and recut the thread. Always good to keep stuff original if possible :)
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Always happy to help out if I can mate :daumenhoch:
Might be worth considering if a local engineer can turn down a bolt to the right diameter and recut the thread. Always good to keep stuff original if possible :)
Agreed...yes, that's not a bad idea either-if I get stuck I will give you a shout, thanks for your input Clint :daumenhoch:
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No worries mate, you know I like drilling holes in things :LolLolLolLol:
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See what you mean, you need a stepped wedge.
What about modifying the wedge off the potts bolt so it's the same shape angle as the ACS wedge, a straight cut across the wedge to make the step, then cut, grind and file to make the same angle.
Here's a crap illustration of what I mean.
(http://i692.photobucket.com/albums/vv281/rodgy1970/Odysseypotts_zpslownmdbt.jpg) (http://s692.photobucket.com/user/rodgy1970/media/Odysseypotts_zpslownmdbt.jpg.html)
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^^^ that's another good shout but out of my capabilities! :daumenhoch:
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^^^ that's another good shout but out of my capabilities! :daumenhoch:
You might surprise yourself :daumenhoch:
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Always happy to help out if I can mate :daumenhoch:
Might be worth considering if a local engineer can turn down a bolt to the right diameter and recut the thread. Always good to keep stuff original if possible :)
Agreed...yes, that's not a bad idea either-if I get stuck I will give you a shout, thanks for your input Clint : daumenhoch:
I bloidy said that ages ago . :D
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See what you mean, you need a stepped wedge.
What about modifying the wedge off the potts bolt so it's the same shape angle as the ACS wedge, a straight cut across the wedge to make the step, then cut, grind and file to make the same angle.
Here's a crap illustration of what I mean.
(http://i692.photobucket.com/albums/vv281/rodgy1970/Odysseypotts_zpslownmdbt.jpg) (http://s692.photobucket.com/user/rodgy1970/media/Odysseypotts_zpslownmdbt.jpg.html)
this is what i'm planning on doing for my acs stem, tried for ages to find a hollow bolt with the correct wedge but no luck. another thing we used to do back in the day was to just hacksaw the stem shaft to the angle of the new wedge.
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See what you mean, you need a stepped wedge.
What about modifying the wedge off the potts bolt so it's the same shape angle as the ACS wedge, a straight cut across the wedge to make the step, then cut, grind and file to make the same angle.
Here's a crap illustration of what I mean.
(http://i692.photobucket.com/albums/vv281/rodgy1970/Odysseypotts_zpslownmdbt.jpg) (http://s692.photobucket.com/user/rodgy1970/media/Odysseypotts_zpslownmdbt.jpg.html)
This is actually a lot easier than you may think. I modded one for a tuff neck potts mod a few years back. Just need a vice and angle grinder with cutting disc. In this day and age a much better option than butchering a stem quill imho. I'll dig it out later and post a piccie if interested.
Go on, take a brave pill and go for, worst that can happen is a lost finger or two ;D
P
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cut the shaft
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Thanks for the input everyone, It has given me some more food for thought although I am not sure I could really carry out cutting the wegde or the stem shaft as I don't have the facilities and even if I did I would probably fook it up! Not sure I want to butcher the shaft anyway! I had no idea it would be so much aggro when I bought the stem as I had one with potts mod bitd which I am sure came from the bike shop like that, I don't remember having to mess with it at all! :idiot2:
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Try and get hold of an ACS Hollow Bolt in the packet is it comes with two wedges, the right one and the wrong one for the stem:
(http://i54.photobucket.com/albums/g114/martycoughlin/BMX%20Stuff%20For%20Sale/IMG_2974.jpg)
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Wicked, thanks for that Marty, I was hoping that would be the case! I used to see loads of those for sale, can't seem to find one now! :4_17_5: