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-   -   converting TA dustcap to self extractor (https://www.bikeforums.net/classic-vintage/899126-converting-ta-dustcap-self-extractor.html)

sokito 07-02-13 12:42 PM
converting TA dustcap to self extractor
 
Hi all.

I was thinking.... maybe I can drill the old TA dustcaps so that I can convert them to self extracting bolts?
Anyone have done it? Is it something doable or am I thinking about something crazy?

unworthy1 07-02-13 04:40 PM
sounds krazy, kat!
The way a SE bolt usually works is the outer "ring" screws into the dustcap threads and the inner (ROUND, not hex) bolt head has to rotate and press against that ring so the ring has to be pretty beefy. I don't think a modified TA dustcap would be up for that service, probably be ruined if not immediately then before too many cycles...and that defeats the whole idea (or at least some) of having a SE bolt, I'd think.
I'd stick to something with 22mm threading and use a commercially-made SE bolt/ring combo that has proved good.

Bianchigirll 07-02-13 04:57 PM
Why not just buy self extractors?

unworthy1 07-02-13 05:05 PM
^I don't know of any that come in the 23mm size for TA, I have only seen 22mm.

bertinjim 07-02-13 06:18 PM
sokito- TA makes self-extractors. Go here.

ColonelJLloyd 07-02-13 06:22 PM
It can't be done.

unworthy1 07-02-13 06:41 PM
Originally Posted by bertinjim (Post 15808292)
sokito- TA makes self-extractors. Go here.
yes, BUT: as they say these are
Standard M22 x M8 x 1 x 20 mm.
so good for a NEW TA (or other brand) crank with 22mm threading, but not for a classic 23mm TA crank (which I assume we are talkin' bout).

ericbaker 07-03-13 01:22 AM
You could weld a nut to the cap perhaps?

unworthy1 07-03-13 09:01 AM
There IS a way to do this right:
just be a skilled machinist with your CNC mill and a slug of billet alloy.
Now match the ring of that modern TA but make the OD 23mm and cut threads to match.
Bob's yer Uncle...

ColonelJLloyd 07-03-13 09:14 AM
Originally Posted by unworthy1 (Post 15810318)
Bob's yer Uncle...
Yep. Easy as pie. I have a $20 bill for the first person who posts pics of this. ;)

Bianchigirll 07-03-13 09:25 AM
I know I have seen these somewhere. If you really want them just let your fingers do the walking through the internet.

Try Bens in Milwaukee or eve Yellow Jersey for starters.

cyclotoine 07-03-13 10:06 AM
It might work. You would want to find the right SE bolt to use with it, but I think it might be worth a try.

JohnDThompson 07-03-13 10:40 AM
Originally Posted by unworthy1 (Post 15807984)
The way a SE bolt usually works is the outer "ring" screws into the dustcap threads and the inner (ROUND, not hex) bolt head has to rotate and press against that ring so the ring has to be pretty beefy. I don't think a modified TA dustcap would be up for that service, probably be ruined if not immediately then before too many cycles.
Perhaps braze a washer under the cap to provide additional reinforcement? You'd want to remove the chrome first.

rhm 07-03-13 10:44 AM
Originally Posted by ColonelJLloyd (Post 15810371)
Yep. Easy as pie. I have a $20 bill for the first person who posts pics of this. ;)
https://lh4.googleusercontent.com/-e...extracting.jpg

And you have my address!

:lol:

unworthy1 07-03-13 10:45 AM
Originally Posted by cyclotoine (Post 15810630)
It might work. You would want to find the right SE bolt to use with it, but I think it might be worth a try.
yeah, might and might...if it was my (old) TA crank I wouldn't mess with it, but if you are game to ruin a couple TA dustcaps, then all you risk is possibly also ruining the crank's threads. Maybe only the outer 3 or so, if you're lucky.
Not a game I want to play, buy YRMV.

HA!: $20 photoshop job^...not bad pay. ;)

ColonelJLloyd 07-03-13 11:02 AM
Well, I will be damned. Check's in the mail, rhm.

TimmyT 07-03-13 11:19 AM
Originally Posted by rhm (Post 15810810)
Hmmm..... Plastic toe clips? Do you actually use those?

Zaphod Beeblebrox 07-03-13 11:53 AM
Rudi is such a shameless weight weenie.

rhm 07-03-13 11:56 AM
Originally Posted by TimmyT (Post 15810952)
Hmmm..... Plastic toe clips? Do you actually use those?
Well, I might, if it were my bike....

cyclotoine 07-03-13 12:36 PM
Originally Posted by JohnDThompson (Post 15810795)
Perhaps braze a washer under the cap to provide additional reinforcement? You'd want to remove the chrome first.
Most self extractor use a brass washer underneath so using one goes without saying, brazing one in could be even better.

Originally Posted by unworthy1 (Post 15810814)
yeah, might and might...if it was my (old) TA crank I wouldn't mess with it, but if you are game to ruin a couple TA dustcaps, then all you risk is possibly also ruining the crank's threads. Maybe only the outer 3 or so, if you're lucky.
Not a game I want to play, buy YRMV.
I have broken a TA ND crank and my girlfriend cracked a ND stronglight 49D, I would guess there is a fair number of ND TA cranks out there that are cracked and could be used for the experiment, although they should come off easier because they are cracked. I think I have a TA dustcap I could send to the OP for shipping for the experiment, but I might have thrown it away. It had been slotted because the hex fitting was so buggered. I am willing to bet there are more than a couple out there like that.

sokito 07-03-13 02:23 PM
Thanks cyclotoine. I would be willing to pay for the shipping if you can find them. I like playing around :D
What are they made of by the way? I suppose it's not aluminum. Chromed steel?

Originally Posted by cyclotoine (Post 15811288)
Most self extractor use a brass washer underneath so using one goes without saying, brazing one in could be even better.



I have broken a TA ND crank and my girlfriend cracked a ND stronglight 49D, I would guess there is a fair number of ND TA cranks out there that are cracked and could be used for the experiment, although they should come off easier because they are cracked. I think I have a TA dustcap I could send to the OP for shipping for the experiment, but I might have thrown it away. It had been slotted because the hex fitting was so buggered. I am willing to bet there are more than a couple out there like that.

cyclotoine 07-03-13 05:06 PM
Originally Posted by sokito (Post 15811738)
Thanks cyclotoine. I would be willing to pay for the shipping if you can find them. I like playing around :D
What are they made of by the way? I suppose it's not aluminum. Chromed steel?
Yes chromed steel. I only have one dustcap (if I have it) and won't be able to look till next week. I could send you a ND stronglight crank-arm but the diameter is 23.35 so not really a suitable candidate for the experiment. The steel is pretty thin though so there is a good chance it wont hold as other's have pointed out. You would probably need to fabricate a washer that is just the right size to fit under the cap, such that it is really wedged in there. Do you have self extracting bolts already?

Grand Bois 07-03-13 05:18 PM
Yellow Jersey has genuine T.A. extractors with the Specialties T.A. logo.

miamijim 07-03-13 05:24 PM
Originally Posted by ColonelJLloyd (Post 15810371)
Yep. Easy as pie. I have a $20 bill for the first person who posts pics of this. ;)
It is as easy as pie. Self extractors are readily available on ebay for $12. I have titanium self extractors on my Vitus that were made by a machine shop in New Jersey.

ColonelJLloyd 07-03-13 09:12 PM
Originally Posted by miamijim (Post 15812378)
It is as easy as pie. Self extractors are readily available on ebay for $12. I have titanium self extractors on my Vitus that were made by a machine shop in New Jersey.
For this crank?

http://farm5.staticflickr.com/4071/4...6a2af725_z.jpg


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