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-   -   Rolling Tube Dents (https://www.bikeforums.net/classic-vintage/522743-rolling-tube-dents.html)

Mike Mills 04-03-09 04:43 PM

Note to self - never buy a frame that has black bands edged with gold pinstriping. :)

Actually, that looks fantastic! Good work.


Would it help if you were able to insert a "balloon" into the tube and pressurize the interior of the tube? This would apply some outwad force and might force the buckled tube wall outward. it doesn't usually take much pressure to remove the buckle. Then you'd just have to roll out any crease that had occurred.

Do you think you repair weakened the tube (or the overall frame) in any significant way?

dobber 04-03-09 04:51 PM


Originally Posted by Mike Mills (Post 8661130)
Note to self - never buy a frame that has black bands edged with gold pinstriping. :)

Actually, that looks fantastic! Good work.


Would it help if you were able to insert a "balloon" into the tube and pressurize the interior of the tube? This would apply some outwad force and might force the buckled tube wall outward. it doesn't usually take much pressure to remove the buckle. Then you'd just have to roll out any crease that had occurred.

Do you think you repair weakened the tube (or the overall frame) in any significant way?


The problem there is that a ballon is going to expand fore and aft before it exerts a sufficient amount of pressure on the tube to force out a dent.

I remember as a kid we use to fill old beer cans with water and freeze them to remove dents.

Mike Mills 04-03-09 04:58 PM

Yes, I knew you'd be thinking of a rubber balloon but I was thinking more of a "football". I was thinking of a fiber bag with a rubber bladder. Deflating the bladder allows you to collapse the "balloon" (the bag) and feed it and position it in the tube. The fiber bag would restrict the size of the "balloon" (the bag) as you inflate it, preventing the unsupported ends from simply stretching.

This is what they do as angioplasty.

WNG 04-03-09 06:19 PM

^^^
Cool idea. Does it have to be pneumatic? Sounds like a hydraulic system would work faster and more off the shelf. Possibly lower pressures too.
Same lateral expanding bladder, non expanding longitudinal ends...use an automotive or motorcycle master cylinder was your pump. DIY hydroforming. ;)

Mike Mills 04-03-09 08:04 PM


Originally Posted by WNG (Post 8661628)
^^^
Cool idea. Does it have to be pneumatic? Sounds like a hydraulic system would work faster and more off the shelf. Possibly lower pressures too.
Same lateral expanding bladder, non expanding longitudinal ends...use an automotive or motorcycle master cylinder was your pump. DIY hydroforming. ;)

It doesn't have to pneumatic. I think the key to success is the "balloon".

I'd still want that clamp/vice over the OD of the tube. The balloon is just suppose to help. I wouldn't want to over inflate and bulge the tube outward, either.

Chuckk 06-07-09 01:49 PM

2 Attachment(s)
Success with the A-D. Started a normal ride rotation on it and it runs and tracks like it should.
Replaced the ugly modern stem with a Cinelli. Put on fenders and took them off and ditched the idea of a rack - it's just too much fun to ride without trim.

Had a massive misadventure on the first shakedown run a couple of weeks ago. Got ~10 miles away from home and overshift on the front and put the rear derailleur into the wheel. Single speeded it home and replaced derailleur and straightened wheel and hanger.

For anybody else that has Gipiemme droupouts - I discovered that the derailleur hanger is HALF the thickness of the forged dropout and easy to bend. When I reassembled mine after straightening, I backed the dropout with a vary large, thin derailleur nut off a old SunTour and tightened it all up together. The flat of the nut fit nicely in the place where the dropout narrows for the hanger.

Should have put the bike in the sun to show off the metallic maroon paint. Next is a decal set.

Chuckk 06-23-09 07:56 PM

Wrote a page on rolling dents:
Link is Here
No video though - maybe next time.

Let me know if you have more hints.

randyjawa 06-23-09 08:17 PM

Where???
 
I like the idea of rolling the tubing this way. Can these frame block be purchased anywhere? If not, does anyone know what the block and hole dimensions are? I can make a set or two up for my own use if I can get a bit more info. Thanks.

JohnDThompson 06-23-09 09:04 PM


Originally Posted by randyjawa (Post 9154999)
I like the idea of rolling the tubing this way. Can these frame block be purchased anywhere? If not, does anyone know what the block and hole dimensions are? I can make a set or two up for my own use if I can get a bit more info. Thanks.

You can get them here.

yuoil 06-23-09 09:28 PM

Wow, that turned out great! Having the same frame downstairs, I think the color might be practically impossible to match without some professional help. It's really complex as was already said. Thanks for taking the time to write up a page on dent rolling!

Kommisar89 06-23-09 09:57 PM


Originally Posted by Chuckk (Post 9154908)
Wrote a page on rolling dents:
Link is Here
No video though - maybe next time.

Let me know if you have more hints.

Great write up, thanks.

perichbrothers 06-24-09 10:23 AM

I have a workstand clamp crimp in a schwinn paramount frame and was wondering how to fix it.
I was imagining working from the inside with a pipe or long seat post,
but now I think it would be best to use both the blocks and a pipe.
Thanks!

TP

Chuckk 06-24-09 06:59 PM

I've already picked up a tailpipe expander for seat tube dents.
It will probably take a little modification to make it slightly smaller, but should work.
Here's the Harbor Freight part
They have brake cylinder hones to clean up the inside of the tube as well.

karmat 06-24-09 07:08 PM


Originally Posted by Chuckk (Post 9161228)
I've already picked up a tailpipe expander for seat tube dents.
It will probably take a little modification to make it slightly smaller, but should work.
Here's the Harbor Freight part
They have brake cylinder hones to clean up the inside of the tube as well.

Great idea about the exhaust pipe expander. Best used with those blocks, though, I imagine, to keep the tube from oversizing.

unworthy1 06-24-09 07:12 PM

great write-up, Chuckk...and nice A-D, too!

TheDL 06-24-09 07:43 PM


Originally Posted by Chuckk (Post 9154908)
Wrote a page on rolling dents:
Link is Here
No video though - maybe next time.

Let me know if you have more hints.

Hmm, link isn't working for me.

[Edit] D'oh, now it is. Weird.

Chuckk 12-10-10 09:36 AM

Rode my 63 miles at 63 years ride on it this year.

http://chuck.kichline.com/bikes/bd/63/DSCN3175.JPG

tugrul 12-10-10 12:04 PM

It's too bad the ratio of locked up snow covered RB-1s to lovingly restored Austro-Daimler's are not in our favor.

newenglandbike 12-10-10 12:49 PM

Wow that bike turned out great! And what a cool thread (among the most inspiring restoration-threads on the board IMHO). :beer:


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