Severne Mast Problem - Page 2

Ola_H · 13th February 2008, 03:30 PM

Thinking som more about the alu-carbon interface: I haven't looked at these mast, but I don't think it will be much of a problem. The alu is not bonded directly to the "internal structure" of the carbon. It's more like something that comes on top. There will (I assume) be some finishing plastic layers in between which will help.

The bottom line is that the splitting problem is more likely to come from the issues Roger mentioned, ie a less than perfect bond and/or a less than perfect interface geometry.

JJay · 18th February 2008, 08:54 PM

Anyone have any info on the collar problem? How serious is it?
Am I looking at a new mast? Will I need to read the small print on my warranty?
Has anyone else had a collar fail?

Tensing up and getting slower!

nifty · 19th February 2008, 01:22 PM

I'm thinking about getting another Redline anyway since they're such a good mast performance and build quality-wise. I'm willing to take the chance on the aluminium splitting. Hopefully if there is a problem, it's only with a very small percentage of masts sold.

JJay · 19th February 2008, 05:07 PM

North have fixed my cracked collar the best way they can,,,,,,
,,,,,,,,,by replacing it with a new one.
Did some investigating. Seems that very few masts have seen such problems over the years.
However it is not unheard of.
I have learned that once the collar splits,,,, the clock starts ticking on the eventual total failure of the mast.

Gotta say thanks to North

And a big thanks to Rachel

"Relaxed and getting faster"

matt12 · 12th March 2008, 09:19 AM

For reference those North aluminium collars are available individually from North. Apparently they can crack partially but even if they do, it is very unlikely to fail completely. The material has a taper so the thin end can crack but there is still a great section with increased thickness remaining on the mast. Agree that it is not perfect, but also it is not necessarily a mad panic to continue to use or replace just the collar.

Not sure of the engineering logic behind the comment that the mast is about to fail? Can you explain please?

steve h · 14th March 2008, 12:22 PM

just to say that Jesper sent me a new collar for the mast. Cut the old one off quite easily and put new one on, seems fine. Thanks Jesper.

nifty · 15th March 2008, 01:46 PM

Hi Steve H, how the hell did you remove the old collar? Can you give us a detailed description? Thanks.

matt12 · 16th March 2008, 06:14 AM

It is very hard to remove the broken collar. Here is the process that I used but it didn't work very easily .... this is a process probably NOT to follow ... I think there must be easier ways?

1. Stand mast vertical on hard surface like concrete.
2. Use a chisel and hammer to try to knock down the collar. Very hard because the material is thin hence cracks and bends easily. I ended up chiseling off small pieces about 2cm in size. Caused some minor damage to the mast.
3. Once the thin half of the collar has been removed, you can eventually get enough thickness to knock with your chisel and hammer.
4. Finally it released and fell down to the concrete.

A better way might be to use a Dremel and very carefully & time consumingly cut the collar off with a vertical grinding line. ... but don't grind down completely through the aluminium. Grind down ALMOST to the full thickness, then split open with a screwdriver.

nifty · 19th March 2008, 05:48 PM

Thanks Matt, yes, I think that's the go - carefully cut longitudinally but not all the way through, then try to split it off with a chisel or the like.

steve h · 20th March 2008, 10:01 AM

Nifty,

Was easy. using a hack saw I cut diagonally from top to bottom of the collar. best to be diagonal to avoid cutting the mast. Cut the groove almost through along its length & then cut a bit further at several points so that the carbon just shows through. It reaches a certain point then cracks open & can lever it off by widening the crack with screwdriver.

The new one fit straight on & I used an old mast base to get a surface to hit it gently with a hammer to force it on, ie, hit the base & it will transmit the force all round the new collar to force it down over the tapered carbon mast.

18th February 2008, 08:54 PM	#12
JJay Member Join Date: Dec 2006 Posts: 31	Anyone??? Anyone have any info on the collar problem? How serious is it? Am I looking at a new mast? Will I need to read the small print on my warranty? Has anyone else had a collar fail? Tensing up and getting slower!

19th February 2008, 05:07 PM	#14
JJay Member Join Date: Dec 2006 Posts: 31	They fixed it!!! North have fixed my cracked collar the best way they can,,,,,, ,,,,,,,,,by replacing it with a new one. Did some investigating. Seems that very few masts have seen such problems over the years. However it is not unheard of. I have learned that once the collar splits,,,, the clock starts ticking on the eventual total failure of the mast. Gotta say thanks to North And a big thanks to Rachel "Relaxed and getting faster"

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13th February 2008, 03:30 PM	#11
Ola_H TEAM Join Date: Aug 2006 Posts: 1,191	Thinking som more about the alu-carbon interface: I haven't looked at these mast, but I don't think it will be much of a problem. The alu is not bonded directly to the "internal structure" of the carbon. It's more like something that comes on top. There will (I assume) be some finishing plastic layers in between which will help. The bottom line is that the splitting problem is more likely to come from the issues Roger mentioned, ie a less than perfect bond and/or a less than perfect interface geometry.

19th February 2008, 01:22 PM	#13
nifty Member Join Date: Aug 2006 Posts: 28	I'm thinking about getting another Redline anyway since they're such a good mast performance and build quality-wise. I'm willing to take the chance on the aluminium splitting. Hopefully if there is a problem, it's only with a very small percentage of masts sold.

12th March 2008, 09:19 AM	#15
matt12 Member Join Date: Apr 2007 Posts: 47	For reference those North aluminium collars are available individually from North. Apparently they can crack partially but even if they do, it is very unlikely to fail completely. The material has a taper so the thin end can crack but there is still a great section with increased thickness remaining on the mast. Agree that it is not perfect, but also it is not necessarily a mad panic to continue to use or replace just the collar. Not sure of the engineering logic behind the comment that the mast is about to fail? Can you explain please?

14th March 2008, 12:22 PM	#16
steve h New Member Join Date: Jan 2008 Posts: 6	just to say that Jesper sent me a new collar for the mast. Cut the old one off quite easily and put new one on, seems fine. Thanks Jesper.

15th March 2008, 01:46 PM	#17
nifty Member Join Date: Aug 2006 Posts: 28	Hi Steve H, how the hell did you remove the old collar? Can you give us a detailed description? Thanks.

16th March 2008, 06:14 AM	#18
matt12 Member Join Date: Apr 2007 Posts: 47	It is very hard to remove the broken collar. Here is the process that I used but it didn't work very easily .... this is a process probably NOT to follow ... I think there must be easier ways? 1. Stand mast vertical on hard surface like concrete. 2. Use a chisel and hammer to try to knock down the collar. Very hard because the material is thin hence cracks and bends easily. I ended up chiseling off small pieces about 2cm in size. Caused some minor damage to the mast. 3. Once the thin half of the collar has been removed, you can eventually get enough thickness to knock with your chisel and hammer. 4. Finally it released and fell down to the concrete. A better way might be to use a Dremel and very carefully & time consumingly cut the collar off with a vertical grinding line. ... but don't grind down completely through the aluminium. Grind down ALMOST to the full thickness, then split open with a screwdriver.

19th March 2008, 05:48 PM	#19
nifty Member Join Date: Aug 2006 Posts: 28	Thanks Matt, yes, I think that's the go - carefully cut longitudinally but not all the way through, then try to split it off with a chisel or the like.

20th March 2008, 10:01 AM	#20
steve h New Member Join Date: Jan 2008 Posts: 6	Nifty, Was easy. using a hack saw I cut diagonally from top to bottom of the collar. best to be diagonal to avoid cutting the mast. Cut the groove almost through along its length & then cut a bit further at several points so that the carbon just shows through. It reaches a certain point then cracks open & can lever it off by widening the crack with screwdriver. The new one fit straight on & I used an old mast base to get a surface to hit it gently with a hammer to force it on, ie, hit the base & it will transmit the force all round the new collar to force it down over the tapered carbon mast.