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-   -   cutting a carbon boom (http://www.star-board-windsurfing.com/forum/showthread.php?t=11606)

carlosgp5 24th March 2011 07:31 PM

cutting a carbon boom
 
Hi all,
Has anybody ever tried to cut (reducing lenght) of a boom?
I have and old NP 260-310 carbon boom, and am planning to cut aproximately 20 cm of it so I can rig a 9-9.5sqm sail... However I am a bit afraid that it will force the boomīs head to structural damage as I will be closing a bit the gap between the two sides of the tailīs end of the boom... any tips?
Cheers

shinobi 24th March 2011 09:00 PM

Hi Carlos,

I've cut down a blue HPL carbon boom so that it could fit my 8.5 sail.
Cutting down the boom was not a problem at all but the fitting of the double push pin was a bit more tricky. Drilling the wholes is not the deal but the diameter of the boom arms where slightly smaller and I had some not so fun time trimming it down.

The boom is now still in a good shape and does the job, the boom head is going strong and I've equipped it with the perfect MauiSail boom head.
The only down side is that the boom feels fairly big and the rig appeals heavier. That might be good for light wind but when it is getting to the limit (that is how it should be in slalom) it doesn't go very smooth.

Anyways, you can do it and the boom will do it's job, even thought that it might not be the perfect solution depending on the bend curve.

~Shinobi

mark h 24th March 2011 11:02 PM

Ausi Tim shortened his X9 boom. The only down side is that the boom will be slightly wider than its supposed to be. Here's a link:

http://whitelionwindsurfing.blogspot...g-x9-boom.html

carlosgp5 24th March 2011 11:59 PM

Tks guys... and yeah mark i saw that article... just didnīt get why did he had to do that mold for the holes instead of just marking and drilling it...

peter n-m 25th March 2011 05:12 AM

Another link:
peterman.dk/windsurf-NP-X9-boom-shortening-1000.htm

Regards,
Peter

Unregistered 26th March 2011 08:18 AM

be careful to be sure the straight back end tubes don't hit in the curve of the boom arms, which prevents actually making the boom shorter. i've had best results cutting with a plumber's pipe cutter, to be sure new ends are square.

Kimba 28th March 2011 09:56 AM

Hi All,
As per a private email to Carlos the mould/jig was to translate the position of the original holes perfectly. Alternatively, the holes could be marked out carefully and drilled using a drill press to stop the drill
"wandering" off centre.

X9 Tail Tube Sizing:
I have a 180 and 200 X9 also and checked the lengths of the large diameter end of the boom(that sleeves the tail) and found the 180 & 200 are from the same tooling and the 225 & 260 are from the same tooling( as far as the start of the larger diameter tail goes). Or to put it another way the 200 has about 80cm of tail tube( and can be cut down to the 180) and the 260 has 100cm (and can be cut down to 225). I ended up cutting a 260 down to 230 to allow for a range of adjustment on a 9.5.
Regards, Tim.

ittiandro 26th February 2014 05:08 PM

Cutting a carbon boom
 
Quote:

Originally Posted by shinobi (Post 48218)
Hi Carlos,

I've cut down a blue HPL carbon boom so that it could fit my 8.5 sail.
Cutting down the boom was not a problem at all but the fitting of the double push pin was a bit more tricky. Drilling the wholes is not the deal but the diameter of the boom arms where slightly smaller and I had some not so fun time trimming it down.

~Shinobi


I may have to cut, too, a a 220-280 carbon boom, but only by 20 cm at most to fit a 7.5 sail and a 6.5 sail . As I see it, it will be the inner sleeve to be cut, at the very end , so I cannot see where the problem is with the fitting of the double push pin. This fitting and the retaining clip are on the outer tube, which is not the one to be cut. Cutting 20 cm from the end of the inner sleeve , even if it means eliminating a few holes, won't be a problem to me because I am getting this carbon boom as a special deal, but I'll NEVER EVER need to use it to the maximum extension of 280 cm.

Maybe there is something I am missing. Any comments?

mark h 27th February 2014 12:16 AM

Hi Ittiandro

Not sure what you mean by "inner tube"' but if you are shortening a boom, you will be cutting the arms shorter, this means you will need two new clip assemblies. Sometimes you can get the old clips off, but it's usually better to make sure that you have a pair off spar clips. Unless it's a Fiberspar boom, you would need to drill new holes for the located pins.

ittiandro 27th February 2014 03:12 PM

Cutting a boom
 
Quote:

Originally Posted by mark h (Post 61399)
Hi Ittiandro

Not sure what you mean by "inner tube"' but if you are shortening a boom, you will be cutting the arms shorter, this means you will need two new clip assemblies. Sometimes you can get the old clips off, but it's usually better to make sure that you have a pair off spar clips. Unless it's a Fiberspar boom, you would need to drill new holes for the located pins.

Not sure what you mean by "inner tube"' [/QUOTE]

Any adjustable boom assembly is made of two telescopic U-shaped sections sliding into one another: one ( the outer one) ends with the clamp which connects to the mast and has a retaining ( or locking) clip at the end of each of the two arms. Then there is another smaller diameter section, also ending with two arms ( with holes) each one sliding into the arms of the main section.This is the adjustable or extensible part, which I call " inner tube" and is fully removable".
The point I was trying to make is that, if I slide out the extensible part, I can't see anything at the end of the two arms ( except perhaps a protective rubber or plastic trim around it ) that prevents me from cutting the arms to the required length, repositioning the above plastic trims and then re-assembling the boom. There is no other mechanism, clip or other at the ends of this inner section, requiring re-adjustments or re-working after cutting the arms, as would be the case if I were to cut the main outer section, because this has, indeed, the locking clips. But why would I have to cut this section?
Perhaps, again, there is something I am missing. Any comments?

Thanks

Ittiandro


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