Measuring rocker on blank after outline cut

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sheffy's picture
Joined: 04/09/2020

Hi everyone. This is probably a stupid question but I've searched and cannot find an answer. I've only made one board and about to make my second. I've got a 6'2" fish blank and I'm making a 5'4" bar of soap nuggety thing.

Issue is I've got an aluminium rocker stick and I'm trying to measure my rocker numbers and figuring out template positioning. When resting the centre of the rocker stick on the middle of the blank there is too much entry rocker/cannot get the right nose/tail rocker mumbers. I've traced the outline onto the blank to get closest I can and I'm taking most of the length off the tail to flatten the rocker out in the back.

Now do I measure the rocker from the middle of the board once I cut the outline, rather than the original centre point? If I measure from there now it obviously affects my rocker numbers and where I'm thinking of placing the template.. 

Im probably overthinking this for my second board but I'd like to understand all aspects this time rather than winging it.

Any help would be great, cheers!

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gdaddy's picture
Joined: 10/31/2008

Planing for your builds starts with figuring your design out first, then selecting the blank and rocker that will best fit it.   Don't be shy about ordering a different rocker than what the blank normally comes with.   These blank companies are very comfortable with adjusting rockers.    Remember, adding rocker to the end points of a too-flat blank is easy.   Reducing rocker in a too-curvy blank is a pain in the ass.    You're sculpting your shape out of the blank, not building onto the blank.   

If I were using a 6-2a I'd take a 5-4 length out of the middle.   Moving it forward just increases your nose rocker.    

Next time, order the 5-10RP with a lower nose rocker.    

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McDing's picture
Joined: 05/22/2004

Good advice.   Get a blank in a rocker that is as close to your desired rocker as possible.  Then you will only be making "adjustments"(aka minor adjustments).  The longer these blank companies stay in biz; the more variety of rocker per blank.  I have noticed that a couple of the Poly blank manufactures are listing several rockers for each blank in their catalog.  I believe that as time goes by(play it again Sam), shapers order and contribute rockers to each plug.  These rockers are then listed as viable rockers for a specific blank.  A point of distinction; "Natural Rocker" is the original rocker for a specific blank.  It is the rocker that fits the blank most naturally as the original shaper of the specific plug intended..  Are there better rockers for that specific blank that may cause the finished board to ride differently?  Absolutely!  But remember;  "better" is subject to ones own objective opinion.  What's better for you, may not be better for me.  Natural rocker in one plug is not natural rocker in a different plug.  Unless a particular natural rocker is used in a series of plugs.  A good example of this would be Millennium's P blanks in a natural rocker.  The rocker in each Size P blank will be similar if not identical.  I am generalizing a bit, but if you break out the catalog and go point by point measurement wise; you can see the differences and the similarities.  I am making this point because I was asked recently if "Natural Rocker" was a specific rocker that you could get in different blanks..  Natural Rocker is unique to each model of blank.

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That which can be assorted without evidence was read in an illegal magazine.

sheffy's picture
Joined: 04/09/2020

Thanks both.

Turned out I was majorly overthinking it. I've since shaped the board and it came out tonnes better than board #1. Rocker fit in the blank nicely without the need for major adjustment. just need to lam the deck next.

In the UK we seem to be stuck for choice as far as blanks go compared to US and Aus. 

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reverb's picture
Joined: 03/20/2004

Hello; regarding rockers and blanks companies. I never ever obtained the numbers that they mention in their catalogues if I order (as almost always) other that is not "NAT" or "STD" I am not talking about minimum errors. The glue man never hits in the nail; never.

Different brands; problem remains.

Almost all the blanks that I order are custom orders so I buy a bulk of them; I need to shape those rockers a lot to finish with the desired curve or even worst, the desired measurements that the customer wants.

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johnmellor's picture
Joined: 03/17/2004

I don't think that considering rocker placement is overthinking anything.  In fact, it's a key element!

As mentioned.... design your board, research blank catalogs and see if you can't find something close.  Order a +/- rocker tweak if needed.

Or.... with some blanks, especially stringerless, shape a blank with just the thickness profiled and bend it to shape as you vacuum bag it on a rocker table.  I've done some rocker tweaks that way when doing deck inlays with wood strips. Guys in the past discovered they could squeeze more blanks out of a block that way.

Rocker = important.

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