Rod Guide Placement and Static Deflection
Learning how to properly space your rod guides is just part of the learning curve in rod building, but it is not quite as difficult as you may think. Just follow these easy steps, and you will have no problem spacing your rod guides on that new blank.
First Find The Spine
Almost all rod blanks are produced by wrapping graphite and/or fiberglass around a steel mandrel. This process causes a slight deviation in the material which results in softer and stiffer sides to the rod blank, and is commonly referred to as the spine.
Think of a rod spine as if it were your backbone. You only want to bend in one direction, forward, and it is the same with a rod blank. Every rod blank has a spine; some are just more defined than others.
Using a device like the CRB Spine Finder & Deflection System, you can quickly and accurately locate the exact spine of any blank. All you need to do is insert the rod blank, apply some load on the front 1/3 of the rod blank causing it to bend, and then twist the rod blank until you feel it roll into the spine. You know it is the spine when the rod blank tends to keep rolling into the same area, and you find it difficult to roll out of that same area.
Note: Make sure the spine finder is secured to a work bench or CRB Aluminum Base Station.
With the rod blank still in the spine finder, take a china marker and mark under the spine (bend) if you are building a spinning or fly fishing rod, or mark the top of the spine (top of bend) if you are building a casting rod. The mark will be used to align the guides (and reel seat) in the following steps.
Now that we have located our spine, we will use the same CRB Spine Finder & Deflection System to apply a static load on the blank and help us place our rod guides.
First we want to add a tip top guide with the hot melt glue so you have an anchor point to place the rod under load. Once the blank is in the finder and the tip top on, cut a 6 foot section of fishing line and tie it first to the tip top, and then to a secure weighted base to load the rod. You can use several large fishng weights.
Before tying off the fishing weights you need to make sure the spine finder and weights will sit along the same plane. The reason behind this is we are going to create a right triangle.
Just as in the photo, we are placing the rod under a load and will not pass a 90 degree angle on the blank or it could be damaged. By flexing the blank it will show the main flex point and then curve down to the weights. At this flex point you will want to place a guide.
From this point you will then follow the flex of the blank and place guides along the rod blank.
Placing the Guides
Once the flex point is marked you can use thin masking tape or guide tubing to temporarily place all the guides along the blank. You will adjust them along the flex of the blank to maximize the efficiency of the guide set and to hold the line off the blank.
Now that you have your marks, untie the blank from the weights and allow the blank to unload back into a straight position. Now place your guides along the blank, paying attention to the flex point mark. If you are building a standard freshwater casting rod, you can estimate around 3" of space between the flex point and the tip of the rod.
As you move from the flex point back towards the butt of the rod the spacing can increase proportionally until you reach your stripper guide. Each rod will vary slightly based on the flex of the rod, but using the flex point will get you were you need to be. If you do not hit the ideal placement on your first try, don't worry, that is why we move to a static placement.Adjusting the Guides
With the guides temporarily placed we will now add in a reel to the reel seat and run the line from the reel through the guides and tie off to our weights again using it as an anchor point.
Once you have the blank loaded and all your guides are placed, you are ready to adjust them based on the line path. You will want to make sure the line does not touch or lay on the blank while the rod is loaded.
Now, yes you could just put 20 guides on a 7 foot blank but that would all but ruin the blanks action and deter from the overall performance. So, we need to try to walk the line of correct spacing while using the minimum number of guides possible to reduce overall rod weight.
With a little practice, this is something any rod builder can do successfully. If you want cut and dry spacing, you can always buy a rod guide kit or check the recommendations from the rod blank manufacturer, both will come with guide spacing recommendations.