I have been playing with this system. I noticed right away different reels have a vast difference in the angle between the reel foot and the spindle. I have a US Reel, it has a spool ID of 55mm, so i figure a 30 for the first guide, there is 67in. from the reel seat to the tip, no problem this is a piece of cake so far. When I square the spindle with the edge of the bench the intersect point where the rod leaves the bench is 31in from the reel seat. The 1st #8 guide is 26 1/2in from the reel seat and a #30 high frame is just 10in from the reel seat. I tested it with a 25 low frame and it ended up 17in. from the reel seat. I looked around and found an Penn reel lying around put it on and lined up the spindle and there was no intersect point, the spindle was virtually parallel with the rod. My question is: What kind of formula do you use to get the best setup when the reel has an extreme angle?
Thanks,
Gar

there is no formula. Remember gravity acts on the line as soon as it leaves the spool. When I cant find an intersect point I test cast it using the size 30 and then the size 25. durring both move the guide and record the best possible distance. I have found that by increasing the size of the choke guide I can add a few feet to the cast.

In a situation like that, I just use an arbitrary "false intersect point" that allows for three or four small fly guides past that point to the tip. Typically, this involves placing the "intersect guide" about 2/3 - 3/4 of the way to the tip. I do this on the theory that reducing the size and weight of the guides quickly is a good thing. This has worked well in practice for me, I've built a number of well-performing (and good-looking) rods that way.

I haven't done this yet, but ot has been posted before and seems to be a popular method. In this situation, many builders use the flex point of the blank as the intersect point..

Mike

This has always been a problem for me with the concept system. When matched to a particular reel, it is very good. But what happens if the reel is changed, like many anglers do? I've checked the intersect point on my own rods with different reels and the difference can be huge. Can the concept system have a negative effect in some cases? I don't know, but suspect it can. If in doubt, I generally use my mid range reel to "split" the difference. Does this offer any sort of advantage? I don't know.

I know it isn't the answer you are looking for, but I go with instinct. Once the line is tamed, use the smallest guides you can. The majority of what I build is a combination of cone of flight/concept system to compensate for the differences that may or may not happen when everything is not specified.

As Mike M. said, building for a specific reel conveniently ignores that most anglers change reels every 2-4 years. Given that reels vary so widely in intercept angle, I believe a builder is smart to choose a middle ground when setting up the guides. A middle ground set up will work fine with both extreme angle and practically no angle reels. But if you set up for a nearly flat angle as is found on many big Penn and Diawa spinning reels, and the angler switches to a Shimano with a steep angle...

One of these days a reel seat company will design an adjustable seat (maybe using a torx screw on the underside of the reel seat foot) to let you angle the seat to match the reel to the first guide. It would be very simple to allow the rear hood to move up and down a few mm, and that's all it would take.

Thanks Everyone!!
Gar