I'm building a couple of 8 foot 2 piece rods based on a 250/2 Purglas blank. Now I've bound the guides on the top tip half of the blank. Purglas blanks ferrules are spigot type. My question is how to determine where the butt guide and reel seat will go on the butt half of the blank. You see the thing is that I've had a bad experience with a glass to glass ferrule in that after binding all the guides and gluing the reel seat the top half moved under pressure. There was a sweet spot for the ferrule. Luckily I had used a metal reel seat so I could remove it and reglue to the better position. I also bear in mind that that fibreglass blank was a cheapy and not up the quality of Purglas. Also the glass ferrule was tapered whereas the Purglas I think is not. Even so the fact that rods have spines leads me to question whether there is a sweet spot for ferrules which for the Purglas is a carbon fibre one. The old metal ferrules are irrelevant in this context.

Anyone had experience of the top half twisting around to a sweet spot?

Is there a way to determine where that spot is other than finishing and using the rod? If I have to do this then I will just temporarily bind on a reel seat such as Fuji's plate seat (thank goodness I have a spare) or the reel itself. May have to do this just for my piece of mind anyway.

ken

Myself I find the spine for each section. Then put the piece together and check for the overall spine. Then I lay out my components. I would not have wrapped the guides on the tip section as of yet myself.

Ken,
Just find the straighest spine on the rod and align the guides on it.

Roger

The problem is poor ferrule fit, not spine. If these are spinning rods, then the lever arm effect means the tip will attempt to twist a little when you cast. If they're casting rods, the tips will attempt to twist when fighting a fish.

Unless you have a good, tight ferrule fit, you won't be able to overcome this scenario.

.............

On a multi piece rod i like to join the pieces by pushing the pieces together but off by 90 degrees. Then the last bit twist clockwise so they are no longer off. Sort of screw them together if that makes sense. I make alignment marks with feather hackles or little decal dots. This twisting stops what you are referring to and over a few years fishing actually wears a very slight thread where they join. Of course to take apart you need to twist als in the opposite direction. Seems to also stop the two parts coming lose so often while fishing.

it is called the Bayonet Twist. Try a search on it.

A spiral wrap may help.

Bill - willierods.com

Tom is right - bad ferrule fit. Ferrules are not supposed to have a "sweet-spot".
Herb

Get your blanks from the guys on the left. Then they will fit correctly.

Bill - willierods.com

Make sure the pieces are clean so they fit like they supposed to.