I like to fix my fishing rod. The tip top's ring has fallen off. I like to order a tip top but I don't know the proper size. How do I measure it?

They're sold in 64ths of an inch ID tip top tubes. You can use calipers if you have them, or you might be able to do a search on the web of tip top sizes and use your old top as a guide.

Many sizes match drill bit sizes. Remove the tip from the rod and try inserting different drill bits until you find one that fits. It should not be real snug as the glue will consume some of the space. Convert the drill size to 64ths and you will have the correct size tip. For example, if the 1/8 drill bit fits, then the tube size of the tip is a size 8 ( 8/64 = 1/8 ). Some tips come in half sizes so you may have to use some judgement. Best way is with a caliper or a tip top guage. I once had a tool company send me a drill sizing guide on plastic stock. It is a plastic card with different size holes used for sizing drill bits. This comes in very handy for tip sizes too. Just insert the rod's tip into the various size holes and compute the drill size in 64ths. Perhaps some tool stores have these available.

Thank you for the answer.
I measured the diameter of rod where bottom of the tip top is. It is 0.099". So I think size 7 will be fine.
But how do I select the ring size?

You do not have a choice as to the ring size on a tip top. Typically, a rods guides are matched to the ring size of the tiptop. You may have a size 6.5 tube size. Where on the blank did you measure 0.099" ?
You should measure about 3/4" down from the tip as the blank will be bigger there. 6.5/64 = 0.101" 7/64 = 0.109 " A size 6 would be too small at 0.937"

Thank you for the prompt answers.

Merrock Tackle's online product catalog, page 73, for a graphic and text on how to measure rod tip tops.

Lou

Typically, a tube size 6 to 7 tip top is available with ring sizes anywhere from 6, 7 or 8.
Putter

Or go to Mudhole and buy that $5 tip top measuring tool.

You should also get a book and wright down all the info of any rod you build. Make, model, size, tip-butt, guides, spacing. This way like now, if you need any info, as to if you sell it or have to repair it, you have all the info

Bill

Good point. I just started doing this on the last three rods I built.

Nice to be able to look back at what you did, what you like, don't like, and apply that to the next rod.