I need someone to explain guide sizes to me…bear w/ me…I am a novice at this…

I thought that a ring size of 20 meant a guide w/ a 20 millimeter diameter opening. I noticed, however, that when I measured the rings w/ an inexpensive slide micrometer they were not exactly 20 mm…the inside diameter was a little less and the outside diameter of the guide (including frame) was a little more. BTW, these are Fuji SiC guides – the model of which I am not sure…

So, my first question…is the size of a guide based on the inside diameter or the outside diameter or perhaps the average of the 2? Does sizing of guides differ amongst manufacturers?

Also, the tube size of the tip-top guide is confusing… I just recently had a tip-top replaced on one of my surf rods. The blank tip measured roughly 4 mm in diameter, however, the rod builder installed what he said was a size 10 tube (16 ring). Obviously, this cannot be a tube w/ a 10 mm inside diameter if the blank tip is 4 mm… I measured the outside diameter of the tube and it was about 5 mm. So, what does the 10 mean?

Thx

Your questions are quite common to all us starting out. There is no consistent means of where the rings are measured. Some are measured per the inside of the frame, with the ring eating up some of the given number, others are measured as to the actual inside of the ring. But they will all be close. Typically ceramics will measure out a bit smaller on the inside ring diameter than what they are listed as. (If you measure the outside of the ring you'll find it to be about right.)

Top sizes are listed in both tube and ring size. Funny thing - the rings are listed in mm the tube ID in 64ths. What you are normally looking at when you see listings of 4, 4.5, 5 and so on are the tube ID's in 64ths. Some catalogs will also list the ring size. Example, 4.5 - 8. This would stand for a tube ID of 4and half 64ths and a size 8 ring.

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Tom…thanks for the clarification.

One last question…if a blank tip will receive a tip-top guide w/ a 11 size tube, but apparently not a 10 tube, could the blank tip be finely sand down to fit the 10? All we are talking about is 1/64’s of an inch! The reason for the question is that one of my rods could not receive a 10 tube tip-top, only 11…but in an 11 tube the smallest ring size available from that manufacturer was a 20 and I really wanted a 16 for the tip top…

Again Thx

No, the last place you want to sand is the tip. Very risky.

The better approach is to incorporate your tip trim wrap so that it extends under/inside the tip top tube which should allow a good fit of next larger sized top.

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Thanks...