How much butt is acceptable

[John Winston]

If you caught my last FNL, you'll know I am building my first lugged frame.

As I am motoring along, I made my first cut on the TT and when I laid out the ST/TT miter, I was completely into the first butt transition.

My question: What is an acceptable distance to stay away from the butt transition for the HT/TT and TT/ST? And should it be even on each end or longer on the front? Again, lugs silver braze.

I have measured the HT side transition at 110mm and the ST transition at 125 or visa versa (no fancy dial mic method just sticking something into the hole....more experience here!.......and using my eyes to spot the measurement)

Hey, thanks in advanced for your direction as I'm not coming up with the info via search-

[steve garro]

just speaking for myself I always have AT LEAST 90-100mm of butting on each end, if not more. YRMV. - Garro.

[John Winston]

Would that be from the start of a transition of the end of it?

Thanks for the reply -

[steve garro]

Would that be from the start of a transition of the end of it?

Thanks for the reply -

no worries, man. for example my ST's have a 90mm butt at the bottom, I just nick it & put a 4 1/8" ST sleeve on the other end. it really matters on MTB's with the long ATC's. my favourite 29er DT has a butt that is 250mm long at one end & 100+ on the other. I like the HOX2TT for this reason, it fits small bikes for a TT. if you would have held the TT you have up to your full sized drawing before cutting it would you be OK? if not, you just have the wrong TT. anybody here that has never chucked a TT cut too short is lying {or save it for a small bike} but.........i'm betting you TT is toast. who wants a .4mm end? you never do know what's under the paint.....OK, damn. I gotta polish brass. coffee gone. - Garro.

[Dazza]

Some times one has to cut both ends of a TT or DT to get the butts correct
more butt means more prang resistance etc
Some of the tube sets are made for TIG and gram reduction phobia and have very short butts and on medium to small frames the butt is lost and the tube is useless.
Thank goodness Columbus listened
any how
if you have to use a different tube get it
for a roadie I like 50mm min of butt from the lug edge (that is butt not transition) at the HT end of the TT and DT
The ST end of the TT can be as little as 20mm from the lug edge! (the lug edge is important)
and DT at the BB can be 30mm min for small or light riders, the DT into the BB is not stressed as much as the myths have people believe, it is the HT end of the DT that is loaded up.
ST, the FD braze should be on butt, which means in an uncut tube the butt will be 150mm. (Curse those ST tubes with 100 and 120mm of butt!)

For MTB butts, listen to Mr Garro

[John Winston]

Garro-Dazza

Many thanks for the direction-

[Proparc]

Having read all the responses, it was obvious they were not giving you what you were looking for. I decided to step in here and correct the situation!!