puchfinnland

I have been kiching around the thought of a custom build for myself.

I love the PUCH ULTIMAs from 1982,

Boca lugs and 531SL tubing= frame weight of around 1800g(not fork)

Now I ask is it realistic to consider a custom build to take a crashed PUCH frame
use the panto fork crown and seat stay tops-
find NOS boca lugs, and build up a 135cm spaced modern version using TI tubing and a professional frame builder?
all the angles will be up to modern specs and brifters.
is there much weight savings on different tubing?



this is only a dream currently,
at my shop we have access to several top frame builders in Italy and I am considering this,

but the architect and details are first.

thanks for any input!

tuz

Your intention is to mix steel lugs with Titanium tubing? Lugged/bonded titanium frames have been done, but they are kinda one of a kind, and probably quite expensive. However I think pressed steel lugs do not provide sufficient area for an epoxy bond. Moreover, Ti is not as strong as steel, and thus in order to save any weight the tubes need to be larger, and thus would not fit in the lugs. And using the crown with Ti is probably impossible...

busdriver1959

I think your best bet is to stay with steel tubes. If you are looking to hit a frame weight of 1800 grams, True Temper OX Platinum should be right there. I've only worked with it in double oversize (or über oversize or xxl, whatever you want to call it). It's very nice tubing, comes in .7/.4/.7 and is easy to source through Henry James.

unterhausen

Pino Morroni and Cecil Behringer apparently made a lugged Ti bike, but they didn't share the secrets of the bike's construction. I think any framebuilder would be foolish to take on this task, and it would be far better for the OP to go with a welded Ti bike or if lugs are really desired, a lugged steel bike.

MassiveD

What is the objective? I hear what you are saying, but an explicit statement of what you want to do would help. Is what worth it?

marqueemoon

Bruce Gordon built a lugged all-ti frame which apparently is epoxied together.

https://brucegordoncycles.blogspot.co...r-kitchen.html

It's a show bike and a ton of work went into making it visually stunning, but if I were paying someone to build me a frame that's not the construction technique I would want. Plus fabricating the lugged bits would take an insane amount of time (and therefore expense).

OP - are you sure you don't mean Bocama lugs? NOS sets pop up on ebay from time to time. Any skilled builder would be able to reshape a chunkier modern lug set into something shapelier.

Just go all steel. Modern steel is very good, and while maybe not ti-light the money you save will be significant enough to allow you to lighten your bike in other places.

MassiveD

That bike was probably the most lightly bonded structure I have ever seen. One can make anything for a show, but it would be cool to know it actually worked and had done 50 000 road miles since. Cause we are all wasting time with brazing if all it takes is a little epoxy. I've been building with epoxy for over 30 years, and that structure was news to me.

Live Wire 

Youre not seeing the whole "lug" there is/was a lot of surface area to bond to on the inside of the tube as well.

Scooper

What's your goal, Mike? Is it having the aesthetics of lugs and lightness and corrosion resistance of titanium? If so, a 61cm stainless steel silver brazed lugged frame will weigh a competitive 1650 grams and offer reasonably high corrosion resistance. There are now thousands of them on the road and the vast majority of their owners are very pleased.

fietsbob

Yea, Bruce Gordon made Titanium lugs to join Carbon Fiber Tubes..

takes it to the 'bike porn' shows for hand made bike builders.

you can buy the carbon tubes ..

graf tech was doing that earlier..

trescojones

My 20 cents worth. Brazing/soldering titanium is an aerospace research topic. It can be done with silver/copper/aluminium filler like incusil ABA,VH720 and others, or very precious and expensive metals but it seems no ones sure about long term corrosion resistance of the filler material. The lugs would need to be titanium and it would have to be done under inert gas. I have thought about building one, getting some ti lugs machined but its not going to be easy, fast, or soon.
Steel tubes would be as light, particularly if you go for new, fancy heat treated pipes like columbus niobium SL, KVA MS2 or true temper platinum/VHT. Its moved on a bit since 531 special lightweight etc. Oversizing means more metal. As other folks have pointeed out, bonding to lugs intended for brazing/soldering doesn't have enough surface area to work because resins are nothing like as strong and therefore need more surface, this makes the lug longer and changes the bikes feel a lot, people who owned raleigh techniums out of ti and other materials said they sort of all rode the same. At least with bonding the lugs can be aluminium which is much easier to machine.

unterhausen

IIRC, Bruce Gordon said he would never build another one because it was so much work. That was one data point I was using when I said a framebuilder would be foolish to build one

hueyhoolihan

i happen to own a '95 model custom TI/steel lugged and bonded frame. top, down, seat and head tubes are TI, rear triangle is 753 reynolds. it was made in Newark Ohio by Franklin Frames. as mentioned the lugs are custom designed to maximize surface area for the bonding. they were probably part of the TI tube/lug set bought by the builder for the frame.

despite looking good and getting some attention, etc, it's NOT my favorite bike. too flexy, not the builders fault...

BTW, after about 30,000 miles (not to mention fifteen years) i recently had it rebonded due to a creak in the bottom bracket area. the builder did it gratis. nice of him i thought.

fietsbob

If course you can put lug looking ends on the frame tubes , and then Tig them together , for the Look..

Maybe as someone elsewhere got a Ti Frame and wondered where the stiffness went,

doubled tube thicknesses and gussets will stiffen things up a Bit ..