Framebuilders - lugged and Fillet braze mix?

good morning ,

as mentioned Im thinking, planning , thinking more , pondering ... of doing up a frame for myself. the bazing /soldering ... is no problem.

ive done a bunch of metal work in the past but never built a bike frame.

also Im afraid to try one as I may like it, did the same with fishing rods I didnt like factory rods so I started building my own. I make very fancy custom fly rods now and started selling them but it was getting to be too much like work so I stopped except for an occasional rod through word of mouth.

I have short legs /long torso ,My 50 CM cross check frame is too small except the SO height.

1) Since I need a sloped top tube would it be cool to do lugged construction on everything but the top tube?? may not be the best look

im thinking alignment would be easier using lugs first time for most of the angles???. [/B]


2) are lugs available for slope top tube fabrication,? I m under the assumption they are not?

Id prefer to work with lugs and silver solder if I could.

many thanks


"John"

Why not a full fillet bike? Why the mix?

Dave

DAVE,

Thanks for the reply, I was thinking alignment would be easier using lugs for all but the top tube which I cant use lugs for if its sloped.

if its no big deal then fillet braze on everything is fine.


many thanks

"John"

Check bikelugs.com if you want sloping top tube lugs.

Hey John,

I think I understand now.

It's a bit trickier to get a good straight all fillet frame (compared to a lug frame) but it's not rocket surgery.

Have you done many fillets?

Dave

It's a bit trickier to get a good straight all fillet frame (compared to a lug frame) but it's not rocket surgery.

I went with lugs because I knew I could pin the joints and not have to build or buy a jig. But I saw a fillet brazed stem the other day that I truly covet. That might be my next project.

Hey John,

I think I understand now.

It's a bit trickier to get a good straight all fillet frame (compared to a lug frame) but it's not rocket surgery.

Have you done many fillets?

Dave

hello dave,

thanks for the reply again. Im sure I could do a decent enough fillet braze though I havent had to do any torch work in a while except some silver soldering.

My concern was that using lugs would be easier to get all the joints right.

I do need a slope top tube, One tubing supplier suggested fillet braze construction hands down for my build but the slant 6 lugset is tempting not to mention I like that old school look.

Ill have to do a layout of what I need .

many thanks

"John"

Building a straight frame is not easy but lugs are most likely going to be easier to manage since they take less heat (which leads to distortion). When building you need some way to verify straightness as you progress through the various steps. A surface plate is a very useful tool for this type of work - far more valuable than a alignment fixture (jig). No disrespect intended to anyone but if you haven't verified your frames straightness on a proper surface plate you can't realistically claim that it is "straight". To measure is to know.

hello dave,

thanks for the reply again. Im sure I could do a decent enough fillet braze though I havent had to do any torch work in a while except some silver soldering.

My concern was that using lugs would be easier to get all the joints right.

I do need a slope top tube, One tubing supplier suggested fillet braze construction hands down for my build but the slant 6 lugset is tempting not to mention I like that old school look.

Ill have to do a layout of what I need .

many thanks

"John"

Hi John,

I'm a bit lost. I don't know why it would be easier to put a lugged frame together unless you plan on letting the lugs act as your fixture. If that's the case you won't have a frame that is anywhere close to the spec's you desire. The lugs just aren't rigid enough to hold stuff where is needs to be. A 73* lug WILL NOT hold two tubes at 73*. Close to 73* but it could vary by a few degrees in every direction. One needs a fixture of some sort. It need not be fancy or expensive. I've done it with blocks of wood, a few cement blocks and a fairly flat cement floor.

If you are thinking that the mitered joints need not be as accurate with lugs I'd caution you again. I suppose it's true that you won't see the issue but rest assured there will still be an issue. My miters are the same whether the frame is to be lugged or fillet brazed. A good tight miter is where the structure comes from. The lug or fillet just provide the surface area to be sure that the tubes stay hooked together.

Get yourself a few chunks of hardwood, a few paddle drill bits the sizes of your tubes and a good machinist protractor and you can build a frame every bit as good as anything out there. Just make sure the miters are tight and you are good to go.

Dave