GT750 build

[baldyshinehead]

the second one ( if i got the right one lol ) i was told is a bit of box section, cut one end off and welded to the axle. so it is held top and bottom. then you have a plate on the frame ends that bolts to that.

[tbone]

i`ll go mm on this one, i prefer to have the axle surrounded by something
maybe its the old belt n braces thinkin, but it looks more secure lol

[baldyshinehead]

i`ll go mm on this one, i prefer to have the axle surrounded by something
maybe its the old belt n braces thinkin, but it looks more secure lol

The guy who explained the box method to me just said, look at how the original ones are, its stronger than them.

Glad i came on here MM, all i got on other forums was silly remarks, thanks.
anyway people, its late and i really need my beauty sleep.  night

[Manky Monkey]

You'll get silly remarks here too but hopefully some help or inspiration too. I'm certainly no expert but happy to share what little I know -& to learn from others. G'night all.

[baldyshinehead]

just out of interest and i know this will cause differing opinions, but what tubeing do you all use on trike rear ends ?
I was adviced to use cfs3

[tbone]

i was told only to use cds but it costs a flippin fortune. BS1387 erw is my choice, it comes in heavy or medium, i use the heavy which has a wall thickness of 3.2mm.
Outside diameter or OD will depend very much on the existing frame OD size, ideally an exact match will give the best look but you can go oversize if you have a particulaly small tubed frame. 28mm OD is my first weapon of choice, with its 3.2mm wall gives an ID of 22mm wich is great for slugging with 20mm solid bar.
Just one more thing, the tube i use is measured in inches n i work in metric, why aint nowt easy lol.

[baldyshinehead]

erw is alot cheaper, just wasnt sure on the strength although i think most modern bike frames are made out off it.

[tbone]

have you tried bending it? youll see how strong it is lol.
Joking aside tho, ERW will be fine mate, as i said i opt for the thicker wall stuff, cant remember off hand the wall thickness  of the smaller stuff but its definatly 2mm plus, 2.7mm rings a bell. the thing you have to bear in mind is the power off your welder, can it cope with 3mm+ steel? if not use the 2.7mm instead.

[baldyshinehead]

I know how hard erw is to bend, i used to drive a side loader in a steel warehouse.  you can drive up the stuff a long way before it bends 

[Manky Monkey]

Lots of "people who know about these things" will tell you you should only use chrome moly or whatever but grade 3 ERW works fine for me. We use 1 inch bore, (pipe is measured on it's internal diameter, tube on the external), which gives a nominal O.D of 1 3/8". Medium weight is around 3mm. Heavy gauge is actually nearer 4mm & is what we use. It'll bend in a standard hydraulic bender, (about 80 quid from "Machine Mart"), but once it's welded into a properly triangulated frame it's as strong as a Sherman tank. We use 1 1/2" bore for our top tubes & off cuts of 2" for the axle clamps. We use a 150 amp MIG by the way.

[baldyshinehead]

I have a turbo 130 migmate. havnt had any trouble with it so far but was looking at finding out if the local welding specialist would do me a deal if i just tacked it all and let him finish it off.

[Manky Monkey]

Our 150 will weld up to 1/4" plate, (6mm). The 130 will probably be O.K if you chamfer the joints to form a V shape for the weld to run into, but if you're not happy then always go to the professionals, (no, not Bodey & Doyle). Better safe than sorry.

[tbone]

i use a 130amp and it will cope with 4mm. thats a good tip from MM about the edges, and it also means you can dress the weld almost flush to the rails, if your so inclined.

[baldyshinehead]

more good advice, thanks.
how do you you cut the ends to match up with tubing ?  a tool in a drill or just a grinder

[Manky Monkey]

"fish mouthing"? Profiling the tube ends to butt against the side of another tube? Angle grinder for me I'm afraid. Laborious but I can't afford a proper bench mounted cutter. My brother had some success with a hole saw in a pillar drill but it didn't really work for me. When I've been working in lock-ups with no electricity getting stuff ready for welding elsewhere, it's been a hacksaw & handfile but that really is laborious!