replication techniques

[unicronicus]

Hi new here,

I need to replicate a metal frame made of box section steel with a few various angles and would like your views on the best way to replicate its size/shape the most accurately. As you can tell, I'm fairly new to metal fabrication but I know my way around a welder fairly well, it's the measuring bit that I usually suffer on... So what are your suggestions for tackling something like this? I thought to buy an angle finder tool, measure each angle on the existing frame and measure length inbetween each one, then cut the desired angle and butt join. Sound simple enough or is there a better, more simpler way?

 

[fixerupper]

Hi and welcome to the forum , well yeah the method you describe is the way forward ...can you give a bit more information or photos of what you want to make ? IMHO if you can clamp the existing frame to a work bench and cut and clamp the new bits to it ,then weld it up is the way to go ....jeff

 

[unicronicus]

Thanks for your reply. I am reproducing a rotting tractor door but have no pics of it I'm afraid. Good idea with laying and clamping onto the existing door!

 

[outofthefire]

clamp the new bits to it ,then weld it up is the way to go ....jeff

That's how I make all my jigs at work, spend ages making one cock on then clamp the rest to it. Personally I wouldn't bother buying an angle finder unless you desperately want one just clamp two bits on and measure the gap in between and transfer it to your steel. I usually leave a couple of mil gap to fill with weld so accuracy doesn't need to be to the nearest thou.

 

[Kent]

Hi new here,

I need to replicate a metal frame made of box section steel with a few various angles and would like your views on the best way to replicate its size/shape the most accurately. As you can tell, I'm fairly new to metal fabrication but I know my way around a welder fairly well, it's the measuring bit that I usually suffer on... So what are your suggestions for tackling something like this? I thought to buy an angle finder tool, measure each angle on the existing frame and measure length inbetween each one, then cut the desired angle and butt join. Sound simple enough or is there a better, more simpler way?

Yes basically then do a drawing and get your head around the order of assembly process. Just in case your new to building such an item remember tack everything and only weld it when you have checked all dimensions when assembled. If it must be true to the last or just plain true remember how distortion works during the welding process.
for angles measure the assembled and halve it for each cut as a 45 degree and a 60 will each have a different joint length to make up a 105 degree inclusive . Better to have a little room in a joint than try and cut 3mm off an end coz its too long. If it needs to be correct you need to measure the angles and mark the stock up accordingly for cutting don't rely on the saw markings.

 

[unicronicus]

Not sure if I follow, I am really really new to this sort of thing, angles etc... are not my fortay tbh, in fact maths in general isn't my desired subject of choice ha! In thinking though, the tractor is still in use heavily so the door has to remain on it until my frame will be ready to transfer everything over to it...

Yes basically then do a drawing and get your head around the order of assembly process. Just in case your new to building such an item remember tack everything and only weld it when you have checked all dimensions when assembled. If it must be true to the last or just plain true remember how distortion works during the welding process.
for angles measure the assembled and halve it for each cut as a 45 degree and a 60 will each have a different joint length to make up a 105 degree inclusive . Better to have a little room in a joint than try and cut 3mm off an end coz its too long. If it needs to be correct you need to measure the angles and mark the stock up accordingly for cutting don't rely on the saw markings.

 

[CRB]

It sounds like cardboard engineering will win the day.

Stiff card, cereal boxes are good enough, and a pair of scissors. Take dimensions between corners of the frame, jot them down on a sketch. Cut the cardboard to the angles, you do not even need to measure them, just mark which angle is which on the sketch.

 

[Kent]

Not sure if I follow, I am really really new to this sort of thing, angles etc... are not my fortay tbh, in fact maths in general isn't my desired subject of choice ha! In thinking though, the tractor is still in use heavily so the door has to remain on it until my frame will be ready to transfer everything over to it...

I cant really explain it any easier in words but I will try the once- to get 90 degrees at a connection you cut both bits to 45 right? if you had 60 degrees at the interconnection you should make both cuts at 30 yes? Get it now? if you tried to get 60 by doing one at 20 and the other at 40 it might still add up but the joint length will be longer on the 40 so the two will not join together.

the issue with cardboard or clamping onto the existing is conspiring tolerances. Measure it, draw it, mark it out and make it. Of course you can do anything multiple ways but if you want it right.

Even so don't jump into buttoning it right up, tack it and check it first for size and function- sometimes we all have stupid mind burp moments

 

[unicronicus]

Clear now buddy, thanks!