Oh no ... not again ... Street Fox fail

Joined
Apr 15, 2013
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Location
Washington state
your last pic is how I built my Street Fox with a triangle in front and back of cross boom.
Have only 320 miles on my ride and still going strong.
Our little village is one mile if you go around the perimeter. I travel around and up n down every street to get my 5 miles per day exercise) NOTE I ride only when weather is good so living in Washington I can only ride in summer but plans on a velo body are brewing.
 
Joined
May 15, 2011
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Location
Cambridge, UK
Hi Folks,

I followed the plans when I originally built my Fox.

Anyway, some other gusset ideas.





I still have some of the square tubing left. Might be simpler to fabricate.

Thanks
 
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Sep 16, 2018
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As you do the front and rear like tgst, tgan you don't need the Bleu parts. I think that the front will be even enough.
 
Joined
May 15, 2011
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Cambridge, UK
Hi Folks,

Thank you for the replies, which do help to fill me with confidence. Any other ideas would be great before I get the welding gloves out at the weekend.

One thing that occurs to me is that the Fox plans called for a boom made up of two parts. This allows you to have the angled boom, which does look great. The weld at the centre joint is then only done on three sides and then ground down to flush. The fourth side is the one that sits flush on the main boom.

Could it been that stresses of up and down as I roll over uneven ground are enough to weaken the joint in this way and a continuous straight boom would be inherently stronger ?

Thanks
Si
 
Joined
Oct 19, 2012
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Wakefield, UK
A continuous boom would indeed be stronger. Keeping the wheels in their current place would move the centre of the boom forward towards the arc of your feet as you pedal. You'd need to check clearance and/or move the front wheels back to allow enough room.
 
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The most force is put on the welds on the left and right side of the frame. That is why you see problems on those sides arround the welds.

The the weld on 3 sides is enough. It isn't having that much of a force on it. Even as you used it out of one piece, best is to ad done extra support.
That is why I added that front part.
 
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Apr 15, 2013
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one must consider that too much welding will weaken the metal itself.
I went with a one piece cross boom and still going strong
 
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Nottinghamshire England
all bar 1 of the street fox variants l built had a straight boom , without any problems .
and did you read the text ? or just look at the pictures ?
 
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Feb 7, 2008
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Nottinghamshire England
Old age Paul

l can only look at pictures .

The "bent " boom l felt had some inherent problems. With the straight boom it could be easier to add a gusset either side of the top side of the main boom .
The clue is probably in the text ?
 
Joined
May 15, 2011
Messages
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Location
Cambridge, UK
Hi All,

I spent today fabricating some gussets and mounting them. Made out of 3mm plate, I have welding then fore of the boom only. The angles are extremely difficult to get the MIG gun head in place and still be able to see what you are doing. That and it has been a while since I did and welding, so a little out of practice.

First repaired the tear.





Then added the gussets.



Welded both side of the gussets.

Do you think I need some aft of the boom or do we think this would suffice ?

The problem with doing one aft would mean it will foul the chain idler, so that would have to be moved. That and I'm sure the gun angle would mean I would only be able to weld the outside of the aft gussets.

Thanks
Si
 
Joined
Oct 19, 2012
Messages
948
Location
Wakefield, UK
Perhaps you could use a different gusset to the rear of it - one on top of the main boom. A pair of simple right angled triangles with the right angle ground away a little to clear existing weld. One on either edge of the top of the main boom to the cross beam. That would avoid the chain issues.
 
Joined
May 15, 2011
Messages
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Location
Cambridge, UK
Yes, you're right, I see what your mean. Inside welds again would be a problem though, as gun angle would make it near impossible to see. So one gusset would only be partially welded on the inside. But better than no gusset.

Mind you if I was using box selection cut to form a gusset that would only be welded on the outside. So maybe that's the answer, box section for aft of the boom.
 
Joined
Nov 9, 2011
Messages
970
Location
Banglen, Thailand and a little bit Reading, UK
Hi All,

I spent today fabricating some gussets and mounting them. Made out of 3mm plate, I have welding then fore of the boom only. The angles are extremely difficult to get the MIG gun head in place and still be able to see what you are doing. That and it has been a while since I did and welding, so a little out of practice.

First repaired the tear.





Then added the gussets.



Welded both side of the gussets.

Do you think I need some aft of the boom or do we think this would suffice ?

The problem with doing one aft would mean it will foul the chain idler, so that would have to be moved. That and I'm sure the gun angle would mean I would only be able to weld the outside of the aft gussets.

Thanks
Si
Your welds look a little on the cold side - not enough fusion going on. Maybe a few more amps, or slow wire feed down a tad?
 
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