Thank you for your very helpful suggestion but it's too late - the job is almost done and I'm just waiting for some kit to enable me to load photos. Like my previous welding, it looks awful but seems strong enough to me. This is for a 'runaround bike'. The worse the bike looks, the less likely it is to be stolen. I wouldn't want to risk the cost of specialised brake parts but it's a good idea.
- Thread starter GeorgeB
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Thank you for your very helpful suggestion but it's too late - the job is almost done and I'm just waiting for some kit to enable me to load photos. Like my previous welding, it looks awful but seems strong enough to me. This is for a 'runaround bike'. The worse the bike looks, the less likely it is to be stolen. I wouldn't want to risk the cost of specialised brake parts but it's a good idea.
Arc welded bike forks - photos
Here are photos of how I increased the length of my front bicycle forks to accommodate a larger wheel. More through luck than judgement, the new wheel is correctly aligned, relative to the new drop plates. First, I overwelded the brazed joint between the fork tube and drop plate, to stop the plate moving and add additional strength. Then I tacked on a new extension plate, before running an arc weld along the length of the joint: 80 amps with 2.5mm 6013 rods from Aldi.
Here are photos of how I increased the length of my front bicycle forks to accommodate a larger wheel. More through luck than judgement, the new wheel is correctly aligned, relative to the new drop plates. First, I overwelded the brazed joint between the fork tube and drop plate, to stop the plate moving and add additional strength. Then I tacked on a new extension plate, before running an arc weld along the length of the joint: 80 amps with 2.5mm 6013 rods from Aldi.
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chunkolini
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Hmm scary
All the load goes into the tiny weld at the botom of the fork leg, any hint of a crack and it will go 'Spdaaang'.
I would at least add a small strip up the outside linking the new dropout wiht the original fork leg, or maybe do the same at the front and back.
Oh, and buy some drinking straws.
Chunko'.
All the load goes into the tiny weld at the botom of the fork leg, any hint of a crack and it will go 'Spdaaang'.
I would at least add a small strip up the outside linking the new dropout wiht the original fork leg, or maybe do the same at the front and back.
Oh, and buy some drinking straws.
Chunko'.
oilcooled :)
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ive broken a top front toooth due to a wheel coming off and had it capped. then i broke my other front tooth when i was cyclying home one nyt and too lazy to get off the bike i kicked the dynamo on and it went in between the spokes, well i took off like a bat outta hell, broke my other front tooth, and broke my other cap again. it may be strong, but i would only use it for personal use.what about the back wheel. ?
Thanks - that's the way I see it, too.
Oilcooled - the back wheel is less of a problem because I only need to weld a new plate, higher up the rear forks to hold the caliper brakes. I don't need to extend the forks.
Chunkolini - do you mean the load is going through the small weld between the tubular part of the fork, and the remnant of the original drop plate? What about the original braze? It's all still there - nothing melted away, as far as I could see.
George,
That's stress riser city. Please lose all the sharp edges, blobs and sharp corners and then either dye penetrant test it (preferable) or at the very least carfully inspect it with a magnifying glass regularly.
Obviously as i'm looking at a photo it could be many things but i see several potental cracks.
Teeth are useful things and don't grow back
Oh and what's going on with using cone lock nuts as wheel nuts?
That's stress riser city. Please lose all the sharp edges, blobs and sharp corners and then either dye penetrant test it (preferable) or at the very least carfully inspect it with a magnifying glass regularly.
Obviously as i'm looking at a photo it could be many things but i see several potental cracks.
Teeth are useful things and don't grow back
Oh and what's going on with using cone lock nuts as wheel nuts?
I accept your concern - the risks - and it will be interesting to see how long it lasts. I should have added that I intend smoothing out the whole assembly to get rid of the sharp corners and rough edges. Does dye penetrant amount to destructive testing? My extension plate was welded both sides so I have most confidence in that joint. The only other joint is the original brazed one. Do you think the integrity of that joint has been weakened by by welding, and that the overlay welds are not enough to compensate for any such weakening?
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George, with the money you've saved on your cheap welder and cheap rods you may want to invest in one of these before the road test. 
The straight run you've done does look very nice, well done for that but the other doesn't.
Please be very careful on it.
The straight run you've done does look very nice, well done for that but the other doesn't.
Please be very careful on it.
George, with the money you've saved on your cheap welder and cheap rods you may want to invest in one of these before the road test. The straight run you've done does look very nice, well done for that but the other doesn't. Please be very careful on it.
Thanks for your comment on the straight weld. I was pleased and it just goes to show - you can do perfectly reasonable arc welds with the cheapest equipment and 'rubbish' rods. Would you have posted a photo like that if the same welds had been done with expensive gear and rods?
As for the welds between the tube and the top of the drop plate, those are just tacks in an attempt to prevent the braze joint from moving. It worked! That was their only purpose. I don't really mind what they look like, or it would be form over substance. The traces of braze filler made it quite difficult to get the weld to 'stick'. It could be that the brazed joint has been damaged by the weld heat and is vulnerable, but I'll have to see over the coming months and years.
chunkolini
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Good luck George.
No way would I go out on the road like that.
Also bear in mind Hotrodders point about using cone lock nuts as wheel nuts, they are not a load bearing component, all they are supposed to do is stop the cones in the bearings coming loose.
I dont want to sound like a killjoy, I have comitted some horrific bodges on bikes over the years, I love the spirit of making the damn thing work with no expense, but I am really wary of messing about with the front dropouts. Spdaaaaaang.
Chunko'.
No way would I go out on the road like that.
Also bear in mind Hotrodders point about using cone lock nuts as wheel nuts, they are not a load bearing component, all they are supposed to do is stop the cones in the bearings coming loose.
I dont want to sound like a killjoy, I have comitted some horrific bodges on bikes over the years, I love the spirit of making the damn thing work with no expense, but I am really wary of messing about with the front dropouts. Spdaaaaaang.
Chunko'.
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i would also weld the original joint up you have no way of telling what state the original brazing is in, most of the brass could have run into the tubing leaving the joint weak.
I agree with you there and was thinking the same myself, so I'm doing exactly as you suggested. The braze looks untouched and undamaged but it seems so unlikely, I'm going to weld over the top, all round, to be on the safe side.
Chunkolini - I forget where those nuts came from but I thought a nut was a nut! Is the normal configuration that one nut holds the ball bearings in place, with determined play/clearance, and then a second nut serves as a lock nut, followed by the drop plate and a 3rd nut on the outside?
chunkolini
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Re nuts?
cone lock nuts are about 3-5mm deep (thick?). Wheel nuts are about 10-12mm deep.
Locknuts stop the cone coming undone, wheel nuts are to hold the wheel in place, they carry much greater loads.
The last picture looks less potentially fatal.
However all that welding would have affected the forks depending on what spec steel they were made of.
Dodgy, may work, probably will work, but a roast dinner through a straw is hard, how so you get yorkshire pudding through a straw?
Chunko'.
cone lock nuts are about 3-5mm deep (thick?). Wheel nuts are about 10-12mm deep.
Locknuts stop the cone coming undone, wheel nuts are to hold the wheel in place, they carry much greater loads.
The last picture looks less potentially fatal.
However all that welding would have affected the forks depending on what spec steel they were made of.
Dodgy, may work, probably will work, but a roast dinner through a straw is hard, how so you get yorkshire pudding through a straw?
Chunko'.
I'm sure you know more than the people at my local, specialist cycling shop. I now think they may have sold me a front axle, a few years' ago, which is too short, so there wouldn't be enough room for the normal wheel nuts. After your advice, thanks, I need to get a new axle and nuts.
Here's the situation with the 700C rear wheel. It's too large and high for the existing brake position, so I'll weld a plate on to the rear forks, higher up, so the brakes are higher. After my work on the front forks, I'm confident one can arc weld a bicycle frame with ease. I also hope the heat is less of an issue than with brazing.
Pic with the wheel fitted has disappeared 
but was a hollow axle designed for use with a quick release rather than wheel nuts. Did you look at the links i posted George? Earlier in this thread i posted a link to a chart that covers different frame/axle widths. Here's another that covers brake caliper reach. Didn't realise until the latest photo how close the wheel is to aligning with the brakes. Very possible that a brake caliper with shorter reach would solve things
but was a hollow axle designed for use with a quick release rather than wheel nuts. Did you look at the links i posted George? Earlier in this thread i posted a link to a chart that covers different frame/axle widths. Here's another that covers brake caliper reach. Didn't realise until the latest photo how close the wheel is to aligning with the brakes. Very possible that a brake caliper with shorter reach would solve things
brightspark
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with welds like that id be worried about me nutsLooking at the time the post was edited I think George must have deleted that pic after the comments about the nuts were made.
