High Roller Build

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Jun 27, 2015
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11
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Michigan
Well, I’m finally starting the build I first contemplated probably five years ago, the High Roller recumbent cycle. I just picked up a couple of 26” 21-speed bikes, and last night I cut the forks off of one of them. I made a practice weld on the square boom and prepared to weld the forks on. But, I encountered some questions that I’d like to get some clarification on before I make these critical welds.

First of all, I’d like some advice on how to clamp the forks in position on the boom prior to tack welding. Of course, the forks are bolted onto a wheel as described in the instructions. I’m looking for a good way to hold them fast to the boom so that I can check alignment prior to tacking in place. My largest C-clamp opens to 7”, but I need closer to 8”. I looked at a ratcheting squeeze clamp, but it did not hold tightly enough to keep the forks from rotating against the boom. So, I’d welcome any suggestions here.

Second, I have questions about the wheel alignment with the boom when using a front fork to hold a rear wheel with a hub of seven sprockets. There is a gap of 1/4-3/8” between the cut parts of the fork (which will be welded to the boom) and the boom when the forks extend at right angles to the axle. If I put the cut part of the fork against the boom in preparation for welding, there is an interference between the fork and the small sprocket. I can put a couple of washers on the axle to provide clearance between the fork and the sprocket, but the the wheel is slightly off-center relative to the boom. The most obvious solution seems to be attaching some plate to the boom as spacers and the welding the forks to the spacers, but maybe you have a better suggestion.
[I tried to add pictures, but I got an error message.]
 
Joined
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To upload a picture first upload it to a picture hosting site such as imgur.com. There are many others. From there you can get a direct link to it and then paste that link into the box that appears when you click the icon above that looks like a picture.
 
Joined
Jun 27, 2015
Messages
11
Location
Michigan
To upload a picture first upload it to a picture hosting site such as imgur.com. There are many others. From there you can get a direct link to it and then paste that link into the box that appears when you click the icon above that looks like a picture.
Thanks. I tried using Flickr, but got an error message. I just created an Imgur account, so I'll upload my pictures from there.
 
Joined
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Messages
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This image shows the gap between the cut part of the fork and the boom. I understated the gap: it's closer to 3/8-1/2".



This image shows the clearance between the fork and the small sprocket. Without the washers, the fork interferes with the sprocket if I "bend in" the fork to contact the boom.

 
Joined
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I'm thinking i should just weld two short pieces of pipe to the tops of the forks to bring them into contact with the boom. I still don't know how to hold it in place, though. I'm a newbie at welding, but I think I could build some kind of fixture out of wood to hold the pieces in alignment. Still looking for any tips from more experienced builders.
 
Joined
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Messages
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The washers may leave you with very little of the axle in the cut-outs. I'd be more inclined to give the offending fork a whack with the hammer to flatten the bit that interferes with the cog or grind a large flat there and then cap it with flat to clear the cog. Another option is to use a bit of box section to bridge the gap at the other end though rather than welding on two capped bits at the sides I'd weld on one capped bit the right width between the fork ends and then weld the main rail to that. Dealing with it at the wheel end is likely to leave it looking a little neater.

Building a jig is usually a good idea weld nothing beyond tacked though until you've cast your eye over it from all angles with a wheel in the forks. If your eye can't spot anything wrong then it's near enough for these purposes. One way of getting alignment for the second wheel to be mounted is to cable tie a long straight edge or two such as planks or beams to both wheels touching the tyres only before you weld the other one on. This ensures they are both in the same plane.

 
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Messages
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Thanks for your reply. I had thought to leave the washers in there only to weld the forks to the boom. You are correct that there is very little axle left with the washers in place. I had not considered deforming the fork to eliminate the interference ("whacking it flat" :) ), but that's a good idea. I am not sure I fully understand your suggestion about welding a box section to bridge the gap at the other end. Are you suggesting I take a short piece of the "boom" square tubing, cap it, and then weld the forks to the caps, followed by welding the square tubing to the boom? What do you think about using pipe to bridge the gap and then cutting a fishmouth where I currently have capped end of the boom and welding the assembled fork there?

I appreciate your comment about constructing a fixture or jig to hold things in place. As a noob, I really want to take my time and make something that rides well, looks good, and provides me with confidence that nothing will break if I hit a pothole while I'm riding.

—DA
 
Joined
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You're correct in understanding my point. I see no reason your idea wouldn't work but would point out that with fishmouthing you'd only weld the half in the mouth and as such you'd have half the amount of weld doing the job. It is a stressed joint and as such needs to be as strong as it can be. It's for that reason I'd modify the wheel end with the hammer, slightly realign the dropouts in a vice to take into account the moving in of the chassis end of the forks and weld the forks as they are at the chassis end. That gives the least joins and the most weld where it's needed most.
 
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