Project "Firebolt"

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I didn't realize you were raising the bottom tube of the frame. That should give you a little more ground clearance.
Exactly. I am abusing my bikes often, riding long distances and on different surfaces. In snowy weather too. And i don't want electric bike to be an exception. I need to make it utilitarian. So extra clearance would be a must :)
 
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Here is some progress.
Started by cleaning the fork from the excessive legs.
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Then i've sacrificed a perfectly fine fatbike fork. Feels silly to destroy a nice working piece just because i have no proper bender. But the bender is more expensive then the fork, so done it anyway :)
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Tried to set up the geometry without a good welding table i had in my last workshop. Kind of worked, though it wasn't easy.
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Since i din't find a way to remove the rubber damper i had to let the fork have a bath after every inch of a weld.
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I am a newbie with TIG welding, but i believe my welds are usually not as horrible :D Seems that the fact i had to put it to water did reduce the weld quality.
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Here is how it looks after new legs are on.
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Those welds are so ugly i can't stand them :D I would have to do something with it :D
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I actually have a plan B for the fork in case something won't work with that one, but i would reveal it later :)
 
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That's an interesting looking fork. I'm wondering if without a 'crown' to tie the legs together and give support to each leg, how sturdy it will be? And how much leverage the wheel will put on the legs in that forward position. Cool idea integrating the mono-shock fork with the frame!
 
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That's an interesting looking fork. I'm wondering if without a 'crown' to tie the legs together and give support to each leg, how sturdy it will be? And how much leverage the wheel will put on the legs in that forward position. Cool idea integrating the mono-shock fork with the frame!
I love my forks offset :) It can be quite a bit of a leverage, but those large fat bike thick wall tubes sure would hold it with no problem. My welds may be ugly, but they're not shallow, so i am sure about penetration as well. I mean not sure like "nothing on earth will destroy them", but sure like "hey, this looks good enough to run some 50mph electric bike on it".
 
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Started my day by cleaning up the table and welding the BB shell into its new place. Got a relief when put a normal weld, that that fork was indeed so ugly because of water cooling, not so much because i am a horrible welder :D
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Then the belly tube was marked on and cut into size, with the new spot for the BB.
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My hole saw almost lost all its teeth by now 😝
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Another geometry lining up and check. I'd need to extend the lower tube a little and notch it for the seat tube arc connection.
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Decided to clean the tube a little now when it is still separate from the bike. It have seen lots of scratching the asphalt in its previous life :)
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Also re-tapping the holes for the cable guides mounting.
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Here it is ready to be welded on! With both ends notched. By the way, when connecting two halves of the bottom tube i found out the pulse mode on my tig very effective and nice. Still learning as i said, and so far that was the work that was made easiest by that technique.
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So, got a special delivery from the USA today! Very glad, i've been long waiting for it :)
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I told you i have a plan B in case if my experiment with the monoshock fork won't work out, didn't i?
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Let me introduce you, third i own now, my favorite, softest of them all, Shockmaster fork :) However i have some concerns about using it for an ebike, since it was obviously not designed for something as fast and as heavy. I am also not sure how would it handle torsion from the roller brake i'd attach to it. So all of those reasons make me wait with it. But if something goes wrong with my monoshock, i'd totally give it a shot!
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Even though the ad said it came off a boys bike, for some reason i believe it was modified from a girls fork. First there is no groove for the spacer on the thread, second i believe the truss rods extend a bit too much into the spring. However, my biggest worry was that it may end up being too short for the Basman head tube.
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As you see, before the headset is installed, it is even a bit too long. So it won't be a biggy to fix it even if after the cups are pressed there is still not enough thread. It looks so gorgeous on this bike.
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In the mean time i have started to weld the bottom tube on. Missed the center of the bb shell at first, so cut up the weld and straightened it once before finally putting the seam around.
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I'm gonna keep you guys updated ;)
 
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Good progress. I like the direction you’re going.

I would also be concerned with the newer fork on an ebike: Looks great, but all the possible issues you mention… I hope the monoshock works out.

Keep up the good work!
 
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So, this morning the delivery service woke me up, telling my argon cylinder has come. Pretty good piece of news, it was originally scheduled for Monday. So that means i can keep working on the project during this weekend!

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So, i've tacked the right chain stay on the place for some further measurements and development.
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Now comes one of my favorite parts - cardboard aided design! Here is the first sketch for the rear drop outs.
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And here is the second one.
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As i revealed in the building thread of @Graffix1972 already, my plan is to integrate the prewar style chain tensioners. I want them to be beefy and strong, so my intension is to use M10 thread, same size as the axle. But instead of threading the piece of tube i am intending to use some long nuts. I have two options - slim and thick. And though thick one would be stronger and easier to weld, my concern is that it may interfere with the hub parts like gear interface or so. I am probably going to use 8mm thick plate for the drop outs and the slim nut for the tensioner.
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Then i've cut out the original mid tube. Since i don't have a bender available at my workshop, the plan for the mid tube curve is to cut up some handlebars. Here is a mockup of one of the possible options.
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Here is a mock-up with the engine and battery at their probable spots. The engine ended up not to fit too well to be put on the inside part, but i am not really disappointed with it. This way it is still stable and in the good position, but then the battery seems to fit on the bottom.
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Here is another mock-up with the mid tube position this time.
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Looks good so far :)
 

kingfish254

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I was a bit behind on your build thread. Excellent progress. I like your fork idea, but I LOVE the CWC springer on there more. That fork probably came from a ladies bike with a taller headtube. Just remember you'll need to shorten the truss rods along with the steertube.
I love watching your work. Keep it up!!!
 
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I was a bit behind on your build thread. Excellent progress. I like your fork idea, but I LOVE the CWC springer on there more. That fork probably came from a ladies bike with a taller headtube. Just remember you'll need to shorten the truss rods along with the steertube.
I love watching your work. Keep it up!!!
Thanks for the feedback! I like the CWC fork more too, believe me! And if i won't have to think about high weight and speed that'd totally be my first choice. I have a feeling that it is a ladies bike fork that was already shortened by someone, because the truss rods extend too much inside the barrel of the spring, and none of my other CWC springers have this. That made me think someone did threaded them further, but forgot to cut the excessive material. Also the thread on the steerer tube looks rather fresh.
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Haven't worked a lot on a bike lately, since there are few more important projects i've got to finish :) But there is a bit of progress.

I've got a new ground clamp for my welder.
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I didn't notice how exactly or when, but i've burned like half of the copper from my last one away. So it was time to change it.
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Since i don't have a bender unfortunately, i've cut up a set of Dyno D stamped moon bars for the curve. Before Dyno fans out there would crucify me, i am aware of how valuable they are, and this particular bar was beyond saving :)
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Here i am mocking up the mid tube.
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I usually don't clean up my welds, but somehow i've started doing it on this bike, and i went ahead ant tried it once again here. With the belt grinder i've borrowed from my work. It has the graphite pad underneath the belt, unlike my grinder you can also see in the pictures, so it grinds smoother.
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Here how the bike looks with both tubes placed.
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It ended up to be a bit more steep then i've intended on my sketch. What do you guys think? I am not sure if i like this look or not. Maybe i'd prefer just a little accent rather then prominent bend.
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I like it. Reminds me of the Western Flyer X-53 mid-tubes. But if you want closer to the Firebolt & your drawing, can you slide the tubes forward so there is less curve intersecting the downtube and still have enough on the rack end?

Keep up the good work.
 

kingfish254

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Definitely some cool X53 lines going on.
I like the curved front better than the straight Firebolt lines. X-Bolt is better.
Don't lock yourself into a corner with a theme. Just flow along where the build takes you.
 

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