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Discussion Starter · #1 ·
After 10 years of dreaming I've finally started my own frame. It's a 650b, rim brake, all road bike (well, hopefully if it turns out ok). I've gotten the front triangle tacked except for where the seat tube covers the downtube, I welded that part.

I don't have a jig, so I've been very careful with the miters and measured a lot. I need to research more on the order of welds to keep it straight. Hopefully done over the long weekend.

 

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Discussion Starter · #3 ·
Metal Steel Aluminium Silver
Workwear Engineering Tradesman Pipe Composite material


I was able to get the chainstays attached with the dropouts. I fully welded the seat tube since it will be tricky to weld after I put on the chainstays. It stayed parallel with the BB shell, so that's a plus. I did realize one pretty big mistake that I can't undo, so hopefully it'll be allright.

After I got the chainstays in the right spot and tacked, I checked to see if it'll clear the tire and crank I'm planning on using, and it will. The bb drop ended up being less than I designed (65mm) so I'm planning on welding the chainstays, then bending them up a tad (8mm each). Any feedback on this idea?
 

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You will slacken the angles of both HT and ST if you do. Check the numbers, it may not change much and be within tolerance. Dropping the BB height may not be that important either and can be within tolerance.

Depends on how you read the numbers.

Sometimes you have to adjust as you go and compromise. I don't think you will end in disaster either way, but this is one of those learning experiences that you don't repeat on the next frame you build.

Keep moving forward, this is what having a go is all about.

Eric
 

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Looking good! Hey what about Bending the chain stays like half as much as you are intending and then facing off some material from the bottom of the head tube so that the BB drops without as much effect on head and seat tube angles.
 

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Discussion Starter · #6 ·
I think if I didn't adjust the bb drop, it would steepen the angles from what I designed. I did bend them, but I agree it's probably within tolerance and wouldn't be too noticeable.
 

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If your chainstays are just tacked it would definitely be the least work with the best results to pull them off and put them back on in the right spot. That one took me way too long to figure out.

That said, looking good for your first frame. My first 10 were probably off more than that and I was so excited about them I didn't really care, just going through the motions you will learn a ton.
 

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Discussion Starter · #8 ·
Thanks, I've been preparing for this for 10 years, lots of small projects, frame modifications, around the house welding and repair. I just had to get over the fact that I don't have a jig, nor am I willing to invest in one yet.

I didn't have the patience to cut out the tacks, and it was easy enough to bend the chainstays. The one thing that I really struggled with is getting a good miter on the seat stays, the gap was larger than I liked, but like Adam says I'm too excited to have it closer to being done and I'm hoping that since the seatstays are in compression it'll be ok. Wood Bicycle frame Brown Hardwood Floor

Wood Brown Hardwood Line Wood stain

Wood Brown Wood stain Hardwood Wall

Metal Iron Pipe Steel Composite material


I'm waiting on a fork (26" mtb, non-suspension corrected, going to relocate the brake bosses) and wheels before I move on. I have a paul racer brake for the rear, probably going to run a paul touring for the front. My goal is to get it ridable before cleaning it up and adding more braze ons in case it doesn't ride well.
 

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Discussion Starter · #10 ·
Update

I had time to reflect over a 3 day tour and 4 days at the beach with the family and I decided to not settle for my mistakes with the seatstays. The miters weren't good, and they were pretty narrow at the tire, which also meant I wasn't going to be able to direct mount Paul Racer brakes.

I'm going to get a saddle and handlebars on it tonight and ride it as a strider to see how it feels, then add on the brake bosses and get it built enough to ride for some test runs.

Built as is the angles are close enough for what I designed. The seat angle is slightly steeper, which is ok with me.
Bicycle tire Bicycle wheel rim Wheel Mode of transport Bicycle wheel
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Discussion Starter · #11 ·
I was able to get more parts hung on the bike. I used U bolt brake bosses turned down for the brake mounts, they'll only work with the Paul Racer, so I'm stuck with that brake forever I think.
I did some strides on it up and down the street, and it seems ok, tracks straight, even no hands. I'm going to add the minimal braze ons soon so I can finish building it up enough for some test riding. Once I'm satisfied with that I'll finish the braze ons and see about paint. Any recommendations for how much test riding I should do on it?
Wood Cable Hardwood Wood stain Flooring

Wood Product Brown Bicycle accessory Bicycle part

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I would observe the behaviour of the upper wishbone section of the seat stays under heavy braking. There is a bending moment taking place and the upper tube is on the small side OD wise and may flex excessively.

Otherwise, looking good.

Eric
 

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Discussion Starter · #14 ·
I think you're right. I got it built enough to take it around the block and though it's kind of dark out it looked like it was flexing a bit. I like the idea of a brace anyways, it'll create a little triangle that I can make a bag for to keep a tube and some tools in. Bicycle tire Bicycle frame Tire Wheel Bicycle wheel
 

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I don't have direct experience with wishbone stays, but that bridge piece looks a little stressed to me. Maybe not, seatstays don't see the most strain of all the tubes, but if you nail a bump while seated, that little bridge is going to take a lot of force.

But at this point maybe just slam the rear brake a few times, and hit a pothole while seated, and if nothing bends then roll with it!

Like others have said, the next frame you make will feel like a whole other project. Just making one is a huge step forward in your skillset.
 

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I would put some kind of cap or plug on that cross bar so you can't cheesegrater a nice curl of skin off of one of your calves. You have all sorts of options here, be creative!
 

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Discussion Starter · #20 ·
I got the braze ons done, paint, and built up again. The biggest thing that I learned is that the propane torch sucks for brazing small parts. It got it hot enough, but heated too much area, and the silver flowed down the tube as well (too much silver). I am getting impatient, so I didn't sand it off, just painted it after cleaning off the flux.
My standard for any new bike I get is to ride it 1000 miles before I really pass judgement on it, so check back in the fall for a report.
I can't post pictures right now for some reason, will try later.
 
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