Custom built, self made ebike frame project

[Promodbike]

Keep up the good work ! Greetings from Augsburg/Germany

 

[Jordan.1]

Update 22.04.2016

As I already said, things are slowing down here cause of uni.. Still found some time yesterday to continue with the bottom bracket area.
So I cut the plates and drilled a 40mm hole in them. And again I've got to say: I'm in love with these hole saws. A measured 40.00mm hole with a small crappy Drillpress is simply awesome!

After that, i faced a problem I didnt think of. of course, I wanted to put a bottom bracket shell in the holes, then weld it, then tap it. So I went to the bike shop first, to check what diameter exactly works well with the BSA Tap. Normally its 33,67mm. I turned 3 short shells just to test diameters from 33,67 to 33,89, but none of them worked. The problem is, that the tap is designed to REcut the threads, not to cut into stock material. A tap to cut with the holder etc would cost about 120€ or even more, so i decided to do smth. else. I turned down the treads from the shimano hollowtech bearing cups just enough so that i have a flat surface (diameter is 33.50 at this point). Then turned the inside of the full length shell to that diameter aswell, so that its a press fit. Didn't really turn inside before, except cones. Normal inside turning was horrible before. :x I shortened the stickout of the boring bar, used oil and it works perfectly now. But I have to use ridiculous amounts of oil . Normally i just use oil for small finishing cuts (cause its not really needed..)

Next step will be to weld the complete assembly, so lots of work to do in one job. And I have to buy some more aluminum tubes to build a stand thats straight, to align the parts properly.

Stay tuned!

 

[Wheazel]

Great build! There has been some discussion about aluminum properties already in the thread and I have some more querstions on this topic.
First of all what thickness aluminum do you consider weldable? Ive welded quite some 0,7mm steel in my days, built various boxes.
Could this be done with say 2mm aluminum, or is it too hard for a reasonably experienced welder?
Will you be heattreating the frame?

 

[Jordan.1]

Great build! There has been some discussion about aluminum properties already in the thread and I have some more querstions on this topic.
First of all what thickness aluminum do you consider weldable? Ive welded quite some 0,7mm steel in my days, built various boxes.
Could this be done with say 2mm aluminum, or is it too hard for a reasonably experienced welder?
Will you be heattreating the frame?

Hi,

i think it's pretty easy to weld aluminum starting at 1mm, with precise cuts and a sharpened electrode. What's important, is to use a foot pedal to control the heat, and to back of at the end of the weld. The most important thing during welding is arc length and the right filler material diameter. 2 mm Aluminium is pretty easy to weld with around 100 amps. I've read much about ~ 40 amps per mm, for me, this is not enough. I'm welding most of the time at maximum 175 amps to start the weld, then back of to around 150 for continues welding. My biggest mistake, when I started welding was not using enough amps cause of this 40 amps rule..
But never weld too hot or too quick! This will result in a huge distortion. If you dab the rod one time in around 0,75 seconds, the speed is enough.

Because I'm using 6060 series aluminium, I will have to heat treat it afterwards.
I'm still looking for someone with a 500° Celsius oven for 20 minutes

 

[Jordan.1]

UPDATE 20.7.2016

Finally I can post something new in here. Even though I've finished my semster with pretty good grades, still, I don't find much time to continue the frame due to work at the bike shop, other small projects and things with higher priority.

You can see the results of 3 hours of work in the pics below. I welded everything together, except the hardest welds, cause the frame was just to hot to reposition it, so that i could finish the welds..

tack welds first:

then aligning the seattube to the downtube/ bottom bracket, had to grind some metal of the tube to get a proper fit:

more tack welds that finally got me sunburned cause i was working in a sleeveless shirt

and then welding everything:

I hope you guys enjoy my work!

 

[Byte]

Sehr schön!

 

[denso]

Awesome build! Should be solid enough. Gussets between top tube and down tube still to come?

 

[Wheazel]

Looking good! What is your thoughtprocess about the frame tubing material?
Reasons for the specific size and shape?

 

[skeetab5780]

Ya it looks solid as a rock but heavy. I like the look of aluminum though sweet design!

 

[recumpence]

One thing you might want to consider is using a wood router to slightly round the endges of the aluminum. This gives a much softer look to the frame and reduces the chance of receiving a sharp bruise while riding. I am building a frame with square tube and I rounded the edges with a router. It looks really good with ruined edge tubing. A normal carbide router bit works wonders.

Matt

 

[Jordan.1]

Awesome build! Should be solid enough. Gussets between top tube and down tube still to come?

Yess of course!

Sehr schön!

Danke

Looking good! What is your thoughtprocess about the frame tubing material?
Reasons for the specific size and shape?

Well the only reason is, that it's easier to handle in terms of cutting and precision. Stock material is always within + or - 0.05mm and that's really helpful.

You don't get this precision with simple steel profiles, except you buy some special stuff but this is even more expensive then aluminium.

But of course aluminium has its disadvantages, too.. Welding is more critical, heat treatment, distortion s.o.

I've chosen rectangular tubing, so that its easier to align and fabricate everything. Another benefit is, that there's more weld length (looking at a 60mm x 60mm square tube vs a 60 mm round tube).

Disadvantages are harder welds in some areas cause you have corners, edges so you will have fillet welds (harder than lap joints). The shape is the same shape that my actual bike has, I just made some geometry changes for higher speeds. My actual frame is "solid flair", you may Google it up it's awesome to drive but its not designed to be an electric bike..:/

Ya it looks solid as a rock but heavy. I like the look of aluminum though sweet design!

Thanks haha I like the design as well. You're right, its quite heavy but thats because I'm using 6060 aluminium, therefore I need a bit more wall thickness (its less strong compare to 7020, but way easier to get + cheap). I think the complete frame assembly will be around 7kg after completion, will post Info's when its done

One thing you might want to consider is using a wood router to slightly round the endges of the aluminum. This gives a much softer look to the frame and reduces the chance of receiving a sharp bruise while riding. I am building a frame with square tube and I rounded the edges with a router. It looks really good with ruined edge tubing. A normal carbide router bit works wonders.

Matt

Thanks for the suggestion! I already thought of that problem, but I don't have a router. But that's a real improvement for later frames maybe!

 

[Samd]

Nice work. Very similar to many DH Comp builds here, but with a single swingarm.
You'll find a lot of custom aluminium frames if you search a few years back. And maybe some tips on aluminium as a material.

 

[recumpence]

Jordan,

I want to thank you for the tip on TIG welding aluminum. I, too, was welding with relatively low amperage. I took your advice and upped the amperage. I was welding 6061 (3mm thick) to 6mm shock mount plates. Innitially I was using 100 amps (240 volts) on my Miller Diversion 180. It took alot of time to preheat the material into a decent puddle, and the weld was not very consistant. Now I am hitting it with 160 amps to start and backing down to around 100 amps using the pedal once I have a good puddle going. This is much better! I have also found my Argon useage has dropped because I am not preheating with the arc for such a long time.

I am a great fabricator, but I am a self taught welder. Any advice from a more experienced welder helps me tremendously.

Thanks again.

Matt

 

[LI-ghtcycle]

Great build! Keep us posted!

 

[macribs]

Because I'm using 6060 series aluminium, I will have to heat treat it afterwards.
I'm still looking for someone with a 500° Celsius oven for 20 minutes

You can make an easy and cheap oven yourself using building blocks / cinder blocks /bricks or even mdf sheets stone wool and metal siding.
Get one of the cheap but reliable PID's from ebay to control the inside temperature of your oven and use 1 or more water heating (coffee pot) elements.
If you got some materials laying around you can make your own oven in one day. Total cost of PID and heating elements less then 50$.

Then you can use the same oven for powder coating as well as heat treatment. Rent it out when not in use to other DIY'ers and even make a profit.

 

[Samd]

You really don't need to t6 the frames man.


Sent from my iPhone using Tapatalk

 

[recumpence]

You really don't need to t6 the frames man.

I agree......

 

[Jordan.1]

Nice work. Very similar to many DH Comp builds here, but with a single swingarm.
You'll find a lot of custom aluminium frames if you search a few years back. And maybe some tips on aluminium as a material.

Do you have any links or names I can look for?

Jordan,

I want to thank you for the tip on TIG welding aluminum. I, too, was welding with relatively low amperage. I took your advice and upped the amperage. I was welding 6061 (3mm thick) to 6mm shock mount plates. Innitially I was using 100 amps (240 volts) on my Miller Diversion 180. It took alot of time to preheat the material into a decent puddle, and the weld was not very consistant. Now I am hitting it with 160 amps to start and backing down to around 100 amps using the pedal once I have a good puddle going. This is much better! I have also found my Argon useage has dropped because I am not preheating with the arc for such a long time.

I am a great fabricator, but I am a self taught welder. Any advice from a more experienced welder helps me tremendously.

Thanks again.

Matt

No Problem! Always a pleasure to help I'm even planning building something like a slider with four "wheels" aka bearings just to rest my arm on it and still being able to do a proper slide. I think its quite hard to weld for longer time periods because you always have to hold the torch steady, and without a support, at least I, start to get shaky hands. Sure, this will be a nice to have, helping tool.
What im also thinking of is buying a new torch (sr17) with a flex head, but I couldn't find anything that fits my needs. Most of them are just rated for 140 Amps, but sometimes I'm using 180..would get to hot.. :/ A bigger torch like a sr26 is not an option, cause there are some tight spots sometimes..
The biggest improvement for the torch was buying a "stubby gas lens" kit. Like that, my torch is really small compared to what it looked like before, and its easier to handle. I can use sr9 cups (shorter).

Great build! Keep us posted!

I will!

Because I'm using 6060 series aluminium, I will have to heat treat it afterwards.
I'm still looking for someone with a 500° Celsius oven for 20 minutes

You can make an easy and cheap oven yourself using building blocks / cinder blocks /bricks or even mdf sheets stone wool and metal siding.
Get one of the cheap but reliable PID's from ebay to control the inside temperature of your oven and use 1 or more water heating (coffee pot) elements.
If you got some materials laying around you can make your own oven in one day. Total cost of PID and heating elements less then 50$.

Then you can use the same oven for powder coating as well as heat treatment. Rent it out when not in use to other DIY'ers and even make a profit.

I thought of that already, but the problem is that I dont have that much space in the basement.. Plus its me AND my neighbours already paying the bill for the electricity down there, but they know.
But I think for now it'll be okay without an oven. After the frame is finished, I will make some geometry tests and riding tests of course. If everything is perfect, I will heattreat it (I know a restaurant owner with a pizza oven ). After that, I wont have any more fear because of stability.

You really don't need to t6 the frames man.


Sent from my iPhone using Tapatalk

You really don't need to t6 the frames man.

I agree......

Wow.. there seems to be a huge lack of knowlegde here. As I'm studying mechanical engineering, I've learned a lot about materials engineering aswell.
This is an extremely important process to regain the almost full strenght of the raw material. Strenght after welding is around 30% of t6 for the alloy I'm using, so thats around 55MPa (SI-Units) in the weld area, which is literally nothing. Theres not a single company that doesnt heattreat its frames!
I've read a book about aluminium called "Anwendungstechnologie Aluminium", its about proper utilization, joining methods, and of course heat treating. There are curves to see regarding strenght, trust me, you SHOULD NOT want to ride a bike without heat treatment as long its a 6000 series alloy!

 

[recumpence]

The issue for these projects is typically being able to repair or add something to the frame later on. That is tight to do after treating. Also, weight is not an issue for an ebike. So most of us just over build and deal with the added weight.

 

[Jordan.1]

The issue for these projects is typically being able to repair or add something to the frame later on. That is tight to do after treating. Also, weight is not an issue for an ebike. So most of us just over build and deal with the added weight.

ok I unterstand your point. But the only thing I will add later are mounts for the box, and these will be soldered (for optical reasons). So temperatures will stay below any critical point. Still, I dont want this thing to break below my *** when im driving at 80 km/h

 

[Jordan.1]

UPDATE 25.07.2016

Today, I've spent several hours "in the office" working on the swingarm. The reason is, that I want to get this thing street legal here in germany, therefore I have to make some frame testing. And of course the people I'm dealing with at "TÜV" should understand that I really made some thoughts. I've read many things about oprational loads in bicylcle frames. with these loads, I optimized the swingarm and confirmed the structural strenght of the frame. I even used up to 400% higher loads, so the safety factor should be quite big.

Below, you can see some pics of some of the simulations I did. For example, I should be able to stand on the swingarm laying sideways on the ground without deforming it. (dont try this with your standard bike frame, it'll bend for sure!)

 

[--freeride--]

Nice Work!
Are you using Solidworks?
For the frame hard braking at the front should be a tough job too.

 

[Samd]

Wow.. there seems to be a huge lack of knowlegde here. As I'm studying mechanical engineering, I've learned a lot about materials engineering aswell.

I'm a degree qualified B.Eng (Mech/Elec) kid. I am the frame maker that the goto guys go to. I've exported frames from Australia to Saudi Arabia, UK, California, Canada, Costa Rica and Sweden. I've put more bandsaws through $5k bikes than you've owned cars.
I appreciate where you are coming from, but really cmon.

Also, your falling/rising rate on the rear swingarm won't work.

Sam.

 

[querlenker]

What are the loads you used (Newton per axis)? Greets

 

[Jordan.1]

Wow.. there seems to be a huge lack of knowlegde here. As I'm studying mechanical engineering, I've learned a lot about materials engineering aswell.

I'm a degree qualified B.Eng (Mech/Elec) kid. I am the frame maker that the goto guys go to. I've exported frames from Australia to Saudi Arabia, UK, California, Canada, Costa Rica and Sweden. I've put more bandsaws through $5k bikes than you've owned cars.
I appreciate where you are coming from, but really cmon.

Also, your falling/rising rate on the rear swingarm won't work.

Sam.

I think you missunderstood me..I dont want to show of or whatever. Maybe my english isn't good enough to express what I wanted, so I'll try again:
I don't want this project to fail, I don't want my frames to break. And, I dont want my results be the results of luck or whatever.
Thats why I try to work as professional as I can. This includes reading many books about all the topics coming up during the development process.
And working with motion and simulation models of course. I'm also in contact with my professors to confirm my calculations/ get tips s.o.

So concerning the heat treatment: I can see the stresses in the frame and swingarm everywhere cause of FEA. Without heat treament, it would just break in some (of course extreme) situations. Without heat treatment the frame could just take around 35% of the load it can with it. Even my prof said "if you want to get scraped of the street, dont do heat treatment."

"Also, your falling/rising rate on the rear swingarm won't work." I dont really get what this means. I assume youre meaning the geometry of the shock / the kinematics. I've tuned my geometry with the program "linkage", some of you might know. I wanted the suspension to be (almost) the same as my actual bike has. when looking at the curves, its almost the same. I will see if everything is like I thought or not, its always possible to change something for the next frames. If you have some tips, I'll listen of course :lol:

Regarding the Newtons I used: Depending the Simulation I put up to 5000N at the rear axle, 2200N at the front. The static load when just sitting on the bike is around 1000N at the read, 440N at the front (120kg biker + 30kg bike)

Nice Work!
Are you using Solidworks?
For the frame hard braking at the front should be a tough job too.

Didn't see this, thanks!! Yes, I'm using SolidWorks. I also simulated this of course, no problem.