BSA B50 -500 APG Build

[Koncretekid]

Bo,
The line you show is what I have in mind to add triangulation.  I will add another from the main frame above the rear axle up towards the tail, but it will have to have a curve in it to clear the rear wheel.

Bones,
I agree with you on the balance factor.  I was not crazy about the 65% factor, but that is what the flat trackers are using with the long stroke motors.   With 65% I'm somewhat balanced in the vertical direction, but poorly balanced in the fore and aft direction.  Next time I take it apart, and I'm somewhere (Colorado) where I can get it dynamically balanced, I'm going to try 50% because it makes sense on a vertical single!  I'm also thinking about adding a balancing weight (flywheel) in place of the rotor which has been removed as acceleration is not an issue.  

I just received a shipment of 1" x .058" wall chrome moly aircraft tubing today, about 2-1/2 times stronger than mild steel, and it's normalized to relieve the manufacturing stresses.  I'll post some photos in a week or so, when I've made some progress.

Tom

[manta22]

It helps to build a model of a frame with balsa wood; then apply force and see what moves or breaks first.

Regards, Neil  Tucson, AZ

[NSF Ed]

Tom, once it's all back together and at the Dyno, can you get hold of a strobe to "watch" things move?

[Koncretekid]

It helps to build a model of a frame with balsa wood; then apply force and see what moves or breaks first.

Regards, Neil  Tucson, AZ

Would I have to make a model of the motor to check on fatigue failure? Maybe an .049 model airplane motor would supply sufficient vibrations.

Tom, once it's all back together and at the Dyno, can you get hold of a strobe to "watch" things move?

Good idea, Ed.   Bring along a strobe light to Loring in July.

Tom

[manta22]

No, the balsa model is just for static tests..

[Koncretekid]

The wife left me...........for 10 days to help with the Grandchildren .  I sure get a lot more done now!

As you can see, I've replaced the upper two frame tubes using an aircraft repair procedure with a scarf joint and an inner tube plus rosette welds. I also made a new "harness" bolted to front and rear motor mount lugs and to the jig.  After tacking in the new uppers (one at a time), I cut the lower main frame tube all the way to the head stock.  You can see the pile of scrap metal on the jig. 

[Koncretekid]

I've now completed the new lower right frame tube as well as drilled and installed new ferrule for lower motor mount.  Tomorrow I'll start hacking up the left lower frame to see if I can get that to fit as well.  I'm considering buying a Thermal Arc 95S stick and tig welder.  I volunteered to help Steve by practicing on one of his J3 Cub frames, but he declined.  Can I learn to tig weld in a couple of days?

[Captthundarr]

  Can I learn to tig weld in a couple of days?

Depends..do the parts really have to stay together for any significant amount of time?

[Peter Jack]

Get your friend to stand over your shoulder for a couple of hours, for a couple of days, and you should have a pretty fair handle on it. Looks like you have lots of scrap to practice on. Just put that "Power Fist" bead blaster to work and clean up where you're going to weld on the practice stuff. The next trick is going to be getting the old tubing in the frame perfectly clean before you weld it. A final wipe with an acetone soaked rag before you weld makes sure you're contamination free. Put the rag where you won't light it up after. That flicker on your bench or beside your hand on the jig is usually that rag. Guess how I know?  

Pete

[tauruck]

Right on. I heard woof and wondered why my dog was in the workshop. Fire!!! It only happened once. Any combustible is now kept in a different room.

[Jon]

Can I learn to tig weld in a couple of days?

Did you used to fusion weld or Braze Tom?
If you did the action and what your looking at will be very familiar.
Get someone to help you with settings, keep things very clean and practice on some scrap and you'll be TIG welding sooner than you think.

jon

[Koncretekid]

Depends..do the parts really have to stay together for any significant amount of time?

Oh yea of little faith!  I only ride it 5 minutes at a time!

Get your friend to stand over your shoulder for a couple of hours, for a couple of days, and you should have a pretty fair handle on it. Looks like you have lots of scrap to practice on. Just put that "Power Fist" bead blaster to work and clean up where you're going to weld on the practice stuff. The next trick is going to be getting the old tubing in the frame perfectly clean before you weld it. A final wipe with an acetone soaked rag before you weld makes sure you're contamination free. Put the rag where you won't light it up after. That flicker on your bench or beside your hand on the jig is usually that rag. Guess how I know?  

Pete

Thanks for the tips, Pete - - I was hoping that would get your attention.  As for getting Steve to look over my shoulder for a few days, I can't even get him over here to check on what I've done so far (like many one-man operations, he's too busy.)  That's the main reason why I want to get my own Tig.  I have already sandblasted the existing frame parts I am going to re-use.  The acetone trick sound like a good one, as things begin to rust in N.S. when you turn around.

Right on. I heard woof and wondered why my dog was in the workshop. Fire!!! It only happened once. Any combustible is now kept in a different room.

Like the gas cans over in the corner?  My shop is all concrete, walls, floor, and ceiling, which helps.  So far, I've only managed to set myself on fire twice from grinding steel.

Can I learn to tig weld in a couple of days?

Did you used to fusion weld or Braze Tom?
If you did the action and what your looking at will be very familiar.
Get someone to help you with settings, keep things very clean and practice on some scrap and you'll be TIG welding sooner than you think.

jon

Jon,
I've done very little torch work, just a little stick and now mig.  But I tried a tig and the result looked pretty good.  I've got lots to practice on.

Tom

[Peter Jack]

Tom, the acetone won't get the rust. Wire brushing will look after that. The acetone gets rid of any oily or greasy deposits and other ilk of that nature. You can't be too clean when you're doing that kind of work. We should have planned things better. I could have come down and visited my daughter and her family north of Halifax over Christmas and then spent a couple of days with you on the bike and it would be well on the way to done.

Pete

[SaltPeter]

I am not a Welder by trade, all the TIG I do is on my Bike Build. I did a TAFE (Night School) Course and it was a great starting place.

Like Jon said first get the settings right.

A few things I was shown and all of these things helped me out big time.

You need steady hand, so sit down when you weld were ever possible. I got a a Bar Stool and a mobile Mechanics seat for doing different height jobs.

The TIG prep I was taught, was Mild Steel wiped clean with solvent and then Linished, Ally needs Stainless Brush and Acetone, Stainless as long as it's clean.

Don't be tempted to keep welding with a contaminated Electrode after touching the Job a few times as you do when your getting your eye in.

I found it easier to sharpen all of the Electrodes you got and line them up so you don't have to keep walking back and forward linishing the end as you keep touching the job when you are learning.

Feed/Dip the Stick into the molten pool rather than just melting it with the arc, took me a quite a while to get this one right.



 
Pete

[Koncretekid]

.... We should have planned things better. I could have come down and visited my daughter and her family north of Halifax over Christmas and then spent a couple of days with you on the bike and it would be well on the way to done.

Pete

Pete,
You still can, you know.  Just think how thrilled your daughter will be to have you there for Christmas!  (Although she may not be too happy when you tell her you're going to take a 3 day trip down to Yarmouth.)

And to the other Pete (Saltpeter), thanks for the tips.  I haven't decided yet.  One problem is that the joints are no longer spot on (originally I notched all the tubes with my mill-drill.)  There are a few holes to fill from my mini grinder, which I know I could make a lot bigger with a Tig torch.  I may buy the Tig for my next project, whatever that will be.  Get some practice in first.

I got the final lower tube tacked in this morning, after having to make it twice due to a brain fart - - made the final bend backwards and couldn't correct it - - 3 hours wasted.  I'll post photo later.

Tom