It will run again

Yep Got a spare   

Drive pin?

That's the stay tuned part!

Can the crankshaft be repaired? Looking at the crank gives me some ideas. If you were going to discard the broken crank I'd like to try and repair it for you as an experiment.  
Thanks for sharing.

coxaddict wrote:Can the crankshaft be repaired? Looking at the crank gives me some ideas.  If you were going to discard the broken crank I'd like to try and repair it for you as an experiment.  
Thanks for sharing.

The front spline part is missing. If it was there it may have been brazed to try to repair it.

One of the Killer Bee cranks with the hole in the crank pin could be tapped with a reverse(preferably) thread, and then a steel stud of the right diameter could be threaded and screwed into it. I wouldn't know how to do it with a Bee crank though. Unless you have the capability in your shop to bore a precision hole in the crank pin.
Rusty

Ah! So you're who outbid me! Well congrats. Price was decent for parts anyway.

I was gonna ask, does the spline part missing really matter? What if you still had the spline part, or took another from another crank, and just screwed the prop on as normal? Would it not still stay in place? I guess it could cause the prop to slip and turn a little. But it could be solved by knurling the end of the crank and the back of the spline piece. I don't know. Just thinking out loud. I assume your doing to try the "drill and dowel" method? Drilling the pin and pressing in a dowel?

I'll take that broken crank off your hands if you don't want it.  

G.O. Stang wrote:Ah! So you're who outbid me! Well congrats. Price was decent for parts anyway.

I was gonna ask, does the spline part missing really matter? What if you still had the spline part, or took another from another crank, and just screwed the prop on as normal? Would it not still stay in place? I guess it could cause the prop to slip and turn a little. But it could be solved by knurling the end of the crank and the back of the spline piece. I don't know. Just thinking out loud. I assume your doing to try the "drill and dowel" method? Drilling the pin and pressing in a dowel?

I'll take that broken crank off your hands if you don't want it.  

The spline is the only part that extends past the end of the crankcase. The front bearing is immediately behind the splined end.

RknRusty wrote:One of the Killer Bee cranks with the hole in the crank pin could be tapped with a reverse(preferably) thread, and then a steel stud of the right diameter could be threaded and screwed into it. I wouldn't know how to do it with a Bee crank though. Unless you have the capability in your shop to bore a precision hole in the crank pin.
Rusty

The plan is to center the crank pin with an independent 4 jaw chuck. center drill the crank pin and drill for a press-fit dowel pin. No need to use a KB crank.

G.O. Stang wrote:Ah! So you're who outbid me! Well congrats. Price was decent for parts anyway.

I was gonna ask, does the spline part missing really matter? What if you still had the spline part, or took another from another crank, and just screwed the prop on as normal? Would it not still stay in place? I guess it could cause the prop to slip and turn a little.

I'll take that broken crank off your hands if you don't want it.  

Well, when I got this engine, it looked perfectly fine until I gave the prop a spin. While I'm sure it would have ran the way it was, I was worried about something coming loose.
https://sites.google.com/site/coxenginecollection/replacing-a-broken-crankshaft-in-a-post-1959-babe-bee

Finally found my 4 jaw chuck. Should make some progress this week on the crankshaft.

I could use one of those too, if you're interested in making another.

You have my attention!   

First attempt......EPIC failure  





Attempt 2 will try with solid carbide drills. The old crankshaft is brittle. Must be case hardned.

Ugly..... Oh well, you have spares.   

Ron Valentine used another approach for his reedies that are converted into rear valve ones. By thinning the lower end of the conrod, this will expose a bit of the regular crank pin which then can be used to drive the valve...

Just something to consider if you don't manage to add a drive-pin to a regular crank...

Surfer_kris wrote:Ron Valentine used another approach for his reedies that are converted into rear valve ones. By thinning the lower end of the conrod, this will expose a bit of the regular crank pin which then can be used to drive the valve...

Just something to consider if you don't manage to add a drive-pin to a regular crank...

I think the problem with this is using the factory valve. So he's needing a very close to factory style crank and pin setup.

Yes, I can understand that, but judging from the first attempt at modifying a standard crank, I'd guess anything that can put the engine back in working order would be useful...

The disc would have to be modified, either extended or moved closer to the crank pin, in order to work with a regular crank, so that is certainly not an easy job either.

I think the carbide drills will be able to drill through the hard surface without causing stress on the crank pin. I will give this a try. The last option is to use a HD crank with a hole alrady in the crankpin and turn a part to press in with retaining compound.

The Carbide drills are a better choice..  Maybe this is a dumb question Jason.. but, are you peck-drilling?

roddie wrote:The Carbide drills are a better choice..  Maybe this is a dumb question Jason.. but, are you peck-drilling?

I was using cutting oil. It wasn't that deep that I felt the need to retract the bit to clear the chips out. The drill walked to the side and blew out the crank pin. I need to order carbide center drill and a carbide drill at .070.

Jason_WI wrote:First attempt......EPIC failure  





Attempt 2 will try with solid carbide drills. The old crankshaft is brittle. Must be case hardned.

Are you trying to drill this in a lathe at a low rpm?

You might be better off to use a drill press.

Also, I'd suggest using a center drill before trying any type of twist drill to remove the crankpin. Twist drills are usually too flexible to reliably start on center. Carbide drills are stiffer, but my still tend to wander at the start.

Yes in a lathe as I can center the crank pin. I will order a #1 carbide center drill and screw machine length cobalt 135 degree split point #50 drills. I will also get one #50 carbide drill. Will go from there. My drill press is in the "ropeless boat anchor" class of tools so I'm not going to use that.