I wanted to use the key way so I tapped the crank 1/4x28. It just started to break trough the bottom of the key way. I figured I could make a stepped stud if I also use it to retain the prop. 1/4 inch in the crank and 10mm for the prop. I like single bolt prop studs so I don't have to mess around drilling the hubs for a multi bolt set up.

Hey Mark. Glad everything worked out. How about a few pictures to inspire us more?

Tim
Thanks again for the short blocks. I will get some pictures before I have it welded.
I got a response from keith on the welding. He suggested using stainless filler rod to join the cranks. On welding the pins he suggested to me not to weld them, but to drill them with a carbide bit and pin them. He said the heat from welding loosens the press fit to the point that it can be a problem.

Thanks Mark. He told me the same on pinning. Either the pin gets drilled or the forging itself and cross pin it. Will have to talk to my welder about best welding practice. Keith did tell me just a few tack welds was all that you need. Would keep the heat down I suspect. Can't wait to see the pictures.

Huey-pilot, Tim in Mobile here and just wanted to check up on you in Enterprise. Saw the destruction via the local TV news people who went up by you. Hope all is well.

1/4 to 10mm is a big step...The early G26s had a 6mm to 8mm stud to hold the prop on...Some broke where the 6mm met the 8mm..Be aware...

Thanks for your concern Tim, I was on my way to the swap meet in Perry Georgia when the tornado hit Enterprise. Very little damage to my place, I wish I could say that about other parts of town.

Okay here you go a couple of shots of the machined crank and of the mocked up engine.

Nice looking so far! I know this is just a mock-up....is both cylinders the same cc in the photo? Can you include a photo with both cranks "pluged together" ? Did someone mention just pinning the crank where they "plug/press" together? Thanks Capt,n

Nice work!! I think it's going to be a sweet little engine!

Looks like the crank snout left sticking out after adding the third bearing is pretty short??

What size carb are you using?

Yeah, any shots of the crank put together?

Here's a pic of a muffler I made for my 23.6cc Echo in my Fokker. It's a steel tube, squashed oval, with two end caps brazed on and two outlet tubes in one end. I also brazed in two tubes for the mounting bolts to go through and tighten up without squashing the muffler. Works great and sounds good! A variation might work well on this twin...

Thanks, and congrats,
AV8TOR

I made the prop hub yesterday, and cut down the fins a little. I also made adapters to convert it to cm-6 plugs. There is about 1/8 of an inch beyond the taper of the stub sticking out. I dropped the crank at my welder this morning I will post a pic. when I get it back. I am going to put a wt-201 that I have laying around on it. I stacked everything on my scale and it will be right at 3.5 lbs when done minus ignition and mufflers.

Very nice. Looks like you got the reed assembly too. I see what was mentioned about the crank not sticking out real far once the bearing is on. Do you need to slide it back yet? Either way I think you will have enough of the hub riding on the taper so it won't be an issue. I have done some short like that too. Do you still plan to pin the journal too? The 201 carb will be perfect for the engine. I use that same carb on the 44 and 50cc Echo singles I do. Actually it is the same carb BME uses on his 44 and 50cc singles too.

You don't have an extra reed assembly laying around do you??

AV8TOR

Hey Mark, forgot to ask what type of tooling did you use to bore and face the cranks? Anything unusual come up with the forged steel cranks? Also looks like you bored the crank all the way through.

Yes, I bored it all the way through. No particular reason other than I am lazy and this way I did not have to measure how deep the hole was. I used a carbide turning tool to face it. Normal HSS drill bits to start the hole and a carbide tipped boring bar. The surface is hard but once you break through it is not.
I do have an extra reed assembely. $10.00 shipped.

I'll take it!!

Where do I send the money order?

AV8TOR

Drop me an e-mail with your address. [email protected]

Here is a pic of the crankshaft fixture we used. Its milled from a single piece of aluminum. You may have to do a little math to get it right but it supports the crankshaft and the two thin pieces in the middle support the crank pins. When all is touching supports the crank pins are 180 degrees apart.

Here is a picture of the crank all welded up. The welder did not follow my instructions on where I wanted it welded. I hope he did not ruin the pin fit with too much heat. I am going to align it, and pin it and assemble the engine.

It looks like the welder may have gotten a little arc blow onto the connecting rods. I have used thin foil (copper is best) to cover things I didn't want that to happen to. Just a thought for the future. John

Yeah, not how I would have welded it, but I think it will be ok. Looks like it's ready to run... What do you mean "align it and pin it"??

AV8TOR

I am going to chuck it in the lathe and use an indicator to make sure it is true then pin both sides of both crank pins as per Keith's instructions. He said the press fit was not up to a twin.

Looks good and should be fine. Please post a picture of your pinned pins.

Your lathe will have to be perfect if you expect perfect alignment...a better way is bore a hole in a 3/4 or 1 inch steel block...Barely larger than the long end of the crank...Put the shaft in the hole and indicate the rear shaft...Way easier to align it to the front if the block is in your mill vise.....The factory press fit is usually tight enough that pins are not necessary....

RCIGN1: That is a great idea to check alignment. You could probably use the block to check about any crank....with the same dia. Now there is a guy that uses his head...besides a hat rack!!!! Capt,n