Machinists? Tapping advice...**Updated**

[Eli]

Originally posted by: Farmall
Case hardened steel is not hard all the way through, it is only about 1/32" thick or a bit more on the outside.

If you are using a lathe use a carbide cutting tool to face the end of the stock and you will have no trouble drilling and tapping into it, use cutting fluid though.

Far as milling the keyway get a carbide cutter or you will have a tough time getting through the case.

I think if you are not going to bore the diameter in the sprocket its hardly worth getting precision ground stock. You can turn the cold roll material you linked earlier to whatever size you want and it will be perfectly straight and true to the hole you drill/tap in it provided you do them both in the same setup.

Its probably not a bad idea to turn the diameter anyway so you can match that dia. to the bore in the sprocket more closely.

Oh well. I'm just going to get the cheap, normal stuff from online metals.. We'll see if it works I guess.. lol..

I suppose instead of using thread locker, I could just screw it on and then weld it if I get concerned about strength.

 

[Squisher]

Oh no, a metal working thread and I didn't get in on it.

Anyway good luck Eli

 

[Eli]

Originally posted by: Squisher
Oh no, a metal working thread and I didn't get in on it.

Anyway good luck Eli

You can still feel free to give any advice...

 

[slag]

I was going to add something mildly funny about JB welding it all together but we all know it really wouldnt be funny so I will refrain.

Joe

 

[Ornery]

You know? After all this, I think the threaded part of that shaft is pretty much out of the equation. If it's only 1/4" of thread, the only use it would be is a safety retainer, no more than a cotter pin would be. Your adapter would have a set screw or two holding it to that shaft, and the sprocket would have a couple set screws holding it to your adapter. The adapter's inner diameter would be keyed to the shaft and the OD keyed to the sprocket. No need to weld anything, but you could slap a 1/2-20 LH jam nut on there if you want. Am I missing something?

Edit: Is this close?

 

[Eli]

Originally posted by: Ornery
You know? After all this, I think the threaded part of that shaft is pretty much out of the equation. If it's only 1/4" of thread, the only use it would be is a safety retainer, no more than a cotter pin would be. Your adapter would have a set screw or two holding it to that shaft, and the sprocket would have a couple set screws holding it to your adapter. The adapter's inner diameter would be keyed to the shaft and the OD keyed to the sprocket. No need to weld anything, but you could slap a 1/2-20 LH jam nut on there if you want. Am I missing something?

Edit: Is this close?

Well, let's see. I wish I could take a picture of the stupid thing. I'll try and draw it I guess.


Here

I think that gives enough information to give a general idea of what I'm talking about. The adapter will have no setscrews holding it onto the scooter shaft, only the threads. That's kinda what the left hand thread is for.. As the engine turns the sprocket and adapter, it will tighten it. If the assembly is not very tight on the shaft, then I'll have to do something.. like lightly weld the adapter to the shaft in a couple of places.

 

[Ornery]

Yikes! If there's really only 1/4" of thread, it's going to get ripped right off unless you weld it solid. I'd hate to see that because you can't ever pull it off. BTW, the tap drill for the 1/2-20 is 29/64, but I still wouldn't depend on that.

You said, "The bore in the sprocket is already 0.500". Couldn't you broach a keyway in it, mill a keyway on the shaft and just slide it onto the shaft like that? You could use that threaded part to hold it on if it butts against a shoulder (but I suspect it won't)

Hey, is that picture of My sweety your girlfriend, wife or daughter? Cute either way!

 

[Eli]

Originally posted by: Ornery
Yikes! If there's really only 1/4" of thread, it's going to get ripped right off unless you weld it solid. I'd hate to see that because you can't ever pull it off. BTW, the tap drill for the 1/2-20 is 29/64, but I still wouldn't depend on that.

You said, "The bore in the sprocket is already 0.500". Couldn't you broach a keyway in it, mill a keyway on the shaft and just slide it onto the shaft like that? You could use that threaded part to hold it on if it butts against a shoulder (but I suspect it won't)

Hey, is that picture of My sweety your girlfriend, wife or daughter? Cute either way!

Like I said in the PM, I haven't bought any of the parts yet.. so I can get a sprocket with pretty much any bore I want.. with or without a keyway already machined.

I don't know about milling a keyway onto the shaft. See.. that drawing I made is sort of misleading.. There is a pillow block(for lack of a better term) bolted to the side of the scooter with a bearing supporting the shaft. The shaft, including threads really isn't that long. Only 0.70" to the block. the diameter of the shaft appears to be 0.45".. The old sprocket was held away from the bolts holding the bearing support on by a small metal spacer. I don't really mind welding it on. As far as I'm concerned.. the project will be permanent, I'd never want to put the old engine back on it.

Yeah, that's my girlfriend.. Soon to be engaged.

 

[Ornery]

Oh hell, weld away!

Your girlfriend, eh? Very cute! "Soon to be engaged." Congrats! What do you think her parents will say? My mother-in-law almost feinted when we dropped the bomb on them!

 

[Eli]

Here's a diagram of how the scooter is setup.. I'm bored.

Her mom won't care at all.. Infact, I pretty much met her through her mom. It's a long story.. lol.. Basically, I met her mom online a little over a year ago. We talked a lot, and eventually started hanging out with eachother. Her kids lived with their dad up in Washington.. I never met them or anything. Then one day.. I was talking to her mom online, and her kids were online.. and Crystal and I started talking.. And she asked her mom if she would bring me up when she came to pick them all up for thanksgiving.. lol.. That was 9 months ago.

 

[Ornery]

Bah, that bored me too. Let's see more pics of your GF! j/k

 

[Eli]

Originally posted by: Ornery
Bah, that bored me too. Let's see more pics of your GF! j/k

...

From right to left.. My mom, me, my Crystal, my brother, and his girlfriend.

Picture of a picture..

Another picture of a picture...

hehe..

I'll let you know how everything turns out.. That's probably what I'll do, weld it on.. for strength. I just hope my tax return comes soon, as I'm -40$ at the bank! :Q

 

[Eli]

Well..

I finally found out what those damn threads are. It is metric. 20 threads per inch, 25mm in an inch..

That means I need a 12 x 0.8mm left hand thread tap.

I can't find such a thing anywhere, lol.

I was thinking about welding the old threads up, turning it down with a lathe... and then rethreading it with whatever I wanted to. That should work... right? lol