keyless shaft help!

[rhapak]

Hi All!
I've got a 3hp Briggs motor I would like to use for my kids minibike. It comes from a pump and doesn't have a keyway on the shaft. Is it possible to cut one in with a dremel or some way other than taking it to a machine shop???
Your help is appreciated!
Rod

 

[jr dragster T]

Yes you can cut a key way with a dremel somone has done it on this site maybe he could explain how he did it.

 

[kibble]

I did it. Here's an excerp from the post I put up about it:

The only things I used to make the keyway on the shaft was a sharpie to mark where the keyway would be and how wide, a dremel with a metal cut-off wheel and lots of patience. It took about 30 minutes to make sure that the key fit in without being too tight or too shallow.

I began by making two lines where the keyway would be and then I cut two grooves into the shaft. I made sure to stay within the boundaries of the marker lines.

I slowly ground away at the walls to make the way wide enough to accept the key.

Carefully I ground away at the bottom of the keyway to keep it square and to make it deep enough for the keyway to go in without having either side raised too much. You just have to slowly and carefully grind parts of it away. It's very tedious but worth it.

 

[jr dragster T]

One more thing to add. Make sure the crank shaft doesnt get to hot or you may distort the crank seal.

 

[kibble]

If you do it carefully enough and don't put too much force on the cutting wheel, the shaft will barely warm up. Don't force it, just let the wheel do the work. That's part of the reason why it takes so long to do.

 

[jr dragster T]

Yeah I didnt think a small dremel bit would warm up the shaft but I was just saying. (Trying to teach somone somthing)

 

[kibble]

I didn't knock it, yours' was a good tip! I was just saying that if done right, the shaft won't get too hot and cause what you mentioned.

 

[gocartkid]

Mmmm......good info here. I have a Briggs 5 w/o a keway and it has a tapered shaft. Is there any way to fit a clutch to it or I'm I going to have to swap cranks?

 

[kibble]

First of all, what size is the shaft? It might be some funky size between 3/4 and 1" like mine was. You would have two options: Get a collar made to make it 1" or use a jackshaft setup like I did with mine where it's got a pulley going to a similar sized pulley on a 3/4" jackshaft. Actually a third and more expensive option, unless you could do it yourself, would be to get it machined to 3/4".

 

[gocartkid]

First of all, what size is the shaft? It might be some funky size between 3/4 and 1" like mine was. You would have two options: Get a collar made to make it 1" or use a jackshaft setup like I did with mine where it's got a pulley going to a similar sized pulley on a 3/4" jackshaft. Actually a third and more expensive option, unless you could do it yourself, would be to get it machined to 3/4".

I can check on size tommorow....you bolted the pully on the end, correct? I was thinking about doing that as it's drilled and tapped. Could you use a sprocket there instead of a pulley? I would assume it would be ok.......

 

[kibble]

Yeah, if you can find a sprocket that will fit, it would be even better. You would still want to dremel a keyway into it though to make sure you have no slipping of the sprocket on the shaft. I should replace my setup with sprockets.

 

[gocartkid]

Yeah, if you can find a sprocket that will fit, it would be even better. You would still want to dremel a keyway into it though to make sure you have no slipping of the sprocket on the shaft. I should replace my setup with sprockets.

Okay....I thought I would have to swap cranks...that would've sucked. Would it matter if I cut it at the second step up and the dremeled it? That would be the way to do it, right?

 

[kibble]

Whichever one the sprocket would fit on. See if you can get a measurement.