Square shaft adaptor for engine

[KieranM]

Hi,

I have got a new strimmer/weedwacker/weedeater engine that has never been used and I have plans to use for my scratch built scooter/goped.

As most have a square shaft which is very hard to work with, I was wondering if anybody knows of a shaft adaptor for strimmer engines.

I have spent the last few days trying to make a shaft/shaft adaptor and its impossible to do with out the proper equipment you could never get it right

I have taught of using a small 4 stroke briggs but most are too heavy and at this moment i dont have the money to buy one

Any info would be greatly appreciated.

 

[frederic]

The motor's output shaft is square rather than round? Interesting, that I did not know.

I'd turn the shaft down on a lathe to make it round, then adapt from there.

Another option is to take two pieces of rectuangular stock that together face to face, looks like a piece of square stock. Separate them and mill a slot into each rectangular piece the length that the engine shaft sticks out. Put them together and now you have a square hole in one end to slip over the motor's output shaft.

The other end, and the outer dimensions you can machine as necessary for whatever clutch, pulley, or whatever it is you're going to attach. You can either weld the two rectangular pieces together or bolt through depending on the size and such.

 

[anderkart]

What's the size of this square shaft?
Do you already have the clutch or gear you want to mount on it?
(if so, what size round shaft is it made to fit?)

Someone might come up with a good solution if you posted a pic of your square shaft.

 

[jmorey92]

i think he means the in side of the shaft is square like on weed wackers they have a flexable cable going through the handle with like a square 2in long section on the end that goes into the crank and trimmir head

 

[KieranM]

i think he means the in side of the shaft is square like on weed wackers

Yes that is right. it would be alot easier if the actual shaft was there but its just a square hole that I need to find something to put in it that fits neatly so I could weld it and then get on to actually making it into a round shaft.

What I mean by the shaft adaptor is something that fits into the hole perfectly. (sorry if I did not make it clear enough its kinda hard to explain)


Thanks

 

[frederic]

Oh, it's a square *hole* and not a square shaft. That's even easier. Buy a piece of round stock that's the same diameter as whatever clutch, pulley, torque converter you will be using, and machine a square "key" on one end and shove it into the square hole on the engine. This type of part would be made on a milling machine in four passes, one for each flat side of the square.

More than likely you'd have to support this new shaft with bearings to keep the tension of the chain/belt off the engine's crankshaft. I'm guessing at this but chainsaw engines and weedwhacker engines are incredibly small and not really a "structure" kind of thing.

 

[KieranM]

Oh, it's a square *hole* and not a square shaft. That's even easier. Buy a piece of round stock that's the same diameter as whatever clutch, pulley, torque converter you will be using, and machine a square "key" on one end and shove it into the square hole on the engine. This type of part would be made on a milling machine in four passes, one for each flat side of the square.

Thanks. I have already taught of this and it is a good idea but I don't have access to a milling machine where I live.

Anything else?

Thanks

 

[frederic]

If it's a small diameter piece of material machine it with a metal file. Takes longer, but you'll have strong forearms

 

[anderkart]

What size is the square hole? (a pic might still help us help you...)

 

[jmorey92]

you could use a piece of key stock

 

[KieranM]

What size is the square hole? (a pic might still help us help you...)

The size of the hole is 5.3mm/0.24".

 

[jmorey92]

so 1/4in key stock should fit?

 

[anderkart]

You might be able to slightly reduce the 1/4" end of an adaptor like this: http://buy1.snapon.com/catalog/item.asp?store=snapon-store&item_ID=74341&group_ID=11424
And somehow start rigging it up from there.

 

[KieranM]

You might be able to slightly reduce the 1/4" end of an adaptor like this: http://buy1.snapon.com/catalog/item.asp?store=snapon-store&item_ID=74341&group_ID=11424
And somehow start rigging it up from there.

Thanks That might just work. I will get back to ya after i try it