Using a gear box for a jackshaft

#1
20200806_173639.jpg 20200806_173628.jpg What I would like to do is the forward/nuetral and reverse as a jackshart. The driven fits perfectly over the threads but is too small to fit over the shaft. Do you guys think I could ream the driven out and could I do it on my drill press. We are talking like 2 mil to make fit. Or should I bite the bullet and take it to a machine shop.
 
#3
Can you get the shaft chucked on your drill press? Get it spinning and sand paper it one inch at a time and test fit a bunch. Or get a friend with a lathe turn it to fit.
A spiral plus one ream would be $50 easy. And you would have to chuck it in your drill press, or hand ream it.
 

chrisr

Active Member
#4
I might be missing something and sorry in advance if I am, but I have a forward/reverse transmission with a driven that goes all the way down the shaft and did not make any modifications.

View attachment 267035 View attachment 267034 What I would like to do is the forward/nuetral and reverse as a jackshart. The driven fits perfectly over the threads but is too small to fit over the shaft. Do you guys think I could ream the driven out and could I do it on my drill press. We are talking like 2 mil to make fit. Or should I bite the bullet and take it to a machine shop.
View attachment 267035 View attachment 267034 What I would like to do is the forward/nuetral and reverse as a jackshart. The driven fits perfectly over the threads but is too small to fit over the shaft. Do you guys think I could ream the driven out and could I do it on my drill press. We are talking like 2 mil to make fit. Or should I bite the bullet and take it to a machine shop.
 

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#5
I might be missing something and sorry in advance if I am, but I have a forward/reverse transmission with a driven that goes all the way down the shaft and did not make any modifications.
Well that sure looks like the same gearbox. I will try a different driven. To me it seems like the size difference between a 5/8 clutch and a chinese 3 hp.
 

Li'l Popeye

Well-Known Member
#6
Well that sure looks like the same gearbox. I will try a different driven. To me it seems like the size difference between a 5/8 clutch and a chinese 3 hp.
I recently received the same gearbox. The shaft is 16mm diameter. Your driven most likely is 5/8" (=15,875mm).

With the stock length 203589 belt it will not fit, or very tight, behind the engine, therefor I have ordered several 203591 belts, which are a bit longer.
In the below picture is an idea for an enginemount with gearbox and jackshaft.


Here's a video:
 
#7
I recently received the same gearbox. The shaft is 16mm diameter. Your driven most likely is 5/8" (=15,875mm).

With the stock length 203589 belt it will not fit, or very tight, behind the engine, therefor I have ordered several 203591 belts, which are a bit longer.
In the below picture is an idea for an enginemount with gearbox and jackshaft.


Here's a video:
You wouldn't be interested in selling a copy of that bracket would you. I think that will work on the Murray kart
 
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