[SEL] A Baker Monitor question

[Curt Holland]

  Ref: Curt,
I'm not quite sure what you mean....
Harry,
On each part mounted on a shaft such as gears and pump jack arms, the 
key ways are broached on an angle instead of parallel to the bore. This 
allows a slip fit of the part. After each part is in place a tapered 
key, sometimes called a gib key, is driven in until it locks up. This 
locks the gear to the shaft.

As a manufacturing method it greatly reduced the complexity of assembly. 
Whereas a .001/.002"  interference fit required the female part to be 
heated, usually 300 to 400 degrees F to allow enough expansion to slide 
on the shaft.

The taper is very slight, generally is around .010 per inch of hub width 
and is easily mistaken for a straight broached key way.

Baker used tapered keys and cut the gib head off, grinding the keys 
flush with the ends of the shafts. This makes them impossible to remove 
and the only way to take the engines apart without risking breaking the 
cast parts is to just bore the shafts out of the hubs, intersecting the 
key ways. Once the key ways are driven in towards the now hollow shaft 
the shaft shrinks and is easily pulled out. You have to make new shafts, 
but that's OK, you saved the castings and generally the shafts are worn 
out anyway.
Curt


Harry Terpstra wrote:

>Curt,
>
>I'm not quite sure what you mean, but on my 4 hp ball hopper Monitor are no
>tapered keys.
>Maybe at some point Monitor changed to other keys?
>
>
>Harry Terpstra
>Sint Anna Parochie
>Netherlands
>h.terpstra at wxs.nl
>http://home01.wxs.nl/~terps027/home.html
>
>
>----- Original Message -----
>From: "Curt Holland" <curt at imc-group.com>
>To: "SEL(new)" <sel at lists.stationary-engine.com>
>Sent: Wednesday, July 21, 2004 5:14 PM
>Subject: [SEL] A Baker Monitor question
>
>
>  
>
>>Making several new shafts for Devin's Baker Monitor. It looks like the
>>parts are held on the shafts with tapered keys.
>>I've done measuring and some math on the tapers and am not coming up
>>with the standard 1 in 100 taper or 1/8 per foot.
>>Taper works out to as little as .192/ft to as much as .480/ft.
>>While difficult to measure on narrow parts (only an inch wide),
>>generally I'll be in the ballpark, but this is not even close to standard!
>>
>>Does anyone know if Baker used nonstandard, steeper tapers in fixing
>>hubs and gears to the shafts?
>>Thanks,
>>Curt Holland
>>Gastonia, NC
>>
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>>
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