[SEL] Sorta O/T..gear making

Tommy Turner lcjudge at scrtc.com
Wed Jan 26 20:10:58 PST 2005


Sounds good Jim but something screwy was going on with the Springfield 
engines.  A gear on Raymond Scholl's 1 HP had a couple of teeth 
missing.  No standard gear would match it.  He had to send it to a guy 
who had a special cutter made to match the existing gear.  Some of the 
"blacksmith" makers of engines, sometimes which produced only a handful, 
did it all.  They made the castings, did all the machining, cut the 
gears, etc.  In some cases, I doubt that they were too concerned with 
the pressure angles and more concerned with making sure they had a 2 to 
1 ratio that would mesh and work.  We have all kinds of standards 
readily available today that some didn't have 110 years ago (standards 
were in place, but not easily accessible to all).  I'm sure that many 
manufacturers adhered to the standards to the letter.  I know some 
didn't though as I've had examples.

Tommy Turner
Magnolia, KY



Jim and Diane wrote:

>It seems unlikely to me that early engine people devised a unique gear
>geometry.  This would have been a pretty demanding and expensive undertaking
>and there would have been little if any advantage over what was already
>invented. Almost surely these gears had a 14 1/2 degree pressure angle and
>used an involute curve for the tooth form. There are other PA's in use today
>and unless you are a real gear pro it almost impossible to eyeball different
>pressure angles. There are also other tooth geometries besides involute, the
>drawback is their shape makes them difficult to machine with no gain in
>performance or life.
>
>For gear terms see http://shopswarf.orcon.net.nz/spur.html
>
>Jim
>
>Jim and Diane Kirkes
>Hemet, CA
>jd.kirkes at verizon.net
>----- Original Message ----- 
>From: "Tommy Turner" <lcjudge at scrtc.com>
>To: "The SEL email discussion list" <sel at lists.stationary-engine.com>
>Sent: Wednesday, January 26, 2005 6:16 PM
>Subject: Re: [SEL] Sorta O/T..gear making
>
>
>  
>
>>JB,
>>
>>    I've done the same thing several times with good results.  I've
>>found it best to purchase  the crank gear and the cam gear and replace
>>them both.  Some of the old timers had an odd ball pitch on their
>>teeth.  I had a friend who needed a gear made and the guy who cut it for
>>him had to have a special cutter ground to match the other gear.  Some
>>of the real early manufacturers may have ground their own cutters and as
>>a result, it was their own "design".
>>
>>Tommy Turner
>>Magnolia, KY
>>
>>
>>
>>jbcast at charter.net wrote:
>>
>>    
>>
>>>>What is the best route to take to get gear(s) made?  One is a
>>>>        
>>>>
>combination
>  
>
>>>>i.e. two gears, one casting.  I also need a smaller gear...all straight
>>>>        
>>>>
>cut
>  
>
>>>>teeth.  This is for manually traversing the carriage on my ole lathe.
>>>>        
>>>>
>Could
>  
>
>>>>the old ones be used for a pattern and is this something Rick Rowlands
>>>>        
>>>>
>could
>  
>
>>>>do?
>>>>
>>>>
>>>>
>>>>        
>>>>
>>>Rick, get a Boston Gear or Rush Gear catalog, see if the gears are
>>>      
>>>
>available, width may be a little different, the center is adaptable also. On
>my lathe I machined the hub and made a ring gear out of the new gear, heated
>and shrunk it on and pinned it. On the double gear, if only one is bad, bore
>it out amd press it on a shaft, bore the new gear and press it next to it.
>  
>
>>>J.B. Castagnos
>>>Belle Rose, LA
>>>
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>>>
>>>
>>>
>>>
>>>      
>>>
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>>    
>>
>
>
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