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rbprice
Senior Member
Username: rbprice
Post Number: 524
Registered: 11-2001
| | Posted on Tuesday, August 18, 2015 - 11:18 am: | 
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The picture shows a new set of helical gears for a 1902 Standard four cylinder engine. The three new gears were missing and the challenge was first figure out the ratio between the gears and then calculate the special helix angles to match the center distances.
With some profound suggestions from George Coates III, we were able to calculate the angles, get the gears made and bring an old engine closer to running order. The work to enclose the gears and and a special collar to make it easy to time the camshaft to the crankshaft is the next phase.
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russell
Senior Member
Username: russell
Post Number: 85
Registered: 08-2003
| | Posted on Tuesday, August 18, 2015 - 02:24 pm: |
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Good to see. Well done and worthwhile. |
jb_castagnos
Senior Member
Username: jb_castagnos
Post Number: 1088
Registered: 07-2002
| | Posted on Wednesday, August 19, 2015 - 10:51 pm: |
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Bob, glad to see y'all got the gears worked out, nice work. That's a fine engine. |
rholcomb
Senior Member
Username: rholcomb
Post Number: 64
Registered: 10-2004
| | Posted on Friday, August 21, 2015 - 06:01 pm: |
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Bob do you have more pics Thanks Bob, |
rbprice
Senior Member
Username: rbprice
Post Number: 526
Registered: 11-2001
| | Posted on Friday, August 21, 2015 - 07:49 pm: |
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Here is a STBD side view showing the cam shaft running alongside of the engine. Note the construction that is much like a steam engine with the large diameter tie rods and diagonal bracing.
The 16T gear that drives the cam shaft is inside the casting on the left.
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russell
Senior Member
Username: russell
Post Number: 86
Registered: 08-2003
| | Posted on Friday, August 21, 2015 - 11:05 pm: |
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Gear cutting is a bit of a black art is it not? A few years back (when I had money!) I got some new 2:1 reduction gears cut for an 8L3 Gardner. I made an impassioned plea to be able to watch him setting it all up. Helical gears of course and real big diameter. But he wouldn't hear of it.
Working on teeth is my trade/profession but I am unlikely to move across to steel -the local garage proprietor always told me "Stick to your trade, laddie!" as I got various parts for the old man's car. I knows me place mister. |
rbprice
Senior Member
Username: rbprice
Post Number: 527
Registered: 11-2001
| | Posted on Saturday, August 22, 2015 - 10:23 am: |
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Actually Russ, gear cutting is quite a well defined art form. There are lots of tricks having to do with the fine points of setting up what ever machines you may have and the older ones more so than the new CNC controlled machines. And knowing what kind of holding tool has a large component of experience in it.
These gears were a little unusual because of the odd helix angles but that is what the precision dividing head is for.
To me, what is really interesting is the display of knowledge shown by the folks at Standard way back in 1902 that allowed them to design the engine first, getting the center distances where they wanted them and then backing into the helix angle for the gears so they had the required center distance. Put another way, the Pitch Diameter of a helical gear is directly related to the helix angle. |
russell
Senior Member
Username: russell
Post Number: 87
Registered: 08-2003
| | Posted on Saturday, August 22, 2015 - 04:36 pm: |
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Ummmm, thank you Robert. It is the sort of art that you can look in books ad nauseum but you have to see it and do it yourself to finally get it. I have a Tom Senior at the yard that I bought from an old (now late) mate. It has all the goodies and I cleaned up and treasure the dividing head at home here. One day soon, after I work a few other things off the list! Until then, we dream, plan and slave! |
