Steam Tractor 3/4" (Rudy K)

[b.lindsey]

Those are beautiful Kim. Well done!! 

Bill

[10KPete]

By golly, Kim, you're the gear maker now!!! Excellent!!

Pete

[joe d]

Looking really good, Kim! 

Joe

[fumopuc]

Hi Kim, some beautifull gears. Interesting learning curve to follow here. Thanks for showing it.

[Kim]

Thank you Bill, Pete, Joe, and Achim,
I appreciate the encouragement and the comments.
It has been a facinating learning curve for sure!
Kim

[Don1966]

Kim those gears look great! I would say you have them down now and a big applause goes to you for taking that step to advance your knowledge. Awesome results......


Don

[Kim]

Hey Don, thanks for the kind words! They are much appreciated, in spite of my slow response

Over the Thanksgiving Holidays I got some time to play out in my shop.  The going is slow, but I’m pushing along.  Part of what slowed it down THIS time is that I decided that I needed to re-do some of those first gear cutters I made – they just didn't meet my newly developed standards.  I learned a lot in the last month or two and I wanted to fold that in to those 16 tooth and 120 tooth gears.  So it was pretty much starting from the beginning on those.  New buttons, new cutters, harden, temper, then cut the gear - you know the drill.

After much work, and a lot of tooth cutting, here is my set of 7 spur gears for the tractor:


And here are the 5 different cutters I made for them (not showing all the ‘practice’ attempts ).


With the Spur gears completed, my next task is the worm gears for the steering.  Those are also 48 DP, but I need to make a different tool for the worm. I decided to cut the basic shape on my mill.  I needed to have a 20 degree slope on each side of the tool face, so I used a 20 degree angle block, and took off some on one side, then I flipped it over and did the same on the other side, leaving the cutting tip at 0.015”, as indicated by Don’s Magic Gear Cutting Spreadsheet (Thanks again Don!)


Then I cut a flat on the top.  I tried to cut this at a slight angle due to the helix angle (just over 3.5 degrees).


Following that, I heat treated the tool, then touched it up on my grinder some to make sure it was sharp, and had a little relief.


Here’s me checking one more time, that I had ~0.015” width tip.


48DP translates to about 15.28 TPI, and I spent some time trying to find a thread setting in my gear box that would get me close to that value.  I’d just about settled for 1.6mm, which would result in about 15.88 TPI.  Not as close as I’d like, but since I’m making both the worm screw and mating gear, I figured it would be fine.

But as I was testing out the chosen 1.6mm setting, I saw that my lathe actually supported actual DP setting!  I didn’t remember that!  I’m actually pretty sure that when I bought the lathe that I had no idea what DP even meant!  But how cool is that?

However, to use the DP settings, I had to do a gear change. Having never done that before on this lathe, it took me a while to dig out the manual, figure out how to get the gears off, adjust the settings of the banjo, and get it all set back right.  But I did it!  At least, I did it well enough that it worked!


And after taking a starting cut, I checked with one of my 48 DP gears and it looked like all that gear change trouble was worth it!


This first test worm I cut in aluminum.  And you can see I need to do some more clean up on it.  But I’m calling it a success!


Now to cut the real one.  I’m thinking I’ll use Stainless for the worm, rather than Brass. Does that sound reasonable?

Thanks for checking in!
Kim

[Don1966]

They all look great Kim and some beautiful work. I just want to mention despite of your setbacks making them, you have gained a vast experience and knowledge making them. Your effects has payed off. Looking at your worm it looks like your tool is not sharp. The aluminum has rolled upwards and made ridges. You may want to pass your cutter on a stone to make sure it is sharp. As for the material to make your worm with would be more your choice and stainless sounds fine.

Don

[scc]

Kim, That's very impressive work                  Terry

[b.lindsey]

I am certainly impressed!!  Very nice Kim. Good to see an update as well.

Bill

[10KPete]

Mr. Gearmaker!!  Outstanding!!

 

Pete

[Tennessee Whiskey]

Kim, only difference between you and the pros,  is you show us your practice pieces  . Damn fine gear train 

Cletus

[crueby]

Nice work on the gears! I like how the worm gear came out, I think cutting it was simpler than figuring out the gear setting on the lathe!

[Kim]

Thank you everyone,
Yes Don, I think you're right about the too, I'll make sure to sharpen it up a bit before I do the 'real thing'.  Another part to that is the Aluminum I used - its really sticky stuff - not exactly sure what it is - it was from Home Depot, so you're never sure what kind of metal you get from there...

... I think cutting it was simpler than figuring out the gear setting on the lathe!

Quite true!
Actually, the challenge cutting the screw was that I couldn't disengage the half nut once I started cutting the worm.  I've always been able to disengage the half-nut and use the threading dial to indicate when to engage it for the next pass, but not for the DP settings.  I had to leave it engaged and reverse the carriage back to the starting point.  Not hard - just different.  And I was concerned that I'd over-run my gap when trying to stop, or forget and disengage the half-nut.  Luckily, I made it for my practice one.  Lets see if I can do as well on the real one! 

Thank you all,
Kim

[Dave Otto]

Amazing work Kim; your stick-to-it-iveness has certainly paid off!
I have been here following along and not always getting comments posted as I should. When you sharpen your tools have you tried the thumb nail method to check for sharp? The cutting edge should be grabby on your nail and not just easily slide along.

Your gears look wonderful!
Dave