Steam Tractor 3/4" (Rudy K)

[Kim]

Pete, Chris, Bill, Dave, Pete, Zee, thanks for stopping by to have a look, and thanks for the kind words.

On those short leg bends; we used to bend 'em long then mill them down.....

That's a great idea!  I'll have to try that next time I have a little shore edge to bend like that.

Kim

[fumopuc]

Hi Kim great progress over all. When may I start to order my next fabrication job at your shop ?

[Kim]

Thanks Achim!

Well, you can order whenever you want.  My shop is kinda like Hotel California - You can order anytime you like, but it may never leave! 
Kim

[zeeprogrammer]

Well, you can order whenever you want.  My shop is kinda like Hotel California - You can order anytime you like, but it may never leave! 

 

[Tennessee Whiskey]

Dang it Kim, the sheet metal work is looking great, but, now I'm gonna be singing that all night   Mirrors on the ceiling, pink champagne on ice, we are all just business here, dang it man

Cletus

[Kim]

Now that you’ve all got the Eagles out of your head, it’s time for my next installment

I’ve been looking forward to making the gears, and now I’m ready to go!  With anything new like this, I spend a lot of time reading and trying to figure out how I’m going to do it.  This was no different.  I downloaded Don’s Gear Cutting spreadsheet (thanks, Don, it's incredibly helpful! ) and re-read other people’s threads where they’ve made gears, and watched several YouTube videos.

Finally, I went out to the shop to actually do something!  But I didn’t have a lot of time left.  So, I made the 3/8” mandrel that I’m going to use to hold the cutters.

I drew up a crude plan and went to it. I made it from 5/8” 12L14. It was all fairly simple turning, but I took a few pictures to share, just so you have proof that I actually did something

Turning down to 3/8”.


Cutting 3/8”-24 threads.  That was fun! 


I cut it off on the band saw, turned it around and cut a 3/8” shaft for holding it in my mill (the largest Collet that will fit in the Taig is 3/8”). I spared you the pics of this.

Then I took another piece of the 5/8” rod and drilled & reamed a 3/8” hole, and cut it off at 3/8” to use for a spacer.  Here I’m cutting it off the main stock.


Completed family shot of the mandrel:


Assembled:


Next I’ll make some blanks and the button tool.

Not much, but its progress!
Kim

[b.lindsey]

Nice work on the mandrel Kim. I am looking forward to following along on the gear making too.

Bill

[Don1966]

Nice job on the mandrel Kim and I am also looking forward to seeing the gears cut.

Don

[Kim]

Thanks Bill and Don,
I'm excited to get on with making the gears too, but shop time is very limited these days, so it will be rather slow progress (as is usual for me).
Kim

[mal webber]

Nice work there Kim, looking forward to seeing some gear cutting as well.

Mal

[Kim]

Hi Mal, thanks for looking in!

On to the button tool!

I decided that for my first attempt I was going to make one of the single button tools, rather than the 2 button tool.  Just seemed like a good way to start.

I cut a length of ½” square 1018 and clamped it in the mill vice at 5 degrees, and made the relief cut for the button.


This button tool is for a cutter to make a 16 tooth gear (DP 48, 20 degree pressure angle).  The button for this is surprisingly small – the diameter is 0.100”.  So I had to narrow the front of the tool down from ½” to just under 0.100”.


Then I drilled and reamed a 1/16” hole for the button stem.


After that, I made the button using W1 tool steel.  Here I’ve cut the 1/16” rod for the button, brought the button down to 0.100”, and am just ready to cut it off.


After cutting it off, I mounted it a 1/16” 5C collet block, and cut the relief for the tool at 10 degrees.  This will give a 5 degree actual top relief (the first 5 degrees just makes up for the 5 degree angle in the holder).


And here’s the family shot:


And assembled:




I still need to heat treat the button, but I’m just about ready to try it out!

Thanks for following along!
Kim

[Kim]

With my update posted, I now have a couple of button tool related questions for all you knowledgeable people.

First Question:
It seems that commercial gear cutters come in Numbers 1 through 8, and each cut a range of gear sizes for a given DP & PA.  So I was figuring that, rather than make one cutter for each gear I need, I would make one corresponding to the cutter number I needed, and use the appropriate one for each gear. That way I make fewer button tools, and fewer gear cutters.

But, for any one specific cutter number, should I make it for the low end gear size, the high end gear size, or the middle gear size?  For example, cutter number 7 covers 14-16 tooth gears.  Should I make that one as a 14 tooth, 16 tooth, or 15 tooth cutter (since that is the middle)?  How are the commercial ones done?


Second Question:
As I was working on the tool, I noticed that as you get to larger numbers of teeth, the diameter of the buttons used for forming the cutter gets larger.  This makes sense, since a Rack should have straight edges, as I understand it.

My issue: The Cutter Number 1 tool, which is for “135-Rack”, shows a very large diameter button.  In fact, the diameter of the button is larger than the distance between the centers of the two buttons.  That means the two buttons will collide.  And when that happens, the shape of the cutter starts to look wrong to me.  Also, the specified infeed is DEEPER than the place where the two buttons meet.  Which doesn’t seem right either.

I drew a quick sketch to hopefully clarify the point that is hanging me up.  On the left side is a sort-of scale representation of a button tool for a 14 tooth cutter.  It looks as I would expect.  On the right is a sketch representing a button tool for a 135 tooth cutter.  You can see that the infeed is behind where the buttons intersect, and the cutter formed by it will have a pointed “V” shape.  This just looks wrong to me.


What am I doing wrong here?  Or maybe the tool is right and I’m thinking of it incorrectly.  But I would expect there to be some flat space on the end of the 135 shape, not for it to come to a point.

Looking forward to your thoughts on this,
Kim

[Kim]

I had a few minutes Sunday afternoon and thought I’d heat treat the button.  That was a fairly short job.

I setup my station and suspended the tinny little button from a magnet.  Actually, I suspended it from a scrap piece of steel that I hung from the magnet.  My thinking is that I don’t want to get the magnets too hot and risk damaging or cracking them. The 1” piece of steel allowed me to keep the flame away from the magnet.

I learned the magnet trick from DaveO – suspend the metal to be hardened from a magnet, dangling over your water.  When it gets hot enough that it is no longer magnetic, it will drop from the magnet into the water.  Works well!


Close up of the button just before heating.


No pictures of the heating process, butit went off without a hitch. After quenching, I cleaned it up and was ready to temper it.

So back I go to my torch station.  I didn’t need the magnet setup this time, so I went to take it down.  I grabbed onto the piece of scrap steel to pull it off the magnet and suddenly my hand jerked away. it was about that time I realized that my fingers hurt.  Wow!  They hurt a LOT!  That steel was still REALLY HOT!  OUCH.  Needless to say, I was done in the shop for that day. I went in and held my fingers under cold water and ice for a while.

Here are my ouchy fingers.  I burned my thumb a bit too, but mostly the inside of those two fingers got it.


Moral of the story?  Remember that the stuff sitting in your heat treating area can still be hot, even if it doesn’t look like it!  Check before you touch!  Dumb, but lesson learned.

Kim

P.S  If anyone has any thoughts on the questions in my previous post (about button tool/gear cutters), I’d love to hear.  Thanks.

[Hugh Currin]

Kim:

Could it have been electromagnetic rather than just heat? There was a magnet involved. Maybe the magnet held the heat in? OK, or maybe it was just too hot. Slick way to heat treat small parts, I'd have never though of it. I would, however, have also burned my fingers!

Nice work. Some day soon I'll have to try cutting some gears.

So, no insight on the button tool cutting tool but I agree. A tool to cut a rack should have a flat end. So I suspect all should have a flat tip. Your 135-rack has no flat on the tip. I have a book, Gears and Gear Cutting by Ivan Law, which gives the dimensions for a button tool. Those dimensions give a small flat at the end of the tool for a 20 deg pressure angle. Let me know if those number would help you. Other than a quick drawing I haven't checked further.

Thanks.

Hugh

[Kim]

Hi Hugh,
Thanks for taking a look at my question on the button tool.

I have the same book by Ivan Law, which is what prompted my first question.  Because the numbers in his table seem to correspond to a number mid way in the range for the large gear teeth, but in the smaller ones its at the top of the range, or even above the range (based on Don's SS, and other calculations I've found on the web, which all agree).

On my second question; my drawing wasn't a very accurate rendering. And I see now, after some careful calculations, that I over estimated the infeed on my drawing.  If I decrease the infeed to the specified distance, it stops BEFORE the button diameters join.  So you are clearly right Hugh, there is a small flat on the tip of the 135-rack tool.

So, question number two is resolved as operator error (not surprisingly ).

Thanks!
Kim