Not gun related but a new machined product.

[KeithB]

We are making a new product for our principal client. It's an aluminum tailwheel for a 4" pneumatic tire. We make it from a 4-1/4" dia x 1" thick disk of 6061 aluminum. First we drill a 15/16" hole in the center, then turn the inside features. The male and female halves are slightly different but use the same tooling. Flip 180 and turn the outside features including the 1.125" bearing bore. Then over to the CNC mill where we drill the three bolt holes and cut out the slots. The next step is to set it on edge and mill a slot in each half that will end up being a round hole for the air valve of the inner tube.

They will take the finished products to the Oshkosh airshow in a few weeks; I bet they sell them all. Meanwhile I will be designing the fixturing and tooling for making a new, smaller tailwheel fork to hold the wheel. the fun never ends....

Male and female tailwheel halves.


Assembled halves. Note sawcuts on outside surface.


Outside half showing recessed hub and bearing bore.


Assembled halves with tire (no tube yet) in place.

 

[Paul Gauthier]

Nicely done Keith, looks real nice.

 

[KeithB]

Thanks Paul. Our client has a couple student interns from the U where I worked, they did basic design work. I've tried to contribute to their learning process by helping them understand the manufacturing process and how to spec/dimension things for automated production. They seemed excited when I texted them a picture of the final product. Something magical for most students about going from a computer screen to a real object, It reinforces their desire to learn. Even 3D printing isn't quite the same.

 

[RBHarter]

Keep that kind of work up and you'll give Cleveland a way to go .

That's sure a pretty wheel .

 

[smokeywolf]

how to spec/dimension things for automated production

GDT?

Some mighty pretty machining Keith.

 

[KeithB]

Thanks for kind words. Apprentice enjoyed making something identifiable that he can show pictures of to other people. He''s been making some parts we picked up as subcontract for the last couple of weeks, it pays the bills but we don't have any idea what the parts are. what they are supposed to do, or even who the original customer is. You know how it is Smokey, you make the parts and cash the check. But it's more fun to make mini-mag wheels.

Not so much GDT as learning to dimension using ordinate dimensions taken from a common reference point. Less clutter on a drawing than using point-to-point dimensioning and the resulting tolerance buildup that causes. Also had to teach them that real cutting tools usually have round corners and how to deal with that. Oh, let's not forget that the tolerance on a bearing bore is a few ten thousandth of an inch while the tolerance on the tire mounting diameter can easily be +/- .005" with no problems.

Hey, we all had to learn. I know a lot of folks seem to always be on a continual lemon-sucking downer about the younger generation and yes I have some concerns but honestly the kids I've dealt with over the last thirty years are as good as any. We did bonehead things when we were younger too you know. Just don't make the mistake of thinking that what is important to you is important to the younger generation.

 

[Brad]

Way more good kids today than bad. Just don't hear about the good ones. I have a staff largely under 30. They need some training and coaching but aren't afraid to work.

Keith, what did you use to do the internal side? Looks like some chatter. I have never done turning like that but I can imagine it can be interesting.

Good on you for giving some students a chance to see the process from concept to finished product. That has to be a huge rush for them to see it all come together.

 

[smokeywolf]

You know how it is Smokey, you make the parts and cash the check.

Yep! Been there and done that. Hate making parts without knowing their exact function.

I think an assumption can be made that, given our occupations and/or hobbies, we are likely to encounter more youngsters with a hunger for useful knowledge than we are kids who are happy in mom's basement "tweeting", "facebooking" and "instagramming".

 

[KeithB]

Brad, to cut the inner half of each part I had to use two tools, one for the outside turns and one for the inside turn and hub. I had to grind a 3/8" square HSS tool to plunge cut, just fed it in. Made huge curly chips and yes I got some chatter. I have a tool holder ordered that uses a 20 degree parallelogram insert. It should be able to do the outside diameters and inside surfaces too, ought to be able to cut one side completely with no tool changes. The outside hub face and bore is already done with one tool.

By anchoring tools rigidly in place in my lathe tool holder setup I can maintain bearing bore tolerances of +/-.0002 easily. Can't do that when I have to swap tools in and out of the Aloris. And of course the time saved by only using one tool and not having to swap multiple tools for every part will definitely kick up the production rate.

I'll post a video the next time we make a batch and use our new tooling to make it clear how I can cut all the surfaces with one tool. My apprentice is still a little puzzled even after I sketched things out, but bless his heart we have worked together long enough he believes me even if he doesn't quite completely understand yet what I'm doing.

I don't mind investing a little money in buying the one toolholder ($200) that can do it all on this part. I think this will be a popular product. My clients already sell a similar product from another vendor that IMHO doesn't look nearly as nice and costs way more wholesale, which cuts my client's profit margin. (They can't sell it if the retail price is too high, right?) I know we can beat that, and with a lighter, prettier product.

 

[Brad]

I understand Al and the huge curly chips. Miserable stuff that way.
Not changing tools to gain both speed of production and tighter tolerances makes perfect sense to me. As a hobbyist I am far less concerned with time but I certainly understand that for a business time IS money.

I have a feeling you think this all thru mentally and picture each step in your mind. That makes putting it all together so much easier even though others sometimes do t have the ability to visualize like that.

 

[KeithB]

I can't sing, can't dance, can't play a musical instrument, but I have always had the ability to shut my eyes and see things in my mind in 3D. It made engineering classes a lot easier. It also made me a very frustrated person until I took a drafting class the summer prior to my freshman high school year. I had finally found a way to communicate my ideas and inner world to other people. Took a lot more time and work to develop my written and verbal communication skills.

I can appreciate other people who have skills in the arts and other areas of science and technology. We are all unique and should take pride in what we do well while remembering that we aren't the only people with some sort of talent or ability.

 

[smokeywolf]

My ability to visualize a part in 3D became much easier and better after I learned to draw in 3D (solid modeling) using CAD.

 

[KeithB]

Just as a wrap up, I thought I'd post a pic of the finished wheel and the tool I bought to do the first lathe operation. A couple of details about the wheel: 1. The cutout for the valve stem on the inner tube is cut in each half as a slot but when assembled makes a nice round hole. Good setup work by the apprentice! 2. There are 240 drill point dots inside the wheel flange (we changed to 180 dots for the second and subsequent pairs) which are designed to roughen the tire/wheel interface enough to keep the tire from spinning on the wheel at touch down. (I think there is something in a tube that the flyboys apply to increase friction.) It only took three lines of code and 4-1/2 minutes to do it on the CNC mill. I'd like to find a better way to roughen the flange but that is what we can do with what we have right now.

The new tool will let us turn the outside, face the inner hub surface, and plunge in to undercut the inner face of the ribs. It has a 1" shank and will mount rigidly in our tool blocks. That should give us maximum accuracy with minimum run time - no tool changes required. I've ordered the right carbide inserts, should be here in a few days. We have all the fixturing built and now we have all the proper tools, by the time we get a reorder we will be ready.

 

[waco]

Very well done Sir! Beautiful machine work!

 

[Pistolero]

Gorgeous tail wheel, Keith. Holding two tenths on the bearing bore.....wow. Only in my dreams
so far. Looks like it will be pretty light, too.

As to mentally dealing in 3D, yep. I learned drafting in HS, and it was FUN! A really solid,
straightforward way to show how to make something complicated with just three views
and an isometric. Loved it, an easy A course for me, it was so much fun. Great instructor,
too. Mr. Baxter, and he drove a '39 Ford sedan.

Bill