Soon to offer blank Lee type sizing dies

KeithB

Resident Half Fast Machinist
I could easily make the pilot hole 1/8” instead of 3/16” on a few. I’m betting very few people mess w .17 caliber cast bullets but making that minor change on a few is no big deal.

All my dies now have a 3/16” pilot. I used to stock dies w/o a hole and ended up drilling them out anyway, everybody wants the hole. Putting in the hole when we backface the die is the most efficient way to do it.
 

Brad

Benevolent Overlord and site owner
Staff member
I didn’t have a pretty drawing. Sigh.

I would imagine an accurate drawing is the first step in writing the code?
 
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KeithB

Resident Half Fast Machinist
Yep. This is the drawing I will print out for shop use, the dimensions are for the finished die. Since I turn the outside with a tool that has an .031" tip radius I use the finished part drawing and lay out a line parallel to all the external surfaces that is .031" away. The coordinates of the tool path lines are actually what I use in the program. My CAD program lets me use layers which I can shut off or turn on, so I put the main object on the first layer, the finished part dimensions on the second layer, tool paths on the third, and so on. I can turn them off and on just like flipping acetate overlays in a book.

Since I have 255 layers available I can make complete assemblies with a different part on each layer. It prevents a lot of errors when you use the same basic part and make all the other parts fit to it in 3D. Holes line up right, you can see interference when one part overlaps/intrudes into another. Most of my files are 3D, but something simple like a die is a 2D file, I just need the outline to work with.

I don't have a CAM program that can directly use a CAD file to generate toolpaths, but what we do is generally simple enough that I can write the CNC code in a text editor.
 

Brad

Benevolent Overlord and site owner
Staff member
Technology has certainly made your job easier. In ways.
The idea of overlays makes sense. Being able to see interference before anything is ever made has to be a game changer. The fact Browning designed guns like the 1911 on paper or in his head is amazing.
 

KeithB

Resident Half Fast Machinist
I don't think I could carry John Browning's drafting pencils. The fact that he designed all the tooling and fixturing at the same time he designed the products is impressive. It also ensures that the product can actually be made!

I do try to think ahead far enough to know how to make the complete part and not paint myself into the proverbial corner, but I'm nowhere near JB's class. Mostly I'm a lazy guy that likes to make toys as easily as possible.
 

Brad

Benevolent Overlord and site owner
Staff member
Just made the beginnings of a Lee sizer. To get to the point of what Keith is making took me 44 minutes.
Your machine will make them in what, 8 minutes each Keith?
 

KeithB

Resident Half Fast Machinist
Sounds about right. That's both ends and the hole. Within a thou every one. All day long. With perfect threads.

Damn I love CNC!
 

Ian

Notorious member
You can also hold class 2 (or any) thread tolerance without having to use pitch wires and a mic on every single one.
 

KeithB

Resident Half Fast Machinist
We use a thread mike, using wires is fine for one or two pieces and can be very accurate but having a thread mike with replaceable anvils to cover the range of threads is much quicker when doing production. We have an SPI in 0-1 and 1-2, that covers all the diameters and pitches we cut.
 

KeithB

Resident Half Fast Machinist
The apprentice got the lathe set up yesterday and cut a couple dies. We weren't able to turn it into a no-toolchange setup. The first tool faces the end and turns the body profile, then we cut the 7/8-14 thread using a threading tool with a "laydown" full profile 14 TPI insert. Then we use a center drill to start the hole, followed by a 3/16 twist drill to peck drill the hole. After that we use a cutoff tool to cut the piece 1/32" overlength so we can finish it to length in the 2nd lathe operation. We have to swap out the threading tool and the cutoff tool for each piece but the turning/facing tool, center drill and 3/16" drill are all mounted in solid toolblocks bolted directly to the lathe cross slide. Very accurate and rigid.

I'll take a video later, right now I thought I'd just post pictures of the first few dies. Oh, and a pic of Big Jake my 20 lb non declawed male cat. He's a big sweety with a rumbling purr.

.LeeDie1.jpgLeeDie2.jpgBigJake.jpg
 

KeithB

Resident Half Fast Machinist
OK, I'm going to prove again my total lack of skill at making videos but maybe these will give you a chuckle.

The first one starts outside our current shop and walks you in the door to the CNC lathe, where I explain the tooling setup. The second vid shows the first step of cutting the face on the end and a little of the OD. Because there is a lot of boring cutting I terminated it there and shot the third video, which covers finishing the OD, threading, drilling, and cutting off. Note how Scott checks each piece by running a nut up on it. Also note how the turning/facing tool resets at the end and Scott pulls the stock out of the air collet up against the tool to start the process over again.



 

creosote

Well-Known Member
Those thread files are handy tools, my set has saved me lots of trips to the hardware store. I didn't chuckle one time. :)
 

Brad

Benevolent Overlord and site owner
Staff member
Great videos Keith.
Apprentice is not what I expected. I expected a tall, gawky, pimple faced kid about 20 years old.
I too use a lock ring to check threeads for fit.

Let us know when they hit your store!
 

Ian

Notorious member
Big Jake looks like a real sweetie and good friend.

Even with automation it's not a slam-dunk, I'm just happy it's not me single-pointing those threads on my mini-lathe. Let us know when they're up for sale.
 

Brad

Benevolent Overlord and site owner
Staff member
Takes me 40 plus minutes to do all that. And mine still isn’t that neat and tidy, or repeatable.
Keith, the fact these are made and I just discussed this with you just 10 or so days ago it amazing.
 
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KeithB

Resident Half Fast Machinist
Scott just turned 55 last week. He looks like a retired lineman for the Bears. When I first came home from the hospital after my foot amputation he was the one that pulled me up three stairs in my wheel chair so I could recover at home with my wife and our fur children instead of in an institution. He is a Navy vet - has the tats to prove it - and one of the most dependable and trustworthy persons I have ever met. His only problem is he sometimes doesn't know his own strength, I have to hide the cheater bars I need to use when he's around. Even w/o help he can twist the head off a 3/8" bolt. He's getting better, he used to work in a fab shop where problems were solved with muscles, in our shop we solve problems with brains.

The lock ring nut is used for a quick check on the part while its in the machine; every die gets its threads measured with a thread mike after its off the machine. The on-machine test is to make sure the threading insert hasn't chipped or has some other problem. If we catch a bad thread there we can usually fix it right away. The off-machine test is to get an actual size which we can use to get an idea of the trend in dimension. Using the material we are using we usually don't see any significant wear over hundreds of pieces and probably won't need to index the insert even once.

Brad, I'm always looking to make things people want. I'm glad everybody with an opinion had a chance to shape the design with their input. We were running Star dies, which use the same material and some of the same tooling as the Lee type dies, and we had a few days between major jobs so it seemed fortuitous to run a batch. When these are done we will start on a batch of pneumatic tailwheel hubs - I've posted a thread on these a while back - and since sales are good we will have the lathe tied up for several weeks. So now is the time.

I'm thinking of making a special collet with a 7/8-14 thread so we can backface the piece w/o damaging the threads. I've made several special collets, I think I even posted two threads about that here, but I've never made one with internal threads. We'll see how that works out.

Jake's perch is right by our dining room table and right next to my chair, at breakfast tomorrow he will do his jungle gazedown on me while I eat my bacon and eggs. When I finish my raisin bran I put a little milk back in the bowl and put it on the floor, he jumps down and drinks a little, and then our mornings start.

More later, its after midnight here and I had an eye injection at 3 this afternoon and my left eye is sore and my vision is still blurry and I've got a bit of a headache so I'm going to call it a day.
 

Ian

Notorious member
Pneumatic tailwheel hubs.....sounds like bush plane parts. Pizza-cutters don't work well in the dirt/gravel/sand/rocks.
 

Pistolero

Well-Known Member
Homebuilt aircraft parts, Ian.

Keith, very instructional. Makes it seem so much easier, and it sure is quicker.
CNC is amazing, but I have known that for decades, watched them work in our shop.
Still impresses me.

Bill
 

KeithB

Resident Half Fast Machinist
Scott finished up first operation on lathe Friday and will start backfacing and backdrilling tomorrow. He needs a way to hang on to the die without damaging the threads, and today I was finally able to see out of my left eye so I made him a 5C collet with a 7/8-14 threaded hole. I keep a supply of blank collets around for purposes such as this.

I've posted one (2?) threads about this before so I will just show the unique parts. After drilling the hole out to 11/16" I used a carbide boring tool to bore the ID to 0.812". I put an 1/8" deep x 0.875" diameter relief bore at the front of the hole, both to help the tap and later the die start straight. I used a straight flute spiral point tap that was guided at the front by the 7/8" relief bore and a tailstock center at the rear. The machine was shut off while tapping. I used a Kobalt ratchet wrench to drive the tap with my left hand while I kept my right hand on the tailstock handwheel to keep the tap snug and straight while turning it.

Note the three 1/8" pins in the face of the collet They allow you to tighten up the collet for boring without collapsing it. After machining the pins are removed to allow the collet to squeeze down and clamp the part.

Tapping the collet with the power OFF using a ratchet wrench.
tapping-a-collet1.jpg

The finished collet showing relief bore, note face pins have been removed.
tapping-a-collet2.jpg

Collet with a sample Lee type blank die in place.
tapping-a-collet3.jpg

I'll take a video tomorrow of the 2nd lathe operation and post it. Once that step is done these puppies will be ready for adoption!