Making a new part for a Saeco luber

KeithB

Well-Known Member
#1
One of the problems with Saeco lubers is that they use top punches that are unique to their brand. I sell an adapter that screws into the luber and permits using Lyman/RCBS style top punches. The price difference between the two top punch types is significant, which makes a low cost adapter an attractive option. The problem is that the adapter takes up some space and limits the length of bullets that can be sized - no problems with most short pistol bullets but a problem with longer rifle bullets.

One buyer sent me photos of a set of lengthened rods and linkage bar to offset the space loss and suggested that I offer those as an option. A sincere suggestion, but it seemed to be a little overcomplicated and duplicative. I have decided to take a different route by remaking the T-piece that holds the top punch.

Rick loaned me the factory part off his luber - thanks again Rick! I measured the part and duplicated it in my CAD system. Then I modified the part to make it easier to machine. Once I had the final part shape and size I pulled the necessary dimensions off of the CAD drawing and used those to write the CNC code. It will take four distinct steps to make the part on the CNC mill. I have the code written already, did that this weekend. In a few minutes I will go out to the shop and start cutting the blanks from a 1" x 2-1/2" x 96" bar of 1018. Then I will set up the mill and start debugging and running the first program.

As I do each step I will add it to this thread, I expect it will take a week or so to complete the entire batch (probably 26-27 parts total). The first part will go to Rick as a thank you. He says he doesn't use his Saeco but having the replacement part will hopefully add some value to a sale or trade he might make in the future. Then I will add the parts to my stock here in Keith's Korner and eliminate the current adapter.

Here is a photo of the CAD drawing of the new part.

SaecoT-piece.jpg
 

KeithB

Well-Known Member
#4
I’m going to talk to my friend that runs Midwest Hydrographics and see what he suggests. He did an industrial black finish on some tool holders and stuff for my lathe that has held up real well. He also does dip paint finishes and some type of ceramic coating that is real tough.

Any suggestions on color? Match or contrast?
 

Rick

Moderator
Staff member
#5
Color? I dunno, don't think it would matter much as long as it has something to prevent rust. Would dip painting be a good option if that would get paint in the holes and slot for the handle?
 

KeithB

Well-Known Member
#6
Not an expert on paints/coatings, but I imagine any dip or spray coating would add enough thickness to interfere with the fit of the pin and handle in the slot. The black industrial finish on my lathe tool holders doesn't seem to add much to the surface, so it could probably be applied w/o masking off those areas.
 

KeithB

Well-Known Member
#7
First step was to cut the raw material into pieces, managed to get 28 pieces from bar. Debugged the first program, loaded up the tools, and cut 6 pieces before calling it a day. At the end of this stage the part is cut to its final profile, the 1/4" handle pin hole is drilled and reamed, and the 8-32 hole for the setscrew (used retain the top punch) is drilled and tapped.

The bar gets cut to 3-3/8" long in the cutoff saw.
T-piece1.jpg

The piece after the first (of 6) roughing passes to rough cut the profile. Note the 1/2" diameter roughing ("hogging") type endmill. It has serrated teeth and generates slivers instead of flakes. Doesn't leave a good surface finish but it can remove a lot of material in a hurry at lower horsepower and force than a regular endmill. It is solid carbide, we run it at 1800 RPM @ 0.004 in/rev feedrate in mild steel.
T-piece2.jpg

Here is the part finish profiled, with the 1/4" handle pin hole drilled and reamed and the 8-32 setscrew hole drilled and tapped. I leave 0.010" stock on the exterior profile when roughing, then use a regular smooth sided finishing endmill to cut to size and get a smooth surface finish.
T-piece3.jpg

The block is 1" thick, the profile is cut 0.812" deep. In the next step I will flip the piece over and face off 1/4" to get the piece to its final 3/4" thickness. I used 1" material just to have a "handle" to hang onto while cutting the profile. A little wasteful maybe but it seemed like the most efficient and practical way to do this. Gotta think ahead and make sure you can hold a part properly while machining it through every step!

The original part is a casting, which is very efficient and minimizes the amount of machining needed, but I don't have the capability to cast steel or iron thus the necessity of using wrought material (extruded or hot/cold rolled bar stock) and material removal processes.
 
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Rick

Moderator
Staff member
#9
Thinking out loud, you have these already under way in steel but in the future would it work to make them out of aluminum so there would be no need to paint or otherwise rust proof?
 

KeithB

Well-Known Member
#10
I thought about that, it would certainly cut down machining time and tool wear. My only concerns are the setscrew hole stripping and the handle pin hole wearing out and getting sloppy. Even on the steel version I am tapping the setscrew hole all the way through. I will supply the unit with two setscrews, no matter how it is assembled there will be a front accessible setscrew and a spare setscrew in the back that can used if necessary.

If I was designing the unit from the ground up I WOULD use aluminum but I would rework the size of various features with aluminum's properties in mind. And if everyone used my Lyman/RCBS style top punches with the O-ring on the stem the setscrew would be unnecessary.
 

Rick

Moderator
Staff member
#11
I see your point, makes perfect sense since the part's purpose is to be bumped up & down. Using aluminum would probably require steel bushing's pressed in and that could be more work than making it of steel. Or so I would think.
 

smokeywolf

Well-Known Member
#12
Keith, with regard to the setscrew hole stripping. For the sake of production, wouldn't you be tapping a 65% (approx) thread in steel, but a 75% thread in aluminum? Tap the aluminum with a GH4 or GH5 tap so you can anodize your setscrew hole.
 

KeithB

Well-Known Member
#13
Rick - Every way I thought of to use aluminum would require redesign of more than one part or making (or at least using) more parts (bushings, etc.). Seemed to overcomplicate something that should be simple.

Smokey - Probably 99% of the folks that might use this would never repeatably tighten a setscrew enough to strip the female threads out. If I were making this for you or me I wouldn't worry, you're smart and skilled and know not to put an 8" cheater on a 3/64" hex wrench. But that 1% that might buy this, use it, and strip out the threads would be unhappy and require some service, something I'd rather not need to do.

Here are some photos of the in-process work.

A box of profiled parts.
T-piece4.jpg

A couple of parts that have had the back milled off, the part is now .75" thick.
T-piece5.jpg

The next step will require making a set of soft jaws, already have the code written. These will hold the piece oriented like a regular T, with the cross bar up so that we can drill/ream the holes for the guide rods and top punch.
 
#14
How timely, I just had my SAECO on the bench this week and was using your adapter for some 32-20 bullets but when I went onto the longer rifle bullets it was tin foil and bullet lube on an existing SAECO punch.

I'll be up for one when you get them done, good job sir!
 

Rick

Moderator
Staff member
#15
Thinking out loud again. I am bound and determined to prove I am no machinist but looking at the photo's would it not be easier to drill the holes for the guide rods and top punch in what will become the bottom of the piece right after cutting the bar into sections, before milling to shape? Much like you did for the set screw and handle pin. I'm thinking it would eliminate the need to make the soft jaws. Ok . . . Edjumicate me? Where would this not be the correct way?
 

Brad

Administrator
Staff member
#16
Possibly Rick but that means each piece needs to have a square end on one side to locate the part in a fixture for drilling.
I am no machinist either but this is largely a case of at what point do you have a surface you feel comfortable using to locate the holes.
 

KeithB

Well-Known Member
#17
I want to make sure the holes in the crossbar are centered up exactly in the finished piece. I am making a soft jaw (only need to cut one of them) that will make it easy to do the next two operations. I finished cutting all the pieces to 3/4" thick and have cut the first cavity in the soft jaw. Ran out of time before supper and was too tired to get back on it afterward. I'll cut the second cavity tomorrow and photograph it. I think when you see how it holds the part to do the last two steps you will understand more of why I opted to do things this way.

There are lots of ways to make one piece; the problem comes in making lots of pieces, all of them the same. Conformal soft jaws make it quick and easy to swap pieces in and out and line them up accurately.
 

Rick

Moderator
Staff member
#18
I see. Wasn't trying to say you were wrong, just letting my ignorance in machine tools show by thinking out loud. Again.
 

smokeywolf

Well-Known Member
#19
Reminds me of what an old Danish machinist told me during my apprenticeship, "Good setup, good parts."

When machining numbers of high precision parts, just holding onto them to perform each operation becomes a high precision exercise.
 

KeithB

Well-Known Member
#20
Rick, no problem with being told there may be better ways to do something. When I narrate a story I tell what went right mostly, it keeps things short. If I told you every way I screwed up we would rapidly run out of server space here!

Keep on thinking out loud, it’s good for everybody.