Sticky: Lapping 301 -- Changing LEE feature diameters
Steve Hurst's traditional "loose lapping paste in the cavity" method has two problems -- the main one is the cavity begins to go out of round with the parting line axis growing larger than the 90-degree-from-the-parting-line axis the more you lap and this ovality gets agravated the more often you have to recast a new (off round) lap to keep on going on up in size. Removing the parting line from your laps helps, but the ovality is still there and it keeps on growing with each new bare lap you create. This technique is slow and is difficult to control for expanding a bullet feature multiple thousandths (like jacking out a nose .004").
Next issue is you can't keep the loose lapping compound located just in the nose area, it unfortunately migrates down into the band areas and starts enlarging other things as well. Even though you did wipe it off AFTER you noticed it moving around that first time -- the grit already got itself embedded in the extra turning slug areas before you opened it up and wiped it off and that grit just keeps on cutting.
================ Lapping 301 ================
The answer to these issues is to take a little fire-lapping technology and add it to your mold lapping technology.
Make up your lap slug as normal, then take it to your steel fire-lapping embedding plates. Roll embed a coarse grit into the desired surface until that surface is just about solid wall to wall embedded grit. Notice that the part of the lap bullet that you wall-to-wall grit embedded has increased its diameter significantly. You just made yourself up a hard aluminum oxide porcupine with a lead core.
Now go to a clean set of steel rolling plates and re-roll your embedded grit portion (bare steel, no additional grit) until you reduce the diameter until it measures the exactly the size you want your lap job to be. Notice how round everything is? This is a natural function of the rolling action. The lead core might not be perfectly round but the cutting tips of the aluminum oxide porcupine ARE perfectly round, this is done naturally by the rolling action of the steel plates.
Now, take your lap bullet and spin it with your drill and SAND/FILE off all the areas you don't want to have lapping action from. You may need to leave the bottoms of some lube grooves to act as aligment zones (bearing journal surfaces) and I generally leave the nose tip form as the front outside bearing journal. I always clean off the gas check shank 100% and the first driver or crush band 100% as they don't need to be growing any as you lap (two critical fit-up areas).
Now wash your lap off and scrub it lightly with a toothbrush to kick free any bit of grit that isn't firmly embedded into the lead. Don't forget to do this step, you don't want any loose grit pieces moving around inside your mold .....
Ok, you got a very hard, very round, precisely sized lap portion that is really quite wear durable. You got selected outboard bearing surfaces and inside bearing surfaces to spin this affair upon and your critical surfaces that you don't want to change have been removed from the equation.
Your first lap should leave at least .002" for your medium & final finish laps to work up to -- this is because when you first try to close the mold on an oversized cutting lap it DOES cut an oblong inital cut that is larger in line with the parting line.
Think about how the oversized first coarse lap sits up on the edges of a single cavity half as if you had just rested it there ...... Your finished laps have to gently recover this natural oblong cutting action from the first lap.
So, you got made-up durable rough laps, medium laps and finished laps. If you lubricate the cutting action with lots of liquid dishwashing soap they will last a long long time before you have to stop and re-grit roll them and resize them. They will only affect the areas you want affected. They will cut fast then they will stop cutting and spin free on your selected inboard and outboard bearing zones. The liquid dishwashing soap keeps every thing CLEAN, cool and lubricated. Just run hot water over the cavities occasionally to see how things are going. (liquid dishwashing soap is so much better for this use than oil or grease, it is a slick lubricating CLEANER after all)
Here is a magic trick -- the rough lap can actually "raise" a surface a little bit by raising a forest of heavy scratch marks for your medium and fine laps to roll partially back down. You can grow an undersized surface a little bit.
You can also intentionally "close down" or reduce an oversized bullet diameter on a LEE single cavity mold by clamping it up on the pin half in a smooth jaw machinist vise, crushing the kurling down and seating the sine forms into each other a little bit. You can dial one down by over a thousandth if you have to. Of course, you want to do this before you final lap it.
Note: If you screw up a final lap, you can close the LEE mold down a bit to recover the error before you retry the final lap.
Final lap has two real functions -- regain some better cavity roundness and reset the parting line to a nice fine line, not a big old nasty free lapping grit type parting line. Clamping forces are decreased and run time is increased on a finished lap engagement. Grit can be smaller too.
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Yes, hand turning your laps has a real function -- fine work, small changes. Slow meticulous fine work is best done by hand. However, trying to remove multiple thousandths by hand is too too slow and that is where these powered hard-rolled lap techniques can do better.
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Living with LEE molds is something those of us who don't have a killing amount of money tend to have to do. LEE molds don't fit individual throats all that well and tend to be undersized for most users in the nose "land rider" area as gun throats wear in this area quickly. These techniques allow you to adjust the size of a standard lee mold nose fairly easily and quite accurately.
Plus, having made up your finish lap --- keep it, you can use it when the naturally occuring simple kurling/sine form wear occurs over time and takes your LEE mold out of round a bit. Or you bang something and kick up a burr on the edge of your cavity and you mold quits dropping bullets out freely.
Oldfeller
Who has a crapped out LEE mold that needs fixing?
This sticky sucks -- it is just words. It doesn't really teach you how to do anything. Useless, useless words .....
A good edumacational sticky needs a strong central character, some action and lots of pictures. I got more picture space available, now we what we need is that central character (a mold that is really really screwed up) to form this here real type edumacational sticky around.
I haven't got a crapped-out LEE mold (I fixed them all). Which one of you guys has got a really really crapped-out LEE single or double cavity mold that you will volunteer for fixing?
Your poor old mold has to have an interesting NAME of course, and an interesting history behind him of how he got in that terrible torn up shape that he is in to begin with. You have to be able to describe what all ails him and HOW what he casts now isn't useable to you.
(that way when you get him back we will have something to compare it to).
Who has a really really screwed up LEE mold?
Let's have a volunteer -- tell us what you got and how it got that way. All it will cost you is shipping one way to me, I'll ship it back to you after we are all done with it.
<g>
Oldfeller
P.S. Jumptrap, not yours -- sledge hammer marks are irretrevable.
What's a nose got to do with it anyway?
Well now, I cast twice and learned something -- I cast several times more to verify that information.
http://photos.gunloads.com/images/Oldfeller/noses.jpg
The mold casts .3595"-.3615" as its natural size (whenever it behaves naturally, that is) and the two cavities appear to be slightly different sizes.
It can cast bullets with extreme size spreads within the one slug itself .362" to .366" all within the same slug -- it didn't shut correctly on that cast. And this was with me taking great care to align everything before casting ..... and I didn't drop them, I caught them in my gloved hand so they are not banged up by hitting something.
I betcha this thing throws them all over the place size-wise when casting at full Bruce B. Warp 3 type speeds.
Note the noses, the one on the right was actually scraped good by the mold edge and maybe even actually struck a glancing blow by the opposing mold side alignment roll pin as the mold faces dropped "down" to each other when the alignment surfaces disengaged. There was enough force here to scrap or peen type roll-over the entire end of the soft, freshly congealed lead meplat surface.
(hummm .... would this one fly very good?)
And stick, lordy did they stick -- the one on the inside fully met my tick on a dog expectations (and then some, yessir).
Now lets talk weight -- weight can affect vertical stringing at long distances. You don't see such large variations in size without seeing weight differences.
I'm gonna use a digital scale in grams 'cause I ain't weighing powder -- I'm weighing heavy as **** cast lead boolits -- just take the differences as a "percent change" if you want to get all technical on me.
Or go punch "convert.exe" into your browser to go get a PC utility that changes any measurement scale over to anything else. That is if you just HAVE to use grains for everything just to get your mind to work right (gun-nut syndrome #17).
for those who ARE complete gun-nuts, the conversion factor is multply grams by 15.4324 to get to real units of measure
15.293 grams___236.0 grains
15.351_________236.9
15.361_________237.1
15.374_________237.3
15.415_________237.9
15.422_________238.0
0.84% min-max difference -- well, maybe it ain't sech a big thang any no-wise.
Still, we gotta fix that nose scraping and get the sizes to be closer to the same size (and get rid of all that flashing nonsense and sticking nonsense) It offends my sense of mold propriety. (syndrome #23)
<g>
Oldfeller
http://photos.gunloads.com/images/Oldfeller/pouch.jpg
PS The pretty leatherwork you see under the mold pictures and up on my wall -- that's Ric's native indian leatherwork. He shoots it, eats it, tans it then he paints and stitches it in authentic Indian motifs and sells it to tourists. (he likes to play with his food, in other words)
Actually, he does good work -- it's been a long time since I touched some real home-tanned leather. Brings back memories of my brother and I tanning muskrat that we had trapped in tidewater Virginia around Norfork when we were little shavers.
Ric spent more time just painting that purty pouch than its going to take me to fix his mold, but I appreciate the pretty thang anyway. I put it up next to my wife's needle-point reminder for me to not to get all wrapped around the axle so much as I go through life -- Ric does the same thing for me on occasion, too.
Now on to the healing .....
Ric, don't get upset, it ain't you -- but I'm not real pleased with LEE right now and it likely is going to bleed over on this here sticky a bit. I got me this nagging bad LEE attitude, you see.
(this is just after LEE changed our distributor initial buy-in amount, doubling it)
Jumptrap keeps telling us LEE sine-type molds wear out too damn fast and it is because of their rotten cheap construction. And intentionally lazy design techniques. They are built to be cheap crap molds -- on purpose.
I agree with him, they could have made this mold 2-3x more durable IF they had just closed down the 1.2 miles of slop between the sides of the handle grooves and the thickness of the handle tang sheet metal portion to the point the blocks were open-close (spatially controlled) within the span of good engagement of the built in mold block alignment features.
That's the major thing I am going to do to keep this sloppy wobbly goblin **** from re-occuring on you. I am going to get the cavities to align correctly just one more precious time and I am going to GLUE the ever living **** out of the mold handle tangs and the block grooves, affixing them to the handles so they go back together exactly right every stinkin' time they open and close.
But before I can do that, I've got to fix some face damage and get out all that gorped up lead in the drill centers up in front of the pins so the cavities CAN go together 100% right & correctly that one precious last time when I glue them to the handles. I will use two of the prettiest cast bullets (least out of round, least flash) to help get everything get lined up real good that last time.
If you did this simple 2-3x life extender trick to a brand new LEE mold when you bought it as part of your LEEMENT, that would be optimal (and it is what I do now every time I get in a single or double cavity mold). Or LEE could just buy a different sized saw blade (yup, that's what they use to cut that handle mounting groove -- a carbide tipped milling slotter blade)
But you see, LEE molds are crappy molds (built by DGAS people). No, that isn't true, the people who work at LEE care some but they have layers of DGAS managers over him who want maximum PROFIT and they want it NOW, screw making good stuff -- "it is good enough for what we charge for it" (the LEE Jr. philosophy). And that means you, operator -- hurry up boy -- you are taking too long to setting that job up, trying to do it right ....
Plus, the reason the groove grew out to that 1.2 miles wide is the handle sets don't go together all that well (buy cheap stuff to make cheap stuff) -- I have actually had to BEND some brand-new handles so the mold was within good open-close range before I could glue them in place.
NOW, DOWNSIDE TO THIS TRICK IS ..... you set the handles up to be the spatial open-close controlling element -- what happens when you drop the entire thing and it hits the wrong way on the concrete and it MOVES the handle set? Answer -- burn & scrape the glue out with a propane torch and start all over again with the fix. Or attempt a counter-bending exercise on the sheet metal tang material (you could do it with your hand strength alone since the blocks are solid to it now and they give you something to get a good grip on)
Good news is you can actually dent a mold corner up pretty good and not move the handles any at all. Got me a couple that got Ooops'd that way .... haven't had to torch anything yet (thank goodness).
Now to the steps -- I will present them in the order you would do them to a brand new LEE mold.
Dressing the top surface true to cavities
Everybody sandpaper laps the tops of LEE molds when they get all scarred up, it is a periodic tune up item that we have all done.
Why? Because LEE buys cheap partially dressed partially vibratory stone media smoothed sprue plate stampings that still have nasty edges that tear up the mold surfaces. We fix them up as much as we can, but the tearing up still happens, ongoing.
You see, LEE extrusions are SOFT aluminum. I have had pieces of lead oxides stuck to the sprue plate tear the crap out of the top of the mold, it doesn't even take steel to do it (although any nick or edge or burr or sanding mark left on that steel sprue plate will certainly do the gouge thing right smartly)
http://photos.gunloads.com/images/Ol...dscf0001_4.jpg
Ric had some real nasties on the Goblin, so much so that I reduced them from huge down to merely there and called it "good enough". I also tried to remove the burrs on the sprue plate that caused the gouges in the first place.
Notice the bullets sitting in place during the sanding -- this keeps you from rolling a wire edge down into the mold and creating a sticking point.
Drop Free Lapping -- non-size changing
Drop Free Lapping -- non-size changing is done using comet powder. I still clean off the gas check shank on the lap bullet with a file (taking it way undersized) so it doesn't change anything in the mold around the gas check shank area.
http://photos.gunloads.com/images/Ol.../dscf0001x.jpg
Goal here is to get the bullets to drop free and to see if there are any restricted areas or if perhaps the cavities are different sizes. This form of lapping is very mild and will not change any sizes appreciably (not unless you do it like forever).
Being the world famed Wobbly Goblin Mold those two cavities are currently two different sizes -- I have PM'd Ric to ask him what size he wants both the cavities to be as our next step is doing the size change lapping.
Ack !! Thread hijacking in progress ....
Ack !! Thread hijacking in progress .... Hijacking a Sticky no less !!
Now I promised everyone I would post the statistical analysis of an entire LEE production run -- this one was the 7mm Soup Can run which was 50 molds long but I only got hands on to the first 25 molds for measurement purposes.
First, let me explain why a caliper was used instead of a micrometer -- the mike I had available had a clicker thimble on it and it would absolutely reliably crush all parting line irregularities flat as a pancake instead of measuring them and it put little bitty minute flat spots on thin ogive "max diameter" areas too (once you laboriously located them and tried to measure them). In other words the mike really wasn't working for me at all and the caliper did just dandy in both finding and measuring the "soft" parting line areas and them frail and downright tiny ogive maximum diameter points.
A caliper isn't an ideal statistical tool. First, it lacks fine division or discernation-- it will only discern to 5 tenth increments while a mike will discern to single tenths (and some good ones will do 50 millionths which is half again finer discernation). Second, a caliper can be "driven" by an operator to achieve a desired goal (conciously or unconciously) and a mike generally tends to be more impartial as well as being more accurate -- on solid steel parts anyway.
But, hey - when you are dealing with lead bullets the only reliable mike I have ever found that won't crush things is a Mitutoyo QuickMike with the "hands off" fast action low contact force slip-type thimble. But the silly things cost $450 and I don't own one personally. And my current company doesn't own one either.
So I used a Mitutoyo caliper for this study -- shame on me. At least I didn't "drive" it, I always recorded what I got and I took all measurements twice and I used two different bullets per mold to make sure I had some basis to call out an "off" number with some level of confidence.
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What can cause cast bullets to vary?
Many things, alloy - temperature - casting speed - head (pour distance) - open close variation on the alignment pins - closure force on the mold cavities - lordy, there are a lot of things. I tried to take some out just to keep things simple and keep things as neat as possible.
To attempt to be fair, all casting was done exactly as the molds were shipped using a Lee handle set to provide the clamping force and using a Lee 10 pound bottom pour pot allowing the nipple to rest in the sprue cone and using the nozzle as a forced pour arrangement. In short, I wanted as wrinkle free a first cast bullet as I could get and I wanted to reflect the size of the cut cavities in WW metal without any smoke or spray or other sorts of stuff that folks normally use on molds.
(smoke and spray all make mold cavities cast smaller, you know that, right?)
So, here is the raw data in picture format so you can see the organization of the rows and columns.
http://photos.gunloads.com/images/Ol...oppagedata.jpg
Once again, right click on the pics, hit copy then paste it into your favorite graphics program so you can expand it enough to acutally see the numbers.
http://photos.gunloads.com/images/Ol...ompagedata.jpg
Got to split this post in two -- list can't take the whole enchalada. This seems as good a spot as any ...
