Alignment Pins/ Mould Closure/ Boolit Weight

[3584ELK]

I hate to wear out this subject (mould prep), but I performed a search and didn't quite find a scenario matching mine. I DID get some good knowledge out of beagle's thread as regards casting bigger boolits with iron moulds:

http://castboolits.gunloads.com/showthread.php?t=382&highlight=alignment+pins

To cut to the chase: I got impatient with the Group Buy on the .378" mould and bought a Lyman 375449. While casting, I noticed the alignment pins were not allowing the mould to close all the way. I slightly chamfered the female side with an aluminum oxide wheel about 3/8" in diameter. It didn't help much. I can see some small burrs on both the pins and holes. GRRRR, I just paid $45 for this damned thing! Then, I noticed I was getting some pretty wild variations in weights of thrown boolits. 278 gr. then 274, next one might be 276, etc. Maybe this is due to the blocks not closing fully??? BTW, the bullets emerged at .378" with WW. 278 grains seems awfully high for a 264 grain mould, even considering the difference between WW and Lyman #2, right?

I know...lots of rambling, but maybe some of you experts can help a novice here! THANKS!

[sundog]

I spend what sometimes seems to be an inordinate amount of time working on moulds. Just got one going for Felix that gave him fits - me too. Just worked over a new 311299 and had the same problem with alignment pins and holes and the sprue plate screw hole. The holes were all cratered probably from overly agressive drilling pressure (time is money, after all). I chamferred the holes and stoned them clean and got good closure. Stoning the block mating edges (all edges for that matter) helps alot, especially the top block mating surfaces. If you are careful (go easy) it will create a new vent line under the sprue plate. Cleaning those edges remove burrs. Some of my moulds have many hours in them just to get them to work. New from the factory don't mean much other than you got some work to do. Kinda like getting new farm equipment - gotta modify before it works the way you want it to (done that more than once). I look at it like this. If I screw up a mould, and I've only messed up one Lee mould in over 30 years, I can always get another one and start over. I know that sounds a little cavalier, but I bet the second one don't get screwed up. A good mould should lock up with no daylight showing, release without sticking, boolits don't hang, and boolits are consistent in roundness and weight. Sometimes it takes a bit to get there. In my experience, your delivered cost is just the beginning - and that includes my favorites, RCBS. I have exactly 2 moulds that I have done almost nothing to other than cast with them. One is the DC David Mos 358009 Improved and the other is a custom made 200 grainer for my single shot 32-40, maker unknown. sundog

How much you wanna bet the streets of heaven are paved with lead?

[Tom Myers]

Elk,

The Specific Gravity of wheelwieght alloy should be about 11.010.
The Specific Gravity of Lyman #2 alloy should be about 10.683.

Wheelweight alloy is 1.0306 times a dense as Lyman #2 alloy. This ratio indicates that if a bullet weighed 264 grains when cast from #2 Alloy it should weigh approximately 272.1 grains when cast from wheelweight alloy.

I imagine that when you alter the mold so the halves fully and consistently close, your bullets will be very close to the 272 grain weight.

Hope this helps

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

[lovedogs]

I'm no expert but even us new folks can have an idea once in a while so I'll give you mine. If your inconsistent weight was due to moulds not closing fully it seems to me that they would not cast as they should but wouldn't throw weights so varied. If you are operating them the same each time the weights should stay about the same. Whenever I've found wide weight variations I've always traced it to operator error, usually inconsistency in the way I was pouring. For example, if you pour large bullets, use a 500 gr. .45-70 bullet for purpose of demonstration, and you pour them holding the mould an inch below the spout
(I use a bottom pour), then you change your method, maybe you pour off to one side of the hole. Or you hold tight against the spout. Each method will throw a different weight bullet, and sometimes quite a difference. Some methods give you more air bubbles than others, which is bad. If your mould is closing properly, you aren't getting fins, everything is lining up right... then try watching to see that your pouring technique is correct and consistent. Hope it helps.

[3584ELK]

Youse guys are great I'm tellin ya! I never sat down and figured the weight change. And, I can see how some stoning might make a world of difference. Of course, I just rushed in after my casting session, and belted out a post!

Thanks for all your advice and help!

[454PB]

Hey lovesdogs......good post.

The weight variation you report is not at all abnormal, nor are the measured diameters. If you aren't getting fins, sounds like a good mould.

[Buckshot]

...............3584ELK, handy to have on hand besides for moulds is a machinist's centerdrill. These are short fat (for their length) kind of a drill type thing used to just start holes. Due to their girth and length they don't bend like a regular drill bit.

The purpose here isn't to start a hole, so the reason for suggesting them is that they have a 2 fluted cutting angle formed from the hole starter nose to the much thicker body. They commonly can be had with 45, 60, 82, 90 and 100 degree included angles. They're just the ticket for removing upset metal out of alignment pin holes.

Two others which are more easily found at Home Depots, Lowes, or hardware stores is either a taper hand reamer or a countersink reamer. The former has a much shallower angle and will reach deeper into the hole, while the later is usually sharper angled at 45, 60, and 90 degrees. I bought one of the taper hand reamers years upon years ago for a couple bucks. It's 1/8 to 1/2" over 5" length and have found it extremely handy to have around.

http://www.fototime.com/B085BA6DEE3EA59/standard.jpg

The above is a kind of mould prep kit I put together some years back to keep it all together in one spot. Not all the pieces are in this photo as it's old. Some of it is NOT suitable for use on aluminum blocks. ANYONES aluminum blocks! One of the items missing is cupped end alignment pin punches. If you bang on the rounded end of the pin you not only put a flat on it but displace metal outwards. This may thicken it to the point it won't enter it's mating hole. At the least it will cause the rounded end to assume a more acute curve.

I made the punches cupped to closely match the curve of the pin. Another board member here wanted me to make a set for Lyman and RCBS awile back. It sounded so neat I made a set for myself. Or you can use a full hard brass punch.

As Sundog said, some brand new moulds are kind of like kits that need some form of final assembly. A bummer, but mass production and such being what it is you almost expect it anymore.

BTW, at Castingstuff.com Gussy offers a mould block closer gizmo that holds the blocks closed exactly the same, time after time. Lots of weight and roundness issues can be traced to that.

.................Buckshot

[3584ELK]

Thanks Buckshot!

I would guess a center drill of appropriate diameter would be nice if used by hand.
In the aircraft industry, everything is 100°- countersinks, tubing flares, etc. I suppose I had better get my stuff out and work those molds over a bit.

[fourarmed]

If you need to reduce the protrusion of your alignment pins, do it in a vise rather than by tapping. Gives you much better control of how far you move it.