Laps for ball molds

[paulvallandigham]

A friend has a two-ball mold for one of his guns, and is getting slightly different weights of balls from the two different cavities. They are within 1 grain of each other, but different enough that it drives him nuts as a target shooter.

He wants to LAP the smaller of the two cavities to bring it up to the same size as the larger one is now. He has made laps many times to use on his barrels, and has the lapping compound. What he is not sure of is how to put a " Shaft" that will be chucked into a drill to turn the ball in the mold with lapping compound on it.

He was told by one source to use something like a finishing nail, with the head filed to fit through the hole in the blocks for the sprue. Then he should heat the ball back up into the mold to its molten state( He has an acetylene torch to do this) and place the brad or nail down into the ball through the sprue, holding it there, while the ball hardens.

To me, this sounds easier than it is. How do you keep the shaft perpendicular to the ball until the ball hardens?

Can any one give me advice about this that I can pass on to him? ( BTW, I talked to him about the small difference in ball weight and ball diameter not being all that much of a factor in accuracy, but he can give us a mighty convincing argument that I am wrong about that, with targets to prove it.!) :shocked2: :hmm: :idunno: :thumbsup:

I suggested that he simply use a straight nail or wire shaft, without a head, with grooves filed or "tapped" on it to give the lead something to grab onto. Then put a cast ball in the mold, and center it on a drill press to drill a perpendicular hole, sightly undersized for the shaft he has. He can heat that nail or wire shaft UP before shoving it down into the drilled hole, keeping the mold block closed so that any melted lead comes back up out the sprue hole, rather than expanding the ball.

Thank you, Gentlemen. :hatsoff:

Paul

 

[Stophel]

How does he know which balls are which when he shoots them??? Tell him to just pick one mould cavity and use it. :wink:

 

[paulvallandigham]

Trust me. This guy measures everything. He is already doing as you suggest, but he wants to double his production, so He spends less time casting, and more time shooting. That is the reason he bought the two-cavity mold in the first place. :hmm: :thumbsup:

 

[jtmattison]

What brand mold?

I'd contact the manufacturer and tell them they made a bad mold.

Other than that the ball and stud idea is the way I would go. Probably take some trial and error to get the stud in the ball straight but probably wouldn't take long.

HD

 

[paulvallandigham]

We discussed that. The mold was made by a company that is now out of business. Thanks. :thumbsup:

 

You might want to look up "Lee-menting" over on the cast bullet forum. If the mould is aluminum it's not that hard. If it's a steel mould it might be a problem.

I have lapped many a mould, all aluminum ones though. You've got the basic idea, except I cast a bullet, or ball, and use a screw and screw into the solid lead. I spray the cavity with mould release, you know, the black teflon stuff, and use comet cleaner and a little water and a battery drill to lap the mould. The mould release will build up in low spots and the lap will take down the high spots. It normally takes 4-5 bullets or balls per cavity to get it rite. I don't know how long it would take with a steel mould, I don't have many of them and don't like them compared to aluminum. This is just cleaning up to make balls or bullets fall out rite, to make a change in weight, you might have to use valve grinding compound and get close, then switch to comet and mould release.

Oh, and the screw I use tends to be a 1/4" head so I can use a driver in the screw gun to turn the ball.

Hope this helps

Just re read the first post, 1 grain?!? Hate to say it but the only way realistically is cast one at a time. Or swag them.

 

[Zonie]

To add one grain of weight to the ball, about all he will have to do is open the "light" mold have his wife give it "The Glare".

I assure you that this will remove enough material from the mold to add 1 grain of lead to the cast ball.

If his wife can't "glare" like my wife can "glare" he can take some 1200 grit "wet/dry" sandpaper and take about 3 swipes from both sides of the spherical mold cavity.

I mean, 1 grain of weight? Hell, a big horse fly fart weighs more than that. :rotf:

 

[paulvallandigham]

Thanks for the suggestions, Jim. Unfortunately, he is a widower, and the mold is made of steel. That is why he paid big bucks for it. :blah: :shocked2: I can assure you that I have already kidded him about wanting to get the two cavities to cast balls the same weight to a grain. :grin: :v

If I already had experience lapping RB molds, I would not have posted this question over a 1 grain difference. I simply have not had to make up a lapping tool for a RB mold of any kind or caliber. And, since I had not read any discussion about the issue here, I thought it might make an interesting question to throw out to the membership to discuss. Then, everyone learns. :idunno: :thumbsup: :thumbsup:

 

[ohio ramrod]

If the mold is a two part mold you can lap each part by turning a bar on a lathe to the desired diameter. Cut off a few thin "wafers" for lapping. Then take a dowel rod slit the end to make a holder for the wafer and use your drill press(or hand drill) to lap the mold. You will need a few wafers as they will lap as well as the mold. Just keep putting in a new wafer every now and then.
It takes time and lapping coumpound but it can be done! :idunno:

 

[paulvallandigham]

Great solution. Thank you for the advice. Paul

 

[Zonie]

IMO, because the volume of a sphere is a function of the cube of the radius any messing around with something that will actually remove any real amount of material will ruin what he has.

Like I said, some sandpaper, his thumb and 15 minutes of time will change the volume enough to equal 1 grain of lead.

Course, that's just my opinion.

Another opinion is that someone who would worry about a difference of 1 grain is probably not to be trusted. They might notice that one of your ears is slightly lower and larger than the other one and try to adjust it so they match. :rotf:

 

[Rasch Chronicles]

Another opinion is that someone who would worry about a difference of 1 grain is probably not to be trusted. They might notice that one of your ears is slightly lower and larger than the other one and try to adjust it so they match.

Now THAT is funny!!! :rotf:

Your friend,
Albert “The Afghan” Rasch
The Rasch Outdoor Chroniclesâ„¢
ΜOΛΩΝ ΛΑΒΕ!

 

[paulvallandigham]

All mammals have bi-lateral symmetry, and the two sides of your face do NOT match. That means that you will have one ear that is not identical to the other, always. Women's breasts are not the same size, Naturally, nor do they hang the same amount. That's far more interesting trivia to "pursue" than any set of ears I have seen, IMHO!! :shocked2: :blah: :rotf: :thumbsup:

 

[JOHN L. HINNANT]

Good Morning Paul,

This is rather late to be jumping into this discussion, but...........

Your friend is too anal about this. I use some double cavity molds and simply drop the balls into different trays, weigh each group seperately And shoot each group seperately.

I do not mix the balls from the different cavities.

As you know not too many, if any, shooters are more paticular than me about obtaining max accuracy with the rifled round ball gun.

Keeping my balls from two different cavites sperated has never been a problem for me.

I have lapped a number of molds over the years, but it has been only to polish the cavity in order to have the ball drop easier from the mold.

My respects to all,

John L. Hinnant

"God and Texas"

 

[Rifleman1776]

Can any one give me advice about this that I can pass on to him?

Yes, first, serious target shooters use only single cavity molds.
Easiest thing for him is to pour only in the cavity he prefers. Ignore the other.
Fuggitt lapping.

 

[JOHN L. HINNANT]

Good Afternoon Rifleman1776,

I do consider myself to be a pretty serious competitor with the patched round ball rifle and use both the single and double cavity molds.

As long as I keep the douuble cavity ball separated and shoot them that way, I have no accuracy provlems or them shooting to a POI.

Of course, they will shoot to a diferent POI if one insist on mixing them or changing balls from a different cavity in the middle of a match.

Just be sure there is enough balls from the same cavity to finish a match before starting to shoot it.

Let common sense prevail.

I do like increasing my production level for time spent casting, when using a double cavity mold.

My respects to all.

John L. Hinnant

"God and Texas"

 

[wmaser]

I, personally, would not worry about such a tiny difference but I have lapped moulds after boring and or rifling a barrel to an odd caliber. I flatten the head of a finishing nail and cast it into melted lead in the mould, just as you described. If the shaft is a little off, causing a wobble, simply bend the nail until it spins without wobbling

 

[paulvallandigham]

I believe I told my friend much the same thing, John, when he first asked. However, since I am not a target shooter, I thought I should honor his request to at least ask the membership for their advise. When you are shooting off a bench rest, or prone, or over a "chunk", the difference in weight and diameter of two different cavities can cost you the match.

Personally, I just can't get involved in that kind of shooting. I respect people who do, but it holds no interest for me. I like accurate shooting, but I prefer to shoot "Trick" shots, at targets that audiences think can't be hit. Snuffing Candle flames with a RB was a particular crowd pleaser when my club did that one evening prior to the 4th of July fireworks display. Using my flintlock, the kids of all ages got a lot of joy out of the flash of the priming powder, the roar of the rifle, the flame and smoke coming out the barrel- the smoke only visible in the brief light of the flame coming out the barrel behind it--- and then seeing a lit candle some 50 feet away suddenly go out. We got heavy applause from the crowd every time we snuffed a candle flame[ without shooting either the wick, or the candlestick.]

This is off-hand accurate shooting, and requires different skills than shooting off a bench rest. Both require much correct practice to learn how to do well, and to do consistently, shot after shot.

Then there is the issue of "Stage Fright", which many great shooters lack, that keeps them out of the winner's circle time after time, because they beat themselves by not learning how to focus their concentration to exclude all distractions. :hmm: I know a lot of great shooters in my gun club who refuse to shoot in front of an audience, simply because they can't "take the pressure". They shake their heads and verbally wonder how I do it. That is one of the reasons I wrote my article on Off-hand and Trick Shooting, which is republished on this forum.

 

[rich pierce]

Might use wheelweight instead of lead.