Frank Savage
02-02-2014, 04:27 PM
Well, not so much without a machine shop, but surely with less machine shop than in the sticky. You need just small lathe with 3-jaw, set of collet holders will make you very hapy and 4-jaw will help you. Add a drill, some taps and youīre done.
Disclaimer and apology-donīt judge the longest nose bullet, I hogged eight of them from almost cold mold for lenght checking purposes. The good ones went down the barrel :-)
Hereīs part of my setup, for 8x60R Kropatschek:
95391
Mold clampholder with sprueplate, mold body, some nosepunches, bullets and bullets set into brass. Itīs the easy Ideal adjustable basepour style, where the basic hole gives bullet dia, nosepunch cavity the nose shape and lenght and overall position of the punch in mold body gives the total bullet lenght. Materials used are el cheapo the most common easy machining steel-once you know what you want, use brass or some better steel. But no point having put the extra time and tooling setup into mold you may use only to prove wrong idea with 30 slugs cast.
The mold body is just a simple cylindrical hole into 25 mm or 1" cold roled bar (machinists and diemakers, donīt laugh here about the "simple cylindrical hole" :-D). Drilled and reamed, then honed with emery cloth to proper dia and surface. If you make a 1-1,5" cut into the end of 1/4" cold roled steel and use a bit wider piece of emery cloth, you can hone it up as much as 0,015 without marring the cylinder except little on one end. Well, it takes a bit of feel and practice, but can be done. Then you get rid of about 1/6-1/5" on the drill entrance side, since from honing it will be coned-so take it into account when cutting the basic material to lenght. Making a set of calibers around your desired dia to determine wherether are you in or still out of the realy cylindrical part helps a lot, albeit it takes a bit of time. But even the cold rolled easy machining stock is sufficient here, since youīll probably end up using a tad smaller caliber and narrow strip of your patching paper sticked into mold cavity to determine the dia as well as finding possible tight spots to have them honed out-while not having a chance to jam the caliber inside. The paper will let it out every time.
After cutting to the cylindrical part and facing, cut most of the face surface off to create a simple dish about 1/32" deep with rim on outer as well inner perimeter, about 1/16" wide. Then cut off the outer rim by about 0,003"-0,004" below the rim of the mold cavity. Why-later.
If you donīt have a reamer of proper size, you can go on with quite easy to make drill rod for calibers .40 and up. 11/32" or a bit bigger cold rolled stock even of 1018 steel will hold up to about 2,5" deep hole, but anything smaller will flutter, destroy the knife set into the rod and overall make a whole lotta mess. Tried it on thisone-and was not pleased at least. Will show the setup later, now donīt have the photos on hand. You must make the knife sharp, well angled and of course use little feed rate as well as small chip thickness. If you can make the drillrod from properly heat treted tool steel, youīre happy campers even at 270-300 cal., but I donīt have the possibility.
The end is then covered with cap about 1/8-1/6" thick, fitted by three 1/8" or so bolts:
95392
Attach the roughed out cap with precisely drilled holes first, then set the mold body into chuck and cut from outside to desired dia. This is the most time demanding part, since you need to drill and tap (M3 or M4 or 1/8" or 1/6" threads) the mold body for all three bolts, make a paper template by pressing the paper with your dirty thumb against the bottom face to get the hole pattern impressed and drawed onto it (do you remember school and "frottage" in arts class?). A white self-adhesive sticker works well here. Place it on flat bar or steel sheet youīre going to use for cap, drill and countersink for bolt heads those three holes, rough out the cap and fit it. Then drill 1/5" or 1/4" hole for nosepunch pushrod and make sure itīs dead center, will be helpful to place a live center into it for turning the cap into mold body contour.
Now the nose punches, where collet holders and their inherent preciosity of repeated grip, as well as surface protecting properties will help you a lot:
Take a cold rolled bar at least 1/12" bigger than desired final dia to get rid of the tougher, roll-compressed "skin" these rods always have. Cut a small part, about 1/5" long about 0,002" bigger than desired final dia of the punch-you know this dia from using your calibers during honing the cavity. Then drill a pilot hole to desired depth, with about 1/25-1/16" adition:
95410
Now set a profile knife into your toolpost and cut the nos shape. Will have to insert the images later, made them extra blurry and worthless. The object is, that the outer surface will rest steady while the knife will cut from inside, leaving proper outer dia and razor sharp edge-meaning almost seamles transition on the bullet. But making a proper hole, then cutting around it from the outside where thereīs almost no wall thickness will result in pressing the material into the cavity, marring the nos shape as well as outer dia and may result in positive locking edge which will lock the bullet in the mold. I hope you can understand here, if not, then just take into account that itīs much more easier to make and measure an outer surface first and cut the hole to intersect it at desired point-since you can see it all around, than opposite.
You wanted the hole a tad deeper than desired nose lenght, because to achieve the properly sharp end, youīll make the knife out through the initial dia surface, so it will end up a bit shorter. As well, youīll deepen it a hair by feeding the knife into the end of the pilot hole-but easy, due to very low speed close to axis it will have audible tendency to flutter, so not harm the inner surface.
Then use the at first made proper dia as a reference point and make the dia in whole lenght you need. You can see the profile knife on the right. With one knife, youīre not stuck to just one profile, by different angling of its axis as well as X-Y toolpost movement you can do quite a magic. All three bullet shapes in the photos here were made with one knife, albeit Iīm not even a machinist, not a lathe magician. But of course, the closer the shape, the easier.
95411
95387
You may fing helpful to touch the inner surface extremely lightly whe the outer is done:
95386
Then touch it with wet kind of 400, 600 and 800-1000 grit cloth or paste inside for polish. Use piece of wood or so. Determine the overall lenght of the punch-to make max. lenght of your wanted bullet, or a tad more-and make a shallow cut in the middle to leave bearing surfaces only between end of the nose cavity and short ring on the bottom end. It serevs to reduce friction, as well as to make room for occasional mess which may get into the mold, preventing the nosepunch from stucking in on every impossible occasion. also, when you get somehow uneven heat distribution while preheating the mold, the cold roled stock warps a bit and this dia reduction on part of the nosepunch shank reduces greatly possibility of stucking due to this.
95393
Cut off the punch for lenght, set it into collet by base out (attention not to damage the lip of the cavity!), face it, bevel the edge, drill and tap a hole for proper pushrod-the thin bar visible on the second photo or here and thread the pushrod in such a lenght that with nut all way onto, the lip of the nosepunch is still in the cavity, as seen on very shallow SWC nosepunch here:
95394
Then take again your trusty emery cloth set, some flat bar and use it to bring the outer surface those 0,001-0,002" down to proper dia, check the fit often. You can take off a bit more material on the bottom ring and from lower portion of the upper bearing part along the cavity, but you can leave 0,0003-0,0006" more than exact on the lip-with shallow aproach angle of the cavity towards the nosepunch surface it will spring this little even in 1018 kind of steel and will provide a good contact even when the body will be a bit hotter than the punch.
You can see a cylinder below the mold body-serves as a weight to pull down the nosepunch, as well as a handle and part to tap onto when the bullet does not come out by its own weight. Simple piece of round bar drilled and tapped all the way through, nothing special.
Easiest way how to set a lenght for initial experiments is to wind a clean, unlaquered cooper wire onto the pushrod, as seen here, along with nosepunch, bullet fit and ejection:
95413
NEVER use a steel wire, it may got the surface loose upon heating, resulting in grit in cavity and ugly stuck nosepunch, maybe even destroyed mold. Wind it tight, or youīll find great difference in bullet weight even with the best casting technique due to springing of the spacer. Different mold temp will also move you more than youīre used to, so use it in this manner only for lenght testing purposes and make proper one-piece, preferably brass spacer for real work.
The clamp holder is somehow self-explaining, just one photo from making the clamp head:
95398
Here the independent 4-jaw will be helpful. Use at least 7/16 or 1/2" flat bar, but be damn sure that 3/8" is too thin. Two hints-make the dia just for your bar stock and, without removing it from the chuck, face the outer flat surface on which the sprueplate will be placed. Donīt rely on the basic bar and "itīs laying dead flat on the dead perpendicular face of the chuck". Did that, couldnīt make the bases square and found out that when drilling the basic hole, one edge moved a little bit upon cutting the hole, which then was not square to the surface. A mess to find this out on finished clamphead.
Make the sprueplate a bit freefloating-let it some up and down play. Youīll adjust the mold into the clamp in such a manner that only the inner lip around the cavity will touch it, or better place a piece of your thinnest patching paper onto it and the set the mold block as to have full contact, but still not lifting the sprueplate up. This way youīll get a ventilation. It is very easy with the sprueplate set rigid achieve such a hermetical fit, that the air can not leave the mold and for God or Hells sake you canīt pour a bullet. Also youīll se here why to make the outer lip a tad shorter-if you donīt, you canīt see the moment of proper contact and you may find out that itīs obstructing the way of the sprueplate by some 0,001īs, making bases unsquare and with lip of lead on one side. Tedious to clear them at least.
May sound weird, but the most accurate setting is done in front of light, seeking "see it-donīt see it" or after a little practice just by feeling of just lifting-now not lifting the floating sprueplate. Get used to to touch the sprueplate bar a bit by laddle to make sure itīs not lifted. May sound inconvenient, but youīll get used to it very quickly.
This way you can for little effort and costs find out the proper dia for your bore and paper combo, as well as something for different oddbals you may encounter. Also, you can try how much accurate is the Greenhill formula for your rifle or whatever "just on the edge" or beyond it you want try.
This mold casts bullets rounder than 0,01 mm or better than 0,0002" for me, while I managed to keep the tolerance between the nosepunches and mold body at about 0,0001-0,0002". Way easier when you have a metric micrometer in milimeters, since you have 2,5 times itīs basic division (a 0,01 mm) in 0,001" and itīs way cheaper than 0,0001" divided micrometer. But for practical purpose 0,0004-0,0005 (6)" is better clearance, since the fit and seal is still perfect and the temp differences does not so much for nosepunch sliding ease.
Disclaimer and apology-donīt judge the longest nose bullet, I hogged eight of them from almost cold mold for lenght checking purposes. The good ones went down the barrel :-)
Hereīs part of my setup, for 8x60R Kropatschek:
95391
Mold clampholder with sprueplate, mold body, some nosepunches, bullets and bullets set into brass. Itīs the easy Ideal adjustable basepour style, where the basic hole gives bullet dia, nosepunch cavity the nose shape and lenght and overall position of the punch in mold body gives the total bullet lenght. Materials used are el cheapo the most common easy machining steel-once you know what you want, use brass or some better steel. But no point having put the extra time and tooling setup into mold you may use only to prove wrong idea with 30 slugs cast.
The mold body is just a simple cylindrical hole into 25 mm or 1" cold roled bar (machinists and diemakers, donīt laugh here about the "simple cylindrical hole" :-D). Drilled and reamed, then honed with emery cloth to proper dia and surface. If you make a 1-1,5" cut into the end of 1/4" cold roled steel and use a bit wider piece of emery cloth, you can hone it up as much as 0,015 without marring the cylinder except little on one end. Well, it takes a bit of feel and practice, but can be done. Then you get rid of about 1/6-1/5" on the drill entrance side, since from honing it will be coned-so take it into account when cutting the basic material to lenght. Making a set of calibers around your desired dia to determine wherether are you in or still out of the realy cylindrical part helps a lot, albeit it takes a bit of time. But even the cold rolled easy machining stock is sufficient here, since youīll probably end up using a tad smaller caliber and narrow strip of your patching paper sticked into mold cavity to determine the dia as well as finding possible tight spots to have them honed out-while not having a chance to jam the caliber inside. The paper will let it out every time.
After cutting to the cylindrical part and facing, cut most of the face surface off to create a simple dish about 1/32" deep with rim on outer as well inner perimeter, about 1/16" wide. Then cut off the outer rim by about 0,003"-0,004" below the rim of the mold cavity. Why-later.
If you donīt have a reamer of proper size, you can go on with quite easy to make drill rod for calibers .40 and up. 11/32" or a bit bigger cold rolled stock even of 1018 steel will hold up to about 2,5" deep hole, but anything smaller will flutter, destroy the knife set into the rod and overall make a whole lotta mess. Tried it on thisone-and was not pleased at least. Will show the setup later, now donīt have the photos on hand. You must make the knife sharp, well angled and of course use little feed rate as well as small chip thickness. If you can make the drillrod from properly heat treted tool steel, youīre happy campers even at 270-300 cal., but I donīt have the possibility.
The end is then covered with cap about 1/8-1/6" thick, fitted by three 1/8" or so bolts:
95392
Attach the roughed out cap with precisely drilled holes first, then set the mold body into chuck and cut from outside to desired dia. This is the most time demanding part, since you need to drill and tap (M3 or M4 or 1/8" or 1/6" threads) the mold body for all three bolts, make a paper template by pressing the paper with your dirty thumb against the bottom face to get the hole pattern impressed and drawed onto it (do you remember school and "frottage" in arts class?). A white self-adhesive sticker works well here. Place it on flat bar or steel sheet youīre going to use for cap, drill and countersink for bolt heads those three holes, rough out the cap and fit it. Then drill 1/5" or 1/4" hole for nosepunch pushrod and make sure itīs dead center, will be helpful to place a live center into it for turning the cap into mold body contour.
Now the nose punches, where collet holders and their inherent preciosity of repeated grip, as well as surface protecting properties will help you a lot:
Take a cold rolled bar at least 1/12" bigger than desired final dia to get rid of the tougher, roll-compressed "skin" these rods always have. Cut a small part, about 1/5" long about 0,002" bigger than desired final dia of the punch-you know this dia from using your calibers during honing the cavity. Then drill a pilot hole to desired depth, with about 1/25-1/16" adition:
95410
Now set a profile knife into your toolpost and cut the nos shape. Will have to insert the images later, made them extra blurry and worthless. The object is, that the outer surface will rest steady while the knife will cut from inside, leaving proper outer dia and razor sharp edge-meaning almost seamles transition on the bullet. But making a proper hole, then cutting around it from the outside where thereīs almost no wall thickness will result in pressing the material into the cavity, marring the nos shape as well as outer dia and may result in positive locking edge which will lock the bullet in the mold. I hope you can understand here, if not, then just take into account that itīs much more easier to make and measure an outer surface first and cut the hole to intersect it at desired point-since you can see it all around, than opposite.
You wanted the hole a tad deeper than desired nose lenght, because to achieve the properly sharp end, youīll make the knife out through the initial dia surface, so it will end up a bit shorter. As well, youīll deepen it a hair by feeding the knife into the end of the pilot hole-but easy, due to very low speed close to axis it will have audible tendency to flutter, so not harm the inner surface.
Then use the at first made proper dia as a reference point and make the dia in whole lenght you need. You can see the profile knife on the right. With one knife, youīre not stuck to just one profile, by different angling of its axis as well as X-Y toolpost movement you can do quite a magic. All three bullet shapes in the photos here were made with one knife, albeit Iīm not even a machinist, not a lathe magician. But of course, the closer the shape, the easier.
95411
95387
You may fing helpful to touch the inner surface extremely lightly whe the outer is done:
95386
Then touch it with wet kind of 400, 600 and 800-1000 grit cloth or paste inside for polish. Use piece of wood or so. Determine the overall lenght of the punch-to make max. lenght of your wanted bullet, or a tad more-and make a shallow cut in the middle to leave bearing surfaces only between end of the nose cavity and short ring on the bottom end. It serevs to reduce friction, as well as to make room for occasional mess which may get into the mold, preventing the nosepunch from stucking in on every impossible occasion. also, when you get somehow uneven heat distribution while preheating the mold, the cold roled stock warps a bit and this dia reduction on part of the nosepunch shank reduces greatly possibility of stucking due to this.
95393
Cut off the punch for lenght, set it into collet by base out (attention not to damage the lip of the cavity!), face it, bevel the edge, drill and tap a hole for proper pushrod-the thin bar visible on the second photo or here and thread the pushrod in such a lenght that with nut all way onto, the lip of the nosepunch is still in the cavity, as seen on very shallow SWC nosepunch here:
95394
Then take again your trusty emery cloth set, some flat bar and use it to bring the outer surface those 0,001-0,002" down to proper dia, check the fit often. You can take off a bit more material on the bottom ring and from lower portion of the upper bearing part along the cavity, but you can leave 0,0003-0,0006" more than exact on the lip-with shallow aproach angle of the cavity towards the nosepunch surface it will spring this little even in 1018 kind of steel and will provide a good contact even when the body will be a bit hotter than the punch.
You can see a cylinder below the mold body-serves as a weight to pull down the nosepunch, as well as a handle and part to tap onto when the bullet does not come out by its own weight. Simple piece of round bar drilled and tapped all the way through, nothing special.
Easiest way how to set a lenght for initial experiments is to wind a clean, unlaquered cooper wire onto the pushrod, as seen here, along with nosepunch, bullet fit and ejection:
95413
NEVER use a steel wire, it may got the surface loose upon heating, resulting in grit in cavity and ugly stuck nosepunch, maybe even destroyed mold. Wind it tight, or youīll find great difference in bullet weight even with the best casting technique due to springing of the spacer. Different mold temp will also move you more than youīre used to, so use it in this manner only for lenght testing purposes and make proper one-piece, preferably brass spacer for real work.
The clamp holder is somehow self-explaining, just one photo from making the clamp head:
95398
Here the independent 4-jaw will be helpful. Use at least 7/16 or 1/2" flat bar, but be damn sure that 3/8" is too thin. Two hints-make the dia just for your bar stock and, without removing it from the chuck, face the outer flat surface on which the sprueplate will be placed. Donīt rely on the basic bar and "itīs laying dead flat on the dead perpendicular face of the chuck". Did that, couldnīt make the bases square and found out that when drilling the basic hole, one edge moved a little bit upon cutting the hole, which then was not square to the surface. A mess to find this out on finished clamphead.
Make the sprueplate a bit freefloating-let it some up and down play. Youīll adjust the mold into the clamp in such a manner that only the inner lip around the cavity will touch it, or better place a piece of your thinnest patching paper onto it and the set the mold block as to have full contact, but still not lifting the sprueplate up. This way youīll get a ventilation. It is very easy with the sprueplate set rigid achieve such a hermetical fit, that the air can not leave the mold and for God or Hells sake you canīt pour a bullet. Also youīll se here why to make the outer lip a tad shorter-if you donīt, you canīt see the moment of proper contact and you may find out that itīs obstructing the way of the sprueplate by some 0,001īs, making bases unsquare and with lip of lead on one side. Tedious to clear them at least.
May sound weird, but the most accurate setting is done in front of light, seeking "see it-donīt see it" or after a little practice just by feeling of just lifting-now not lifting the floating sprueplate. Get used to to touch the sprueplate bar a bit by laddle to make sure itīs not lifted. May sound inconvenient, but youīll get used to it very quickly.
This way you can for little effort and costs find out the proper dia for your bore and paper combo, as well as something for different oddbals you may encounter. Also, you can try how much accurate is the Greenhill formula for your rifle or whatever "just on the edge" or beyond it you want try.
This mold casts bullets rounder than 0,01 mm or better than 0,0002" for me, while I managed to keep the tolerance between the nosepunches and mold body at about 0,0001-0,0002". Way easier when you have a metric micrometer in milimeters, since you have 2,5 times itīs basic division (a 0,01 mm) in 0,001" and itīs way cheaper than 0,0001" divided micrometer. But for practical purpose 0,0004-0,0005 (6)" is better clearance, since the fit and seal is still perfect and the temp differences does not so much for nosepunch sliding ease.