Random thoughts and observations while home-shop die making

[PWS]

There's a lot of really useful info already on this site and perhaps I can contribute more.

Last summer, with the information and motivation of the "Let's Build a Swage Press" thread, I made a press. It's not the same as the thread press but more along the lines of the Corbin S-Press with a different toggle. Anyway, I've finally gotten around to the daunting task of making dies. Last week, I learned a little about what NOT to do with a jacket draw die (see "Oopsy" thread).

I've been working on a point forming die now. Some things I've run into are:

Annealed O1 is a bugger to machine! I've yet to come up with an edge that will give a good finish, even my best efforts at sharpening HSS bits. Perhaps O1 just isn't the material to finish with a point? I've been turning to about .002" over and finishing with various grits of sand paper. This is primarily in making the d-reamers for inside profiling and wanting a fine finish to leave a smooth edge.

There's a bit of info on-line regarding the making of D-reamers but I've had my struggles with the details. Had to scrap a die right away as the first reamer cut .004" oversize. Then, I read in Ted Smith's PDF file that this is typical for D-reamers to cut oversize. So I make the next reamer .004" under and it only cuts .0025" oversize (which is ok, I can lap that out). The big difference is that the first reamer was cut .005" beyond halfway and relieved under the cutting edge to what Paul Rodgers suggests in his write-up (.020"-.030" of flat below the edge, about .060" of relief) while the second reamer was .001" beyond halfway and had almost no relief other than during stoning on a red diamond hone. Both reamers are heat treated O1 and annealed to where they just start to blush (straw?).

First reamer cut pretty well the whole way but left a lot of scoring and I think it was riding up on the chips due to the relief under the edge? Not sure. Second reamer cut even better but three times it grabbed and gouged so badly that I thought I'd have to scrap the die. Fortunately, none of the scores were so deep that they didn't lap out. I read somewhere during research that using the same material as both your cutter and stock tends to gall much more than when using dissimilar materials. The second reamer did have edge buildup despite frequent cleaning and a thick, high-sulfer cutting oil. I was much more fastidious about clearing chips the second go-around and that seemed to help.

Still, I'm not getting a good finish in annealed O1without abrasives.


So two day's of struggle and I have a rough shaped cavity of the proper length and profile with a crummy finish but workable at .008" undersize. I made a set of brass laps similar to what Cane Man posts in his thread, starting at .405", .407", .408", and .409" for a finish size of .412". Incidently, I don't have a radius cutter so I filed out a dummy ogive and used it as a template to make a arc profile cutter out of a piece of truck leaf spring. I clamped it in the tool post, cut my reamer blank to size, spun the tool post and finished the nose. Then, turned down four rods of 360 brass for the above laps and used the same cutter to profile the nose. Worked pretty well although I did notice when getting close to final size, the cutter would only show chips on a portion of the edge so I rocked the carriage back and forth until the cutting stopped. Three of the four laps show full contact so it worked ok.

I don't have the "proper" lapping compound but used some of the leftovers from a Midway three grit kit. Perhaps it's that darn soft O1 again but the laps wore much faster than the steel! The .405" turned into a .400" in a few minutes and likewise with the rest. I used the 220grit on the first lap, then 320 on the next two. After three hours, I'm out to .409" and close to quitting for the day. The goal was .410", heat treat the die, then finish to .4115" with the last lap and 600 grit. Then, buff the final .0005 with 800-1000 grit sand paper.

Since the .408 lap ended up .405 and seemed to quit cutting, I tried a trick suggested in the "Weet" method of opening a mold. There, you roll your lap (a bullet from the mold in question) under pressure between two files to knurl the surface and effectively make it a larger diameter. So, I did that to the third lap, gained back the .003 lost, and ran it into the die one last time with 320 grit. SHEEZ!!! While the other laps were coming out golden color, this one came out silver. In less than a minute, the 320 grit on the knurled surface removed .0015" (measured with my sized bullet po'boy pin gauge). Time to walk away for the day before it gets out of hand.

I'll cut the threads first thing tomorrow and try to heat treat the die before lapping out the final .0015.

Sorry I'm too lazy for pics tonight.

[jimbull34]

Brother, I feel your pain! I started making dies a few years ago and encountered most of the problems you have described here. A few suggestions, ideas for you to ponder, most of which I will get a series of "your wrong", that won't work, etc. Get a lot of that here from those who know every thing, but this worked for me. First, try using 12L14 for your point forming die. It machines very well, readily available and is fairly cheap. Contrary to what a lot of people think about using only "tool steel" for dies, consider this, your dies are steel and you are using brass cases, which one wears out first? I have found that it is so much easier to turn dies from 12L14 even if they get out of deminsions, its still better then fighting with 01 or the others. I once tried using A10 graphmo. what a problem that was. Broke more tools then I ever had. Just too hard and difficult to work with... just my opinion.
Secondly, I tried and still do, use d reamers that I make myself. Some work, some don't. So in searching for the solution, I asked people on this site who they used to make their reamers, to which I got this: "I'm not going to tell you who does mine, it took me three years to find one and I'm not giving it up". So with that in mind, I started looking for another method of doing it. What I ended up with is using a drill bit which I ground down to the ogive and size I wanted and, yes it works and was a lot easier then trying to do a straight D reamer. Try it, you might be converted!!!

[just bill]

I,m just starting down that road. Getting the tools and steel ready to put the lathe and my talents to the test. Lots of ideas on procedures to wade through and glean from. I'm sure there are a lot of heart breaks ahead, but metal lathe operations have been on my bucket list. The garage is too cold now, however it's March and spring is only 20 days away.
Jim PM sent.

Bill

[Cane_man]

the d-reamer never really worked well for me, which to me is just a one edged reamer... the reamers that worked best for me had two cutting edges... just take your profiled blank, turn perpendicular to the lathe in the tool post, and mill it in half with an end mill, HT/anneal and hone the edges... its self centering, you can use the tail stock, and if you use coolant from a spray bottle it works really well... before you use the 2-edged reamer step drill with as many steps as you can possibly handle!

making point forming dies can make one go insane [smilie=b: but the satisfaction of completing one that works is a great feeling, stay with it, its an endeavor of attrition to see if you can outlast the die :2gunsfiring_v1:

[PWS]

Hmmm, some good ideas to chew on in the shop regarding reamers. Jimbull, I would assume you have to use something like a tool post grinder or just free hand it with a Dremel to get a HSS bit profiled correctly? Any need to relieve the front of the flute to get it to cut? I'm also guessing that you're limited to available diameter - which is probably a good thing to start small!

I'm just a hobby machinist starting about 13 years ago when I bought a cheap-o 7x10 bench lathe. Figured for the price and availability of custom molds back then, $500 for the lathe and a bit of tooling was worth a few molds and I'd have a lathe when done. Naturally, it hasn't quite worked out like that as mold making can be about as much of a PITA as this point die project! The most successful way I found to make a grooved cavity was with a profile cutter, much like the D-reamers but narrower by about .100" final size. That split in half would provide the necessary edge clearance and usually be strong enough and stay sharp enough for one hole. That said, I've got quite a bit of time in making and using D-reamers and it's so true, some cut like the proverbial hot knife and others are worse than useless. I'd sure like to lick the technique and transition into chamber reamers some day as I finally got a larger lathe and have started fitting rifle barrels.

CaneMan, you make a square holder for your reamers right? I'm trying to visualize how to cut multiple flutes. I do have a milling attachment for the 7x10. The goal is basically two "D-reamer" edges offset and 180 degrees to each other in the same piece right? Do they typically cut to size or do you have to account for a fudge factor?

I got my point die threaded and hardened (good 'ol coffee can forge!) and lapped at it the rest of the day. Gotta take a break and get off my feet.

I'm struggling with the laps wearing and had to make a few more. Even used test slugs speared on the end of a drywall screw. The file knurling trick works to gain a few thou but I feel like I'm missing something. How can a lap that quickly wears off up to .008" smaller keep cutting? Any links or titles for info regarding laps and their use?

File Trick:
132718

Good 'ol CC Forge!
132719

[PWS]

The sheet metal flange lying on the vice grips is a little door for the forge. There's a 1/4" soft rod in the grips, bent to hold the die in position. When it was hot enough, just picked up the grips and dumped the die off the rod and into the quench oil. Tempered it in the oven for an hour at 350 per right away per CaneMan's suggestion and it came out just a tick under file hardness. It's polishing up nicely on the inside!

[Cane_man]

the finished reamers fit in the tail stock chuck, so I don't have to square them up... I have to make a special holder for them when I mill the two flutes... the holder is made from aluminum so its easy to make, I rotate the piece in the tool post so that it is perpendicular to the end mill and just mill two flutes on it, then file some relief on the cutting edges, harden, temper, hone, etc. it reams to about 0.005 over, so I account for that... so for example when I made my .224 pointing die I made the reamer 0.216, and that gave me about 0.004 or so to lap... the coolant in the spray bottle helps a lot, keeps it all cool and keeps the chips moving, also the step drilling is important... you got to get some diamond lapping paste, its not that expensive on evilbay and easy to use... get some 500, 1500, and 5000

[blaser.306]

I have a spin indexer with 5 - collet. I have started cutting 3 and 5 flute Remer. Cut 5 thousands under size. And they cut an almost perfect surface.

[fast ronnie]

When having problems with finish on machined parts, you might try some Buttercut as a lube/cutting fluid. It is a modifeied lard oil. I'm not sure where to get it anymore. I bought a five gallon bucket years ago and probably still have a gallon or so left. I use it mostly for tapping, and have yet to stick a tap with it. It works when nothing else will. I keep a can of it on the lathe and use an acid brush to apply it. Only takes a little bit, you don't have to flood it.

[PWS]

Looks like Buttercut is still available and here's a bit of chat regarding it's use: http://www.practicalmachinist.com/vb/general/buttercut-cutting-fluid-192555/. Have to laugh about one guy's complaint that when it smokes, it smells like bacon and makes him hungry!

[PWS]

I'm not quite to the point of calling it conquered but the point forming die works well enough to prototype a few slugs. Unfortunately, I did run oversize about .0007". I already made a .411" sizer to swage .416" slugs so I'm just finishing up mine with a run through that.

I am running into the problem of the bullet getting speared on the end of the ejector pin. The temporary pin is a piece of allen key, basically .085" diameter and penetrated the nose of every bullet anywhere from 1/8" deep to all the way through to the base. Most of the time, I can pull the finished slug off of the ejector pin by hand. Sometimes the pin comes out with the bullet though. The pin hole was drilled at 3/32" for a .093 ASTM228 music wire pin (when it shows up!) so I'm hoping that the full, round diameter of the music wire will be just enough more to eject and not stick.

Darn it, I just thought that I'd better confirm that the pin isn't proud in the cavity. I think it's recessed but better recheck... Anyway...

A few factors that might be contributing to the pin sticking is that I stopped the polishing at 600grit. As I need to final size anyway, perhaps a 1/2hour with 800&1000 grit would help. Also, my cores are 8-10bhn range scrap and is showing spring back. There's never a point where the ram relaxes completely so I wonder if a softer core would allow easier ejection.

By playing with it, I found that if I backed off the base punch and started the point about 1/3 of the way, ejected the bullet, relubed it, point it another 1/3, eject, relube, then finish, the e-pin penetration was minimized. The bullet seems to want to stick the most right when it starts to taper, which makes sense as that's where it's getting wedged inwards moreso than at the very tip.

Another factor might be that I've overannealed the brass. It's coming out with a 'gator skin. The cases were annealed in an old metal gallon can in a wood fire. I purposely got it pretty darn hot. Research on annealing last night came across mention of a "white, powdery bloom that forms when the zinc in the brass is burned out of the metal". Sure enough, I recall seeing some cases with a "white, powdery bloom" just like what forms when welding on galvanized steel (cough, cough...). CaneMan is ahead of me again with his write-up of softening brass - case necks really should just be "stress relieved" and cases for jackets should be heated to only 1000-1200F and never over 1350F. I'll do better next time!

I tried three different types of lubricant and found that while general purpose lithium auto bearing grease feels the slickest and worked fine for drawing, it wasn't the best in the point die. Plus, it's messy!

Imperial sizing die wax also feels super slick on the fingers and proved to be the best for drawing, it didn't work as well in the point form die.

RCBS Case Lube-2 proved to be the best of the three, worked well enough for drawing, worked best in the point forming die, and was the easiest for cleanup.

So, any feed back on the ejection pin sticking? Is my pin too small for a 320gr .411 bullet? Should I polish the die more? Different lube? Different core material? THANKS!!!

Here's a few prototypes, 320grSP w/45ACP case and 280grHP w/10mm case,
132857

[PWS]

Just confirmed - the ejection pin is NOT protruding into the die cavity. The first time I assembled everything it definitely was too long so that was addressed. It sits about 1/8" below the cavity point.

[Cane_man]

hey those look pretty good... the ejection punch/wire sticking early is always just part of the process for me, and it always had to do with breaking in the die... as the die gets polished and broken in the wire will stop getting stuck and the swaged bullets will just start popping out when you punch them... get some 5000 grit diamond paste and get it good and polished

[blaser.306]

hey those look pretty good... the ejection punch/wire sticking early is always just part of the process for me, and it always had to do with breaking in the die... as the die gets polished and broken in the wire will stop getting stuck and the swaged bullets will just start popping out when you punch them... get some 5000 grit diamond paste and get it good and polished

I would have to agree with this 100% if the slug is being held tight enough , my thoughts would lean towards a "jug shaped die " or rough internal surface finish.

[sprinkintime]

I used 2 flute reamers for all my dies, but I agree that more than 2 is better 4 if possible, also I used O-1 and the problems and length of time in getting a good finish is not good. I think going to a 4350 steel you will have easier machining and better finish. Sprink

[PWS]

Well, gee whiz! I got out and shot some of the slugs yesterday and they did pretty darn well! Being timid, I loaded them over a one-grain-increase ladder, starting pretty low, with four different powders. At 100yards, the two worst group were 2 1/2", two groups were 1 1/2" and one was 1 1/4" for five shots each. Pretty darn happy about that especially since each shot represented a different powder charge. The bullets weigh 320grains and velocities ranged from 2100 up to about 2300fps.

The 0.093" ejector pin wire showed up yesterday so I'll try that. I'm pretty sure the die is not jugged as it was a factor I kept in mind while polishing. Doesn't mean it isn't (and I don't know how to measure for it) but if it is, it's minor.

Anyway, thanks everyone for the advice and feed back!!!

[aaronraad]

I typically specify H13 tool steel for dies when ordering from die makers with no bullet swaging die tolerances experience. Primarily because there is minimal change between the pre- and post-hardened dimensions with H13 and therefore less chance of them making scrap to my mind. It's typically used for hot work dies (because of it's dimensional stability), but pretty safe to say you just get more wear out of using it an equivalent cold work application.

Example data sheet: Bohler-Uddeholm H13 TOOL STEEL (http://www.bucorp.com/media/H13_data_sheet_09032013.pdf)

For ejection pin material it's pretty hard to go past K&S Music Wire for both tensile strength and ductility. It's readily available from most hobby stores for a reasonable price. Just take you're micrometer with you if their +/-0.0005" diameter tolerance is too critical for your ejection pin hole.

[BT Sniper]

It's always nice to surprise ourselves with the accuracy potential of these bullets made from scrap brass.

Good shooting and swage on!

BT

[fast ronnie]

Well, gee whiz! I got out and shot some of the slugs yesterday and they did pretty darn well! Being timid, I loaded them over a one-grain-increase ladder, starting pretty low, with four different powders. At 100yards, the two worst group were 2 1/2", two groups were 1 1/2" and one was 1 1/4" for five shots each. Pretty darn happy about that especially since each shot represented a different powder charge. The bullets weigh 320grains and velocities ranged from 2100 up to about 2300fps.

The 0.093" ejector pin wire showed up yesterday so I'll try that. I'm pretty sure the die is not jugged as it was a factor I kept in mind while polishing. Doesn't mean it isn't (and I don't know how to measure for it) but if it is, it's minor.

Anyway, thanks everyone for the advice and feed back!!!

One possible way is to use a small dial bore gage. My smallest goes down to .240. It's part of a set that cost around $70 if I remember right from MSC. I use mine for measuring valve guide clearance.

[PWS]

One possible way is to use a small dial bore gage. My smallest goes down to .240. It's part of a set that cost around $70 if I remember right from MSC. I use mine for measuring valve guide clearance.

I've looked at those bore gages but didn't buy as it would be nice to have a tool that will also measure the grooves in a bullet mold. I have an $80 "dial caliper gage" with the long feeler fingers. It's VERY touchy but can tell you if you're close. It's not sensitive enough to measure a taper as small as what I might have. Anyway, I lapped out another .001" starting at the entrance to the die and tried to purposely cut a taper. Forming and ejecting remain the same so I'm at the point where I'll just run with it an hope it breaks in with use.

[PWS]

I don't want sound like bragging (things just happened to work right the first time) but I started and completed another PF die within one day yesterday! 8:00AM found me in the garage with a few sketches and some rod stock, 8:00pm I was sitting at my press swaging some .35cal rifle slugs.

A few things that REALLY helped speed the process were:

1. I purposely copied the ogive of the Speer 250gr Hot Core .358". I filed a gauge from a .08" thick piece of banding that fit the arc of the bullet nose. The gauge was used to profile the nose cutter. Then all that was necessary to produce laps was to size down bullets and drill the base for a screw shaft.

2. I cut the parallel section of the die to rough diameter with a boring bar. The nose profile D-reamer was sized to slip fit in the rough bore. Then, the nose profiler only had to ream the step drilling at the nose. This saved a good hour of futzing with the reamer and circumvented scratching and gouging on the parallel section. This is the boring bar and I couldn't live without it. It's a bit spendy but a perfect size for cutting sizers and dies and such. http://www.grizzly.com/products/Solid-Carbide-Mini-Boring-Bar-5mm-Shank-Right-hand/T10248

3. I used a lard based cutting fluid for the reaming and while the finished hole wasn't silky smooth, it worked much better than the other fluids used last time. Something occurred to me while doing the reaming; it wouldn't surprise me if I've been decarburizing the steel with the long heat times required with the small propane torch I've been using. I'm going to experiment a little with grinding back edges to see if they hold better than the as-treated surface.


I'm still having trouble lapping the very point but CaneMan described his steel wool trick. It doesn't seem to effect the final finish or ejection of the bullet so I'm not too worried about it. I have thought of partially forming the point on a few slugs, dabbing a little fine compound on the nose and finishing the forming. It might cause an out-of-roundness but the lap pattern would be parallel to the forming direction. Just an idea at this point.


Also made a cutter and stop for the mini-lathe to shorten .223 brass. Within the spindle taper inside the chuck is a male taper with a 3/8" hole stepped down to 1/4" to hold 3/8" rod stock. The rod then provides a depth stop for the case. The carriage is run close to final length and the compound is used to set the final length. Lock the carriage in place and the cross feed is run in and out. The slitting tool was a recycled D-reamer and it got me thinking about the possibility of decarbing the steel. First edge wore out right away but I ground it back, honed it and it's held up for 300 cases now. The case does collapse a little at the cut but a quick bumpout by poking needle nosed pliers inside brings it back.
134252

[PWS]

All formed and drying on the boiler after a final cleaning!

134254

[clodhopper]

That is a nice boring bar! I never even thought of looking for one made of carbide.

[fast ronnie]

I don't want sound like bragging (things just happened to work right the first time) but I started and completed another PF die within one day yesterday! 8:00AM found me in the garage with a few sketches and some rod stock, 8:00pm I was sitting at my press swaging some .35cal rifle slugs.

A few things that REALLY helped speed the process were:

1. I purposely copied the ogive of the Speer 250gr Hot Core .358". I filed a gauge from a .08" thick piece of banding that fit the arc of the bullet nose. The gauge was used to profile the nose cutter. Then all that was necessary to produce laps was to size down bullets and drill the base for a screw shaft.

2. I cut the parallel section of the die to rough diameter with a boring bar. The nose profile D-reamer was sized to slip fit in the rough bore. Then, the nose profiler only had to ream the step drilling at the nose. This saved a good hour of futzing with the reamer and circumvented scratching and gouging on the parallel section. This is the boring bar and I couldn't live without it. It's a bit spendy but a perfect size for cutting sizers and dies and such. http://www.grizzly.com/products/Solid-Carbide-Mini-Boring-Bar-5mm-Shank-Right-hand/T10248

3. I used a lard based cutting fluid for the reaming and while the finished hole wasn't silky smooth, it worked much better than the other fluids used last time. Something occurred to me while doing the reaming; it wouldn't surprise me if I've been decarburizing the steel with the long heat times required with the small propane torch I've been using. I'm going to experiment a little with grinding back edges to see if they hold better than the as-treated surface.

When most tool steels are heat-treated, there will be some decarburizing on the outside of the steel. Two things will help; first, when using a heat-treating oven, it is common practice to wrap and seal parts in stainless steel foil while bringing up to temp. The other general practice on many (not all) tool steels is to grind a few thou off the outside to get down to stable material. Steels that are fired in an inert atmosphere oven usually do not require this, but almost all oil quenching steels do.


I'm still having trouble lapping the very point but CaneMan described his steel wool trick. It doesn't seem to effect the final finish or ejection of the bullet so I'm not too worried about it. I have thought of partially forming the point on a few slugs, dabbing a little fine compound on the nose and finishing the forming. It might cause an out-of-roundness but the lap pattern would be parallel to the forming direction. Just an idea at this point.


Also made a cutter and stop for the mini-lathe to shorten .223 brass. Within the spindle taper inside the chuck is a male taper with a 3/8" hole stepped down to 1/4" to hold 3/8" rod stock. The rod then provides a depth stop for the case. The carriage is run close to final length and the compound is used to set the final length. Lock the carriage in place and the cross feed is run in and out. The slitting tool was a recycled D-reamer and it got me thinking about the possibility of decarbing the steel. First edge wore out right away but I ground it back, honed it and it's held up for 300 cases now. The case does collapse a little at the cut but a quick bumpout by poking needle nosed pliers inside brings it back.
134252

When most tool steels are heat-treated, there will be some decarburizing on the outside of the steel. Two things will help; first, when using a heat-treating oven, it is common practice to wrap and seal parts in stainless steel foil while bringing up to temp. The other general practice on many (not all) tool steels is to grind a few thou off the outside to get down to stable material. Steels that are fired in an inert atmosphere oven usually do not require this, but almost all oil quenching steels do.