DIY mold making.

[Gordoncourtney]

Iron oxide back as usual..Burning embers ...Roy in Norfolk, regrets he has no information if paper was used, he was never a full member just a guest at the club, and not there at the time of the incident, and with Colvid he's lost touch with members. I note they were rapid fireing a Brown Bess and he was loading a wad., perhaps a shotgun felt type, neither do we know he was loading with ball, perhaps just blank firing....but makes me think the BP could have been in paper cases ...which he shoved down the barrel...ill let you know if I get any more. Information......sorry I am absolutely no help to you so had better shut up.

I can only wish you well

 

[Ironoxide]

Gordoncourtney, No worries. I think the conclusion we all agree on the "burning embers" is that sometimes it does happen. Perhaps in favourable circumstances which let's many people avoid it all their life while others may encounter it.

Regarding aluminium and other metals. Based on "heat expansion coefficient" tables online we can tell your aluminium rod was heated 350C (662F) over room temperature
(For comparison sake, I have a soldering iron that has tips factory preset to 360C - so that's just under about good temperature to melt solder)

I put those thermal expansion coefficients together with specific heat (how much energy it takes to heat a given weight of metal) and density to come up with
my "ironoxide metals thermal stability index" in relative units(the lower the better).
- aluminium 9
- cast iron 3
- brass 5
Think of it as how much a given dimension of the metal will grow given the same energy input and same initial dimensions.

So with regards to heat stability there is no question cast iron (and various steels) are the best option, but a hobby machinist has to also consider the ease of machining (brass wins hands down), price and most importantly for some availability of raw materials or what they already have.

There are also person specific considerations. For me personally the fact aluminium (and brass) are not magnetic makes holding them at the surface grinder a pain. That's why I'll be trying free machining steel (If I'm able to get it).

There are also casting techniques that allow one to obtain good results with less thermally stable metals.

 

[Gordoncourtney]

That all seems OK to me Ironoxide well thought out and presented, when we shut down an engineering company I had an interest in, much came here but the lack of three phase supply , and cancer, I decided to dump most stuff regrettably the cutter and surface grinder, in fact 7 truck loads of smashed up machinery.....I kept the magnetic table though .....I have plenty of bars of aluminium and blocks of brass , little cast iron but I'll have a search. I must get back to making a proper .622 winged bullet or ball for my cape rifle , 1862 by EM Reilly, photo, EM used French walnut, unlike his father, perhaps I'll try cast iron, but on my big Elliot lathe 6 ft long.

I have a. 1875 double rifle 577-500 no 2 I have never fired in anger, mint bores , 1906 nitro proofed, more likely nitro for black, by Thomas bland and sons London there's a guy firing one on Google , I had it BP proofed too it was the idea of the proof house in London. Load 440g jacketed bullet 140 g of BP, 79 g of Varget seems reasonable too. My apology for hoping off the ML theme . But there's a reason

I went a different way, have you seen the cost of .510 jacketed bullets and most are 580 g

I started spinning copper jackets out of 15 mm copper pipe, (you need a 25 ton press to punch out jackets, ) it's so easy , I have made different sizes for gunny friends, quite pleaseant and rewarding to do , largest around .75 " I have done, even pressed out wings to fit the two groove bore cape rifle I usually fill with lead and finish on lathe, they are bespoke bullets with hunting in mind, I have also had much fun turning up jackets from spent cases even buying new brass but that's a well established topic.

Better end here or I'll fill ten pages, as I do with gunny pals most days on email....I wish you well and look forward to more exciting topics from you Regards to you Gordon

Ps I had no comment from our French friend on this castle I previously posted, It Forarges, south of Rouen , France , see images Google, 8 the century. Bows and arrows times, A forbidding castle bloody evil if you ask me, but wonderful to see .

 

[Ironoxide]

I love the double gun and your idea to spin jackets from a thin copper tubing. Nice looking castle too.

I've never tried spinning metal on a lathe. I have to try it at some point.

 

[Gordoncourtney]

Oh spinning is so easy.......the brass ones are turned down new brass , they make super bells for earings etc ha ha

Turn up a piece of bar so copper tube pushes over it then turn up the mandrel shape

Hold the mandrel together with say 2" of copper tube in the lathe chuck ( sometimes I anneal it sometimes I don't.. Trial and error ) I use a length of 1/2" round stainless bar to roll , or stroke, it along the mandrel stretching it out over the end point if mandrel....takes less than two minutes. Done it in 30 seconds. .actualy a wood lathe is ideal. ..I finish off with some emery sanding cloth ......I give it a few taps along its length and it falls off the mandrel I don't finish it on the mandrel, but put the form into a split brass collet and trim to length ....ok so you waste an inch or so 15 mm heating pipe tube is £8 per 3 metre length

After turning the filled lead off smooth I usually roll the base over to make it perfect

I can do a video as before But I need to post it on email due to its length......not the sort of thing I want on utube....remember it's the UK police state

Rumours now among police on Internet they , Suggesting access to emails etc , for would be gun applications to access people I mean we are generally just and upstanding people, this ain't Rusdia or China , I mean if I wanted to get heavily into action there's always Afganistan, but which side....

Ps I had sudden hopes of hunting with the 577-500 no2 in Poland Ahhhhh the Carpathian Mountains have you heard of them across the pond ...big game there..... The cape rifle is brilliant but heavy......it's not for this forum but for surviving cancer and my 70th birthday I bid and won a double 450-400 at Bonhams auction London, now in the safe.....brass and dangerous game bullets are expensive but how many elephants do I want to kill I keep it in the safe as it cost £5,200 ,not insured , and the wife did not say a word.....it's the top gun for Africa and I have lived and worked there...just had to have one......ha ha And its obsolete so no police certificate to buy or hold 400 grain bullet 2250ft sec. Just over 4000 ft lbs of energy dangerous game bullets are steel jackets copper plated

Kindest regards from a 78 year definatelly old nutter , but I feel like 35. The wife wishes I was 80 My email address is somewhere above. She ain't so bad at 74 better show a photo too

Ok heres. my 450-400 Bit embarrassing showing it realy it says on it " Lyon and Lyon London and Calcutter late of PURDY" Ha ha I wish you all well. IT lacks the charisma of my cape rifle or a flintlock. Bit like my sons Tesla it ain't a V8. Goes like hell though!!!

Stay safe all ove you, dare I say love from England.

 

[Ironoxide]

No need for the video as it'll be a while before I try spinning. I may have a wood lathe by then

I'm pretty sure the police are going to be on their way to you first thing in the morning regarding that previous post, you know which part

I'm joking of course, but you would be surprised. I'm in the IT field of work and all those years ago before I left the UK we were told in two years metadata on all communications will have to be stored indefinitely. If they succeed with this, then all data will soon follow. It is much easier said than done though. That piece of "soon to be" regulation was initially welcomed by some in the industry with high hopes of government money, then when it transpired service providers were supposed to fund it themselves every kind of service provider tried to say nope, "our service is out of scope of this law, we just provide the interconnect wires, or the building, not the data itself" etc. So beyond initial scoping how much it'll cost (a huge lot in short) I never had any more to do with it. Years later I heard they limited the scope to just ISPs that serve the public, only keep the metadata 12 months etc. This was long time ago, but I doubt even with resources of the Gov they could collect everything. They would have to get rid of people in that doughnut shaped building and have only datacentres there And then searching through that pile of data. They would need as much manpower(and of similar quality) as Google in CA at least.

Regarding email, I get so much email these days I skip reading it most days of the week and just sift through it now and then. I ought to set up another account. I saved your email for when I've done it.

There is plenty of commercial hunting going on in Poland. You'll just have to load nitro for black (or don't tell them what's in the cartridge). In fact those two hunters I mentioned that shot a deer a 100m from my house few weeks ago it was a local guide and an English speaking guy on a commercial hunt. I couldn't tell by the accent where he was from as we only exchanged few words when they were coming back to the car. They had to drive to get to the roe deer as there is a stream blocking a direct path.

Coming back to subject, a very fine rifle. I would love to have a similar one, but here anything that has primer, powder and bullet in a cartridge is considered modern weapon. Same licensing procedure would be required for those doubles as for let's say an AK or AR. So in this regard UK is more free Perhaps one day I'll go through it. Being in a shooting club, taking part in competitions, having a gun safe at home etc, I already meet 90% of requirements.

Coming back to the subject of the thread Once I'm done making the second set of mold blocks I'll post pictures of all the machining steps, just in case someone in future wants to make their own.

Also, for those not having a surface grinder, it is nice to have, but not real necessity. You just need a milling machine and a lathe , plus a way to heat treat steel. So some kind of oxy-fuel torch or an old fashioned forge to harden the cutter.

 

[Ironoxide]

If there is anyone left reading the thread I have a question to anyone with knowledge of construction of bullet molds.

We often see venting lines cut on the top surface of molds like in Lee molds. Some other brands like Lyman don't have them(or at least I didn't notice). Are those venting lines at the top surface, the surface sprue plate rides on, necessary?

I made a new set of blocks and I cut the same bullet design in them, but slightly smaller diameter. I thought it is useful to document the steps and show pictures for any person wanting to make their own. Looking at the number of operations it is amazing it is possible to buy finished molds for under $40 and custom ones under $100. DIY approach makes no sense whatsoever if one values one's time I chose this route only because of the time it would take for me to have one delivered.

So here it is.

Starting with 50mm(2in) bar stock aluminium two 20mm(3/4in) slices were cut with a cold cut off saw.


They were faced off to roughly the same thickness on a big and rather inprecise lathe.

Then using some creative workholding they are ground together on a surface grinder so they are both precisely the same thickness. In absence of a surface grinder, a fly cutter on a mill could do.

Then once both sides are surface ground (kerosene applied with a brush makes for great coolant, much cheaper than wd40) vent lines are scribed with a steel scriber and a ruler. Then extra half a micron is ground off again to remove the burr and both sides are clamped with a little machinist clamp. The whole resulting block is put in a milling machine vice and top flat is milled (only top now).

Then a line is scribed to mark alignment pin location and alignment pin holes are drilled and renamed on a little Chinese milling machine.

The result looks like this so far. Holes are chamfered by hand with a chamfering cutter shown. Also after every operation deburring is done with a needle file.

Next guide pins are made using 18mm(under 3/4in?) medium carbon steel rod turned down precisely to about 0.1mm(4 thou) oversize then sandpaper strip is used to carefully sand it so it is only 0.05mm(2 thou) oversize for a press fit that will not become loose with temperature. The end of each rod is sanded some more so it is no more than 2 tenths oversize for the guide hole. Then a chamfer is cut at the end and sandpaper is used to ease the transition between the chamfer and main diameter in hope it will limit galling in absence of a steel bushing. If one is making a mold that is supposed to last a steel insert bushing is a must in my opinion. Here is one guide pin before being pressed in.

The pins are pressed one at a time with a vice carefully checking the fit frequently so there is a tiny bit of interference between blocks. This way when they heat up they will be just right.

Then once both guide pins are installed the bottom surface of the mold is created on the milling machine.

And back to the surface grinder, now with much more traditional workholding the task is much easier.

Once ground, vent lines are scribed at the top surface and extra half a micron is ground. I have no idea if it is required, but some molds have these. Image shown before extra grinding pass.

More pictures in next post.

 

[Ironoxide]

Continuation of the previous post.

Now slots are milled on a Chinese mini mill for handles using guide pin holes to align 6mm(1/4th in) milling cutter to exactly the mold centerline (holes were renamed to 6.02mm previously).

Then holes for the handle mounting screws are drilled, threaded and countersunk.

Then a sprue plate screw hole is drilled and taped. A hole for the sprue plate stop pin. A shoulder like feature is milled and a hole for the screw that prevents the sprue plate screw from backing out is drilled and taped. Then a pin is made (again 2 thou oversize) and is pressed into the sprue plate stop hole.

This is the blocks so far.

Unfortunately the stop hole was drilled too large so the pin had to be filled by hand to center the sprue plate hole location relative to future cavity. This resulted in slight cosmetic scarring of material next to the pin. I guess I'll just have to live with it :-(

Now the blocks are ready for boring. A 4 jaw chuck with copper foil on its jaws is prepared on the mini Chinese lathe and the picture below shows how the blocks are dialled in to be precisely on center.

Once the blocks are dialled in holes are predrilled to remove as much material from the cavity as possible. Then the cavity cutter is centered and it is fed in very carefully with help of a "poor man's dro" (a dial indicator showing depth of cut - only partially visible).

Very slow speed is used (around 100rpm) and the cutter is stoned once mid way so it is razor sharp.

Then the depth position is marked using the stationary lead screw clamp so returning to it is easy in future. The dial indicator is mounted to show not the depth of cut, but position in radial direction. As we have lube grooves to cut, now the cut is very carefully fed out in the radial direction. The cut is interrupted frequently by returning to starting position, removing the cutter from the cut, measuring the diameter, and resuming. The mini lathe carriage is flexing so much dials are pointless in estimating depth of cut. One has to use "the feel" and check frequently.

Here is how it looks like during this process.

I'm sorry for partial blur, I had to switch to another phone with a busted lens as my primary one had its battery die.

When approaching the target diameter it is very easy to overshoot or make a mistake in measuring so a custom pin gauge is made that first half a mm (20 thou) is 0.01mm(a quarter of a thou) under size, then it is bang on target diameter. It is inserted into the cavity to check the progress of the cut. The cutting is stopped when it can be pressed in with moderate hand pressure.

Here is the mold cut, removed from the lathe. Prior to cavity deburring.

Deburring the cavity edges on top of the mold will be done by rubbing it gently back and forth with a finger. I defido not want a chamfer there. Just the burr needs to go. This mold has a slight burr on the grease grooves. As smaller diameter was cut this time ( 0.5944 to cast 0.596 bullet hopefully) the grease groove part of the cutter didn't "bottom out" this bottoming out cleans up the top of the grease groove band. I hope that burr will be removed when I cast the first bullet, or I can rub it by hand to get rid of it. An alternative is some lapping, but I doubt this will be necessary.

Quite likely my next mold will be cut in a Lee round ball mold used as blocks if they are still in stock and cheap in future.

 

[BS]

I split an old end mill in half, then radius on a "Spin Index".
This .615 diameter drops a .611 of PB.
I use cast iron, brass and aluminum blocks.
One of many sizes.

 

[Ironoxide]

View attachment 90258
I split an old end mill in half, then radius on a "Spin Index".
This .615 diameter drops a .611 of PB.
I use cast iron, brass and aluminum blocks.
One of many sizes.

Nice ball cutter. Thanks for the picture. It was saved for when I need to remind myself the geometry when making one.

Regarding round ball molds. There is a much simpler way to make "mold blocks". Jeff Tanner makes round ball molds like that. This picture is from his website ballmoulds.com

They are cut from a round bar. Instead of guide pins he uses a shoulder and a matching shallow cavity cut in brass. Also no sprue plate so no need to have a very flat surface on top etc.

Those molds work very well. I have one for my 9-bore. The only disadvantage is that one needs to cut off sprues later. I wouldn't be surprised if they were lathe bored one half at a time. That's how I would cut them with a cutter shown by BS.

 

[BS]

I made this one just to see if I could. It drops a .684-5 ball.

 

[Ironoxide]

Great brass mold BS

I've since tested my new mold. This one casts undersize
It makes no sense for mold sized 15.57mm(0.613) to cast 15.63mm(0.615) bullets, and another mold made of the same material casting the same alloy at same temperature mold sized 15.13(0.595) to cast 15.02(0.591) bullets.

I suspect I must have somehow had a burr in my first mold during measuring. Which explains why it was cut oversize despite using pin gauges.

That is not a big problem. I want to test slightly undersize bullets too. Then I can always put the mold back on the lathe (using a 4 jaw chuck) and cut it a little more if required.

 

[Gordoncourtney]

Who here makes their own molds?

I recently made my first proper mold and I've learnt quite a few things in the process. If there is interest I'll describe it in detail. I would like to also hear any tips other people learnt when making their own bullet molds.

Here are few pictures.
The cutter before being heat treated:
View attachment 89302

And after the first test cut (what's left of it) :-(
View attachment 89303
Not to worry, enough of unhardened shank was left to machine another one. This time with better relief angles.

Here it is making a cut in the mold blocks.
View attachment 89304

Mold blocks were made with 7xxx grade aluminium rod. 2in diameter. Flats and other features were milled, surfaces were surface ground.

I borrowed a sprue plate from a Lyman mold. I initially planned to use lyman handles, but I ended up using Lees as they work better with long blocks like this one.

Here is the mold completed.
View attachment 89305
And during use
View attachment 89306
Results
View attachment 89307

Those bullets are 0.612 for an original rifle I have.

Training here.

Great brass mold BS

I've since tested my new mold. This one casts undersize
It makes no sense for mold sized 15.57mm(0.613) to cast 15.63mm(0.615) bullets, and another mold made of the same material casting the same alloy at same temperature mold sized 15.13(0.595) to cast 15.02(0.591) bullets.

I suspect I must have somehow had a burr in my first mold during measuring. Which explains why it was cut oversize despite using pin gauges.

That is not a big problem. I want to test slightly undersize bullets too. Then I can always put the mold back on the lathe (using a 4 jaw chuck) and cut it a little more if required.
[/QUOTE

Great brass mold BS

I've since tested my new mold. This one casts undersize
It makes no sense for mold sized 15.57mm(0.613) to cast 15.63mm(0.615) bullets, and another mold made of the same material casting the same alloy at same temperature mold sized 15.13(0.595) to cast 15.02(0.591) bullets.

I suspect I must have somehow had a burr in my first mold during measuring. Which explains why it was cut oversize despite using pin gauges.

That is not a big problem. I want to test slightly undersize bullets too. Then I can always put the mold back on the lathe (using a 4 jaw chuck) and cut it a little more if required.

Hello from London in the rain. I just fitted a spare £7 Aldi vernier to the little east German lathe it’s actually very Good. I can now accurately put groves in bores Also I can grove jacketed bullets for my .36 double ML. Thought you might be interested. The elastic band works well too. Enjoy

 

[Ironoxide]

Good work with the grooves and the dro

I remember when those cheap electronic calipers came out first. I bought few to reverse engineer. I found all of the electronics is in the slide and they use a simple capacitive sensor in the ruler that can be replicated with a pcb. So I measured the original and I replicated the sensor design on a meter long pieces. I had a pcb company fabricate 5 of those and they worked with original slides

Unfortunately this was so long ago I didn't have any machines to put those "dro's" on and I stored them somewhere for safe keeping. They were stored so safely I'm still looking for them from time to time

I tested bullets from the latest mold and it seems the size is correct so I'm quite happy with it.

I'm also hoping to be able to get some free machining steel to test in near future. If it cuts well I'll post about it.