Sprue Plate Design

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  • Last Post 12 October 2008
jimkim posted this 14 September 2008

I was wondering if any of you have made your own sprue plates. I want to make one for my Ranch Dog mould. I was thinking about making it .375” thick and connecting the pour-holes with a shallow channel. I like how the bullet bases come out when I shear one larger piece of lead as opposed to two small pieces. I want to build it with two adjustable set screws so I can use the plate to help square the mould when I close the plate. I even thought about putting a latch on one side. I know I haven't been doing this long, but I noticed things that I thought could be improved and started thinking about features I would like to see. Any input would be appreciated. After all I am new to this.

PS: The reason for that much thickness is because I want it rigid and I want to be able to true it up from time to time.

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vmwilson posted this 08 October 2008

I made a few for some single and double cavity moulds out of aluminum plate and was happy with them, though I don't presently have any moulds set up with em'.

The old NRA book of Harrison's discussed the advantages of aluminum sprue plates and it was a material I could work with my elementary tools easily enough.  It helps the sprue cool a little quicker I believe but since I've gone to using a cooling box for my moulds I don't get any problems with overheating anyway.  I'm too ignorant of machining to know how one cuts the trough, but assume that's a milling type job.

 

Mike

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JeffinNZ posted this 09 October 2008

Cheers from New Zealand

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jimkim posted this 09 October 2008

Nice piece o work m8! Did you you use a ball nose? The funnels look rounded. How thick is it? I think that is what I'm wanting.

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vmwilson posted this 09 October 2008

I used a standard hardware item countersink on mine with similar results.

Mike

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linoww posted this 09 October 2008

I did a similar thing as Jeff with a Lyman 225438 4-cavity.The original sprue holes were gianormus!!I had the original holes tig'ed up then filed and re-cut new smaller holes on my drill press with a center drill form a lathe.it is nice to have a sprue bump smaller than the base! Accuracy was unchanged,but with a 4-cavity 225438 how could i really tell<G>Castability was sure better though.

George

"if it was easy we'd let women do it" don't tell my wife I said that!

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CB posted this 10 October 2008

I made a sprue for a SAECO mold made for a Magma casting machine so I could use it with a ladle. I will have to try and get a picture of it today when I am out in the shop. I have also made several for a couple lyman molds and even an Egan mold I bought that didnt have one. I prefer to use cold rolled steel about 1/4 inch thick. I tried T-6 and 2024 aluminum but it warped. I have access to a surface grinder so I can do a very nice polish and true job on the bottom of the plate. Then I can polish it up with some 800 grit emery cloth as need be. I like the smaller sprue holes, makes it easier to pop by hand and I get better results.

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linoww posted this 10 October 2008

I like the smaller sprue holes, makes it easier to pop by hand and I get better results.

Another good point.If you get those enormous holes it make the “gloved hand trick” a little harder.But when you are not paying attention to your glove wear it sure is a surprise when the meat of your hand grabs the hot sprue plate!!I now have a glove with a heavy chunk of leather epoxied to the web so it takes longer to wear through.

George

"if it was easy we'd let women do it" don't tell my wife I said that!

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JeffinNZ posted this 10 October 2008

Thickness is 5mm.  Standard countersink bit did the job nicely.  High grade alum though ex an aircraft facility.

Cheers from New Zealand

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CB posted this 11 October 2008

Thats a good point George. I also have an extra layer of protection fixed to my glove to prevent the sprue from giving me another burn in the palm.

I have been using one of those “ovgloves” inside a standard harbor freight leather work glove that has an extra piece of leather from a previous glove stitched into the palm.

I went to popping the sprue by hand to reduce the “bump” in the base of the bullets and also to reduce the galling of the top of the aluminum molds by the sprue plates.

The only molds I swat with a leather mallet are the 6+ cavity models that are either Ideals or H&G and are mainly pistol molds. That is just more sprue than my old hands can break on their own.

On the sprue plates that I redesign I tend to make them similar to the configuration that Veral Smith of LBT uses because are easier to break by hand. I am a firm believer to a thicker sprue at least .250 simply because they are more resistant to warpage.

I cast hot, around 750 to 800 degrees so I can get by with a 1/8 for lino and up to 3/16 hole for higher lead content alloys. It is easy to start small and try it and then go a bit larger if it doesnt work just right.

I also try to cast only in the fall, winter and early spring. Sitting over a hot lead pot for 3 hours in 80 degree weather just doesnt do it for me, it is miserable. I would rather sit in the garage when it is 20 degrees outside and the garage gets up to around 50 with the lead pot going.

I cast around 10,000 bullets for competition each year and then 10 times that for goofing around with the pistols and other rifles I dont shoot in competition. With 3 people shooting competition you go through a goodly amount of lino and all of the goof around stuff I use reclaimed range scrap with some tin and a touch of antimony added so I keep pretty darn buzy casting.

Going through that many bullets each year it is easy to see why I work on my own bullet lube.

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runfiverun posted this 11 October 2008

you can use the magma sprue plates for handcasting you just gotta hit them to the left then back to the right.

left breaks the sprue loose and right opens it.

figured that out when i ruined a sprue plate by ovaling a hole i was opening.:shock:

  gotta tighten the vise before drilling..>

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CB posted this 12 October 2008

I did that for a few bullets and decided this is nuts and went at designing a new sprue to accompany the adapters I had to make to get them to fit on RCBS handles. A bit odd looking, but they work.

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