Sprue Plate Adjustment with New Mold

[ColColt]

I have a Ballisticast mold that cast a great looking boolit but it's a real bitch to keep the tension the same on the sprue plate. I'll have it so it's swings loose on it's own and then tighten a bit then fill the cavities with lead. By then you can't hardly knock or push the sprue plate to cut the sprues. Loosen up on the tension by loosening the set screw and changing the sprue screw and all goes well for a few times and it's loose again or too tight if I try to tighten the screw.

I thought of cutting a notch with a file once I got it right and then later filing a flat on the screw but it seems it will only hold the right tension for a time or two of casting and then it changes again so, I've been hesitant to try that method for fear of filing the screw in the wrong place. Any suggestions?

[Catshooter]

Col,

Mmm. I think I'd take everything apart and clean the snot out of each and every surface.

Then I'd look (and feel) to make sure that all contact surfaces are smooth and burr free. Then reassemble and try it again. Alot of times I'll even run taps & dies over the threads to clean them up and return them to spec.


Cat

[ColColt]

Worth a try. This is probably, no- it IS the worse offender in this respect than any of my other molds. You just can't keep it adjusted once right. It slowed down my casting cadence drastically.

I have an old tap and die set but sort of doubt it's the kind that will fit the holes/screws in this mold. None of them are really that small.

[largom]

Had a similar problem on an old mold. I placed a belleville spring washer under the screw head, set my tension and then locked the set screw. The sprue plate would not swing on it's own but the tension stayed constant. The spring washers are available from McMaster Carr or MSC industrial supply.

Larry

[Le Loup Solitaire]

A sprue cutter plate should swing free on its own weight; that's a given. It has to lie flat on the tops of the blocks with no up and down slop. The belleville or wave washer helps keep it "honest". The bolt or screw that keeps the plate fastened to the blocks cannot turn; it must remain fixed. Some folks file a flat on/in it to keep it from turning. I dislike altering things especially when there is an alternate remedy. A sometimes overlooked little thing is that under the end of the bolt is placed a small piece of lead that looks like a miniature "split-shot"sinker that bears against the threaded part of the sprue cutter bolt and keeps it from turning without damaging (the threads) it. When this small chunk of lead (brass also works) is lost or absent the sprue plate bolt will not stay fixed and you get the situation that you have described....sprue plate keeps getting loose and you have to retighten it all the time. Check for the little s(t)inker and see if it is there and if it isn't make one and install it. It just may be the happy solution. LLS

[GLL]

Is your mold a 4-cavity? On all of my 4-cavity Ballisti-Cast molds the set screw does not set directly against the smooth portion of the pate hold down screw but attacks at a distinct angle. If the threads of the set screw are a bit buggered or the hold down screw smooth area is worn it could still rotate. Try another set screw and check for any wear once you pull both screws out.

Jerry

[ColColt]

It's a 2-cavity mold. The set screw is not worn and is much like your in that it screws in at the side more or less, of the plate's screw. The sprue plate screw has it's final 3/16" fairly smooth for the set screw to tighten against at an angle. You can see where threads were but that area is not entirely smooth, per se, but looks more or less like the threads have been purposely filed down.

A couple of my molds have the wave washer but most don't. Next time I'm at Lowe's I'm going to look for one.

[Horace]

Brass pull chain at ACE works under set screws also.

Horace

[ballisti-cast]

Check the surfaces of the mold and sprue plate that mesh and make sure there is no burs or lips. The parts are buffed, but it's very possible there is a burr that is giving you trouble. A board with some 180+ grit sand paper on it works great for taking a burr off but not scarring up the mold, be gentle though and sand the face of it as you don't want to take any edges off that are supposed to be sharp. Let me know when you get it fixed, need more help, or just can't seem to get it: sales@ballisti-cast.com

[runfiverun]

[StratsMan]

The MP-Molds I've bought have Belleville washers for uniform tension, but the screw hole for the sprue plate is also drilled short so the screw can be bottomed tight, plus have the retaining screw against the threads so the sprue plate always moves freely, but with tension from the washer... Nice feature...

But best thing I've seen is what Solitaire and Horace mentioned: a small brass plug in the retention screw hole. Then tighten the retaining screw firmly against the brass, and the brass plug conforms to the shape of the threads on the sprue plate screw without deforming those threads. That little piece of brass locks a screw in place securely.

[ballisti-cast]

The MP-Molds I've bought have Belleville washers for uniform tension, but the screw hole for the sprue plate is also drilled short so the screw can be bottomed tight, plus have the retaining screw against the threads so the sprue plate always moves freely, but with tension from the washer... Nice feature...

But best thing I've seen is what Solitaire and Horace mentioned: a small brass plug in the retention screw hole. Then tighten the retaining screw firmly against the brass, and the brass plug conforms to the shape of the threads on the sprue plate screw without deforming those threads. That little piece of brass locks a screw in place securely.

Right on with the brass or lead plug. Thanks for the trick. I'm going to make that a standard feature, and will look into the disc springs too. The disc spring is something that would come in the package with the mold so it can be installed if desired.

[Catshooter]

Y'all want to be a bit careful with the plugs under the set screws.

In my shop, lead shot does indeed comform wonderfully to any thread and does it without damage. But it often conforms too tightly, making it very difficult to break it free.

Brass on the other hand is a whole lot harder than lead and won't conform too tightly at all. And in using just a small brass plug under a set screw I've never had an issue. But I've seen RCBS dies that used a brass set screw. The flattened the tops of threads it was engaged on to the point where I had to file 'em to get the die to screw smoothly again.

So, Col, did you sort your mould out?


Cat

[DX250]

Why not use red Loctite as it is good to 550 degrees?

[ColColt]

I'll check for the burrs but don't recall feeling/seeing any as I cleaned it prior to the first casting. The washer works as I mentioned I have those on a couple more molds and have had little if any problem.

I haven't cast since the last time, Cat, so I won't know until I can procure the washer and double check possible burrs.

I don't think the red Loctite is a good idea on molds. BTW-where does one get a "small brass plug"?

[montana_charlie]

lead shot does indeed comform wonderfully to any thread and does it without damage. But it often conforms too tightly, making it very difficult to break it free.

Brass on the other hand is a whole lot harder than lead and won't conform too tightly at all.

If you have done any electrical work in your house, you may have some leftover wire of different diameters.
A short section of copper or aluminum wire makes a suitable insert.

CM

[Catshooter]

Col,

Charlie has your answer to the brass problem. Ten or twelve gauge copper works and I think it works even better than brass. Easier to get too.


Cat

[ColColt]

Just a few hours ago I cut a small piece of 12 ga and put it in the hole of the set screw, loosened the screw a bit and tightened up the sprue plate screw till it would barely swing of it's own accord and then tighten the set screw. It seems to work good but casting time will tell. I had thought I had several washers around here that would work but they were too big. Guess it's time for a trip to Lowe's or order online.

[canyon-ghost]

When I get one that loosens up like that, that's what I do. I tighten it just enough that it's tight when closed and swings open almost too good.

Small brass plugs? How about the brass flats for a micrometer case trimmer like the RCBS Trim Pro? Sounds similar.

[ColColt]

How about the brass flats for a micrometer case trimmer like the RCBS Trim Pro? Sounds similar

You totally lost me there. I have no idea what brass flats you're talking about.