New sprue plate for an old Ideal mold

[Pistolero]

I got an old Ideal mold at a gun show, cheap, because it was missing the sprue plate and screw.

I have spent some time sawing and filing out a new sprue plate from 4130 0.125 plate today. I was getting
ready to drill the hole for the screw, so I needed to know the size, and decided to check the thread
pitch too. OH darn! This one is a mold block integral with the handles, so pretty early, and clearly before
there were standardized screw threads. The screw is #10-36. Eric at Hollowpoint Mold Services sells them,
and I started to order one - with the washer, for $3.00, pretty reasonable for a very oddball screw......
That stopped when I got to the shipping. $9 shipping, meaning it would be a $12 screw. Nope, not
biting.
So tomorrow I will be single pointing a 3/4" long 10-36 screw.....a challenge, no doubt, but better than
paying $12 and I will learn somthing, no doubt. Fortunately, I don't have to make two of them, the locking
screw on the side is present, and is also 10-36 pitch, which helped a lot in identifying what it was. Far
easier to measure the pitch on a screw than in a hole!

The mold is the 36072 which casts a .360 nominal RN bullet and has a nominal weight of 110 gr. Ideal
catalog calls it a 'light target bullet' for .38 caliber, should be nice in my Colt Police Postive .38 S&W
which is a good shooter, quite accurate.

Papa Roseannadana was right.

Bill

 

[Brad]

If it isn’t one thing it’s another.....

Making a screw isn’t too bad. 36 TPI is pretty dang fine threads.

I made a plate from 7075 and so far it is doing fine. Pretty nice stuff to work with too.

 

[Pistolero]

Years ago with the Sheldon, I made an adaptor between my camera and a telescope.
This meant threading a thin wall 2" OD aluminum tube to, IIRC, 48 TPI. I got that to work
just fine, I can do this. But it is pretty fine.

I believe Papa Roseannadanna said, "It's always something." pretty much the same sentiment
as what you said. Yes, aluminum is easy to work with. This wasn't bad, the thing is fairly
tiny. 7/8" by 1" mold, add in the tab and the biggest dimension is 1.5" on the sprue plate.
It's a shame Eric can't drop it into a padded envelope. It would actually mail for about $0.65,
or so and if he charged $2 or $3 shipping I'd be a customer.

Bill

 

[KeithB]

What kind of material do you plan to use? Do you plan to harden it?

 

[Jeff H]

..................It's a shame Eric can't drop it into a padded envelope...................

He might. I've asked people to do that before and they've obliged - and I bought from them again. When they say "no," I just say "OK, thank you" and keep shopping. Hamilton Bowen goes so far as to mention (at least he used to) on his site that he would do that for really small items.

 

[Pistolero]

I'll use 4140, and no, I will not harden it. 4140 will be fine in the normalized condition.
I have it in stock and it cuts pretty nicely, strong enough. The plate itself is 4130, again,
because I have it in stock.

Bill

 

[KeithB]

Thank you.

 

[Pistolero]

What is your opinion on those alloys for those applications, Keith?

 

[358156 hp]

Red River Rick makes a really great sprue plate for the old small block Ideal single cavity moulds. I think Erik stocks some of them, or did in the past. I will say that they don't look like the original sprue plates, it's much thicker, but it comes with the mounting hardware. http://kal.castpics.net/Molds3.html

 

[Brad]

I have a Lyman 4 cav plate by Rick. It is set up with a lever like the Lee 6 cav. I also have his handles for the Lyman 4 cav that pivot like normal.
Rick’s stuff is top notch.

 

[KeithB]

I think its a great choice for both. Plenty strong enough, don't need to harden the sprue plate, just wondering if Lyman used a hardened screw. It would self-temper at 400+F mold temps if you quench hardened it. Probably not necessary at all. But I know the attention you pay to things and I was just curious.

 

[Pistolero]

That was what I was thinking about hardening, Keith. I may go ahead and harden the screw, thinking
a bit more, since the lock screw bears on the threads to lock it in position. Otherwise, it should be fine.
But it would make the theads more resisant to damage from the lock screw. My initial view was only
from a strength standpoint.

And tempering at 450 or so should still leave it fairly hard. The only reason for the chrome moly plate is
that I have some sheets of it around for other purposes, and it has a good surface finish to start with.

As far as Red River Rick....wish I had known that to begin with, would have ordered the setup. At this point
I am 2/3 done so will continue on.

Bill

 

[Brad]

What did you use to countersink the plate for the fill hole? What angle in particular?

 

[Pistolero]

I have not done that yet. I have some counter sinks but I wonder how well they will
stand up to this. Any suggestions?

Oh wait!
I have a really nice rivet countersinking microstop setup that will do a bang up
job on this, has hardened piloted cutters. I hadn't thought of that until just now.



The top item allows you to cut the countersink to a controlled depth in 0.001" increments. Used for flush riveting
aircraft. In stock and will do fine, even though they normally are for aluminum. The cutters last forever on
aluminum, may take some wear in cutting steel but are pretty hard.
Just grabbed a web pic, but mine is about the same.

Bill

 

[Brad]

I am leaning towards buying a 100° countersink, 3/4” head. Should be about right.
If it wasn’t such a pain I would just throw it in the lathe chuck and cut the taper that way. Just too much hassle for a multiple hole plate.

 

[Pistolero]

Aircraft rivets are most commonly 100 degrees, but other angles are available.

Aircraft Countersink Cutters | Counterbore Pilots | Spotfacers | Yardstore

Aircraft countersinks with 1/4" x 28 threaded shanks for every application. Yardstore has a large selection of sizes, angles, and diameters. Materials to choose from include high-speed steel, cobalt, carbide-tipped, and solid carbide.

www.yardstore.com

And available in carbide at substantial cost increase.

Check out Airparts, they are local, can get used stuff at huge discount, comes out of
Wichita surplus from the airframe makers.

Aircraft and Vintage camper building supplies - COUNTERSINK CUTTER

COUNTERSINK CUTTER *surplus* High Speed Steel 1/4' -28 Threaded Shanks 100deg For Use in Micro-Stop Countersink Units

www.airpartsinc.com

 

[Brad]

Looked at Airparts. Price is right but they are awful small in diameter. With a 1/4” thick plate I calculate that a 100° countersink with end up making a roughly 1/2” hole on the top of the plate.

 

[KeithB]

Might want to look at a 90* countersink. A 100* only gets you 5* less angle which I don't think makes much difference cutting lead but really widens the top of the hole out.

 

[Brad]

That is part of what I am looking for Keith. With a 1/4” thick plate I would like a 1/2” or bigger hole at the top. That is based on plates I have looked at. Not sure how to accurately measure the angle on things like an NOE or MP plate.

 

[freebullet]

Not sure how to accurately measure the angle on things like an NOE or MP plate.

Me either, but I've quickly learned precision machining involves more complicated math than a math class, so that made me chuckle. Least we can learn good.

Really no help for Bill either. Had to buy a 5/16x36 hole tap to make hornady modified cases myself, least you got a lathe to do'er. Best of luck.