1-1/4"-12 rethreaded to 1-1/2"-12 - Lee Classic Cast Press Modification?

[treysoucie]

would it be possible to re cut the 1-1/4"-12 thread to 1-1/2"-12 thread to use a broader range of 1-1/2" 50 bmg dies? Not sure there will be enough material to pull this off.....

[joec]

Why not simply buy the 50 BMG parts for that press which would be $132 plus shipping as shown below. With this no need to even try to resize the 1 1/4 to 1 1/2 size as well as it will work fine without giving up the press as is.

https://fsreloading.com/lee-precision-2-die-set-50-bmg-90515.html
https://fsreloading.com/lee-precision-50-bmg-shell-holder-90903.html
https://fsreloading.com/lee-precision-50-bmg-ram-prime-90901.html

[fishhawk]

simple answer is no! how do you expect to go from 1 1/4 inch stock to 1 1/2 inch? Now if it was 1 1/2 to 1 1/4 that would be different.

[treysoucie]

Guys there is a 1-1/4" diameter #12 thread hole for lee propietary dies. I do not want to use lee dies i want to use 50bmg industry standard 1-1/2" diameter #12 thread

[fishhawk]

If you have a 1 1/4 hole and going to 1 1/2 hole would be pretty close not sure of the minor thread dia. there. biggest problem I see is alignment to keep the dies and ram strait

[Catshooter]

trey,

Welcome to the forum.

Without trying to be a smart aleck, this is one of those questions that if you have to ask I'm pretty sure you can't do it.

Unless you're just asking if it could be done, not if you could do it? Sorry, but I can't answer as I don't have a Lee press to measure.

There are usually two ways to this sort of thing, drilling and tapping by hand or setting the press up in a machine (lathe or mill) and doing it with power.

Is this press cast iron? I think it may be. If so, doing it by hand would probably be out as it takes quite a bit of power do both drill and tap that large, even in cast iron.

If the press has enough iron in it to make it work then it could be set up in a machine tool and then drilled & tapped. Cost some money though.

Hope this helps.


Cat

[Norbrat]

In theory, it is quite feasible to open up a 1 1/4" x 12 to a 1 1/2" x 12.

The theoretical tapping drill size for 1 1/2" x 12 would be 1 1/2" - 1/12" = 1 5/12" = 1.417"

This is bigger than 1 1/4" = 1.25"

So, yes, the tapping drill would completely removed the 1 1/4" x 12 thread.

So now the question is, is there enough "meat" in the press where you want to open up the thread. Personally, if there is about 1 3/4", I would consider it more than strong enough.

If you have the machinery to ensure alignment and the power to do the threading, go for it.

Of course you will also have to make an adaptor if you want to use 7/8" dies in it.

The worst that can happen is that you ruin a $150 press.

[bbqncigars]

Naaah, the worst would be ruining the press and the tooling you're modifying it with. Which could easily cost more than the press itself.

[treysoucie]

Thanks for the info guys. if its possible think i may attempt it if it makes sense to do so monetarily.... i will get some prices locally for a machine shop to do the work. i won't be doing this myself. if the cost is too high i will just go with an rcbs ammomaster which will be about an extra 150 bucks.

[Norbrat]

Naaah, the worst would be ruining the press and the tooling you're modifying it with. Which could easily cost more than the press itself.

Yeah, that's true! :???:

While I work in an engineering workshop, my role has nothing to do with shop floor supervision, so broken tooling is not my problem and I tend to forget that. [smilie=1:

[treysoucie]

What kind of machinery/ tools would i need to accomplish this?

[gunoil]

lock nuts want go on if ya drill/tap.

[country gent]

Id3eaally a big jig bore or Mill will do the job. At a macnineshop your going to have to make sure they understand the alighnmant issues or it will get ran thru a drill press and hand taped. The set up and tad are going to be expensive. The dril they may have or can drill close and bore to finish size. While a simple procedure to tell its not simple to hold alighnment, location nad square, to these tolerences. And it is expensive.

[dragonrider]

Yes it can be done, not difficult. I believe I have the tap. Send me pm and we can talk.

[Mal Paso]

Do you really want to remove metal from a machine that was engineered to minimum standards?

Not being smart, but.............

[jmort]

"Do you really want to remove metal from a machine that was engineered to minimum standards?"

Classic example of ignorant throw-away bashing of Lee Precision. What evidence do you have that the press is "engineered to minimum standards?" None, but it sounds good if you are intending to gratuitously bash Lee Precision. It may be that the proposed modification is unwise. If you took the time to read Modern Reloading by Richard Lee, you would see a Turret Press with all four structural supports turned-down to a tiny minimum and the press is still functional. The Classic Cast is robust in design and construction, which is why it is the highest rated single stage press regardless of price at Midway USA.

[Mal Paso]

"Do you really want to remove metal from a machine that was engineered to minimum standards?"

Classic example of ignorant throw-away bashing of Lee Precision. What evidence do you have that the press is "engineered to minimum standards?" None, but it sounds good if you are an ignorant low information reloader. It may be that the proposed modification is unwise. If you took the time to read Modern Reloading by Richard Lee, you would see a Turret Press with all four structural supports turned-down to a tiny minimum and the press is still functional. The Classic Cast is robust in design and construction, which is why it is the highest rated single stage press regardless of price at Midway USA.

Based on all my Lee Equipment, I would not remove metal then do 50 BMG.

I am sure the Lee casting is fine for it's intended purpose.

[treysoucie]

would boring this out on a drill press and hand tapping it for 1-1/2 12tpi be precise enough for a reloading application? I imagine any inaccuracy in squareness of the hole to the ram stroke would cause an imperfection/warped round when I size them, press the bullets or apply crimp?

[375RUGER]

How much "meat" beyond the 1-1/4" do you have to play with now, at the thinnest section? Will the 1-1/2" thread break through anywhere? There is probably a reason that Lee only put a 1-1/4" thread to begin with. If you screw it up you're only out $103 anyway, right?
If you're going to bore it out on the drill press you should at least get the threads started with the tap chucked up too.

[45-70 Chevroner]

The stroke for the Classic Cast Press is only 4". My concern is, the 50BMG is quite a bit longer than that, is there something I am missing here?

[treysoucie]

apparently you need to "angle" the 50 bmg case to fit it into the press... the 4" stroke is fine

[joec]

The stroke for the Classic Cast Press is only 4". My concern is, the 50BMG is quite a bit longer than that, is there something I am missing here?

Lee has a piece that you replace the shell holder and part of the ram below that or the slotted part for the primer feed. I've never used the setup but did see how it might work. If you look at the top of the shaft and how Lee is setup to replace it might help. Once it is setup you have almost 5" of distance.

Check out the in larged picture here https://fsreloading.com/lee-precision-50-bmg-kit-90859.html

[cwheel]

One thing that hasn't been addressed yet. If you have adequate wall thickness after the 1.500 X12tpi to do this, ( I don't have Lee presses, I have RCBS ) you need to be careful with alignment of the bore. I wouldn't tap this one, I'd single point thread it in a lathe. Setting it up would require a " spud " be cut that was a tight fitting thread to the existing 1 1/4 X 12. This thread would extend to a precision smooth shaft at least 6" beyond the top of the press. This would allow " dialing in the bore " that the existing thread is in. If you miss center here, none of the dies will align. Your press would be scrap at this point. I'd then bore on the lathe to the bore size for the thread. ( 1.417 ) I don't care how you try to drive a tap through this one, you aren't going to stay on center unless you single point the threads. Not a big deal for a machinist, couple of hours. But shop time around here runs $200+. Way better off doing what joec suggested. Can't mess up the press this way with a buba job. The kit would be half the labor at a machine shop.
Chris

[rr2241tx]

The Lee setup works just fine once you have de-milled brass. In my experience depriming military brass is best done with a punch and cup which you can buy or make. The first full-length sizing of military brass needs a lot of Imperial Sizing Wax and is best done in several small increments. When the brass stops going in, back it out and re-lube. That will also show you where all the weak points in your mounting are. You do have to tip the brass in to clear the decapping pin. Epoxy the ball to the handle. The Lee dies are as good as any. If I was going to compete and make a lot of 50 BMG, I'd buy an Ammomaster and get all my crying done up front.

[treysoucie]

Well I am getting a Hollywood afterall... actually the one for sale on this board...

[theperfessor]

Getting a more appropriate press is probably a less costly solution to your problem. If it were my press and I wanted to do what you want to do I'd expect to spend 2-3 hours lining up the press on a milling machine table and then boring out the hole to the right size. I think I could tap the hole straight enough using a tap and guide on the mill. Add in the time to make a threaded bushing like the one that comes with a Rockchucker so you can use 7/8-14 dies, and I could easily spend half a day on the project. As a hobbyist I'm not out anything it time, if I did it for some one else it would cost $150-200.

Just my opinion, free advice is worth what you pay for it.

[bbqncigars]

I do most of my 50BMG reloading on my Lee CC. Initial resizing of milsurp M2 brass is via my Walnut Hill press (bought after breaking the CC linkage twice). The priming setup on the CC is as good as it gets w/o big bucks. Add two shaft collars to the priming punch and you have a very precisely adjustable primer seater for the fifty (assuming all primer pockets have been uniformed).

[Cap'n Morgan]

It would be an easy job on a CNC mill. Clamp the press on the table using parallel blocks. Probe the thread to find the center. Cut the hole and the thread using helical interpolation. One hour, top, provided the operator knows what he's doing.

[dkf]

would boring this out on a drill press and hand tapping it for 1-1/2 12tpi be precise enough for a reloading application? I imagine any inaccuracy in squareness of the hole to the ram stroke would cause an imperfection/warped round when I size them, press the bullets or apply crimp?

IMO no. If it was a job coming into my shop I would not only find the center of the hole but put an indicator on the ram to ensure it is square and the new larger thread will not be bored at an angle and is inline with the ram bore. Bore to diameter, tap with a center or use a thread mill and interpolate it. I figure anything worth doing is worth doing right. You have to expect to have to pay to get something done right. Although sometimes even when you pay the price it not done right.

IMO you are better off putting the money towards another press.

[ku4hx]

IMO you are better off putting the money towards another press.

When I was in the Navy, I was stationed on the USS Ranger - CVA-61. I came on board just as it was leaving dry dock in Hunters Point, CA in 1969. It had just been "refitted" with a new $100,000 central tool room which at that time was an enormous amount of money. Being a PO Machinist Mate, I visited that counter quite often. On one of those occasions, a fellow sailor was there wanting a wrench. The guy behind the counter kept asking what size and the young sailor kept saying it didn't matter. Finally in desperation, the fellow wanting the wrench blurted, "It don't matter; I'm going to use it as a hammer anyway". The tool room had many, many new hammers or all sorts but this guy persisted in wanting a wrench to use as a hammer. True story.

You're going to be better off putting the money towards the purpose-built proper tool ... another press.