I bought a RCBS Lube-A-Matic 2 and a LYMAN .459 sizing die. When I put the LYMAN die in the RCBS Lube-A-Matic 2 it appeared to be to long. The hexagonal die locking cap did not screw down all the way. It was approximately 1/8" from touching the top of the die cavity casting.

Without the locking cap being down all the way it also appeared to be crooked thus possibly not being aligned properly.

Mid-way claims LYMAN dies are interchangeable with RCBS dies but not having a RCBS die to try I would like to know if anyone out there has had the same problem.

Are the dies interchangeable or is my RCBS Lube-A-Matic 2 not drilled/bored out deep enough to accept the dies correctly?

Your help will be appreciated.

The bottom tapered part of the die makes a seal on the same tapered bore bottom inside the luber/sizer body. If you can, with the die and nut down as far as you can get it without forcing it, look at the bottom of the luber/sizer and see if you see that taper part seating. If it isn't, then the die body is just a tad fat. There's a hole that the die body meets down inside the luber/sizer body that guides that die to position it to seat both tapered seats like a valve. If you had other dies that fit without a problem I would tell you to mic the body on the one that fits comparing it to the one that doesn't fit.

Check that out and post back.

Joe

P.S Make sure that the bullet depth adjustment on the bottom of the luber/sizer isn't screwed all the way up towards the main body. You may have to screw it down to observe the hole I told you to look into to see of the two tapers are seating.

starmetal:

The bottom inside does have a taper/bevel and as far as I can tell the LYMAN appears to match. It seems to me that the LYMAN die is to long. If you have a 6 inch caliper please measure how long a RCBS dies is, and how long to the top of the tapered area of the die I may be able to determine if the LYMAN die is to long. Also is the center piston in the RCBS die the same length or is it about .25 inches shorter like the LYMAN die is?

The only reason I bought a LYMAN die is because Midway did not list a RCBS in .459 they only had it in .458

Thanks for your help it is greatly appreciated.

Mine is the same way but the hex nut thread is long enough to engage and tighten to hold the die in place. It's not ideal but it works.

Swede,

I measured a handful of RCBS and Lyman sizers. The length from the top of the dies to the beginning of the taper is approximately 1 15/32ths. I then measured the diameter of the body of the die right before the beginning of the taper is it about 22/32thns which would be 11/16ths.

I've read the same exact problem you're having on another forum, and in this fellows case he didn't have the bottom adjustment stop set down far enough.

Let me know how my measurements compare to yours.

Joe

Do the LYMAN and the RCBS dies appear to be the same length and have the same bevel? I had/have the bottom adjustment stop set down as far as it would go and the die still stuck out to far. Next time I will take the bottom adjustment stop off and see if it makes any difference.

T fix the problem die I ground the LYMAN die and ground it off for length in my Lathe so the outside is the same length as the piston inside and moved the bevel up on the die so it will go all the way in and I can now screw the hexagonal die locking cap down flush and Lube-A-Matic and die bevels match. It will now work with this die but if RCBS and LYMAN dies are the same outside dimensions then the RCBS Lube-A-Matic 2 wasn't machined deep enough to work with standard size dies. I sure don't want to have to do this to all future dies it is a serious PETA

I guess I should have stuck with RCBS dies and not tried to use a LYMAN die.

What you didn't tell me is what the diameter of the body of the die giving you the problem is. Measured on your calipers. If your adjustment on the bottom is screwed all the way down, that is sufficient and not the problem. I still think that your die body is too fat, or (hope not) the hole in the luber/sizer is too small.

I can guarantee you that Lyman and RCBS dies are close enough to be identical. I have about 50/50 mix of the two brands and have never encountered a problem.

I hope you didn't lathe the die unnecessarily.

Check the diameter of the body of the die. Like I said mine are about 21 to 22/32ths. If you had a micrometer I could give you an exact dimension.

Joe

One more thing. I assume when you "ground" the die in your lathe that you machined off some of the bottom end, that is the end with the taper. If you take any off the top you might get too close to that sealing O ring and being the dies today have a tapered mouth to ease the bullet into the die without shaving it, you may accidentally remove too much of that taper.

Joe

I didn't think to check the diameter of the die for clearance problems. I will have to pull the die out again and measure the diameter with my dial caliper. I will post the dimension.

I first ground the die bevel further up on the die without making it any shorter. I was able to make it go down far enough to be able to tighten the die locking cap enough so it touches the top of the die casting cavity. With this done I found out that I could not eject the bullet out far enough without grinding the die body to match the die piston length. I didn't grind on the top of the die for the reason you stated.

When you tighten the die locking cap on your RCBS-Lube-A-Matic does the cap sit tight with the die casting cavity?

Thanks a lot for your help

If it is a Lube-A-Matic lemon it may go back to RCBS

I'm almost positive you're going to find that die was fatter.

I have a Lyman luber/sizer, but there is hardly any differenc in them, they were closer to being alike years ago, but only subtle changes now. So to answer your question, the nut sets flush with the Lyman machine and probably pretty much should with the RCBS model.

You know that die only fits into a little bit of the hole on the bottom of the machine. The part of the machine above has a bigger cavity so that the lube can flow around the die and into the lube holes in it's body.

Joe

I measured the diameter of the die it is .702 and now is 1.479 long. Even if the die was not to fat/big the piston in the die center would not let the bullet be pushed up far enough. It had about .25 of the bullet left in the die and made it hard to remove without pliers. Since I am using a gas check on the bullet they would be pulled off also.

I plan on purchasing a RCBS die for a .430 bullet with a gas check maybe it will work properly.

I am also going to make a spacer/washer I can put under the die locking cap so it can be screwed down tight and square if the next die is to long. I really don’t want to send the Lube-A-Matic back to the factory especially without having seen another one with the die fitting properly.

Thanks for your help

I have had both Lyman and RCBS sizer/lubers and had both brands of sizing dies. I have been able to freely mix them either way. Sounds like there is something wrong with machine or operator if you cant????

After reading this last night, I took some measurements of both Lyman and RCBS dies. They are identical in dimensions:

length 1.558"
top diameter (above the O-ring) .722" to .723"
bottom diameter (lube area) .702

I've been making my own for many years, and I learned that the O-ring at the top is unnecessary. However, the taper at the bottom IS. If a die is too short, it is going to leak at the bottom.

As we know the little O ring on the top of the die was for when Lyman had the older luber/sizers that didn't use the nut to hold them in. Now depending on how precise your die fits inside the nuts, you may still need that O ring. More then likely not though.

quote:

Originally posted by 454PB:
After reading this last night, I took some measurements of both Lyman and RCBS dies. They are identical in dimensions:

length 1.558"
top diameter (above the O-ring) .722" to .723"
bottom diameter (lube area) .702

I've been making my own for many years, and I learned that the O-ring at the top is unnecessary. However, the taper at the bottom IS. If a die is too short, it is going to leak at the bottom.

Thanks for your information it is very helpful.

I had a RCBS Lube-A-Matic years ago but I sold it to a friend. His wife tossed it in the trash after they had a flood so I couldn’t use it for a reference.

I have a small lathe and have considered making my own dies. How do you get them to exact internal size such as .430?

After you machined the outside and bored the hole for inside diameter to a smaller size, you ream it to a .001 or .002 smaller then your desired size, which in your case is .430. Then you honed it with a very fine abrasive and preferably a brass rod to the final size. One of my friends does this honing with expensive diamond dust, which he recovers and reuses.

There is some controversy over whether you have to heat treat the die when finish and the general believe is no.

Joe

I do it about like Joe says. I use a split bolt with abrasive paper wrapped around it. Depending on how closely the last drill bit is to the desired diameter, start with coarse paper and gradually reduce that to crocus cloth. You have to really be careful when doing it this way, there is a natural tendency for the die to "wasp waist" because the abrasive removes more metal at the die entrance and exit than it does in the center. However, with some practice and experience it becomes easy, and the increased honing at the entrance becomes a handy taper for sizing. A guy that is fully equiped would use carbide boring bars, a toolpost grinder, honing reamers, etc, but it can be done sucessfully without the added expensive equipment.

I don't use anything but mild steel, and I don't harden them afterwards. I have some home made dies that have sized many thousands of bullets with NO dimensional change.

Right now, I'm building two sizing dies for my Star sizer. They are quite a bit different than Lyman/RCBS, but the procedure is the same.