Lapping out H & H sizing die - how to measure when done?

[huntinlever]

Dumb question but I've totally forgotten. I will be sizing a 405 grain to .460 using the Lee sizer. I'll only be lubing with the LAM and the H & H sizing die I have is 459, so I want to open it up to .461. IIRC I used a dowel and some fine emory, perhaps with a touch of oil. I went bit by bit and at some point it was perfect. I just can't remember what I used to determine when I'd opened the die out to the right dimension.

I have calipers for outside dimension but nothing for inside....how do you guys do it?

[Polymath]

Well, I have made a few sizers and the trick is to get close and then size a few, check diameter. Proceed until desired size. Remember it is a taper ID, and narrower at the top (if using a Lee push through) Luber sizers tend to be cylindrical. I find there will be some spring back so it's important to stop and check when you get close. The final result is what matters. I modified a Lee 405 Sharpes mold RNHB. Turned it into a wide flat nose for tubular rifles. I easily lube them by hand with Goblin Snot and then size them. With opening up the sizer a bit you have to watch for chambering issues. Good luck.

[huntinlever]

Well, I have made a few sizers and the trick is to get close and then size a few, check diameter. Proceed until desired size. Remember it is a taper ID, and narrower at the top (if using a Lee push through) Luber sizers tend to be cylindrical. I find there will be some spring back so it's important to stop and check when you get close. The final result is what matters. I modified a Lee 405 Sharpes mold RNHB. Turned it into a wide flat nose for tubular rifles. I easily lube them by hand with Goblin Snot and then size them. With opening up the sizer a bit you have to watch for chambering issues. Good luck.

OK, thanks. I know the case has a slight taper but wasn't aware the bullet does as well, though I should look more closely at boolit specs. My gg slugs out at .458, to give me a bit of play with changing alloys Tom is making the mold at .461, I planned to size the Lee at .460, and just lube the boolit with the LAM and die at the opened-out .461 from its OEM .459.

Given the H & H die is the proper taper (sounds like, anyway, if I've understood you correctly), I'm wondering if I should just leave it alone at .459, and accept only a 0.001 overbore rather than the 0.002 I used previously.

[Tim357]

huntinlever, I believe Polymath was referring to the inside of the sizing die is to have a taper. That's to facilitate pushing the boolit thru with a steady narrowing, as a funnel. The boolit will be cylindrical once it leaves the sizing die

[huntinlever]

Oh, lol, thanks. Yep, now I see that its narrowest diameter will be the boolit's final diameter.

If the sizing die is somehow opened to .461 (evenly - not sure how to make a cylindrical chamber when it's slightly tapered, now), and it's sized at ..460 out of the Lee, i.e., used only for lubing the bullet - that will work, right? Should I just size them at the Lee, incrementally open up the luber-sizer die and put test bullets through the LAM so that barely any resistance is felt, and the bullet goes down snugly but without any actual "sizing," would that work?

[Willie T]

It is not gonna take much. .001 all the way around will give you the .002 to get to .361 from .359. That is not much. Chuck a bore mop of the appropriate size in your power drill with lapping compound and run it in the top end and polish it. Go slow. Clean it out and size a bullet. Repeat till you get there. Go slow.

[oley55]

if you really need to known the size, slip a pin gauge in there. But know those pin gauges are as close to perfectly round as is reasonably possible. Consequently, the opening you just opened up with a dowel and emery cloth is surely not as perfectly round as the pin gauge will be. Meaning the pin gauge is going to tell you what the smallest portion of the opening is.

You can buy individual pin gages from the known and respected gauge manufacture but it is hit or miss on what gauge/s you will need at .001" increments. A Chinesium gauge set can be had on fleabay for less than $100 that will serve for many uses. I got a set for use in measuring/honing revolver cylinders.

Guess what I'm saying is a set of Chinesium pin gauges can be used for many purposes. On the other hand MICing the bullets pushed through the die tells you exactly what you need to know, Alloy spring back being real life versus having your die measure exactly .XXX" isn't telling you what size your boolit will be. note: MICing means using a micrometer not a caliper.

[oley55]

It is not gonna take much. .001 all the way around will give you the .002 to get to .361 from .359. That is not much. Chuck a bore mop of the appropriate size in your power drill with lapping compound and run it in the small end and polish it. Go slow. Clean it out and size a bullet. Repeat till you get there. Go slow.

I am not following how .001" off the diameter equals .002". We are not talking about using a lathe and taking off .001" which gives you .002". He is honing and measuring the finished diameter or I am way confused.

[woody1]

I am so confused. Why not size and lube with the LAM? One H&I to hone out and done. You don't have to measure the diameter of the die. Measure the boolits that come out of it becsuse some spring back is likely. Or am I missing something? Regards, Woody

[BK7saum]

It is not gonna take much. .001 all the way around will give you the .002 to get to .361 from .359. That is not much. Chuck a bore mop of the appropriate size in your power drill with lapping compound and run it in the top end and polish it. Go slow. Clean it out and size a bullet. Repeat till you get there. Go slow.

I am not following how .001" off the diameter equals .002". We are not talking about using a lathe and taking off .001" which gives you .002". He is honing and measuring the finished diameter or I am way confused.

0.001" of material removed all the way around (circumferentially, NOT diameter) is 0.002" off of the diameter.

He was illustrating how little material has to be removed from the inside of the die to get the increase in diameter.

[huntinlever]

Hey Woody -

I know it's an extra step, I just found it was easier to size and mount the GC's first with the Lee, then just lube with the luber (at the time, Lyman 450). I'm sure it works great both ways, just had good luck this way.

[huntinlever]

So - plan to do the "lap-lapping" with split dowel and first, 400 wet-dry and a little oil (leaving some room for the final polishing with 600 grit), then slugging either with one of my old boolits or some lead balls, like bore-slugging. Rinse and repeat until done.

Is that a good plan?

[lar45]

H&H is Holland & Holland, the sizer die is H&I

I agree with polish, size and measure the slug. You will probably get some spring back, so measuring the slugs will give you the closest measurement for your end product.

[huntinlever]

H&H is Holland & Holland, the sizer die is H&I

I agree with polish, size and measure the slug. You will probably get some spring back, so measuring the slugs will give you the closest measurement for your end product.

Lol, tad different, the .375 Magnum and this sizer die...!

Thanks. Will do. For the lapping, is a standard gun oil OK to use, or should it be something lighter?

[murf205]

Paul, those Lee sizers are softer than you think. It wont take a whole lot of lap-lapping to get where you want to go. I was surprised how little it took to get .001".

[huntinlever]

Paul, those Lee sizers are softer than you think. It wont take a whole lot of lap-lapping to get where you want to go. I was surprised how little it took to get .001".

Hey Murf, thanks. I'm actually planning on leaving the Lee sizer alone because with a bore at 0.58, I've had good luck with the .460 of the Lee. It's the H & I sizer luber die I want to open up a tad because I have one at .459", which is the widest I've found. Most I've seen are actually 458 in my experience.

[Larry Gibson]

If I wanted to increase the bullet size after sizing I measure the diameter of the sized bullet and determine from that how much I want to hone the "H" die out. In your case if the bullets are sized .459 and I want them .461 then I want a .002 increase in sizing. I would then measure the diameter of the "I" die (the push rod) after removal and order a pin gauge .002 over that diameter. I then chuck the "H" die in my lathe turning it it a low speed while honing it out. I frequently stop honing, run a patch through the "H" die and try inserting the new pin gauge. When the new pin gauge is a tight fit I then polish the hole. I then make the pin gauge into a new "I" die for the honed out "H" die. I slightly cup one end of the pin gauge and shorten it to the original "I" die length. The final fit of the "I" die is then similar to the original "I" die in the "H" die before honing so I get minimal lube flow up around the base of the bullet and out the bottom of the "H" die. Those that have honed out "H" dies and used the original "I" die know what a PITA that excess lube flow can be.

[huntinlever]

If I wanted to increase the bullet size after sizing I measure the diameter of the sized bullet and determine from that how much I want to hone the "H" die out. In your case if the bullets are sized .459 and I want them .461 then I want a .002 increase in sizing. I would then measure the diameter of the "I" die (the push rod) after removal and order a pin gauge .002 over that diameter. I then chuck the "H" die in my lathe turning it it a low speed while honing it out. I frequently stop honing, run a patch through the "H" die and try inserting the new pin gauge. When the new pin gauge is a tight fit I then polish the hole. I then make the pin gauge into a new "I" die for the honed out "H" die. I slightly cup one end of the pin gauge and shorten it to the original "I" die length. The final fit of the "I" die is then similar to the original "I" die in the "H" die before honing so I get minimal lube flow up around the base of the bullet and out the bottom of the "H" die. Those that have honed out "H" dies and used the original "I" die know what a PITA that excess lube flow can be.

Well, that seems just about ideal Larry. Unfortunately I don't have a lathe and zero of the experience to use one if I did. I am starting to think I was just lucky - with the hand lapping, the old Lyman 450 performed perfectly, effortless and great looking lubing. I can understand what kind of fun lube splooging out the sides must be.

Starting to wonder if a local machine shop is the better option.

[Larry Gibson]

Might just look at getting a Pin gauge the fits the lapped out H die.

[huntinlever]

Might just look at getting a Pin gauge the fits the lapped out H die.

I'm intrigued Larry - but not sure, how would I do the process without a lathe?

Hi Larry - I found a pin gage at 0.461 (-) 0.000-0.0002. Are you just saying go ahead and hand lap, but use the pin gage in place of slugging the die, then replace the gage for the "I"? If so, awesome. How do you actually cup the end of the pin, without machining tools?