Lyman sizer die question

[johnh57]

Not being able to readily find a .452 sizer without resorting to ebay I decided to try and turn one on the lathe. I've read, I think, that the groove below the o-ring is for the #45 sizer set screw. Since I'm using a 450 that doesn't use the set screw do I need to mess with the groove at all? Or does it serve some other purpose like a lube overflow reservoir or some darn thing?

What about the o-ring? Is that necessary?

I have the body and top lip turned, I have the .452 id and a slight taper leading into the bore, (my .457 sizer is 0.020 oversized at the mouth of the die and tapers to .457 at about 0.220 depth, I pretty much copied that.) I thought I'd wait on drilling the lube holes and see If I can locate them to match up with the lube groove on the bullet (Lyman blocks - 200 gr swc design). I have actually already done the set screw groove - but if I need to do it again I'll leave it out if it isn't needed.

The o-ring groove has me thinking a bit. I'm not exactly sure how to freehand grind a tool with a 0.032 radius on it.

John

[country gent]

I would grind a tool.064 wide and with a coarse arkansas stone hand stone it on. Luffkin, starrtet, browne and Sharp along with you chinese makers all make radious gage sets also. A .064 drill bit could be forced into a grinding wheel thus forming the radious to grind the tool also. To polish and clean up the finish a string with lapping compound does a great job.

[johnh57]

That should work, I have a blank 5/16" HSS bit that I can worry down. The string and lapping compound is good tip - thanks!

[detox]

The large pin that rides thru the Lyman die is ground concave on the end just in case you have a boolit with raised sprue plate cut. This seals the boollit base better so that less lube will get on base of boollit. The RCBS versions are ground flat.

[454PB]

I make my own sizing dies, and I don't put any grooves in them. I've found that the O-ring groove is not needed if the die is a correct fit for the sizer, and the threaded nut fits tightly over the top of the die. That nut is actually a lube seal, and the snug fit prevents the relatively low lube pressure from leaking past.

You are going to have problems drilling the lube holes without raising burrs on the finished ID. I always drill the lube holes before the inside dimension is finished, usually right after a pilot hole is drilled in the die.

[johnh57]

Thanks 454- I was wondering about the lube holes. Oh well, there's always Mk II! I am using stressproof 1144 for the stock.

Hopefully I can make a couple passes with the sandpaper / rod and clean them up. I bored the hole to within about 0.003 and then used an aluminum rod and wet/dry paper wrapped tight to clean up the bore and dial in the diameter.

Been an interesting first try. Could probably make the things - for about $200 !

[country gent]

A fited brass rod with lapping compound to finish the bore Possibly. Drll and reame a small taper pin hole in the end add a taper pin. Lap with this when becomes loose give pin a couple of taps deeper and it enlarges the od slightly to slowly remove more.

[detox]

With my RCBS Lube-a-matic some thinner lubes such as SPG leak out from everywhere. Be sure to fit to tighter toleances to prevent or reduce the mess.

[Faret]

What angle is the taper? I might make some of my own too.

[johnh57]

my .357 and .457 Lyman sizers both taper 0.010 x .220 (0.020 on the diameter) it works out to a whopping 2.5 degrees [arctan(.010/.220)]

[Faret]

Thanks John should have asked about the bottom too?

[johnh57]

I get 30 deg on the bottom angle. Corners are a bit rounded on my factory sizers which makes it hard to get a very good number.

I cut mine at 30 - but haven't yet had a chance to put it in the sizer to check fit.

[JMtoolman]

Just cut the O ring groove with a flat bottom, just allow for .005 to .010 compressing of the O ring upon seating. It doesn' need a round bottom to work. An old machinest.

[johnh57]

yes, but it's way harder to do it the other way! Flat bottomed groove would probably seal better anyway - more compression.

The o-ring groove came out fine. Now I just need to figure out how to get the id right.

Next one of these I make I think I'll leave out the o-ring and set ring and see what happens.

[johnh57]

Todays project was fitting the inner pin, making a nose punch, and making a guide for drilling the lube holes. I did learn one lesson, if you run a 4' piece of 1/2" bar stock through the tailstock on the lathe - it's a bad, bad idea to run the thing at 800 rpm :mad:

Thinking about making a copper or aluminum slug to insert in the die body to minimize burrs from the drilling operation.

Hopefully I can cast a few boolits with my still handleless blocks to see how well this thing works.

[JIMinPHX]

A few years ago, I posted a drawing for those things. If you use the search function, you may be able to find it.

I concur with JMtoolman. O-ring grooves do not need to be round at the root. Square cut grooving tools work just fine.

One little trick that I sometimes add is an O-ring groove on the piston. That sometimes helps to prevent extra lube from oozing up around the sides. It also lets you share a single piston between a few close sized dies.

[johnh57]

Thanks Jim, looked for the dwgs - couldn't find them, but i'll keep looking. If I'm going to make many more of these things I'll need to find a better way to create the bore. I used a modified boring bar followed by a dowel and wet/dry paper, followed by scotch brite. Decent bore - but probably not real uniform in diameter. Maybe a bronze piston with lapping compound.

[Cane_man]

Todays project was fitting the inner pin, making a nose punch, and making a guide for drilling the lube holes. I did learn one lesson, if you run a 4' piece of 1/2" bar stock through the tailstock on the lathe - it's a bad, bad idea to run the thing at 800 rpm :mad:

Thinking about making a copper or aluminum slug to insert in the die body to minimize burrs from the drilling operation.

Hopefully I can cast a few boolits with my still handleless blocks to see how well this thing works.

do you think i can use brass for the inner pin, or would it be to soft?

[454PB]

Brass will work fine, all it does is eject the sized boolit. I make my dies from cold rolled, and none of them has ever changed dimensions from being too soft.

[Cane_man]

^^^ excellent... i opened up my Lyman die some and now a little wax oozes out on the base of the boolit when i crank on the pressure nut, so i need to make a new pin now that fits better

[johnh57]

Tried it out today - seems to work fine - boolets are actually round! A tad undersize, 0.4515, so I may need to open them up slightly.

I put the lube ports at 120 deg. apart for no particular reason. The Lyman lube takes a bit of pressure to fill the groove at that diameter probably should have just gone with the 90 deg. version on that large of boolit.

I did machine down a slug of bronze to act as a backer when I drilled the lube ports - worked fine, no burrs at all on the id.

[Gliden07]

Midway had RCBS dies in stock last week?? I heard that they fit the Lyman press but sometimes you have to cut the bodies down a little to get them to fit correctly? With a lathe this would be easy for you? Just a thought!

[JIMinPHX]

Thanks Jim, looked for the dwgs - couldn't find them, but i'll keep looking.

It was pretty well buried.

Post #97 (about 3/4 of the way down the page)
http://castboolits.gunloads.com/showthread.php?48453-Adventures-in-top-punch-making-%28Long%29/page5

[johnh57]

Thanks Jim - pretty close to where I ended up. I did open it up slightly as I was getting a touch of leading. I opened it about 0.0005 or so and have not seen any leading. Shooting 200 gr SWC BB bullets at about 920 fps. I also countersunk the piston to seal the bevel base. Did a nice job of keeping the lube out of the bevels. I also added 3 more lube ports - so I now have 6 ports filling the single groove. For that size bullet 3 ports were not quite enough.