Core seat die???

[customcutter]

I'm trying to figure a plan of attack for the core seat die. I'm thinking of drilling to just undersized and then lapping with one of these expanding internal laps. Seems like it would eliminate making a reamer to size and laps also.

http://www.americanlap.com/Internal%20Laps.htm

Should be able to adjust the lap to compensate for the different sizes of lapping compound used.

How do you guys do it???

[blltsmth]

Contact LaFaun Floyd in the sponsors section. He has the process down and should be willing to help. Don

[mactool]

I would buy a reamer, and then lap. This way you dont have issues straightness of the hole, and much less material to remove. I also would make a test part to find out how much the material shrink/ expand during the hardening process. Depending of that outcome a .2225" might be the right choice

[Cane_man]

just drill and lap? that is how i do it... drill to .004 under, then lap to 0.002 under, heat treat, and lap the last 0.002... key imo is to make a test probe the right size... seems like a probe that is 0.002 under will slide in barely to your target ID

[customcutter]

just drill and lap? that is how i do it... drill to .004 under, then lap to 0.002 under, heat treat, and lap the last 0.002... key imo is to make a test probe the right size... seems like a probe that is 0.002 under will slide in barely to your target ID

Yes, a tight slip fit would be .002". What do you make your laps from, and what size??? What drill are you using to drill to .220"? I'm asking because most drills don't drill to size.

[Cane_man]

i don't make anything special to lap out the core seating die... just use a dowel and sandpaper with lubricant...

to drill to 0.220 i use a 7/32 (0.2188), which makes it a little bigger than desired but i just don't lap as much before heat treating...

[Reload3006]

make your core seat die the same way you make your core swage die. or squirt die except dont drill a bleed hole. Lap or hone it to .0003 under finish size. or for a .308 it should be around .3077 in diameter your core seat punches should be made to seal the jacket so lead doesn't flash by that size will depend on jacket size and thickness.

[customcutter]

I need to try a different drill. The last time I drilled a 7/32 hole it turned out over .224 before lapping.[smilie=b:

[customcutter]

make your core seat die the same way you make your core swage die. or squirt die except dont drill a bleed hole. Lap or hone it to .0003 under finish size. or for a .308 it should be around .3077 in diameter your core seat punches should be made to seal the jacket so lead doesn't flash by that size will depend on jacket size and thickness.

I haven't made the squirt die, I'm hoping that I can get by with casting them. Yes, I'm going to shoot for .2235, and everything I've read says to make the core seating punch .002 less than the jacket opening.

[customcutter]

Cane, do you remember if you pre-drilled with another drill that was close to 7/32???

[Cane_man]

no cc i don't remember

[aaronraad]

Yes, I'm going to shoot for .2235, and everything I've read says to make the core seating punch .002 less than the jacket opening.

...depending on your seated core depth and any internal taper on the jacket. So more like '0.002" less than the jacket ID at your finished core seating depth', hence the need for multiple core seating punches if your jacket walls and your core weights bounce around a bit from batch to batch.

[Reload3006]

...depending on your seated core depth and any internal taper on the jacket. So more like '0.002" less than the jacket ID at your finished core seating depth', hence the need for multiple core seating punches if your jacket walls and your core weights bounce around a bit from batch to batch.
+1 thats exactly right

[garandsrus]

Keep in mind that if you want a lead tip, the punch should match the die diameter as the lead will extend beyond the jacket in the seater die.

[Cane_man]

Cane, do you remember if you pre-drilled with another drill that was close to 7/32???

cc, not sure if this answers your question but i try to pre-drill to the closest size i have to 7/32... so i might drill 13/64" (.203), then #3 (.213), and finish with 7/32 (.218)

[customcutter]

Thanks guys, I was laying in bed trying to get pictures of these dies out of my head and I had an idea I'm going to try that isn't SOP for seating cores. I'll let you know how it turns out.

[Prospector Howard]

CC, Take a look at these, if you haven't already.
http://www.mcmaster.com/#cylinder-hones/=qk8lit

[garandsrus]

A good option for lapping are brass laps. Search for "Expandable Brass Cylinder Laps" on the McMaster site mentioned above.

John

[customcutter]

PH and GRUS, thanks for the heads up. I had done a google search for laps (looked through 3-4 pages) and saw the flexible laps, actually have one I used years ago to polish a shotgun bore. I didn't think I would be able to polish the dies evenly to stay concentric so the only rigid adjustable lap I found was the ones from American Lap, I haven't contacted them for a price yet. They had brass laps but not expandable IIRC. Seems like the expandable brass laps and 3-4 extra barrels for grit changes (diamond paste) would be perfect.

[alfloyd]

KBC Tools has them also.
http://kbctools.com/usa/Navigation/NavPDF.cfm?PDFPage=608

These are the ones that I use.
Lafaun

[customcutter]

Going to order some tonight. I had 5-6 items on order last night and was about to checkout and got kicked off the website.

KBC doesn't have the size I need as a single lap only in a set, so I guess it will be McMaster Carr. Core seating die is ready to lap from .221 to .223. Also got the core squirt die done today. I'll try and post some pics tomorrow. I can't send pics from my phone to my email, have to send them to the wife and have her send them to my email. Go figure, even Verizon can't figure it out.:-?

[customcutter]

Don't have the lap yet for the core seat die, but I lapped the core swage die with a piece of 1/8" brass rod with a slit in the end and 220 grit wet/dry sandpaper. Should be good enough for lead cores. On the left is the core swage die, with top and bottom caps for adjustment of core weight. The die on the right is core seat die, I still need to lap it to .223 from .221 now. Also need to make the punches for the bottom of both dies. Just learning how to thread on a lathe with this project so they are a little rough. Also doesn't help if you try to rechuck them after they are threaded. But the threads are tight and functional so I'm not worried about pretty yet.

EDIT: Anyone have any ideas how to remove the scale after heat treating from the bottom cap on the core swage die? Can't polish it off because of the threads and knurling. I'm thinking a small wire wheel in the foredom flex shaft grinder might work?

[ProfGAB101]

"any ideas how to remove the scale after heat treating"

Glass bead blast.

[customcutter]

I've been wanting to buy one of the small HF sand blasting cabinets. That's just another reason to get it. Where am I going to put it?

[Cane_man]

Don't have the lap yet for the core seat die, but I lapped the core swage die with a piece of 1/8" brass rod with a slit in the end and 220 grit wet/dry sandpaper. Should be good enough for lead cores. On the left is the core swage die, with top and bottom caps for adjustment of core weight. The die on the right is core seat die, I still need to lap it to .223 from .221 now. Also need to make the punches for the bottom of both dies. Just learning how to thread on a lathe with this project so they are a little rough. Also doesn't help if you try to rechuck them after they are threaded. But the threads are tight and functional so I'm not worried about pretty yet.

EDIT: Anyone have any ideas how to remove the scale after heat treating from the bottom cap on the core swage die? Can't polish it off because of the threads and knurling. I'm thinking a small wire wheel in the foredom flex shaft grinder might work?

looking good... 220 then some 600 and then finish with some 0000 steel wool?

i use steel wool to take off the black stuff after heat treating but i can see how that would be worthless on the knurling... could you vibratory tumble it with ceramic media or stainless pins? brass wire brush is a good idea too