opening up a gas check shank

[ubetcha]

I have a Lee 310rf bullet mold that has a gas check shank of about .395 and I would like to open it up to .404. My alum gas checks in .016 do not stay on. Very loose.My RCBS and Lyman mold cast about .404 and the checks are nice and tight. What would be an easy way to open the shank area up to around .404?

[Ben]

The safest way is to send it to Buckshot.

[Lefty SRH]

Have it reamed out.

[Ben]

But will the reamer method end up with a shank that is exactly .404 "

[Lefty SRH]

But will the reamer method end up with a shank that is exactly .404 "

Honestly its hard to say. I've a few 7mm molds and I use a .253" reamer to achieve a .2510"-.2515" GC shank.

[GLL]

I like Ben's plan of contacting Buckshot.
He has opened up several molds for me !

Jerry

[Ben]

May not be the cheapest, but it will end up with the BEST results possible.

I have the utmost confidence in Buckshot's abilities.

Ben

[JonB_in_Glencoe]

If you want to try it yourself...
I have that one in a 2 cav mold...same issue.
first I lee-mented the cavities.
then I cut the gas check shank off of a boolit, I put that boolit into the cavity, to protect the rest of the cavity. Then I took a wooden dowel wrapped in fine emery cloth and slowly removed some of the metal, then checked by casting a few. repeat till you achieve the desired size.
Jon

[ubetcha]

If you want to try it yourself...
I have that one in a 2 cav mold...same issue.
first I lee-mented the cavities.
then I cut the gas check shank off of a boolit, I put that boolit into the cavity, to protect the rest of the cavity. Then I took a wooden dowel wrapped in fine emery cloth and slowly removed some of the metal, then checked by casting a few. repeat till you achieve the desired size.
Jon

That's kind of the way I was thinking about doing it,But one of my sons( a tool and die maker) stopped by today and I explained to him what I wanted to do and he said no problem to do. So I will have him do it. I hope he doesn't sit on it too long like the other things I have asked him to make for me.
Thanks for all the suggestions

[JonB_in_Glencoe]

...one of my sons( a tool and die maker) stopped by today and I explained to him what I wanted to do and he said no problem to do. So I will have him do it. I hope he doesn't sit on it too long like the other things I have asked him to make for me.
Thanks for all the suggestions

I recently bought a Micro-Lathe that also converts to a micro-mill. I bought a teeny tiny fly-cutter for it, thinking I might be able to use that in the mill to do such a thing...if you get a chance, ask him how he is gonna enlarge that shank.
Thanks,
Jon

[country gent]

It can be done several ways. By hand a reamer will work, lapping will work also, but lapping .009 ( .0045 on a side) is a long process. On aluminum a 3 cornered scraper will remove it also. In the lathe a 4 jaw chuck and indicate to dead zero. a small boring bar and work in passes of .001-.002. In the mill, jib bore, or jig grinder indicate square and centered with spindle. Appropriate tooling and work slow and easy. I have done several for guys at work. Its more set up than work. Getting everything true and square, set up solidly is the work.Blacken the first driving band with a marker so you can see the first touch or use pin gages to check size. I normally did them in the lathe with a small boring bar as set up was easiest.

[ubetcha]

I recently bought a Micro-Lathe that also converts to a micro-mill. I bought a teeny tiny fly-cutter for it, thinking I might be able to use that in the mill to do such a thing...if you get a chance, ask him how he is gonna enlarge that shank.
Thanks,
Jon

If I recall ,he said he would clamp it in a machinist vice on an end mill and locate the outer edges of the hole with a center finder then use a small end mill bit to take a few thou off. I guess with all the new fangled digital read out stuff,this would be an easy thing.Ya know with the X-Y axis thing-a-ma-jig. When I see him again, I will get more exact info, or even better yet I may have him post what he did using my computer and user name, if that ok with the the mod's.

[MGySgt]

A long time ago there was a Group buy for a RD 460 350 and 460 grainers. both had the shank cut too small. Someone here made a reamer/cutter we passed around (I think it was a grade 8 bolt used to make the reamer).

All we did was chuck it in a drill press and turn the drill press by hand. Worked real slick. I have a MM that had a small shank I used it in that one too.

Long way around - but you might go into the GC area and ask if someone can make a reamer to cut the shanks on Aluminum moulds for someone using XX thick material.

[detox]

I would like to remove the bevel base section from my Lyman 158 Cowboy mould. I may try this after giving it more thought. Sizing should correct any imperfections.