remove gas check on an aluminum mold

[Whiterabbit]

I know, there must be 1000 ways to do this, I want your opinion on the way to make the cleanest cut.

More specifically, I want you to modify my plan by increments to do the same. Here is what I am thinking:

Step 1: turn a piece of AL or steel or whatever (aluminum) to exactly the diameter of my shank size on the mold.

Step 2: chuck that in my mill and put the mold blocks in the clamp. Adjust table position until I can plunge the AL shank rod into the mold cavity. Lock table into place.

Step 3: replace alignment rod with cutter (reamer? end mill? normal drill bit??) and plunge cut or drive the bit into the mold.

Will this give me a clean cut? Also, reamers and end mills are expensive. I know filks use a drill bit, but I also know such a large drill bit can grip and drive into the material ruining a cavity quick! I could drive the Z axis into the mold, that should fix the risk there, is that the best way to go about this? Or is it worth finding a reamer or end mill the exact diameter I need?

Is there an easier way to align the mold? could I just use a smaller drill bit? maybe install backwards in the chuck so I'm plunging the drill bit shank into the gas check shank hole? Not that it is a problem to turn an AL blank down to .443 or whatever the shank size is.

[Whiterabbit]

that's hardly educational!

On the other hand I don't want my education to be a gouged mold. thus the thread.

C'mon man, this is Cast Boolits! If I wanted to be told I should pay someone else to do anything like mow my lawn, handload ammunition, or cut a plank of wood, I would have posted on Calguns.net! We are a forum of do-ers!

[Outpost75]

I like DIY projects as much as anyone else, but if you value your time as more than day labor wages, Erik does a fine job at reasonable cost. He bored the GC heel out to make a wider base band in plainbased configuration for me on several gang molds and I have been well satisfied.

[clocker]

If you already have a mill, then you should have most of the parts necessary. I would do the following:
1. Clamp the mold into the vise. Use a dial indicator to make sure that the top of the mold is perpendicular to the mill axis (shim if necessary)
2. Use a dial indicator with a fine tip to determine the exact center of the base opening (Traverse the table until when you slowly rotate the spindle there is no movement on the indicator)
3. Install a very small boring head and boring bar. Slowly bore the mold to remove the gas check. Verify your final diameter

This should result in a pretty good precision. You're welcome to try step 3 with a mill cutter or drill bit if you don't need the precision.

[Whiterabbit]

http://littlemachineshop.com/product...ProductID=3662

Well, $90 is a little much for this project, but it certainly looks like a must have tool for the future!

Can you describe the setup for step2 a little more? installing a dial test indicator in a boring bar, is that it?

[clocker]

Here is a good video that describes the process for step #2 . You can also use a wobbler or edge finder.

That boring head is good, but may be too large for our boolits. Check Enco or one of the other tool catalogs for boring bars with smaller cutting edges if necessary.

[Maven]

Whiterabbit, You'll get an education here (Your thread is also included): http://www.google.com/cse?cx=0019512...hank&sa=Search Look for posts by Ben in particular.

[donhuff]

Whiterabbit,
Your alteration doesn't have to be all that complicated or presice. Your gonna MASH it into shape later anyway.

I opened up the bottom driving bands on a 4 hole lyman 429421 mold a few months ago. It was dropping at .429-.430 and I wanted it to be big enough that I could size em to .432. Beagleing works but is aggravating to me. I had a bunch of 7/16 chucking reamers for some reason, and I got to looking at them and wondering. Sooooooooooo. I put the mold in the kurt type vice on my little bench top mill, and the ream in the collet, and kept sticking the tip of the ream into the mold opening and moving it slightly until I saw no sideways movement at all. Then BY HAND, turn the ream while lowering it into the mold. It's only taking off a little bit so it was easy to do by hand. Plus it WILL probably chatter with power (ask me how I know!). I took the cut down into the grease groove since it is pretty big on this style mold. The tip of the ream is cut on a 45* so it makes a nice bevel on the groove that look like it ought to be there. Big deal, Your gonna fill it up with grease anyway. The ream is .437 and I forget what the bullets drop at now, but they size down perfect and shiny ALL the way around. I figure the bottom band is doing the majority of the sealing anyway (if it's big enough and working right) and the rest of the bands are still centering up in the chamber and catching the rifiling just like they did before.
If you were doing a 44 mold, I could send you one of my reams for $5+ shipping, but it sounds like you are doing a .45.

I posted about doing this a while back and it got read a bunch but not a single reply was made. I thought at least one person would scold me for mutalating a "perfect" mold. 429-421 too small....not anymore.

[MtGun44]

One of our members here has "proven" that it is impossible to do
with a drill bit. . . . . . . (kidding, and mean the opposite).

I forget who, maybe Ben.

Spend some time on search and PM Ben.

Bill

[1_Ogre]

I know, there must be 1000 ways to do this, I want your opinion on the way to make the cleanest cut.

More specifically, I want you to modify my plan by increments to do the same. Here is what I am thinking:

Step 1: turn a piece of AL or steel or whatever (aluminum) to exactly the diameter of my shank size on the mold.

Step 2: chuck that in my mill and put the mold blocks in the clamp. Adjust table position until I can plunge the AL shank rod into the mold cavity. Lock table into place.

Step 3: replace alignment rod with cutter (reamer? end mill? normal drill bit??) and plunge cut or drive the bit into the mold.

Will this give me a clean cut? Also, reamers and end mills are expensive. I know filks use a drill bit, but I also know such a large drill bit can grip and drive into the material ruining a cavity quick! I could drive the Z axis into the mold, that should fix the risk there, is that the best way to go about this? Or is it worth finding a reamer or end mill the exact diameter I need?

Is there an easier way to align the mold? could I just use a smaller drill bit? maybe install backwards in the chuck so I'm plunging the drill bit shank into the gas check shank hole? Not that it is a problem to turn an AL blank down to .443 or whatever the shank size is.

Send it to Erik at Hollow Point Molds. His work is above good, he's a true machinist. He's done a lot of work on moulds for me and I've never been dissapointed. His work is GOOD

[shredder]

Ben has opened up many a mould with a drill bit on his drill press, and has posted pics and procedure on this site. That is what got me started doing just that. I took the gas check portion off my Lee 160 RN .30 cal in this manner and the result is excellent! Read the posts and take your time, use a sharp bit and slow speed.

There are always those who will tell you to expect failure. Don't let that stop you!

[Ben]

Ben has opened up many a mould with a drill bit on his drill press, and has posted pics and procedure on this site. That is what got me started doing just that. I took the gas check portion off my Lee 160 RN .30 cal in this manner and the result is excellent! Read the posts and take your time, use a sharp bit and slow speed.

There are always those who will tell you to expect failure. Don't let that stop you!

Glad you've had good luck with the procedure.
------------------------------------------


Alignment is critical.

A sharp ( Super Sharp ) bit is critical.

Slow drill bit speed is also critical.

Good shooting,

Ben

[JeffinNZ]

Still think Ben uses smoke and mirrors........

[Ben]

Gee,....... I thought all of us used smoke and mirrors ? If you're to have success, isn't that a big part of it ? ?

Ben

[Lefty SRH]

I've opened up several 7mm GC shanks. I've always used a chucking reamer and a milling machine. I always indicate/locate the back driving band them ream the GC shank to .253" or .254". Removing the GC shank would be essentially the same thing.

[Echo]

I removed the GC shank from one cavity of a Lee 8mm 2-banger with a drill in my drill press. I believe it was a 21/64 drill (Not at home now), and worked just fine.