Cherrys

[Buckshot]

...........Willbird, you must be talking about a 6 jaw independant chuck? As a 6 jaw scroll chuck would have a very hard time clamping to anything other then round stock. Sorry about the following llinks as I can't yet figure out how to download images directly from my host site, LIKE I USED TO BE ABLE TO !!!!!


The above will open a photo of a 6 jaw Buck Adjust-Tru I have, and was using as part of getting my lathe leveled and set up.


And turning a test bar. You can use an Adjust-Tru to get right down into the tenths, but just like a 4 jaw independant, everytime you put in a new workpiece you're back with your dial indicators setting up again.

In using a 4 jaw to hollowpoint bullet moulds, at first I wore myself to a frazzle chasing thousandths back and forth across the parting line of the blocks. Mould blocks aren't always as square as we'd like, and the chuckjaws may not apply even pressure, especially with a 2 cavity set as the jaws may be well across the parting line, as in the photo below:


What I've gone to is to place copper wire (ground wire stripped out of old Romex) between the jaw and block. You also have a 'bell mouth' situation with the jaws able to tilt a bit in the chuck body. The copper wire compensates to a degree.

After doing a couple moulds, I have come to understand that having the test indicator bounce a thousandth and a half, or two across the parting line is just something to expect, so the REAL alignment measurements are taken opposite them on the clean cavity surfaces. Naturally you want everything to be as perfect as possible, right? Early on I would stick the pointer of a .0005" TI down into the cavity to ride a lube groove. That was pure idiocity. I spent hours re-setting, flipping the mould blocks back and forth from cavity to cavity, etc & etc. Oh my aching back!

I even set up block halves on a granite surface plate to try and find out what was happening, only to accept that cavities aren't always cherried straight. I told one guy when I'd first started that I was unable to get the cavity to run straight to the blocks. I was chasing a thousandth back and forth all over the place on a cherry cut block. I have a piece of paper stuck on the cabinet over my reloading bench, opposite the lathe that says, "Remember the RCBS".

This was a 7mm-168 that was oval. I guess the blocks didn't completely close on the cherry when it was made. Trying to get THAT abortion to run true would turn a saint into a blithering lunatic and have you sitting in a dark corner sucking your thumb. I have become much more serene and can accept a .001 to .002" bounce across parting lines if I can get the opposing surfaces to run within a thou.

It's still spooky to 'do the deed' and I always lean against the bench and have a smoke reviewing what I saw before advancing the spotter to centerpunch the nose.

...........A rotary table used to cut varying diameter cavities with one cherry sounds interesting. Sounds kind of like using a router? I hope someone does that and reports back. I'd sure be interested in hearing about how it worked. Remember that whatever minimum level of accuracy the rotary table has in 360* rotation will reflect X2 in the cavity you cut that way.

.............Buckshot

[Willbird]

Most of the work we did in 6 jaw scroll was round, that is true, BUT the 6 jaw could also become a 2 jaw with a holding fixture on each jaw.

personally I would like to give a mag chuck a whirl, I have used them lots on ID grinders and they worked great,most touching up on a mold will be low torque stuff that shouldnt move the blocks around.

also it is common to find on ID grinders, older ones that the spindle does NOT run the same when powered as when rolling over by hand, IE you can dial it in to .0001 TIR by hand, and turn her on and have .0005 runout.

I have had to dial in some things that werent nearly round, and the only way was to indicate where each pusher screw (buch adjust tru) is and adjust accordingly, when it is as true as it can be the indicator movement makes sense, if it is running out and you are trying to correct that it does not make enough sense to ever get her in.

I think when I do my first mold re-work I will find a gage pin that fits snug on the bottom of the grease grooves and indicate that to start with, then check the cavity. maybe while I have the 429421 in there to enlarge the dia, lengthen the front driving band, and make the grease groove shallower I will go on and hollowpoint it.

If time were not an issue, and with home made molds it usually isnt, I would make the blocks, and have a hollowpoint pin hole wire edm'd right on parting line, then I would have a datum to use for the lathe work. you could make one block 1/2" wider than the other to have a datum surface to indicate the blocks in straight on the wire machine, and a trough cut with a small ballmill while in the milling machine would be your wire start. the wire machines make holes perfectly straight for the most part and where they belong within .0001.

then one could indicate a gage pin that jusssst fit in the hp pin hole in the lathe.

Bill

[carpetman]

Buckshot--do you use ground wire as those jaws have trouble chewing solid wire?

[Buckshot]

Buckshot--do you use ground wire as those jaws have trouble chewing solid wire?

.............Well actually Carpetman, the jaws have no problem (ahem) chewing solid wire, at all. I just happen to ah, prefer ground wire. Just a personal thing is all.

.........Willbird, "Most of the work we did in 6 jaw scroll was round, that is true, BUT the 6 jaw could also become a 2 jaw with a holding fixture on each jaw."

As it happens, I have a Buck 2 jaw Adjust-Tru also. I've never used it. I asked on the HSM board what you do with a 2 jaw chuck. Basicly I was told it's to hold things a 3 or 4 jaw won't hold. Well, awright!

".............I think when I do my first mold re-work I will find a gage pin that fits snug on the bottom of the grease grooves and indicate that to start with, then check the cavity."

That's what I TRY to do, but you can't always. First of all I have pin gages (.0000, -.0002) in sets from .061" to .625. These are by thousandths. IF you have a mould that will close on a pin snugly with both blocks touching, that's half the battle. The other half is that there has to be a pair of lube grooves the same depth to hold the pin concentric.

Just one lube groove and the pin gage will wobble. The only other possibility is if the nose will accept the end of the gage pin. In other words if you can press the pin gage into the nose so as to hold that end, with the lube groove providing the other support. Otherwise a gage pin is a non-starter.

Wire EDM is great stuff, especially if you have one in your home shop. On the other hand, if you should have to take your set of blocks to a company to have the EDM work done you might get to wondering if having that spark cut hole is really worth it afterall.

I once had the brainy idea to have some blocks cut to produce a bullet for the Whitworth muzzle loader. These bullets were to be as the originals, 6 sided and with the 20" twist cast in. You cannot have a mere 2 block type mould as the bullet form would lock the blocks together unless the skew of the twist was sufficiently blurred to almost delete any benefit.

The only way to utilize 2 blocks and cast a sharply formed bullet like this was to have the parting line cut on an identical helical type form, with the parting line following an opposed set of 'corners' of the bullet. So, you have wire EDM to cut through the set of blocks while the blocks had to rotate through a few degrees of rotation.

After that was done, you'd drill and set alignment pins. At that point they'd be set up for plunge type EDM. This would also include the machining charge for the carbon EDM. When I got an idea of the expense I said thank you very much for your time, and hung up!

.................Buckshot

[Catshooter]

that hard to turn, 44Man. Since you turned the threads on the bolts for your vice, all you'd need to turn up the same thing in an Acme thread is a properly ground tool bit and the technical specs for the pitch and diameter you want.

Also, if you can thread, you can also make a tap and/or die to whatever you want. Just make it out of tool steel and harden it just like your cherries.

If it was me, I'd probably stay with unified threads as the Acme are much stronger but also much coarser. I would think the unified pitch would give better control, but then I've never made my own cherryering (can you spell that that way?) vice, and you have. Just my .02.


Cat

[Willbird]

Buckshot, I think the 2 jaw are often used with soft jaws machined to fit the part, they could also hold round, square, hex, and octagon stock with the proper jaws.

another nice thing to do with a 3 jaw chuck with bolted on top jaws is to machine a set of top jaws to hold warner-swasey collet pads, these come in lots of sizes, and round,square, hex etc. of course this only works out if you have a ton of them already

[James Wisner]

Buckshot, Willbird.

Have been lurking now for a couple of weeks.
Am fed up with Lyman molds in general and and am just about to start making my own moulds.

Will try making them as Willbird, is taking about using a single sided half cherry with the profile and the dia undersize, then move either the Y or X axis.

Also most tool sharperners can grind a straight flute end mill into a cherry for you.

Have several options to spin the moulds.

Manual lathe with a face plate and spl fixture to hold mould in place, then reindex and cut next hole.

Manual mill and rotary table with 3" kurt vise and then reindex for next hole, use digital readout to keep track of axis movement.

CNC mill with 4x axis, lay it on its side and clamp the 3" kurt vise on it and use it as a rotary table, this way simply write a short program to do the work and then reindex and repeat for each hole.

Mold material, have a few questions.

Have tested Lyman, Saeco, Rcbs, for hardness, only have a C scale so most of these are really on the B scale or even a Brinell scale. The Lyman is the softest, the Rcbs and Saeco will run aobut 20 RC. So have two types of steel avaiable in my inventory. 12L14 or 1144, the 12L14 runs about 20 RC, the 1144 will be 28 RC. Both will machine nicely.

Comments regarding the use of these metals for moulds.

Jim Wisner
Custom Metalsmith
www.wisnersinc.com

[45nut]

Welcome to CB Jim.
A most welcome addition,those of you that may not know of Wisner's should click on his link. He has a very nice assortment of gun parts available and a nice reputation as a gunsmith as well.
Someday I plan to get off my duff and send my 500A2 up there for a feeding re-work and general "finishing".
Having read a lot of his posts on A.R. I believe he is certainly up to making quality molds. And we can always use more options in that field.
Nice to get you out of the "lurk" mode Jim.

[Buckshot]

..............James, welcome aboard! I have no comment of value as regards type of steel to use other then to say it should be fully stress relieved. Pretty sure you knew that. I would be partial to either cast iron as a material, or aluminum. One reason for aluminum would be it's cost and ease of machining. Plus you can buy it in suitable rectangle sizes for block halves.

The only bad thing about AL is regardless if you start with 7075-T6, after heating and filling with hot lead it's going to lose it's hardness. Might be neat to anodize the top surface the sprueplate slides on.

Lyman blocks are steel. RCBS and Saeco are cast iron. I really don't think that ultimate hardness is an issue. If aluminum makes good blocks, which it does, then steel or cast iron, even if fully annealed would be MUCH sterner stuff. I'm still aways off from when I attempt to cut any moulds. I did buy a 3/4x1.5x6' piece of 6061-T6 as material to practive on, and 36, 1/4" HSS drill blanks to grind into nose forming spoons and drive band tools.

One of the posters here has bought some CI from Dura-Bar and has offered to have them machined and parted into blocks for a nominal cost. He wasn't quite overwhelmed with takers . I said I'd take a couple to have against the day I try my hand at it. I don't have any CNC capabilities. It's all manual for me with dial indicators everywhere!

.................Buckshot

[Greg5278]

Buckshot, the cast iron is ordered. I am not sure of how much machining I am going to do on the iron. I haven't had time to get the one CNC shop to quote out the job. I was just going to finish all sides of the blocks with a shell will, and mill the handle slots for the RCBS handles. I was going to cut the handle slots at .305" to tigthen up the fit. The blocks will be 1.000" thick. If enough people wanted some sort of block set, and we could agree on a "standard" the CNC shop could cut the vent lines, and all holes could be drilled and reamed. I don't think we have enough to make it worthwhile right now. The shop has a minumum charge for CNC machine time, and setup. They don't charge for programming.

I have also talked to a moldmaker who used S-7 tool steel for some machine cast molds. He said they were difficult to cut, but should last forever. I have several 360 brass molds, and really like them. I am not a huge fan on Aluminum molds, because they can be damaged easily. Greg