Making a Drive Band Cutter (opening a mold)

[slughammer]

Making a Drive Band Cutter (opening a mold)

I made a 2 drive band cutters to open up the cast diameter of my (2) cavity Lyman 311041. My mold was dropping at .309 and I wanted it larger to fit the .312 throat of my Savage 340. I made the first cutter .090 long for opening the three main drive bands. When I decided to make a second cutter and open the shorter drive band at the crimp groove, I figured I’d take some pictures and share with my friends.

I started by cleaning my work area, anything that had fallen on the floor was picked up and put back on the work bench!

Then I chucked up a 3” piece of ½ “ O-1 drill rod and turned about an inch of it to .319 dia. After that, I used a file and then sand paper to take it down to a nice smooth .3160.
http://i237.photobucket.com/albums/ff162/slughammer/IMG_1360.jpg


I back cut for the shank to .236 dia. (this is .080 smaller, I plan on cutting teeth .035 deep, When setting the milling head, I wanted to “touch off” on this dia and then back off .005).

After it was back cut and the back face was square I faced off the front until I reached the desired .060 length.


http://i237.photobucket.com/albums/ff162/slughammer/IMG_1376.jpg


I put the drill rod in the boring bar holder and leveled the “hexagonal indexing indicator” which is a ½” nut with the threads bored out. I brought the milling head around, touched off on the shank and backed off about .005, then I set the center using my calipers until I had it at .118 (1/2 the shank dia).



http://i237.photobucket.com/albums/ff162/slughammer/IMG_1379.jpg


After I made my first cut I indexed with the level for each successive cut.

Once all the flutes were cut I turned the hexagonal indexing indicator point up, backed off the cutter and then brought it back down to cut some relief on the back of each flute(by eye) . The first cut had left about .050 and the relief cut took that down to about .020.


http://i237.photobucket.com/albums/ff162/slughammer/IMG_1389.jpg

After the flutes were cut I put the cutter back in the lathe and added a 3/16 hole so I could install a longer rod for holding in my drill. (This way I could heat the whole cutter without putting heat into the jaws of my drill chuck.)


http://i237.photobucket.com/albums/ff162/slughammer/IMG_1394.jpg


My assistant and I turned the assy with a drill, heated it until cherry and then quenched it in oil.
After cleaning it up I installed the cutter in my round tuit (I’m glad I finally got one).

http://i237.photobucket.com/albums/ff162/slughammer/IMG_1412.jpg

I added a bushing to clear the sprue plate stop pin, then set the depth and tightened the set screw. After a few turns with hand pressure on the mold handles I cleared the chips, cut the other cavity and then added a c-clamp for a little more pressure.


http://i237.photobucket.com/albums/ff162/slughammer/IMG_1421.jpg

The end result shows the 2 freshly opened drive bands, the others have been cast from so they have a seasoned look.
This last picture also shows the .060 cutter on the left of the original .090 that was used on the three main bands.

http://i237.photobucket.com/albums/ff162/slughammer/IMG_1500.jpg

As far as diameters go, I had figured on .316 for the cutter, 2 thou of shrinkage to cast at .314 and then size to .312. I’m just a bit above that; the cutters grew about ½ thou when heat treated, the casting dia with wheel weights is .315-.316. They do size nice at either .314 or down in one step to .3115 using my Lyman 450.

Regards - Slughammer

[Trailblazer]

Good job! I have a couple molds that I would like to open up a bit. Might have to try your method. I wonder if you could get away without hardening the cutter.

[slughammer]

For aluminum maybe you can get away without the heat treat, but it's not that hard to do.

Hardest part of the heat treat was pulling the car out before firing up the torch.

http://i237.photobucket.com/albums/ff162/slughammer/IMG_1402.jpg

Heat

http://i237.photobucket.com/albums/ff162/slughammer/IMG_1406.jpg

Quench

[45nut]

wow,, very impressive thread sir. kudo's are in order.

[lathesmith]

Very nice work...you have made yourself a custom, one-of-a-kind mold, just right for YOUR stuff. That is the hallmark of a good home machining project! I assume in order to get it hot enough to heat-treat, you needed an oxy-acetaline torch? How long did you heat it before quenching?
lathesmith

[Hackleback]

Fellow member "drinks" made me a couple of cutters out of a grade 5 bolt that looks very simmiler. They worked fine for opening up a couple of Lee moulds that I have. I think that he cut the teeth with a hack or jewlers saw. same idea though.

[slughammer]

Very nice work...you have made yourself a custom, one-of-a-kind mold, just right for YOUR stuff. That is the hallmark of a good home machining project! I assume in order to get it hot enough to heat-treat, you needed an oxy-acetaline torch? How long did you heat it before quenching?
lathesmith

This little projest is nice because it doesn't require all the time required to make a set of blocks.

I used the oxy-acetaline because it was right there and I knew it would work. I had annealed a 7/8-14 die with a hand held propane torch once and it took forever. I think perhaps (2) hand held propane torches, a weed burner or a turkey fryer would do the job. I heated it until it was red, then I quenched it, didn't take long at all. Just kept the drill turning and the flame moving. You can see from the picture I concentrated the flame on the largest mass first.

Along with helping me face it off and drilling the back end of the cutter, my 7 year old assistant really liked putting the cutter in oil and watching a flame pop up [smilie=w:

[Single Shot]

NICE WORK FOR A CUSTOM MOLD.


Very nice work...you have made yourself a custom, one-of-a-kind mold, just right for YOUR stuff. That is the hallmark of a good home machining project! I assume in order to get it hot enough to heat-treat, you needed an oxy-acetaline torch? How long did you heat it before quenching?
lathesmith


I have used a BernzOmatic® Jet Torch with MAP GAS

http://www.lowes.com/lowes/lkn?action=productDetail&productId=77463-000000717-JTH7&lpage=none

[standles]

I for one would like to express my appreciation for your post. Many times folks think this stuff is mundane and no one would be interested. I always learn from these type posts and with pictures it is even better.


This from someone that is patiently trying to accumulate funds for a mill/lathe set.

Steven

[imashooter2]

Along with helping me face it off and drilling the back end of the cutter, my 7 year old assistant really liked putting the cutter in oil and watching a flame pop up [smilie=w:


Is there a 7 year old boy that doesn't like helping his Dad? Even more so when there's fire!

Great detailed step by step post on a very worthwhile project.

[454PB]

Nice work and great pictures!

[lathesmith]

In one of life's great ironies, I have discovered that since I have acquired a few basic machine tools--small lathe, mill, drill press--I spend a great deal of my time in the shop using my tools...to make or improve tools. Your post clearly demonstrates this! Most folks don't realize that a lot of seemingly difficult jobs can be fairly easy...with exactly the right tool at hand. It's making that tool that consumes so much of our time and attention sometimes!
I have used one of those Mapp Gas torches, they work great. The only real drawback is the expense of the bottles. Ouch, the locals ARE proud of them! But for small occasional jobs, they do the trick. I am kinda lucky, I know a couple of guys who have the big setups, which is good for my occasional torch needs. I'll try the spinning technique the next time I need to harden something, that is a good idea. Thanks for sharing!
lathesmith

[scrapcan]

You can make a nice propane burner that will heat better and hotter than you have experienced with a small propane torch.


Here is alink to some atmoshpheric eductor (venturi jets) type burners.
http://ronreil.abana.org/design1.shtml

I built a couple and have longed for one of the T-REx series built by Rex Price. Here is a page about the t-rex series.
http://ronreil.abana.org/Hybrid.shtml

Great design and should be easy for any of you with a lathe and mill (are combo tool).

For reference I built my burners using a drill press with vise.

[mag_01]

Nice Job --- Well done --- Thanks Mag_01

[Buckshot]

.............Great post! Nice neat work and easy to understand. Best of all it works :-)!

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

[quasi]

How is the cocentricity of tthe bullets after the modification? Or how accurate are the bullets from this mold now.? Very creative, I would not have thought of this in a billion years.

[Blammer]

great job!

makes me want to get a lathe!

[slughammer]

How is the cocentricity of tthe bullets after the modification? Or how accurate are the bullets from this mold now.? Very creative, I would not have thought of this in a billion years.

I didn't set any boolits in the vee blocks, but I imagine that someone could. With opening the diameter maybe .005 - .006 and having full contact on the entire surface from the start I do belive it stayed as concentric as it was before I started.

I have 200 cast and have lube/sized 100 of them at .3115. I plan on shooting them with IMR 4198 within the next week or two hopefully.

[lastmanout]

Nice job and a great wirte up. Thanks.

[oldfart]

I want one in 358 :)

[leftiye]

I'm going to make one a them for my 7.62X25. Needs a .315" boolit. Great thread Slughammer. Great idea which solves many of the problems encountered in enlarging boolit molds. Also could be used to widen front driving bands.

[Hackleback]

I am in need of a full bore 12 ga slug mould. Do the machinists out there think that one could cut driving bands on a Lee slug mould with this type of cutter??

[slughammer]

I am in need of a full bore 12 ga slug mould. Do the machinists out there think that one could cut driving bands on a Lee slug mould with this type of cutter??


That depends on the diameter change you are trying to get. These cutters are only cutting a few thou out and stay centered based on the small amount of material.

Trying to go .010 on a twelve bore mold may be easier done on a lathe with a boring bar. How much are you trying to accomplish?

[longbow]

Hackleback:

Check out the work Buckshot did for another member: http://castboolits.gunloads.com/showthread.php?t=21823&highlight=slug+lyman

Likely a similar operation could be done for the Lee.

Something else you might try if you don't want to use the shotcups is paper patching - though the Lee must be pretty small to fit into a shotcup. I have had some pretty good success with paper patched Lyman Foster style slugs (0.705") but it is a little tedious so I am going full bore.

In fact I am toying with the idea of using a 0.730" to 0.735" round ball and drilling a hollow core for testing the idea is to produce a home made version of BPI's AQ slug which shoots real well from my smoothbore. If it works well I would make a core pin to cast hollow cre "balls"

Are you using smoothbore or rifled? Rifled probably wouldn't like the paper patching - at least real thick paper patching.

Longbow

[Hackleback]

My other idea would be to run a 3/4-10 tap into the mould. This would make it a bit over size so one would have to run them through a push through size die. Plan on using a fiber wad behind them to get a gas seal.

[leftiye]

Flatten the points of the tap first, and you have spiral lands (and maybe the right size)! Might be fun to get to cast though.

[leftiye]

Actchumually, This opens up a very interesting way to produce lands in a mold. Maybe use a skip thread die, or set up the threading on a lathe to produce a flat bottomed skip thread? You could use an Acme thread setup, or move the compound front to rear (longitudinally?) with each pass at full depth until the desired driving band width was reached. Would need a tool post with threaded adjustment to move this way if not starting at full depth. Fifteen degrees on walls of lube grooves.

[home in oz]

Nice work!

[44man]

Same problem I have when making a cherry---diameter to start with!
I had trouble with cherries warping when hardening until I spin the thing in my drill press when I heat. I put the can of oil under the cherry and when red I stop the press and open the chuck so the cherry drops straight into the oil. Seems as if just dropping one in oil a little sideways will cause a warp.
Then I put them in the kitchen oven for an hour at 300* to temper. I shut the oven off and let it all cool slow before removing the cherry.
I tried a cherry from some special steel that said it didn't need hardened to cut aluminum---ate the cherry UP!
I also tried one without tempering and it chipped all up.
It is too easy to do it right. :drinks:
I needed some cherries for a .501" and a 512" boolit for the JRH and Linebaugh. The only O-1 I have is 1/2" but I have some A-2 that measured large enough.
Seemed to have less dimensional changes and I hardened in oil and tempered in the oven, worked out fine.

[HollowPoint]

Over the last three or four years I've ruined at least three perfectly good aluminum Lee mold simply because I lacked a tool like the one you've just shared here.

Very well done. Thanks for the info and the pictures.

Right not I have a couple of dedicated paper patching bullet molds I just put together for testing. With one of these little driving band gizmos I think they can easily be converted to a more traditional "Grease-Grooved" cast bullet if I were so inclined.

HollowPoint

[Doc Highwall]

I was thinking of just making a lap along those lines. Nice job you did, maybe I will make a T cutter like you.

[dragonrider]

A couple years ago one of the Lee group buys arrived and it cast real small, I made a cutter similar to yours but never used it as the consesus was to send the molds back and I did. I did not harden it as the mold was aluminum and I only had the one mold to use it on. I wondered if it would work. Obviously yours worked very well. Great job Slughammer.

[deltaenterprizes]

I made a similar cutter to make the shellholder slot for my nutcracker press(copy of Hunnington) from a grade 8 bolt and it was hard enough to cut aluminum very nicely. I got the idea from a member on The Home Shop Machinist forum.

Taking orders![smilie=1:

[peterthevet]

Excellent post/tutorial !!! Fantastic thought processes and planning and superb execution (machining)!@!! Thankyou for your generosity in sharing your technique and the time and effort that went into photographing the sequential steps....this is what keeps me coming back to this superb forum....selfless sharing of thoughts/ideas...chewing the fat etc....greatly appreciated.

[akajun]

Made one of these last night to cut .003 out of a lyman mould. Made it out of a grade8 bolt, and did not harden it. It cut both cavities fine. I did make one adjustment. I did not use the big guide that you did on top of the blocks, rather I used pin guages to find the minor diameter of the grease grooves, and made the shaft of the cutter that diameter, hence using the shaft and grease grooves as my alignment tool.

[leftiye]

I've since (since this thread was first opened) made bearing band enlarging tools from reamers. I grind a relief behind the part that I want to cut the grooves deeper with with a toolpost grinder, and make a holder with a hexagonal part to it to turn the cutter with by hand. Do not make the relief the diameter of the bottom of the grooves in the mold (you have zero guarantee that the reamer is straight unless you center it - and not much then - and it will cause the reamer to cut oversize), make it with sufficient clearance that the cutting teeth are all that bears side to side. The holder/driver has set screws so that all of the bands can be cut by resetting the cutter depth.