T slot cutter for shellholder

[Jmp50]

You wouldn't. At least not without some resuscitation from Harold Hall. Tried any other supply houses or ebay?

14x3mm is the closest I've found
Yea, a tool post grinder would be easy.

 

[Jmp50]

The pocket has to be an arc, a 1/2" cutter would make an oblong. The undersize cutter would be a bit tricky with a rotary table, but be doable.

Too bad the OP has no tool post grinder on hand, though that still might not be easy unless he has developed the second sight for cutter geometry. I think if one is able to hand grind a small internal groove boring bar, it would be no different to hand grind a similar D-bit milling cutter to the needed dimensions. Best done in a fixture, it will challenge your freehand skills, but should not be impossible. In this hobby, we often have to make a tool to make a tool. Or in this case, make a tool to make a tool to make loaded cartridges.

The rcbs ram prime die I used previous worked fine and allowed me to set the ram height so I could interchange dies with Lee classic with zero changes.... something you can't do with the rcbs a4 ram. It's just a bit ugly..... lol. Thought it would be a cool project to make a custom ram that appears factory. Didn't think the 9/16x1/8 cutter would be a big deal. The big reloading manufacturers are probably useing the 14x3mm cutters with a slight offset. They must buy them by the pallet....just a swag guess.

 

[Ischgl99]

You could send a standard size to an end mill grinding company to modify to the right diameter. I’ve used Gruschow Grinding to sharpen my end mills and am happy with their service. https://www.endmill-sharpening.com/Services.htm

 

[Jmp50]

You could send a standard size to an end mill grinding company to modify to the right diameter. I’ve used Gruschow Grinding to sharpen my end mills and am happy with their service. https://www.endmill-sharpening.com/Services.htm

Thanks....I have a few end mills that need sharpening and will send with the T cutter.

 

[Eddyde]

You could rig a tool post grinder using a die grinder or even a Dremel mounted to the tool post. I did one by clamping a die grinder to a short piece of steel angle with hose clamps, The angle had a ½" square boss welded to the side that clamped in the tool holder. Sorry I don't have any pictures as it was back in the film days.

 

[Ischgl99]

Thanks....I have a few end mills that need sharpening and will send with the T cutter.

You’re welcome! I didn’t notice your location when I first posted, Gruschow is not that far away from you in the Finger Lakes region, so shipping should be quick. When he first quoted my job last spring, he said it would be a few weeks, but I got them back in a week. Not sure if I got lucky, or he was just being conservative in his estimate.

 

[mickri]

What is critical about the diameter of the cut. The difference between 9/16 and 1/2 for an oblong cut is .0128 at the widest point of the oblong.

 

[pontiac428]

What is critical about the diameter of the cut. The difference between 9/16 and 1/2 for an oblong cut is .0128 at the widest point of the oblong.

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Seems minor, but what happens is when you ram a primer in to the shell pocket, the force will tear the case rim away from the oblong shellholder and you will ruin both a case and a primer in the process. I have been there done that with a Dillon shellplate that they thought they could get away with that type of oblong cut, and it made me want to scream. They went back to the non-oblong cut and the problems went away. It makes no difference when pressing on the other steps in a push motion, but upon withdrawal from the resize die, the same action is needed where the shell holder is pulling the shell and it will rock and pop out, jamming a stuck case in the resize die. The shell needs to fit into the apex of the shell holder to fit tightly all the way around the semicircle, and leaving a flat spot from the oblong cut will push the case rim away from the ridge. Not acceptable in this case, unfortunately.

 

[Jmp50]

When trying to achieve .0005 bullet runout in a loaded cartridge .012 is way too much built in error.

 

[mickri]

I hear what you are saying. I am just trying to figure this out. There was a post above about a 14mm cutter. A 14mm cutter has a radius that is .00565 smaller than 9/16 radius. In looking at SAAMI cartridge specs I saw a lot of cartridges with a case head size of .532 to .534. That's almost .030 smaller than 9/16 diameter. The radius is 015 smaller than the 9/16 radius. So where does this 9/16 diameter come into play that it is so critical? I would think that the critical dimension is the diameter just above the rim.

I have not done any reloading in a long time and don't have a shell holder that I can measure.