Fixed a bad HP job

[Brad]

A few Weeks back I botched a job making a 357466 HPmould. The pin was off center.

Easy to see which cavity has the hole off center.

 

[Brad]

Messing with the off center hole to make it right wasn’t a viable option. Would have required a long, skinny boring bar to make a .200 hole .7 deep. Just wasn’t something I was willing to try.

I could always HP the other cavity but the it becomes a single cav mould. I thought on it and decided to make a pin held in place to fill the off center hole.

Made a pin, got the end flush with end of cav in mould and clamped it in place. Found the center and drilled a 1/16 hole with a countersink on either end. Peened a brass pin on each end to hold the pin. Repeated that then milled the excess pin flush with the bottom of the mould.

Just needs a test run.

 

[Ian]

Extra alignment. I think that actually will improve it.

 

[Jeff H]

Ingenuity at work!

How did you HP to begin with? I'm not looking for something to criticize, as I am no machinist and am curious how you got the second one the way you wanted it.

I once tried to use a short, stout center-drill, which the lube groove (reverse image thereof) of a 30 cal mould held the body of the drill centered so I could get a pilot hole in the right spot. Would have been a real genius move, had it worked.

It did not.

 

[Brad]

I drill them on the mill. I get them close with a pin gauge in the Chuck. Then I use a .0005 indicator to get the cavity centered. Center drill, drill under size, and ream the hole.

The bad one I didn’t use the indicator to get it truly centered and paid a price. Stupidity on my part.

When I do things right I get good results. Far easier on the mill than using a 4 jaw on the lathe.

 

[harm]

Looks good! I don't think I could manage any of that work with the tools I've got here.

 

[smokeywolf]

Stupidity on my part.

NOT stupidity. It's called gaining experience. If you aren't making mistakes, you aren't learning much.

Nice fix.

 

[Wasalmonslayer]

Very nice repair
Alignment should be superb now!!

 

[Jeff H]

I drill them on the mill. I get them close with a pin gauge in the Chuck. Then I use a .0005 indicator to get the cavity centered. Center drill, drill under size, and ream the hole.

The bad one I didn’t use the indicator to get it truly centered and paid a price. Stupidity on my part.

When I do things right I get good results. Far easier on the mill than using a 4 jaw on the lathe.

Thanks, Brad. Always enjoy the creativity of "machinist-types."

I don't think I could pull that off with my drill-press. The quill is tight enough for making straight holes in wood, but not as straight as you can get with a mill.

 

[Ian]

The quills in mills aren't perfectly tight, either, though a sight better than most drill presses. That's why for super-precision drill work you lock the quill and move the table up with the knee.

ETA, there's no such thing as "super-precision drill work", that's what boring bars are for. You can get close though with a spot drill, well ground twist drill, and a reamer.

 

[Brad]

My problem initially wasn’t a hole wandering or not perpendicular. My problem was not starting the hole in the center of the nose of the cavity.

I ream the hole so I get a consistent, round hole. I also have a reamer .0005 over the ground rod I use for the pins. That makes fit in the hole so much easier.

I’m not smart, just lazy.

 

[Ben]

That is a great fix ! !

 

[Snakeoil]

Nice save. But you missed a chance to stamp you initial in the plug so you bullets would be monogrammed.

 

[CWLONGSHOT]

I never doubted your abilities Brad!!

Now lets see some of the castings!!

CW

 

[JonB]

That is some nice work.