Center of Meplat...

[BCB]

Is there a way to find the exact center of a meplat?...

If so, then is there some type of a bit with a point that would direct the main drilling body of the bit into that center punch hole on the meplat so a hole would be drilled exactly centered in the meplat…

Hollow pointing is my intention—just to mess with it a bit (sorry ‘bout the pun)…

Thanks…BCB

[williamwaco]

Look at the forster hollow point attachment.
Even if you don't like it it will show you how it can be done.

[fourarmed]

"Exact" is a relative term. It would be pretty easy on a lathe. With a drill press, you could make a jig to hold the boolit while it was drilled. Clamp a thin piece of wood to the press table, chuck a bit the size of the boolit and drill a hole through the wood. Place another piece of wood or metal under the drilled one, and recenter the whole thing under the bit. Now change to the size bit you want to use for the hollow point and start cranking them out.

[Larry Gibson]

Forster HP tool works like a charm.

Larry Gibson

154095154096

[bangerjim]

Very easy......a correct sized 5C collet in a metal lathe. I have done it many times. Drills perfect centered hole, using a centering drill or carbide stubby drill. Not a standard long one.....it will wander.

Or just buy an HP mold and solve all those centering problems!

[BCB]

I have the Forster hollow pointer and I have used it, but I wanted a bit bigger hole than the 1/8” that you use with the Forster setup…

I tried to use the hole made using the Forster, as a guide for a bigger bit using my drill press, but it seems to not be centered…

I do have the cartridge in a block of wood and that holds it in place, but I guess the bits wonder some. I start small and use increasing larger diameter, but I am still having problems…

Possibly, a drill press might not be the way to go?...

Oh well, I will look for one of those centering drill bit—or do they only work in a lathe?...

Thanks…BCB

[Cap'n Morgan]

You'll need some sort of drill guide bushing. It could be a simple short steel rod with a hole the size of the hollowpoint and countersunk to slip over the cartridge.

I once made a hollowpoint tool for 22LR from an old combination pliers. The pliers would hold the bullet tight enough that it wouldn't spin when drilling the hole.
You could make a similar tool from the same mold used for casting the boolit - although it would probably be just as easy to modify the mold to a hollow point style to begin with.

[paul h]

If you're not using a lathe, then a drill guide as mentioned would do the trick. You'd need to incorporate a means to clamp the bullet to keep it from spinning.

Yes, center drills work in a drill press. In fact you can do much more accurate work in a drill press by starting your holes with a center drill and then swapping out to a longer drill as needed. I rarely use my drill press without a center drill to start the hole where I want it.

Center drills come in different sizes. A #5 has a 3/16" pilot

http://server2.smithy.com/media/jpg/machining%20handbook/Chapter_3/3-39.jpg

[Larry Gibson]

For a wide mouth HP in handgun rounds I use the 1/8 Forster HP tool first in the trimmer as shown in previous photo and then use a #4 center drill by hand or in a drill press as paul h shows.

Larry Gibson

154102

[bangerjim]

I have the Forster hollow pointer and I have used it, but I wanted a bit bigger hole than the 1/8” that you use with the Forster setup…

I tried to use the hole made using the Forster, as a guide for a bigger bit using my drill press, but it seems to not be centered…

I do have the cartridge in a block of wood and that holds it in place, but I guess the bits wonder some. I start small and use increasing larger diameter, but I am still having problems…

Possibly, a drill press might not be the way to go?...

Oh well, I will look for one of those centering drill bit—or do they only work in a lathe?...

Thanks…BCB

I am talking round stock here:

A "center drill" is only a big thick shank drill with a small cutting portion. It is used exclusively in the tailstock of a lathe to mark the center of the stock rotating in the headstock. It is NOT a magic voodoo center-finding tool!!!!!!! It prevents walking and wandering of a standard long drill when end drilling. And it also makes the correct taper hole for a live/dead center in the stock.

For flat stock in a drill press:

A center drill is used in conjunction with a center punch to start a hole. You lay out the hole position, mark it with an automatic center punch (I use an optical punch for accuracy), and then use that dimple to start the center drill.

Just another reason to buy a metal lathe, my friend. I have 5 of them. Only costs a little more to fly 1st class.

You cannot find the center of anything using a drill press! You have no ACCURATE control of x/y positioning with any repeatability. You could.......but you would have a significant investment in precision machine tools like used on my milling machines. And the runout of a cheap drill press is another drawback.

And we normally deal in 0.001 or so when talking boolits, right?

banger

[jcren]

If you don't mind a scored "x" . make a wood lathe center jig. Not sure how to explain, but is easy to make with a standard square or speed square and some scrap boards. Will Mark exact center for any diameter round object.

[bangerjim]

If you wanna get fancy for not a ton of money, get one of those pen blank centering vices from Woodcraft. I have one I use for drilling exactly in the center of pen blanks before I mount them on the mandrels for turning on the wood lathe. But you could hold boolits in it also. Once you get it PERFECTLY aligned and centered with the drill press quill/chuck and firmly clamped down, it will allow you to put in and remove "stuff" and always be on center....within a tolerance. Again it depends on the quality of your drill press. I would NOT attempt this on any HF drill press!

Check it out on Woodcraft's website. Probably would solve your problems.

http://www.woodcraft.com/product/143609/pen-makers-center-drilling-vise.aspx

banger

[BCB]

If you wanna get fancy for not a ton of money, get one of those pen blank centering vices from Woodcraft. I have one I use for drilling exactly in the center of pen blanks before I mount them on the mandrels for turning on the wood lathe. But you could hold boolits in it also. Once you get it PERFECTLY aligned and centered with the drill press quill/chuck and firmly clamped down, it will allow you to put in and remove "stuff" and always be on center....within a tolerance. Again it depends on the quality of your drill press. I would NOT attempt this on any HF drill press!

Check it out on Woodcraft's website. Probably would solve your problems.

http://www.woodcraft.com/product/143609/pen-makers-center-drilling-vise.aspx

banger

I wonder if a rimmed case could be clamped in place with that vise?...


Thanks...BCB

[BCB]

For a wide mouth HP in handgun rounds I use the 1/8 Forster HP tool first in the trimmer as shown in previous photo and then use a #4 center drill by hand or in a drill press as paul h shows.

Larry Gibson

154102

I used the hollow pointer and then used the #4 center drill...

The problem is holding the case in place. I drilled a hole in a piece of wood and then placed a clamp and tightened it so as to "crush" the wood against the case. Still didn't work very well. I did get 2 that looked pretty good, but way too much time getting each set up...

Something to hold the cartridge would solve the problem...

Thanks...BCB

[JSnover]

FWIW, the other reason they're called center drills is because they cut the proper taper for use with a "live" center mounted in the tailstock. This provides better support for a long piece or when turning between centers. You can buy center/spot/countersink drills which will cut the correct taper (countersink) for countersunk screws. Using one of these, your cavity wouldn't have to be quite so deep, if you wanted your HP boolit a smudge heavier.