Re: drill size for measures.

[al56]

At one time i saw that a certain drill size drilled .100 deep equals 10 grains.  I keep thinking it is 29/64 flat bottom.  Any help or what do you use.

[Tim Crosby]

 I try not to over think it, drill a hole pour some powder in it, then into a measure and see what you've got. I do a LOT of stuff in the Trial and Error mode. 

  Tim C.

[Natureboy]

  I've used a succession of drill bit widths, narrower as the hole deepens. Then I grind the shoulders smooth. After I've established the optimal amount of powder by using a graduated measure, I mark the top of the powder in the hole, and saw almost all the way down to that level, using a coping saw. Then I grind a channel to aid in accurate (no spillage) pouring. Dremels come in handy for this, but a grinding burr on a regular drill also works. I posted a photo of my silly "fish" measure a while back, but I'll re-post it here so you can see the hollowed-out channel. This helps, no matter how you design the mouth of the measure.

[P.W.Berkuta]

YUP -- "silly fish" -- nicely done .

[Mike from OK]

If you have another measure, brass for instance, set it for your intended charge and measure the depth and diameter. Use those to find the volume of a cylinder for that charge...

Once you have the cylindrical volume, you should be able to divide that volume by your chosen drill diameter and come up with a correct depth.

For my .32 rifle measure I drilled a piece of antler with a 5/16 bit. I don't remember the precise depth now, but for a 30 grain charge it was in the neighborhood of 1.500 to 1.600 inches deep.

Mike

[David Rase]

al56,
When I started making my adjustable powder measures I needed to come up with a standard measurement.  I ended up using a 3/8" diameter hole .355" deep to throw 10g of black powder.  A 3/8" hole .710" deep =20g, 1.065 =30g and so on.  These are the dimensions I have been using when I make my powder measures.
David

[Scota4570]

I made a couple of adjustable measures recently. With 3f Goex,  I figured out that 0.410" bore is 0.304" per 10 grains.  A 0.435 bore is 0.280" per 10 grains. 

[Mike_StL]

At one time i saw that a certain drill size drilled .100 deep equals 10 grains.  I keep thinking it is 29/64 flat bottom.  Any help or what do you use.

I used that as a rough approximation to make a measure.  I think it was based on a fairly dense black powder.  GOEX 3fg was the closest.

That approximation does not apply to substitute powders. 

To make a measure, you should drill the cavity and measure. 

[D. Taylor Sapergia]

When making measures out of antler or horn, I bore a hole as big as I can into the end of the stock as deeply as I dare.  Then I use a rotary file or burr to continue to enlarge the cavity, pouring powder and measuring the result as I go, until I reach my goal.  I like my measures to be as thin as possible.  If I go too far, I fill them with beeswax, again, filling or paring it away until I reach the desired weight of powder.