Drilling Brass

[Wayne Smith]

I just ordered a foot of .50 brass rod to cut into 1/2" pieces and drill out for my Pacific (Hornaday) Pistol Powder Measure to make bushings for it.

My question: How do I hold onto that piece of brass to drill it out without crushing or distorting the result?

I have a drill press and both wooden clamps and a drill press vice. Do I need something like rosin on leather to hold on without distortion? Is there a better way?

[mongoosesnipe]

I would make some appropriate sized wooden vblocks to hold them into place.... Blocks are where it's at for holding round stock in a vice but a lathe would be optimal to ensure center drilling though it shouldn't be nessisary for powder bushings

[joesig]

Are you lucky enough to have one of the presses that have a hole below the quill? You can feed the rod up from the bottom and have the solid rod clamped while you drill above the vise/clamp. Baring that, you may want to make a metal or hardwood "collet" (split block with a .495 ish hole. Rosin wouldn't hurt) and clamp that in the vice for more uniform clamping around the circumference. Are you really planning on hogging a hole out to 7/16 or so? You may have better luck getting some of the K&S brass tubing from the local hobby shop.

Also brass is tough to drill as the bit tends to bite. Ideally you want a slightly dull drill bit. I hope the below provides some detail and help for this.

http://www.homemodelenginemachinist....grabbing-7914/

[john hayslip]

I think you should find someone with a Machinist's Handbook and look up drilling brass for if I remember correctly the drill angle of a recommended drill is quite a bit steeper. If you want a really smooth hole, drill undersize and ream to final size.

[Willbird]

I know for BRONZE you web thin the drill and carry that out into the flute, remove the helix more or less. The first time as a tyro you drill bronze without doing that, especially with a pilot hole things will get exiting real quick . Seen it spin the handle on a multi spindle drillpress 180 and crack a guy on the head once . My learning incident I had drilled the pilot hole no problem, put a 1" or so drill in the lathe tailstock, snuck it up close and it touched the part before I locked the tailstock down, and YANKED the tailstock forward and drilled the part at the helix rate of the drill ...all in about 1/3 of a second .

I have made quite a few of the bushings out of plastic and aluminum, but I suppose you already have the brass .

At one time I made up a spread sheet to calculate the hole size used to throw a given powder charge used Lee's vmd values in the Perfect powder measure instructions. You can buy 1/2" dia nylon standoffs as lowes in the little drawers of parts in a range of dia that will let you make a lot of bushings by drilling larger.

[Big Rack]

Can't say much for drilling but for holding drill a strip of hardwood drill to OD then split one end for clamping pressure. Or take two hardwood blocks put a few layers of grey paper tablet type cardboard in between drill to OD then remove the cardboard for clamping pressure.
For a fact listen about the drill edge or you will be amazed how fast that little piece eats the drill and I swear grabs so hard you think it threaded. I guaratee your hand will make sure and tell you not to do it twice.

[cody9999]

I know for BRONZE you web thin the drill and carry that out into the flute, remove the helix more or less. The first time as a tyro you drill bronze without doing that, especially with a pilot hole things will get exiting real quick . Seen it spin the handle on a multi spindle drillpress 180 and crack a guy on the head once . My learning incident I had drilled the pilot hole no problem, put a 1" or so drill in the lathe tailstock, snuck it up close and it touched the part before I locked the tailstock down, and YANKED the tailstock forward and drilled the part at the helix rate of the drill ...all in about 1/3 of a second .

I have made quite a few of the bushings out of plastic and aluminum, but I suppose you already have the brass .

At one time I made up a spread sheet to calculate the hole size used to throw a given powder charge used Lee's vmd values in the Perfect powder measure instructions. You can buy 1/2" dia nylon standoffs as lowes in the little drawers of parts in a range of dia that will let you make a lot of bushings by drilling larger.

I've never had to thin the web on soft materials but if you hone the cut edges so that you have about . 010-.015" flat at a 90° to the work this gives a neutral rake and will prevent the drill from sucking into the brass. This works equally well on plastic.

[kywoodwrkr]

I'd if needed fast and dirty, would take a block of Aluminum and drill a 1/2" hole in it.
I'd then split this with a hack saw.
I'd then use the two halves much like a V block to hold the brass sections while drilling.
If possible, I'd use end mills instead of drills as well
If drills it be, I'd take a ruby(or arkansas) stone and dull the cutting edge just a tad to keep it from threading into the brass.
Like what you would do for drilling plexiglass and acrylic. Peck drill-drill, then up, drill, then up etc.
I'm trying to do the same thing for the Accumeasure, making my own brass drums.
But I have access to mills and lathes as well as good drill presses.
What ever method you use, make sure the brass is secured! Don't hold the mechanism, you use for holding the brass, by hand. ie milling vise etc etc. CLAMP it down.
PS willbird, I have a similar Excel spread sheet using MasterCam to calculate hole depth in drums with different diameter holes.
Takes into consideration curvature at top of the hole etc etc.
D.

[Wayne Smith]

I know for BRONZE you web thin the drill and carry that out into the flute, remove the helix more or less. The first time as a tyro you drill bronze without doing that, especially with a pilot hole things will get exiting real quick . Seen it spin the handle on a multi spindle drillpress 180 and crack a guy on the head once . My learning incident I had drilled the pilot hole no problem, put a 1" or so drill in the lathe tailstock, snuck it up close and it touched the part before I locked the tailstock down, and YANKED the tailstock forward and drilled the part at the helix rate of the drill ...all in about 1/3 of a second .

I have made quite a few of the bushings out of plastic and aluminum, but I suppose you already have the brass .

At one time I made up a spread sheet to calculate the hole size used to throw a given powder charge used Lee's vmd values in the Perfect powder measure instructions. You can buy 1/2" dia nylon standoffs as lowes in the little drawers of parts in a range of dia that will let you make a lot of bushings by drilling larger.

I don't know what "web thin" means in this context. Could I get a copy of your spread sheet or is that all gone? Actually, since I don't have a complete set of drills over my set of numbered drills I was planning to use my Lyman 60 degree edge cutter to adjust the size of the holes. I do have a set of metric drills and a couple of lettered drills from my pen making.

I was able to get a Hornaday #19 bushing which I would guess is the thinnest of them.

One of my aims is to get close to 1gr Bullseye repeatedly and work up from there. The holes in the nylon bushing are too big for that target. I do want some reasonably large ones, though. I need sizes for the .45 ACP and Schofield. (1gr is for my H&R top break 32 short)

I do have some experience with tropical hardwoods climbing drill bits. I know how quickly it can happen. I'm assuming that's what you guys are talking about.

End mills, eh? I'll have to look into those, but expense may (probably will) be an issue.

[timbuck]

http://www.chaski.com/homemachinist/...hp?f=4&t=90388

This is what you do to the drill to cut brass.
Scroll down to the picture.

[leftiye]

Collet, straight flute drill. ("D" drill) As was stated, on a lathe, drill first, then cut to length, more waste, less problems. Hogging isn't a 100% occurring thing, slow feed with a normal drill will often avoid it. It gets worse when you drill a pilot hole.

[Willbird]

I don't know what "web thin" means in this context. Could I get a copy of your spread sheet or is that all gone? Actually, since I don't have a complete set of drills over my set of numbered drills I was planning to use my Lyman 60 degree edge cutter to adjust the size of the holes. I do have a set of metric drills and a couple of lettered drills from my pen making.

If you have never web thinned a drill it can be tough to describe, Timbucks link does a good job of it, I would actually "dub" as some call it the flute a bit more. All you are doing is providing a zone of zero back rake.

I'm sure I do not have the spreadsheet any more. But I can probably hack up a quick version again .

[Willbird]

powder chamber.ods.zip

OK here is a quick hack up, I did the math in steps so if you want to check it you can, change values for vmd (from the lee perfect measure instructions or Lee's book) charge weight, and the length of the bushing. The stuff in red is the answers, don't mess with them, the grey boxes are steps of the calculations, don't mess with them either .



There are two tabs in the spreadsheet, the first is for calculating powder column length in a smokeless muzzle loader, ignore that one, the other tab is powder chamber dia. I used to be a bit better with excel than I am with open office, so I break formulas down into steps to get stuff done, a whiz might be able to combine it all in one formula.

[Wayne Smith]

Thank you, Timbuck and Will. I'll have to get my wife to help me with your spreadsheet, Will! She uses them every day as a geologist, never do. I think this is doable.

[W.R.Buchanan]

Gosh guys: why don't we just make it real complicated. It's brass and is about the easiest material to work there is.

Just take a drill and drill the thing. Try putting some oil on the bit. Faster you run the drill press the less likely it will be to catch and thread thru. Better yet drill a pilot hole in the thing first.

Use two pieces of wood in a vise with the a hole drilled thru the crack to hold the parts.

No need to worry this job to death. IT's brass! Besides if you do have problems you may learn something from the job.

Randy

[Whiterabbit]

I'd drill a hole .49X through a pair of hardwood blocks that were carpet taped to my vise on the drillpress. That way, the rosined piece would hold a .5" brass rod like no-ones business AND center in one shot.

But really, I'd use the lathe. such a nice tool to have! the minilathe would make short work of this.

[jmorris]

Here is another idea. If you have an old drill chuck, like one off a drill you replaced with a keyless chuck, drill and tap a block and attach the chuck to it. Take a dowel and clamp in it the block/chuck then into the drill press chuck. Now clamp the block into the vice and they are aligned. Put drill bit in one chuck and brass rod in the other and make centered holes.

[Wayne Smith]

I have a chuck on a MT1 taper I use in the woodlathe. I could drill a corresponding taper in a piece of hardwood and do the same thing. Way too cold to be working in the garage other than casting boolits, though! Got a fire going in the fireplace, gotta cut some chicken for dinner, too.

[DCM]

+1 on #15 & #17!
Definitely keep the oil flowing!

Also (not needed for this though) depending on your endmill needs they can be had fairly cheap @ http://www.use-enco.com/

[Doc Highwall]

I made a drill for making hollow points in lead bullets and what I did was use a 118 Deg split point drill and ground the cutting edge like in post #10. When I was a cutter grinder, changing the rake angle on the face of the flute like in post #10 was called a #24 point but I also thinned the web at the same time.

I did it by hand with a grinding wheel that had a radius on the edge.