Help me make a D-reamer

Ian

Notorious member
Bill, Keith simply showed me an elegantly simple way to accomplish what I mentioned in post #8 without having the tooling to off-set both ends of the reamer: Just face off the end that goes in the tailstock, offset it in the 4-jaw the necessary amount and clock position, and re-drill the center. As he says, cutting the relief on the lathe doesn't provide any significant rake at the cutting edge and I'll still have to do that by hand.

This first reamer will be so small that I'll probably just grind off the material freehand on the bench grinder and do the rake with a stone.
 

KeithB

Resident Half Fast Machinist
I'm going to make this educated supposition that the reason a lot of D reamers were used successfully by gunsmiths for years is because a lot of the steels used for barrels were pretty soft. Can't imagine how a D reamer would work on a stainless steel barrel. Hell we can hardly cut the stuff with the best tooling available, deliberately ground for that material.

I'm always willing to listen and learn.
 

Ian

Notorious member
5.56X45mm nose-first H-die reamer, in progress.

Turning the form with homemade HSS tool:

20181002_214523.jpg

Relief edge hand-stoned, showing the tiny black mark on the very edge where I stopped. The back side has been relieved as well. Relief angle is about five degrees or so. I'll finish the edge with an Arkansas stone after the heat treatment.

20181002_230005.jpg
 

Ian

Notorious member
Forgot dimensions. .2265" for the parallel body, .218" for the pilot, 1.2° per side taper. I hit the drawing pretty close, went a touch under on the body, right at .2260" and finished the pilot dead on .218". To set up the taper angle I did some trig, set the compound, and trammed between two points with a test indicator until I got the desired .010" difference. After cutting the angle I re-measured between the actual cut end points, did the math again, and came up with 1.29°. Close enough for me, now all I have to do is heat treat it, sharpen it, ream and hone the die out to .2185", and find out if it cuts true negative image or not. Then size a bullet and see if all that translates through the alloy to the final dimensions I want. Fingers crossed.
 
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Ian

Notorious member
Ok, no fotos but I got the reamer hardened and sharpened, then drilled the die to size and reamed it out. Worked pretty shnazzy, but I learned one important thing that I'd wondered about: tool flex. It made sense to not relieve the trailing edge so it would drag and keep the cutting edge pressed against the work (like a following rest in a way), and I tried not to touch it when cutting the relief....but got carried away and ground off a few thousandths anyway. Oops. So the reamer went all the way in and barely cut at all. What I had to do was choke up on the reamer with the tailstock chuck, leave the quill lock fully loose to give a little lateral wiggle, and apply pressure to the side of the chuck with a bar (no hands! Stuff that can break, dig in, and suddenly spin like an MT chuck is no-touchy territory) to flex the reamer to the side to get it to bite. Fortunately I managed not to bell the hole doing that and it turned out just fine.

I ran out of time to make an "I" ejector, so no finished bullets yet, but I sized a few with vise, hammer and punch and they turned out almost exactly as intended. When sizing 21 BHN heat treated bullets, the nose band is about half a thousandth large at .2191", the taper is spot-on, and the base is a little small at .2256". I might hone out the base a little more on the lathe with a rod and sandpaper since I got a little trailing-edge leading with bullets smaller than .2265".

The die also works very well to uniform and slightly re-shape the 75-grain, powder-coated silhouette bullets that I use for subsonic loads. That will ensure that the noses will chamber reliably in my ARs. The powder coating introduces enough thickness variable to jam occasionally and the odd elliptical bullet can get stuck in the throat. The air-cooled ww bullets sized out at .2185" on the end of the nose, just perfect for my rifles.
 
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Pistolero

Well-Known Member
OK, I was thinking about Keith's original sketch today, and it finally dawned on me that he
was showing how to get the relief grind on the back side.......damn, I can be dense some days.

Bill
 

Ian

Notorious member
Finished reamer:

20181004_222846.jpg

Ejector, bored with 11.5 degree per side taper to match bullet nose profile:

20181004_223116.jpg

Finished die:

20181004_223215.jpg
 
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Ian

Notorious member
MX3 bullet after sizing, it goes into the throat one full driving band further. This is how it should have fit if the mould had been cut to the drawing's dimensions.

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ACE .226-75 grain bullet nose sized from .222" to .2195" by about .100" long and gradually tapering up at 1.3 degrees:

20181004_223734.jpg

I used the wrong end of the ejector so there's a ring on the ogive. The other end of the ejector is center drilled and polished for the pointy bullet designs.
 
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Ian

Notorious member
Better photo, nose-sized bullet on left; push-through sized after coating. The push-through die sizes them half a thousandth larger on the bands than the nose die sizes them:

20181004_223744.jpg

Now there will be no more nose sticking in the throats with my subsonic AR load. That load doesn't cycle the action so consistent, no-jam fit is a must. Irregularities in the coating on the nose or proud parting lines are no longer an issue.
 
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KeithB

Resident Half Fast Machinist
That.s what Ian does with a mini lathe - give him a full size lathe and he would build a space ship or time machine or a dimensional portal. Sheesh!
 

KeithB

Resident Half Fast Machinist
Bill, I could probably explain things a little better. This is one of those things where seeing someone do it is easier to understand than hearing how to do it.
 

Brad

Benevolent Overlord and site owner
Staff member
Damn fine work Ian.
What Ian has that makes up for a lack of tools is a dogged determination. If he wants to do it the by damn it is gonna get done. That kind of patience is something I tend to lack.
 

Ian

Notorious member
It's amazing what you can do when you have good instruction. Just determining what material to use would have taken me forever without help. Hardening and tempering I already knew a little about from knife making, but every material (and tool) has different requirements. Now I can catch fish a little better on my own. Thanks to all who replied to my call for help and walked me through it, I learned a bunch in the process.
 

GRMPS

Active Member
I'm jealous of you "boys" with your "toys" and the place and knowledge to use them:p

When my bullet seating stems leave marks, I clean them,fill them with hot glue and press a lightly lubed bullet nose into it, let it cool and trim the sides.
 

JWFilips

Well-Known Member
To You machinist guys:
I just love these threads!

When I wanted to learn how to forged metal. I had a very old blacksmith teach me everything he knew & I absorbed it!
He was working on the weekends, as was I, at a small 19th century museum.
Once I got my own little forge I set about to make a set of 18th century gunsmithing tools!
When I showed him the fruits of my labors he said to me ....."Wow I can't do that kind of stuff!" I just make metal art for the kids!
Then he asked me where I learned how to make forged tools? I smiled and said, "from you, sir!" Guess I just needed to understand the Theory and principal and learn the skill.
 
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Ian

Notorious member
Iirc there's eight basic techniques you need to master as blacksmith, once you got those down you can do anything in the realm.

Same thing with a lathe. Learn turning, facing, parting, drilling, boring, threading, and a whole lot about measuring and indicating, and the rest is just variations of the basics.
 

Ian

Notorious member
Made another .30-caliber, two-step reamer today. First one I made had a .299" pilot and cut at .3095", making bullets closer to .3005 and .3105" if they are over 15 bhn. So I ground this one with a .297" pilot and .308" body, tapering at about 1.5 degrees per side. Bored and honed one of Keith's Lee die blanks to .2993" and reamed it to .309, deep enough for any .30-cal bullet. The leade-in starts at .315" and tapers to ths body size. Result is parallel .3098" bullet body tapering to .3000", sizing water quenched 6/4 bullets. Made this one for Fiver's .300 Blackout.

Then I made myself an H-die with ejector, but honed it out to make .3000 X .3100" bullets for my M1A. Now I need to grind down the first .30-cal reamer I made and make an H-die that produces bullets that are .300 X .3093" for my blackouts and one of my .308s.

20181118_130429.jpg

20181118_153036.jpg
 

Ian

Notorious member
Forgot to add, I did the eccentric thing and cut the relief with the lathe, then filed the relief angle on the cutting edge while the reamer was indexed in the lathe. Used a level on top of the file to keep it nice and flat. It all worked like a champ. Every one of these I make comes out better and takes less time.