HomeNewsMachining a Inflexible Reamer Holder (Rifle Chambering) – Final Reloader | The...

Machining a Inflexible Reamer Holder (Rifle Chambering) – Final Reloader | The Global Today

I’ve talked about inflexible reamer holders many instances, most not too long ago in my 50 BMG construct kickoff. At this time, I’m displaying you how one can make your individual! 


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About Inflexible Reamer Holders

Bruce Thom, proprietor of BAT Machine, launched me to inflexible reamer holders at his private store. I’ve used a number of varieties of reamer holders over time, however I’ve absolutely transitioned over to Thom’s tool-holding methodology. 

Inflexible software holding is sweet software holding. This assertion rests on the coronary heart of Thom’s technique. The extra inflexible, the higher it’s. Inflexible software holding additionally helps remedy one other concern. If the tailstock in your lathe isn’t completely aligned with the spindle within the headstock (incorrect angle, top, and so on.), making your individual inflexible reamer holder will get rid of the issue, offering excellent, inflexible tool-holding traits. This reduces chatter and may be very correct.

Making Your Personal

Making your individual inflexible reamer holder may be very inexpensive. They’re additionally very versatile. 7/16” is the U.S. commonplace for reamers. The usual for Triebel reamers is usually 12 mm for normal cartridges. It’s simply as straightforward to make a metric inflexible reamer holder as it’s to make an SAE one. 

Begin with Morse Taper #4 blanks with a tang. I purchased them on-line for about $17. That is minimal in comparison with the $500 to $800 prices of high-end tool-holding gear from Europe. One other advantage of the inflexible reamer holder is it’s completely aligned to your particular machine. (You continue to have to align your lathe earlier than you narrow the tooling.)


Start by placing the Morse taper clean into the tailstock and getting the tailstock into place. Place a drill bit within the chuck within the headstock and get the suitable velocity going. Feed the tailstock in and pre-drill the majority of the fabric. Subsequent, put a boring head within the headstock. 

As I’ve gone by this course of, I’ve discovered a couple of issues. After I first positioned my boring head within the headstock, I chucked up on the straight shank, leading to a ton of chatter. I made up my mind this wasn’t a really inflexible software, and channeling my inside Bruce Thom, I made a decision to chuck up on the physique as an alternative. I used to be positive to go away entry to the adjustment screw. This was an enormous enchancment. 

The Global Today Machining a Inflexible Reamer Holder (Rifle Chambering) – Final Reloader | The Global Today

It’s essential to not over-cut your gap. I zeroed the dial indicator on the again aspect with the boring head intact earlier than loosening the locking clamp screws. I watched the indicator intently as I loosened the screws, stopping when the dial matched the quantity I needed to take away by way of radius. (The lower can be twice the radius, aka the diameter.) I took a couple of passes to be additional cautious. You’ll be able to take away materials, however you possibly can’t add. 

I accomplished my most up-to-date holder, my 18 mm inflexible reamer holder for my 50 BMG construct, in two completely different drilling steps. They don’t make pin holders for this measurement, so I needed to take approximate measurements with digital calipers and use the reamer as a reference. (Take a detailed have a look at the reamer and also you’ll discover a small floor floor on the flats that’s the similar diameter because the shank physique itself.) Turning at a reasonably quick spindle velocity, I fastidiously labored as much as the specified numbers. Utilizing this methodology, every thing is lower completely straight and true, completely coaxial with respect to the spindle. Earlier than you take away the Morse taper from the tailstock, mark the highest of it with a silver Sharpie or another marker. It’s essential to do that to make sure it indexes correctly. (If you happen to neglect to do that, you must use a dial indicator and comment it.) 

Clamp the inflexible reamer holder you simply lower the outlet for within the headstock and hone it to the ultimate form. This step doesn’t change the size, however improves the floor end. I used some sandpaper on a picket dowel by a cut up lower on the top for this course of together with some machine oil. I test-fit the reamer till I bought the proper match with an hermetic seal (no O-ring required!).

The Global Today Machining a Inflexible Reamer Holder (Rifle Chambering) – Final Reloader | The Global Today
Tapping for the set screw

I then drilled and tapped (5/16”-18) the holder for a set screw and inserted the reamer to the correct depth. After I felt the set screw hit the flat as I twisted the reamer in, I knew it was able to go. There is no such thing as a give in a reamer. At this level it’s going to both lower completely or snap off. 

Sidebar: Triebel Gun Instruments

The explanation for making my 18mm inflexible reamer holder was for my 50 BMG physique/neck reamer from Triebel Gun Instruments! Right here’s an outline of the reamers and gauges they manufacture:

In case you are wanting to take a look at these instruments, go to the Triebel Guntools Website.


The Global Today Machining a Inflexible Reamer Holder (Rifle Chambering) – Final Reloader | The Global Today

I’ve made 7/16”, 12 mm and 18 mm inflexible reamer holders. All have labored very nicely for me. The proof is within the lower. You’ll be able to hear the chips curling contained in the reamer flutes—a very completely different sound than you hear with a floating reamer holder. Making your individual inflexible reamer holder is a very customized, completely aligned and inexpensive various to costly, specialty tooling. 

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Gavin Gear

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