Fun things to do with your reloading bench, part IV

[rbstern]

For cast bullet lubrication, I have an RCBS Lube A Matic. It's a fairly good machine, but can be balky in applying bullet lube. I use LARS Red Carnauba lube (fantastic high performance lube, BTW), with a Lymn heater under the lube machine. The mechanical pressure system works, but is tricky to keep flowing well, even with the heater on.

A few months ago, I experimented with replacing the mechanically driven press-lube assembly, using air pressure instead, to see if I could get more consistent lube application as well as faster throughput when processing my cast bullets.

The results have been excellent. Here are some Lee .358" 125 grain bullets after the sizing and applying the lube using air instead of mechanical pressure. With the mechanical system, the lube tends to get under- or overapplied, resulting in messy bullets. These came out with the lube perfectly full, in the groove, with no shortage gaps or overfill.

In the next post, I'll show the details of the conversion.

 

[rbstern]

Replacing the mechanical lube pressure system with air pressure on the RCBS Lub-a-matic:

Materials used
- Cork gasketing material (sold in sheets at automotive stores)
- Plumbers tape
- 10 mm x 1.5 x 30mm hex bolt (Crown Bolt upc #30699-36068...Home Depot)
- (2) 4-40 screws, 1/2" length
- 1' length cut from end of PVC air hose (50' hose for $9.99 at Home Depot)
- Small hose clamp (3/8" to 7/8" or similar)

Tools used
- 10mm x 1.50 tap
- 4-40 tap
- #43 drill bit
- 1/8" drill bit
- Drill press (not essential, just makes some of the drilling easier)
- Cordless drill
- Metal cutting wheel or hacksaw
- Air compressor
- Handtools (screwdrivers, center punch, etc.)


The cap assembly:

1) Remove cap from RCBS press and use the 10mm x 1.5 tap to thread the center hole of the cap.

2) Drill a 1/8" centered hole lengthwise through the the 10mm x 1.5 x 30mm hex bolt.

3) Using a cutoff wheel or hack saw, cut the hex head off the bolt.

4) Wrap all of the threads of the now headless bolt with two to three wraps of plumbers tape.

5) Thread the bolt into the RCBS cap from the top side, leaving about half the length of the bolt exposed.

6) Cut one foot (or whatever length you find suitable for your setup) from the PVC air hose.

7) Using the hose clamp, clamp the cut end of the hose onto to exposed end of the bolt protruding from the RCBS cap.

Threaded RCBS cap, drilled hex bolt:

Mated:

Cap assembly looks like this:
(shown with a quick disconnector attached to the 1/4" NPT fixture on the hose)

Making the base air tight:

1) Remove the threaded rod/mechanical pressure assembly from the lube reservoir. The press can easily be returned to mechanical pressurization, so be sure to store these parts, in case you need them again.

2) Using the gasket material, cut three circles 1.5" in diameter. A 1.5" fender washer makes a good template for this cut. Depending on your mounting system, you might need additional gasket thickness. Just add another 1.5" disk. I experimented with several different shapes of gaskets before settling on making these disks to fit into the bottom of the reservoir. This proved to be the most airtight solution.

3) Place the three circular gaskets in the opening at the bottom of the press and remount the press to your lube heater or work surface. This is more easily done if there is lube in the reservoir. Just push the gaskets onto the lube.

Gasket material in place:

Mating the cap to the RCBS body:

1) Clean off the top of the press so that nothing impedes the cap from being seated as tightly as possible.

2) Place the cap in the press (without the hose assembly attached). If possible, clamp it on firmly using a woodworking clamp, or whatever you have available.

3) On my press, there is only about 0.2" of mating between the cap and the press body, so I chose 4-40 screws to hold the cap to the body. I carefully marked and drilled #43 holes through the body, into the cap and then threaded the holes with the 4-40 tap.

Drilling and tapping these holes is the toughest part of the process, because the working area is small. Go slow. This needs to be a good fit.

Threading for 4-40 screws to hold the cap in place:

Cap held in place with 4-40 screws (one on each side):

Final assembly:

1) Reattach the hose to the cap.

2) Use some plumbers tape to make a seal around the edges of the cap. I used approximately four wraps around the circumferance of the cap.

3) Place the taped cap assembly in the body and fasten it in place with the screws.

Finished and working!

Additional comments:

My setup has a Lyman heater, and the lube in my press is LARS Red Carnauba. With the press fully warmed up, and a 358 sizing die in place, I found I could get lube to flow anywhere from 20psi to 40psi. I finally settled on about 32psi for good fillout. The only problem I ran into was when an air pocket reached the die, with a void all the way to the pressurized air in the reservoir. Air can then escape through the die as bullets are cycled, and the lube won't flow. I removed the cap assembly and used a wooden dowel to pack the lube down firmly in the reservoir, to purge any air pockets. I also melted another stick of lube and poured it in on top of the lube that was already in the press. Unfortunately, with the hollow stick lubes, you may have to go through this a couple of times until you've eliminated air pockets. Best way to avoid this is to start with any empty reservoir, and pour in melted lube. You can also melt the existing lube in the press by heating the press with a heat gun.

This setup is not air tight. It took some experimenting to figure out the right gasket configuration for the base (3 stacked disks), and I had to re-tape the cap a couple of times. Air still escapes, but at a very low rate, and the press seems to be able to hold pressure well. I have a 60 gallon compressor in my basement shop. Even with all of my experimenting over a few hours, the compressor never had to cycle on. This setup should be efficient even with small compressors, as long as you do a decent job of gasketing and taping the connections.

Once in operation, the thing was a pleasure to use. I haven't timed myself, but I suspect my throughput rate is going to double. I can keep one hand on the RCBS press lever at all times, with no reaching for the pressure wrench. The boolits fill out consistently, so I don't have to run some a second time.

Potential improvements? I could see mounting a standard NPT coupler directly onto the RCBS cap, and atop that, a pressure gage for being able to view and manipulate the air pressure without moving from the press.

And a safety note: Wear eye protection when working on this setup. By air tool standards, 32psi is low, but it's plenty enough pressure to get a small part flying fast enough for an eye injury.

 

[RamRoddoc]

rbstern,

While lubing my own bullets is more than I care to do, your pics and explanation make for good informative reading. Really good post.

 

[magna750]

Nice! You are a man whose wheels are always turning...

 

[rbstern]

Nice! You are a man whose wheels are always turning...

Spinning. But I appreciate the sentiment.

 

[TacticalTaco]

So how much does it cost you to RL 9mm FMJ?

 

[SteelRinger]

Great write-up. I have the same issue with my Lyman lube-sizer. I might have to give this a whirl.

 

[rbstern]

So how much does it cost you to RL 9mm FMJ?

TT, I don't load much FMJ. Pretty much all of what I load for pistol are my own cast bullets. Assuming scrounged lead, range pickup brass, and powder and primers bought in bulk, my cost is about 2.5 cents per round for materials. My cast 38 special and 9mm loads are cheaper to shoot than bulk 22LR.

FMJ bullets, bought in bulk, would add about 10 cents per round.

 

[rbstern]

Great write-up. I have the same issue with my Lyman lube-sizer. I might have to give this a whirl.

If you do, please share your results.