RCBS Green Machine Fix

These RCBS Green Machines were made back in the early 80's for only a couple of years and I can see why now. They are an interesting reloader design built for 38/357 rounds only. They have a linear stage that goes through all the reloading operations, then drops the finished round into a bucket. Out on the forums people either hate them or love them but they are still being used, however they do have some of what I would call "engineering issues". I also found that some people have "one way" converted them to take 45ACP but there are issues with that also. Overall I think they were a good concept but probably rushed to production. The newer turret style is much more versatile and reliable but pretty pricey by the time you get all the dies and goodies to go along with them.

My brother picked this one up because it was broken, thinking he could get replacement parts from RCBS. However they only have a few things available (not what was broken) and really didn't want to talk much about it. He gave me a ring to see if I could whittle up a piece and it sounded fun and doable in my small shop. I did some research on them prior to getting it from him and realized this was probably going to be more than making a replacement part. @¿@

The part that broke was the yoke for the bullet inserter. It had sheared the ears off a hardened part that pushes and sets the bullet through the die. The picture on the left is with all the new parts installed on the third die from the left. The one on the right is the old broken yoke assembly next to the new one I made.

When I got this machine in hand I realized what the real issues were with this driving mechanism: bad tolerance and alignment from the press posts in the rear all the way to the over center cam that drove it, and poor maintenance.

The first issues were being able to accurately measure the broken yoke to get some basic dimensions to build something better. And to measure all of the other components for diameters, slot and post dimensions, alignments, etc.

These pictures are with all the new parts but gives an idea of all the mating surfaces, alignments and holes and slots to create the motion.

What I found was pretty bad. The hole in the cam for the clevis clip had about .020 radial slop to the clip. The slots were not square and had been galled by something and the cam plate was bent. The center pivot was a 1/4-20 button head cap screw with a crimped lock nut so the hole and slot were riding on the threads. The cam slot had about .035 radial slop on the pin from the cast post and was out of plane with the yoke. Likely worst were the threads in the base casting that holds the vertical slide plate which allowed that whole thing to wobble like a carnival ride. So when this was all assembled and working it was a wonder in my mind why it didn't bend the driving pin...luckily it didn't but there was some wear on it.

Making the Yoke and Pin

The first thing to do was make a new yoke so I could then take a look at how to solve the other issue. After measuring as best I could I made the drawing below to give me some idea what to come up with so it would not break again.

The new post design on the right was a first cut to give more material at the base of the yoke and heavier ears. However I realized that the new .625 OD was going to interfere with the cast hex on the side of the powder measuring system...so that wouldn't do and it turns out the original OD is about as big as it can be. I decided to definitely give the base more material because the hardened steel was too fragile for all the lateral slop and stresses. I also decided to make it out of 17-4 SS which I had and would be less brittle.

After turning the basic shape and diameters for the new yoke, I did some basic layout on the part, center punched the side hole, then center punched 3 spots equal distance across the slot width on top. On the drill press I drilled the side hole through then drilled the three top holes to depth. The trick on this for me was how was I going to cut the slot? Basically I used my Dremel holder in the tool post and used a 1.5" cut off wheel and walked it in slowly a bit then backed out and over to the width I wanted...rinse, repeat until I reached the depth. The 1.5" wheel also gave me a nice radius at the bottom when it was done. The 3 top holes really reduced the amount of material I had to cut out and gave me a good reference for the width of the cut. It was a good trick and went pretty smoothly.

The other thing I did was to create as close to 12-28 UNF 3A threads as I could with an adjustable die. The hardened shaft was in pretty good shape so I just chased it with a tap. The old piece had Way Sloppy thread and may have contributed to its demise. The new threads have virtually zero lateral slop. I used the old jam nut because there was no small hex stock on hand to make a new one, nor did I want to try to track one down.

The last thing I did for the yoke was to build a "Thumb Pin" that had a tight transition fit through the yoke and cam plate and didn't stick out and hit the hex of the powder tube. I used a cut off from the shank of an old #31 HS drill bit for the pin and some of my brass ground rod for the knurled thumb knob, then pressed them together for a nice fitting and strong "clevis replacement". Overall I was pretty happy with the final pieces and that I was able pull it off with a little ingenuity and my Mini.

Cleaning up and a Drawing

After assembling the new yoke, some more thorough measurements and testing, what needed to be done became clear: First was to straighten the bent piece. It took a little finesse but finally got it as straight as I could. Then lapped the faces a bit to remove any persistent high spots, particularly along the slots. Next I cleaned up the holes and slots. The slots were not parallel by a lot and had gall marks in a few places so I tackled them first. Turned out the plates were hardened as my file would barely touch them, so I reverted to a silicon carbide stone set and spent probably an hour squaring them up to within about .005 parallel and deburred the ends and side for a nice smooth, running surface.

After that I put everything back together to have a look and test the clean and straight slides. I realized that a big issue was the rear pin which is pressed in (a bit off angle) and uses an E-clip as the running surface on the cam plate. This gave a bunch of slop and allowed the cam plate to cant over and put odd pressure on the yoke. At this point I knew it needed a new rear pin and some type of shoulder bolt for the center pivot and proceeded to make a drawing to work from.

Making the Rear Pin and Shoulder Screw

The shoulder screw was first and relatively straight forward from 1/2" brass stock. The interesting thing is that it fits the hole in the cam plate well but the vertical slide plate is a bit sloppy. This was done because I didn't want to weaken the cam plate by drilling it larger. It had already bent once between the hole and end of the slot and didn't want to take a chance. Basically there isn't a lot of movement in the vertical plate so I could make up for it with Delrin washers.

The rear pin was a bit more tricky because it was straight knurled and press fit into the casting. It also has the E-Clip very close to the far end and wasn't sure I could straight knurl a hard material or cut a tiny slot that close for the E-Clip. As you can see in the picture below I changed the design considerably based on the measurements and alignment issues I found.

The part was made from a piece of 1/2" 1144 stress reduced steel which turns better than cold rolled on the Mini. I had tried it first with a piece of CRS but bunged it up and tweaked it when I tried to do the straight knurling. I really need to practice my straight knurling but haven't spent a lot of time with it on steel. So to overcome my limitations I decided to ball mic the hole all the way through and shoot for a press fit of a couple of thousandths at the far end. That all worked fine. Making the basic shape was also a bit tricky because of the small size and skinny shoulder in the middle. Basically I turned down the threaded end to .264 and created the shoulder face, then flipped it around and made the other end. Turned it down to the press in diameter and finished the shoulder, then turned the final end diameter and the E-Clip slot. Flipped it around once more and turned the thread diameter and length then put the 1/4-20 die on it to get the threads started and finished by hand. My1/4-20 die has seen better days so don't look too close...not my best threads.

Hemingway, it came out to spec and the press fit works great with just enough room to get the E-Clip on to lock it down...On to try it out and making custom washers.

Making Washers till you're Green

Everything went together nicely and seemed to slide pretty smooth. One thing I do is make various Delrin washers every time I work with it...especially if I bore it. It helps square off my stock and doesn't waste material. I have a container I throw them into for soft clamping or nice sliding fits when I need one. I grabbed a couple that seemed close to what was needed but realized I was going to have to make a couple custom of pieces for this. I also wanted to use some brass for rigidity as well as smooth sliding. I mistakenly thought the brass would be good on the outside of vertical slide and the rear pin to stop any side canting of the plates...but turned out it needed the flex of the Delrin on the center pivot (inside & out) and it needed both Delrin and brass on the nut side of the rear pin.

Basically to keep from writing a book about finding the best thicknesses (which are in the drawing above), all I will tell you is, I made quite a few, trimmed a few, tossed a few, and Finally came up with the Optimum thicknesses for all parties involved in the parting of a sea of Delrin and lapping-dazically of brass washers all in the pursuit of clean, straight linear motion...

After trying it quite a bit I disassembled it and cold blued the 2 plates and the new rear pin, then reassembled with some light lube (Boeshield T-9) and ran it through another round of tests. Twas All Good!

Epilogue

Once assembled with the nylock nuts adjusted to proper tension and a little light lube this thing sings like a sowing machine and runs true as can be. It really made me grin that it operated soooo smoothly now and unlikely to tweak and break again. ~¿@ I am actually kind of enamored with this machine now as it is unique in all the linear mechanisms and a nice, heavy bench top unit you can crank out some rounds with.

The other thing about this machine is: I see some opportunity to make some other refinements for it, including new press heads (lower right corner of the above picture) for different kinds of bullets. It was mainly made for wad cutters but I'm pretty sure I can come up with an insert for hollow points and copper jacketed slugs as well. The other thing I noticed was the set screw to hold the casing tube magazine (top left picture) was pretty sloppy and think it might hang up a casing periodically. It could be tightened up with either a bushing of some kind or maybe a custom set screw with a knurled nob

Overall it was a great fun and fulfilling project to bring something useful back to use with a little fingering & ingenuity, elbow grease and my Mini. Mostly I was happy to be able to help my fine brother who has taken over the family reloading after Dads passing and really excelled at it. After he got it back from me, he called a few days later and had run 30-40 rounds through it perfectly, smooth as glass he said and could hear his grin through the phone. I encouraged him to sell it if he has the opportunity as I know he has been eying one of the pricey new turret types. He said he might be persuaded to sell it for the going price on E-Bay, otherwise he'll keep using it forever. If anyone is seriously interested contact me through the contact page and I will hook you up with him...for a smooth running, singing Green Machine!