I’m Bill Rhinehart. I live in Riverside. I am a member of GPAA and Route66 Gold Miners here in Southern California.
My sincere thanks go out to Mark Keene and Keene Engineering. His help took my 1960’s homemade dry washer and took it into the 21st century using today’s modern technology.
I have an old wood dry washer that was given to me about 9 years ago by a very old prospector who has since passed away. For years it sat unused. Recently I noticed it in the very back of one of my sheds and pulled it out. I decided to get it back into the game. I was cleaning it up and I was looking for ideas on how to make it work better. What better place to get mining equipment help than at a Gold Show?
I went to GPAA’s Gold Show in Pomona, Ca. in February of 2016.
I met Mark Keene there. I showed him a few pictures of the old girl and he fell in love with her. He presented me with some awesome design ideas. I was all ears.
The next week he sent me a “care package” that included a board-rubber-cloth-carpet assembly from a discontinued Dry Washer they once produced. He also sent me a Lexan piece and a silk screen cloth in a bag.
On the phone we discussed the design and engineering of the changes that he had in mind. After some time it finally hit me. The design of the Keene Dry Washer is pure genius.!!
I went right to work.
This project was a struggle because there were several things that I had not initially noticed.
Designing a way to slide the riffle tray in and out of the shaker box was a kick. Cutting the Lexan was a challenge. The fan assembly had frozen up.
One question I had was the use of the flat punch plate underneath the carpet. It held the tray up off of the carpet. Was it necessary?
I also wondered if more screws would do better job holding the tray assemble tightly together.
I had a lot questions along the way and Mark graciously and patiently stayed with me until I finally got it.
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I immediately noticed that because the original design of the riffle tray was so that the tray just lifted up, but not out, that there would be a huge gap between the first riffle and the area where the hopper feeds the tray. The old tray would have had an opening if I had attached the cloth directly to the first riffle like planned. So I got a piece of aluminum, cut it and bent it to size then drilled and pop-riveted it to the tray so there would be something to attach the silkscreen too.
I cut slots in the riffle tray so it can slide in and out of the shaker box itself. I cut the slots at an angle so when the tray is inserted it’s pressed down into the box. I worked the box to allow smooth installation and an air tight fit.
I cut and glued the silkscreen to the bottom of the riffle tray and let the cement dry. I then cut the rubber under piece and set it on the silkscreen. I then took the Lexan piece, marked where it needed to be cut and used a Jig saw to cut out the rectangular holes under the riffles themselves. I utilized Mark’s recommendations and created a “Dead Space” under two of the six riffles.
After sanding and smoothing the edges of the cut Lexan bottom piece I drilled then screwed it to the riffle tray. The tray itself was now a complete and removable assembly with the riffle, the silkscreen, the rubber tool box liner and then the Lexan.
The tray is now 21st century technology that with the vibration and air movement will create a static charge on the cloth screen. The Lexan base creates a “Dead space” under a couple of the riffles to attract the gold. The tool box rubber works with the vibration thus creating a “Balloon Effect” where the silk screen will become charged with static electricity just like rubbing a balloon.
As I said I asked Mark if that base punch plate set under the riffle tray was necessary or if it was just there for support of the carpet under the tray. I was wondering if I could use the ¼” metal hardware cloth instead. When I used the punch plate the entire assembly would sit up too high. (IMO)
Mark told me the ¼” H/W Cloth would work just fine.
This carpet is for easy underside cleanup and helps to more evenly distribute the air under the riffles.
The riffle tray was now complete and removable for instant cleanup.
I disassembled and rebuilt the fan/offset weight unit. One of the bearings was frozen solid. It is totally custom fan unit made by using two ball bearings with a bolt in the middle. The bolt is the shaft. The fan is 7 ¼” in diameter and sits 1” over the air inlet.
After I made more modifications I can now add and remove offset weights to increase or decrease tray wobble as necessary.
I installed 9 “Scrubbing Pins” to help the hopper material enter the riffle tray more evenly.
I made the shaker box hangers so they allow the chains to drop straight down from a hanger assembly to the box itself. There is NOTHING in the way of the tray now. The hanger holds the chains apart so cleanup is more like the fantastic Keene models. It also makes it VERY easy for me to change the riffle box angle. By adding or subtracting links of Jack Chain to the spring on top of the bar that holds the two chain hangers apart I can make a very fast tray angle change.
Now it’s a snap to take the tray out for cleanup, put it into a five gallon bucket and Tap-Tap…Done
I set the box for an 11 degree drop angle without any added chain. By adding 2 links to the center holding point it sets it to 14 degrees drop, add two more and its 17 degrees and two more to 20 degrees.
I can make the change in seconds and do it without shutting down the blower.
All the wood is treated, the riffle box fits tight and I got rid of the springs holding the rear to the grizzly. I made the offset weight system easy to modify on the fly. I can make changes and level the riffle tray now too. All I need is my torpedo level and my phone which has an Angle Meter installed.
I don’t have any way to check the Echo’s engine speed. Mark wants me to set it at above 750 rpm but not over 1750 rpm. The Echo also needed repair as the Primer Bulb had cracked. The throttle cable was set incorrectly so it only reached ¾ throttle. I fixed both and it’s running like a champ.
Now for the fine tuning…
After sending Mark a video of the system running, he said he thought the vibration looked “Soft”. I removed the smaller weight and put on that large one. It is heavier but I do not know how it will work. I suspect that to get the fan spinning now I will need to increase the throttle but the added weight should make the vibration stronger. We’ll see.
How do I make the vibration more pronounced? Should I lower the air intake speed or add more offset weight? These are questions like the drop angle of the riffle box that will need to be answered out in the field.
In conclusion:
This old Oak wood dry washer looks very good. In fact it’s downright gorgeous. This is Modern day technology with Las Vegas Elegance.
I’ll get the opportunity to try it out soon.
I’ll report.
Bill
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