(37) Stamp Mill Mortise & Tenon

There are two major locations where mortise & tenons are used in stamp mill construction. They are in the stamp mill feeders and the stamp mill uprights. The following are details on the use of the mortise & tenons.

Stamp Mill Feeders: The floor model stamp mill feeders are constructed of 4X4 timbers that are assembled with the use of mortise & tenons. It is a very stable and strong configuration to use. The feeders take a lot of rough punishment from the action of the stamps pressing down on the feeder actuators, and with about half a ton of material in the feeders it can be very hard on the framework of the feeders. That is why they use this type of configuration.

The restoration of the feeders on the American Boy 10-Stamp Mill (Goffs, CA) was completed by using the original timbers as patterns to make the new timbers. The pictures below show the before and after conditions for the feeders on the American Boy mill. The Golden Reef 10-Stamp Mill (Cave Creek, AZ) did not have any of the original timbers for the feeder, and we had to redesign the feeders so that they would properly fit the mill.  

The feeders needed to be disassembled and the wood parts saved and used as patterns for the new feeders.

The mortise and tenons make the feeders extremely strong and allow them to take a beating and keep working. The picture below shows the mortise & tenon wood cuts and also the method used to attach the mortise & tenons together.

The results are a very strong joint that will hold the several hundred pounds of ore and deliver it to the mortar box. The picture below shows two views of that assembled joint.

Once you have mastered the art of making the mortise, tenons and the bolting configuration you can go onto making the mortise, tenons and joints for the feeder and assembling the feeder.

The assembly stages are shown below: 

The finished product below yields two feeders for the American Boy 10-stamp mill.

Stamp Mill Uprights The stamp mill uprights generally have a mortise and tenon where they come in contact with the stamp mill base timbers. I had found two occasions to work with the mortise & tenon in the area of the bases. The first were uprights that were too short to be used as is on this stamp mill. It was a 10-stamper and the center timber was not only too short it also had rotted about 2 feet up on the upright. You can see the condition on the picture below:

The first thing we had to do was to make up a template of the tenon. The table below shows the dimensions that were taken off the original mortises. This is an important step since the mortises were not all the same size and orientation on the uprights.

The next thing was to purchase the pieces of lambeams for this particular mill to replace the rotted wood which included (2) 12” X24” X 22” and (1) 9” X 24” X 35”. Each mill replacement would be different. The center timber was thinner than the outside timbers. The timbers were ordered to size. All we had to do was drill out the mortise for each timber, using the patterns that we had made up.

Once the rough holes are cut out with the forcner bit the rest of the material is taken out with a chisel as shown below to “hand fit” the two pieces of wood:

The next step is to put glue on the pieces and clamp then in place and drill holes and install wood pins in the side of the timbers going through the upright where the tendon is located.

The final completed mortise & tenon installation on the American Boy 10-Stamp Mill.

THE END

(36) Stamp Mill Feeder Devices

(35) Stamp Mill Design Differences

THE END

(34) Gippsland Mining District Stamper Batteries, Waratah, Australia

Stamper Batteries

Gibbsland Mining District

Wahalla, Australia

April 22, 2014

We drove from Lakes Entrance to Melbourne via Wahalla. We drove to Walhalla to look at stamp mills. We traveled over 60 Km of narrow, twisting and winding road to get to the town. Walhalla is located in Gippsland Mining District and has a lot of stamp mill remnants. The mining district of Gippsland has over 70 stamper battery locations with many still in place. Unfortunately, none of the stamper batteries were operable at this location. When we arrived at Wahalla we saw two 5-stampers, 2 10-stampers and two 2-stampers just riding along the main street. There were also a lot of spare parts in the area. This would be an excellent place to restore Stampers since there are so many parts. We went from there to Melbourne and stayed there for two days to get some rest.

The town was very small and the streets were extremely narrow. Of course it was raining most of the day, but the town was very interesting. I took two pictures of buildings in the town that I thought were interesting below. They still use telephone booths in this country. I saw many of them in our travels down under.

 The poster picture below explains the following picture. It is worth a thousand words.

  

There were stamper batteries all over the town, so I just started at one end and took pictures as we went. The first one we came across was a small portable 2-stamper battery. As you can see, it was right in someone’s front yard amongst the flower garden.

There were stamper batteries all over the town, so I just started at one end and took pictures as we went. The first one we came across was a small portable 2-stamper battery. As you can see, it was right in someone’s front yard amongst the flower garden.

 

It had the classic geared bull wheel and the simple round tappets that were held on the shaft with steel shims. The sluice table needed a little work.

This stamper battery was sitting behind a barn. The interesting thing about the stamper is that the bull wheel was made with steel spokes, not cast iron. This would have made the wheel a little stronger and less affected to the vibration of the stamp operations. This mill needs some tender loving care to get it back to condition for operations. 

We pulled into the Long Tunnel Extended Gold Mine site. The building in the picture below was a museum of stamper batteries and the “check in” point for the Mine tour.

We went into the museum and saw quite a few artifacts of the local area. There was a 2-stamper battery that was a portable type and a small model stamper.  I met a person by the name of Ben Holmes that was interested in restoring a stamp mill at Wahalla. 

This is the entrance to the Long Tunnel Extended Gold Mine. We did not go on the tour since we were strapped for time. We had a long trip back down the twisting and winding road to Melbourne.

We went outside of the museum and found more stamper batteries and a bunch of spare parts. We actually met a person that worked for Thompson & Company. You can see that this mill was made from cast iron. There were quite a few mills that were made in Australia that were steel framed.

 

The stamper battery below was one of the early ones since it had a full feeder inlet in the back of the mill. You will notice that it has the classic geared bull wheel on one side and a belt pulley on the other side. This generally meant that this system had a Berdan wheel that would run off the belt pulley.

The rest of the photos show the stuff that was in the yard area. The next picture shows a couple of spare mortar boxes ready to be restored behind the museum. Note the mortar boxes are bolted together and are made of steel, not cast. This is a typical configuration for Australia and New Zealand. This makes the boxes lighter and also cuts down of the cost.

Below is a spare set of stamps in their guides ready to be assembled into a 10-stamper battery. Notice the square shoe cones. The guides were very simple and easy to work on with only 2 bolts per individual guide.

Here is the camshaft for the above stamps.

Last picture shows some ore carts to move the ore to the stamper batteries. There is one last Berdan wheel in the background.

 THE END